Mean Line Pump Flow Model in Rocket Engine System Simulation

NASA Technical Reports Server (NTRS)

Veres, Joseph P.; Lavelle, Thomas M.

2000-01-01

A mean line pump flow modeling method has been developed to provide a fast capability for modeling turbopumps of rocket engines. Based on this method, a mean line pump flow code PUMPA has been written that can predict the performance of pumps at off-design operating conditions, given the loss of the diffusion system at the design point. The pump code can model axial flow inducers, mixed-flow and centrifugal pumps. The code can model multistage pumps in series. The code features rapid input setup and computer run time, and is an effective analysis and conceptual design tool. The map generation capability of the code provides the map information needed for interfacing with a rocket engine system modeling code. The off-design and multistage modeling capabilities of the code permit parametric design space exploration of candidate pump configurations and provide pump performance data for engine system evaluation. The PUMPA code has been integrated with the Numerical Propulsion System Simulation (NPSS) code and an expander rocket engine system has been simulated. The mean line pump flow code runs as an integral part of the NPSS rocket engine system simulation and provides key pump performance information directly to the system model at all operating conditions.

Effect of diastolic flow patterns on the function of the left ventricle

NASA Astrophysics Data System (ADS)

Seo, Jung Hee; Mittal, Rajat

2013-11-01

Direct numerical simulations are used to study the effect of intraventricular flow patterns on the pumping efficiency and the blood mixing and transport characteristics of the left ventricle. The simulations employ a geometric model of the left ventricle which is derived from contrast computed tomography. A variety of diastolic flow conditions are generated for a fixed ejection fraction in order to delineate the effect of flow patterns on ventricular performance. The simulations indicate that the effect of intraventricular blood flow pattern on the pumping power is physiologically insignificant. However, diastolic flow patterns have a noticeable effect on the blood mixing as well as the residence time of blood cells in the ventricle. The implications of these findings on ventricular function are discussed.

Initial in vitro evaluation of a pediatric vortex-mixing membrane lung.

PubMed

Peacock, J A; Bellhouse, B J; Abel, K; Bellhouse, E L; Bellhouse, F H; Jeffree, M A; Sykes, M K; Gardaz, J P

1983-05-01

A new design for a pediatric membrane lung is described in this paper. The lung consists of eight blood compartments, each having six U-shaped blood channels, with microporous PTFE membranes supported on rigid plates in such a way that the membranes form furrowed blood channels. Two rolling diaphragm pumps are attached to the open ends of the U-shaped blood channels; these pumps are operated in antiphase. Mean flow is provided by a roller pump placed at the inlet end of the membrane lung. Pulsatile blood flow within the blood channels produces successive vortex formation and ejection, leading to good blood mixing and high efficiency in gas transport. The design of the rolling diaphragm piston pumps ensures that the blood prime volume is low (280 ml), and the grouping of the pumps at one end of the oxygenator allows the driving mechanism to be simple and compact. The relatively wide blood channels (minimum width 0.5 mm) and vortex mixing make priming the membrane lung particularly easy. The membrane area is 0.39 m2. Preliminary performance testing of the pediatric membrane lung was undertaken by pumping blood around a circuit containing a roller pump, the membrane lung, and a bubble oxygenator (to adjust the blood gases at the inlet to the membrane lung). In five such experiments it was shown that the membrane lung transferred 80 ml O2/min and 120 ml CO2/min at a blood flow rate of 1.5 L/min.

A novel application of dielectric stack actuators: a pumping micromixer

NASA Astrophysics Data System (ADS)

Solano-Arana, Susana; Klug, Florian; Mößinger, Holger; Förster-Zügel, Florentine; Schlaak, Helmut F.

2018-07-01

The fabrication of pumping micromixers as a novel application of dielectric stack actuators is proposed in this work. DEA micromixers can be valuable for medical and pharmaceutical applications, due to: firstly, the biocompatibility of the used materials (PDMS and graphite); secondly, the pumping is done with peristaltic movements, allowing only the walls of the channel to be in contact with the liquid, avoiding possible contamination from external parts; and thirdly, the low flow velocity in the micromixers required in many applications. The micromixer based on peristasltic movements will not only mix, but also pump the fluids in and out the device. The developed device is a hybrid micromixer: active, because it needs a voltage source to enhance the quality and speed of the mixing; and passive, with a similar shape to the well-known Y-type micromixers. The proposed micromixer is based on twelve stack actuators distributed in: two pumping chambers, consisting of four stack actuators in series; and a mixing chamber, made of four consecutive stack actuators with 30 layers per stack. The DEA micromixer is able to mix two solutions with a flow rate of 21.5 μl min–1 at the outlet, applying 1500 V at 10 Hz and actuating two actuators at a time.

Study and development of an air conditioning system operating on a magnetic heat pump cycle (design and testing of flow directors)

NASA Astrophysics Data System (ADS)

Wang, Pao-Lien

1992-09-01

This report describes the fabrication, design of flow director, fluid flow direction analysis and testing of flow director of a magnetic heat pump. The objectives of the project are: (1) to fabricate a demonstration magnetic heat pump prototype with flow directors installed; and (2) analysis and testing of flow director and to make sure working fluid loops flow through correct directions with minor mixing. The prototype was fabricated and tested at the Development Testing Laboratory of Kennedy Space Center. The magnetic heat pump uses rear earth metal plates rotate in and out of a magnetic field in a clear plastic housing with water flowing through the rotor plates to provide temperature lift. Obtaining the proper water flow direction has been a problem. Flow directors were installed as flow barriers between separating point of two parallel loops. Function of flow directors were proven to be excellent both analytically and experimentally.

Study and development of an air conditioning system operating on a magnetic heat pump cycle (design and testing of flow directors)

NASA Technical Reports Server (NTRS)

Wang, Pao-Lien

1992-01-01

This report describes the fabrication, design of flow director, fluid flow direction analysis and testing of flow director of a magnetic heat pump. The objectives of the project are: (1) to fabricate a demonstration magnetic heat pump prototype with flow directors installed; and (2) analysis and testing of flow director and to make sure working fluid loops flow through correct directions with minor mixing. The prototype was fabricated and tested at the Development Testing Laboratory of Kennedy Space Center. The magnetic heat pump uses rear earth metal plates rotate in and out of a magnetic field in a clear plastic housing with water flowing through the rotor plates to provide temperature lift. Obtaining the proper water flow direction has been a problem. Flow directors were installed as flow barriers between separating point of two parallel loops. Function of flow directors were proven to be excellent both analytically and experimentally.

Pumping Characteristics of a Helical Screw Agitator with a Draught Tube

NASA Astrophysics Data System (ADS)

Hwang, Jung-Hoon; Kim, Youn-Jea

In the use of helical type agitator, the mixing process is usually restricted to the laminar flow regime. Common examples of laminar mixing are found where the fluid has a very high viscosity, i.e., pseudoplastic fluids. It can be indicated that a helical type agitator is sufficiently suited to the creeping flow mixing. The pumping characteristic of a Helical Screw Agitator with a draught tube (HSA) is required to evaluate its capacity for the optimal configuration of the mixing chamber. It could be executed by changing some parameters such as the number of helix, the angular velocity and the rotating direction and so on. In this study, the numerical simulation was carried out with the Eulerian multiphase mixture model and the moving mesh approximation. Some of the optimum design parameters have been developed with the aid of numerical data from the Computational Fluid Dynamics (CFD) analysis. Using the commercial code, Fluent, the pumping characteristics in the HSA are investigated from the rheological properties, and the results are graphically depicted.

Transport and mixing of a volume of fluid in a complex geometry

NASA Astrophysics Data System (ADS)

Gavelli, Filippo

This work presents the results of the experimental investigation of an entire sequence of events, leading to an unwanted injection of boron-depleted water into the core of a PWR. The study is subdivided into three tasks: the generation of a dilute volume in the primary system, its transport to the core, and the mixing encountered along the path. Experiments conducted at the University of Maryland (UM) facility show that, during a Small-Break LOCA transient, volumes of dilute coolant are segregated in the system, by means of phase-separating energy transport from the core to the steam generators (Boiler Condenser Mode). Two motion-initiating mechanisms are considered: the resumption of natural circulation during the recovery of the primary liquid inventory, and the reactor coolant pump startup under BCM conditions. During the inventory recovery, various phenomena are observed, that contribute to the mixing of the dilute volumes prior to the resumption of flow. The pump activation, instead, occurs in a stagnant system, therefore, no mixing of the unborated liquid has occurred. Since an unmixed slug has the potential for a larger reactivity excursion than a partially mixed one, the pump-initiated flow resumption represents the worst-case scenario. The impulse - response method is applied, for the first time, to the problem of mixing in the downcomer. This allows to express the mixing in terms of two parameters, the dispersion number and the residence time, characteristics of the flow distribution in the complex annular geometry. Other important results are obtained from the analysis of the experimental data with this procedure. It is shown that the turbulence generated by the pump impeller has a significant impact on the overall mixing. Also, the geometric discontinuities in the downcomer (in particular, the gap enlargement below the cold leg elevation) are shown to be the cause of vortex structures that highly enhance the mixing process.

Research on energy conversion mechanism of rotodynamic pump and design of non-overload centrifugal pump

NASA Astrophysics Data System (ADS)

Zhang, X. L.; Hu, S. B.; Shen, Z. Z.; Wu, S. P.; Li, K.

2016-05-01

In this paper, an attempt has been made for the calculation of an expression for the intrinsic law of input power which has not yet been given by current theory of Rotodynamic pump. By adequate recognition of the characteristics of non-inertial system within the rotating impeller, it is concluded that the input power consists of two power components, the first power component, whose magnitude increases with the increase of the flow rate, corresponds to radial velocity component, and the second power component, whose magnitude decreases with the increase of the flow rate, corresponds to tangential velocity component, therefore, the law of rise, basic levelness and drop of input power curves of centrifugal pump, mixed-flow pump and axial-flow pump can be explained reasonably. Through further analysis, the main ways for realizing non-overload of centrifugal pump are obtained, and its equivalent design factor is found out, the factor correlates with the outlet angle of leading face and back face of the blade, wrap angle, number of blades, outlet width, area ratio, and the ratio of operating flow rate to specified flow rate and so on. These are verified with actual example.

Self-Calibrating, Variable-Flow Pumping System

NASA Technical Reports Server (NTRS)

Walls, Joe T.

1994-01-01

Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

Analysis and Modeling of a Two-Phase Jet Pump of a Flow Boiling Test Facility for Aerospace Applications

NASA Technical Reports Server (NTRS)

Sherif, S. A.; Steadham, Justin M.

1996-01-01

Jet pumps are devices capable of pumping fluids to a higher pressure employing a nozzle/diffuser/mixing chamber combination. A primary fluid is usually allowed to pass through a converging-diverging nozzle where it can accelerate to supersonic speeds at the nozzle exit. The relatively high kinetic energy that the primary fluid possesses at the nozzle exit is accompanied by a low pressure region in order to satisfy Bernoulli's equation. The low pressure region downstream of the nozzle exit permits a secondary fluid to be entrained into and mixed with the primary fluid in a mixing chamber located downstream of the nozzle. Several combinations may exist in terms of the nature of the primary and secondary fluids in so far as whether they are single or two-phase fluids. Depending on this, the jet pump may be classified as gas/gas, gas/liquid, liquid/liquid, two-phase/liquid, or similar combinations. The mixing chamber serves to create a homogeneous single-phase or two-phase mixture which enters a diffuser where the high kinetic energy of the fluid is converted into pressure energy. If the fluid mixture entering the diffuser is in the supersonic flow regime, a normal shock wave usually develops inside the diffuser. If the fluid mixture is one that can easily change phase, a condensation shock would normally develop. Because of the overall rise in pressure in the diffuser as well as the additional rise in pressure across the shock layer, condensation becomes more likely. Associated with the pressure rise across the shock is a velocity reduction from the supersonic to the subsonic range. If the two-phase flow entering the diffuser is predominantly gaseous with liquid droplets suspended in it, it will transform into a predominantly liquid flow containing gaseous bubbles (bubbly flow) somewhere in the diffuser. While past researchers have been able to model the two-phase flow jet pump using the one-dimensional assumption with no shock waves and no phase change, there is no research known to the authors apart from that of Anand (1992) which accounted for condensation shocks. One of the objectives of this research effort is to develop a comprehensive model in which the effects of phase slip and inter-phase heat transfer as well as the wall friction and shock waves are accounted for. While this modeling effort is predominantly analytical in nature and is primarily intended to provide a parametric understanding of the jet pump performance under different operating scenarios, another parallel effort employing a commercial CFD code is also implemented. The latter effort is primarily intended to model an axisymmetric counterpart of the problem in question. The viability of using the CFD code to model a two-phase flow jet pump will be assessed by attempting to recreate some of the existing performance data of similar jet pumps. The code will eventually be used to generate the jet pump performance characteristics of several scenarios involving jet pump geometries as well as flow regimes in order to be able to determine an optimum design which would be suitable for a two-phase flow boiling test facility at NASA-Marshall. Because of the extensive nature of the analytical model developed, the following section will only provide very brief highlights of it, while leaving the details to a more complete report submitted to the NASA colleague. This report will also contain some of the simulation results obtained using the CFD code.

The Li And Be Dips Revisited: The Role Of Gyroscopic Pumping.

NASA Astrophysics Data System (ADS)

Garaud, Pascale; Bodenheimer, P.

2011-01-01

The existence of a dip in the observed abundances of Li and Be in young stars in the mass range 1.3 to 1.5 solar masses strongly suggests the presence of an additional mixing mechanism to transport these elements from the outer convection zone down to the region where they are destroyed. However, no simple model to date has been able to reproduce simultaneously the respective amplitudes of the Li and the Be dips, as well as their shapes. We study here the effect of an important new mechanism for rotational mixing called "gyroscopic pumping", first noted for its importance in the dynamics of the solar interior, and find that it does indeed provide an elegant answer to this long-standing problem. Gyroscopic pumping is a simple and very generic consequence of angular momentum conservation in differentially rotating convective regions. The perpetual azimuthal force driving the differential rotation also drives a large-scale meridional circulation through angular momentum conservation. We show here how, specifically for the mass range of the Li-dip stars, the flows thus pumped form a slow, large-scale "conveyor belt" between the inner convective core and the outer convection zone. Li- and Be-rich material flowing down from the outer regions is slowly replaced by Li- and Be-poor material flowing up from the inner regions. Meanwhile, turbulent mixing in the thin overshoot layer also replenishes the outer convection zone with Li- and Be-rich material. Overall, the balance between advection by gyroscopic pumping and turbulent mixing by overshooting motions is found to provide a rather good agreement with observations of Li and Be, within a single and very simple framework. This work was funded by an NSF CAREER award of the presenting author.

Simultaneous injection-effective mixing analysis of palladium.

PubMed

Teshima, Norio; Noguchi, Daisuke; Joichi, Yasutaka; Lenghor, Narong; Ohno, Noriko; Sakai, Tadao; Motomizu, Shoji

2010-01-01

A novel concept of simultaneous injection-effective mixing analysis (SIEMA) is proposed, and a SIEMA method applied to the spectrophotometric determination of palladium using a water-soluble chromogenic reagent has been demonstrated. The flow configuration of SIEMA is a hybrid format of flow injection analysis (FIA), sequential injection analysis (SIA) and multicommutation in flow-based analysis. Sample and reagent solutions are aspirated into each holding coil through each solenoid valve by a syringe pump, and then the zones are simultaneously dispensed (injected) into a mixing coil by reversed flow toward a detector through a confluence point. This results in effective mixing and rapid detection with low reagent consumption.

Cruise control for segmented flow.

PubMed

Abolhasani, Milad; Singh, Mayank; Kumacheva, Eugenia; Günther, Axel

2012-11-21

Capitalizing on the benefits of microscale segmented flows, e.g., enhanced mixing and reduced sample dispersion, so far requires specialist training and accommodating a few experimental inconveniences. For instance, microscale gas-liquid flows in many current setups take at least 10 min to stabilize and iterative manual adjustments are needed to achieve or maintain desired mixing or residence times. Here, we report a cruise control strategy that overcomes these limitations and allows microscale gas-liquid (bubble) and liquid-liquid (droplet) flow conditions to be rapidly "adjusted" and maintained. Using this strategy we consistently establish bubble and droplet flows with dispersed phase (plug) velocities of 5-300 mm s(-1), plug lengths of 0.6-5 mm and continuous phase (slug) lengths of 0.5-3 mm. The mixing times (1-5 s), mass transfer times (33-250 ms) and residence times (3-300 s) can therefore be directly imposed by dynamically controlling the supply of the dispersed and the continuous liquids either from external pumps or from local pressurized reservoirs. In the latter case, no chip-external pumps, liquid-perfused tubes or valves are necessary while unwanted dead volumes are significantly reduced.

Comprehensive and Critical Literature Review on Insitu Micro-Sensors for Application in Tribology

DTIC Science & Technology

1994-04-01

Electroosmotic flow provides a pumping method that is convenient for small capillaries. Electrophoretic separation is shown to be useful. On the left hand...analysis systems on glass chips (1 centimeter by 2 centimeters or larger) that utilize electroosmotic pumping to drive fluid flow and electrophoretic...elucidate the interaction mechanism. Additionally, using two types of sensors in a mixed array increases selectivity by providing different information

Determination of pump flow rate during cardiopulmonary bypass in obese patients avoiding hemodilution.

PubMed

Santambrogio, Luisa; Leva, Cristian; Musazzi, Giorgio; Bruno, Piergiorgio; Vailati, Andrea; Zecchillo, Franco; Di Credico, Germano

2009-01-01

During cardiopulmonary bypass the pump flow is usually set on 2.4 L/min/m(2) of body surface area (BSA) to guarantee adequate tissue perfusion without differences for patient constitutional type. The present study attempts to evaluate the adequacy of pump flow rate in obese patients, considering the ideal weight instead of the real one, avoiding the overflow side effects and hemodilution. Obese patients with body mass index (BMI) > 30 presented for cardiac surgery were randomized in two groups: in one the cardiopulmonary bypass was led traditionally, in the other, pump flow rate was calculated on ideal BMI of 25. Demographics, preoperative tests, and monitoring data were registered. Mortality at hospital discharge and 30 days after were analyzed. The pump flow rate between the groups was different (4.46 vs. 4.87; p = 0.004); there were no differences in organ perfusion (SvO(2); diuresis) and mortality, but the study group presented fewer complications and blood transfusions. The BSA is widely used as the biometric unit to normalize physiologic parameters included pump flow rate, but it is disputable if this practice is correct also in obese patients. The study group, in which pump flow rate was set on ideal BSA, presented no difference in diuresis and mixed venous saturation but fewer complications and fewer perioperative blood transfusions.

Theoretical and experimental investigation of turbulent mixing on ejector configuration and performance in a solar-driven organic-vapor ejector cycle chiller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kucha, E.I.

1984-01-01

A general method was developed to calculate two dimensional (axisymmetric) mixing of a compressible jet in a variable cross-sectional area mixing channel of the ejector. The analysis considers mixing of the primary and secondary fluids at constant pressure and incorporates finite difference approximations to the conservation equations. The flow model is based on the mixing length approximations. A detailed study and modeling of the flow phenomenon determines the best (optimum) mixing channel geometry of the ejector. The detailed ejector performance characteristics are predicted by incorporating the flow model into a solar-powered ejector cycle cooling system computer model. Freon-11 is usedmore » as both the primary and secondary fluids. Performance evaluation of the cooling system is examined for its coefficient of performance (COP) under a variety of operating conditions. A study is also conducted on a modified ejector cycle in which a secondary pump is introduced at the exit of the evaporator. Results show a significant improvement in the overall performance over that of the conventional ejector cycle (without a secondary pump). Comparison between one and two-dimensional analyses indicates that the two-dimensional ejector fluid flow analysis predicts a better overall system performance. This is true for both the conventional and modified ejector cycles.« less

Performance evaluation of rotating pump jet mixing of radioactive wastes in Hanford Tanks 241-AP-102 and -104

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Y.; Recknagle, K.P.

The purpose of this study was to confirm the adequacy of a single mixer pump to fully mix the wastes that will be stored in Tanks 241-AP-102 and -104. These Hanford double-shell tanks (DSTs) will be used as staging tanks to receive low-activity wastes from other Hanford storage tanks and, in turn, will supply the wastes to private waste vitrification facilities for eventual solidification. The TEMPEST computer code was applied to Tanks AP-102 and -104 to simulate waste mixing generated by the 60-ft/s rotating jets and to determine the effectiveness of the single rotating pump to mix the waste. TEMPESTmore » simulates flow and mass/heat transport and chemical reactions (equilibrium and kinetic reactions) coupled together. Section 2 describes the pump jet mixing conditions the authors evaluated, the modeling cases, and their parameters. Section 3 reports model applications and assessment results. The summary and conclusions are presented in Section 4, and cited references are listed in Section 5.« less

Use of environmental tritium to characterize ground water flow systems in regolith and crystalline fractured-rock hydrogeologic settings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, L.M.; Rose, S.E.

1993-03-01

Environmental tritium concentrations measured in 84 ground-water, surface-water, and precipitation samples collected throughout the Piedmont and Blue Ridge physiographic provinces of northern Georgia were used in conjunction with available geological and hydrochemical data to develop general concepts of ground-water flow within a regolith and crystalline fractured-rock system. Tritium concentrations ranged from 0 tritium units (TU) in water sampled from unpumped wells completed in fractured bedrock to 34 TU in water sampled from pumped wells screened at various intervals within the overlying regolith. Tritium concentrations measured in spring discharge, streamflow, and precipitation also were within this range. The distribution of tritiummore » indicates that tritiated water is retained within the regolith and that pumping is an important mechanism for mixing water of different ages within the flow system. Simulations using an analytical mixing model were performed to estimate the degree of mixing and the residence time of ground water within the flow system. Results of the simulations compared favorably with other geological and hydrochemical data. Simulated residence times for tritiated water indicated that ground-water residence times may be greater than 37 years within the bedrock fractures, but as little as 15 years in pumped bedrock wells and streams. Estimates of ground-water ages were based on environmental tritium concentrations produced by thermonuclear bomb testing conducted during the years of 1961-1962.« less

Silicon micromachined pumps employing piezoelectric membrane actuation for microfluidic systems

NASA Astrophysics Data System (ADS)

Koch, Michael

Microsystems technology is a rapidly expanding area that comprises electronics, mechanics and optics. In this field, physical/chemical sensing, fluid handling and optical communication are emerging as potential markets. Microfluidic systems like an implantable insulin pump, a drug delivery system and a total chemical analysis system are currently being developed by academia and industry around the world. This project contributes to the area of microfluidics in that a novel thick-film-on-silicon membrane actuator has been developed to allow inexpensive mass production of micropumps. To date piezoelectric plates have been surface mounted onto a silicon membrane. This single chip fabrication method can now be replaced by screen printing thick piezoelectric layers onto 4 inch silicon substrates. Two different pump types have been developed. These are membrane pumps with either cantilever valves or diffuser/nozzle valves. Pump rates between 100 and 200 μl min-1 and backpressures up to 4 kPa have been achieved with these pumps. Along with the technology of micropumps, simulators have been developed. A novel coupled FEM-CFD solver was realised by a computer controlled coupling of two commercially available packages (ANSYS and CFX-Flow3D). The results of this simulator were in good agreement with measurements on micromachined cantilever valves. CFX- Flow3D was also used to successfully model the behaviour of the diffuser/nozzle valve. Finally, the pump has been simulated using a continuity equation. A behavioural dynamic extension of the cantilever valve was necessary to achieve better prediction of the pump rates for higher frequencies. As well, a common process has been developed for microfluidic devices like micromixers, particle counters and sorters as well as flow sensors. The micromixer has been tested already and achieves mixing for input pressures between 2 and 7 kPa. This agrees with simulations of the diffusive mixing with CFX-Flow3D. Together with the micropump, a combination of these devices allows future development of microfluidic systems for the medical and (bio)chemical market.

Using a tracer technique to identify the extent of non-ideal flows in the continuous mixing of non-Newtonian fluids

NASA Astrophysics Data System (ADS)

Patel, D.; Ein-Mozaffari, F.; Mehrvar, M.

2013-05-01

The identification of non-ideal flows in a continuous-flow mixing of non-Newtonian fluids is a challenging task for various chemical industries: plastic manufacturing, water and wastewater treatment, and pulp and paper manufacturing. Non-ideal flows such as channelling, recirculation, and dead zones significantly affect the performance of continuous-flow mixing systems. Therefore, the main objective of this paper was to develop an identification protocol to measure non-ideal flows in the continuous-flow mixing system. The extent of non-ideal flows was quantified using a dynamic model that incorporated channelling, recirculation, and dead volume in the mixing vessel. To estimate the dynamic model parameters, the system was excited using a frequency-modulated random binary input by injecting the saline solution (as a tracer) into the fresh feed stream prior to being pumped into the mixing vessel. The injection of the tracer was controlled by a computer-controlled on-off solenoid valve. Using the trace technique, the extent of channelling and the effective mixed volume were successfully determined and used as mixing quality criteria. Such identification procedures can be applied at various areas of chemical engineering in order to improve the mixing quality.

Design of an interface to allow microfluidic electrophoresis chips to drink from the fire hose of the external environment.

PubMed

Attiya, S; Jemere, A B; Tang, T; Fitzpatrick, G; Seiler, K; Chiem, N; Harrison, D J

2001-01-01

An interface design is presented that facilitates automated sample introduction into an electrokinetic microchip, without perturbing the liquids within the microfluidic device. The design utilizes an interface flow channel with a volume flow resistance that is 0.54-4.1 x 10(6) times lower than the volume flow resistance of the electrokinetic fluid manifold used for mixing, reaction, separation, and analysis. A channel, 300 microm deep, 1 mm wide and 15-20 mm long, was etched in glass substrates to create the sample introduction channel (SIC) for a manifold of electrokinetic flow channels in the range of 10-13 microm depth and 36-275 microm width. Volume flow rates of up to 1 mL/min were pumped through the SIC without perturbing the solutions within the electrokinetic channel manifold. Calculations support this observation, suggesting a leakage flow to electroosmotic flow ratio of 0.1:1% in the electrokinetic channels, arising from 66-700 microL/min pressure-driven flow rates in the SIC. Peak heights for capillary electrophoresis separations in the electrokinetic flow manifold showed no dependence on whether the SIC pump was on or off. On-chip mixing, reaction and separation of anti-ovalbumin and ovalbumin could be performed with good quantitative results, independent of the SIC pump operation. Reproducibility of injection performance, estimated from peak height variations, ranged from 1.5-4%, depending upon the device design and the sample composition.

High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

DOEpatents

Comaskey, Brian J.; Ault, Earl R.; Kuklo, Thomas C.

2005-07-05

A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

Sampling strategies exploiting multi-pumping flow systems.

PubMed

Prior, João A V; Santos, João L M; Lima, José L F C

2003-04-01

In this work new strategies were exploited to implement multi-pumping flow systems relying on the utilisation of multiple devices that act simultaneously as sample-insertion, reagent-introduction, and solution-propelling units. The solenoid micro-pumps that were initially used as the only active elements of multi-pumping systems, and which were able to produce pulses of 3 to 25 microL, were replaced by syringe pumps with the aim of producing pulses between 1 and 4 microL. The performance of the developed flow system was assessed by using distinct sample-insertion strategies like single sample volume, merging zones, and binary sampling in the spectrophotometric determination of isoniazid in pharmaceutical formulations upon reaction with 1,2-naphthoquinone-4-sulfonate, in alkaline medium. The results obtained showed that enhanced sample/reagent mixing could be obtained with binary sampling and by using a 1 microL per step pump, even in limited dispersion conditions. Moreover, syringe pumps produce very reproducible flowing streams and are easily manipulated and controlled by a computer program, which is greatly simplified since they are the only active manifold component. Linear calibration plots up to 18.0 microg mL(-1), with a relative standard deviation of less than 1.48% (n=10) and a throughput of about 20 samples per hour, were obtained.

Study of the flow mixing in a novel ARID raceway for algae production

DOE PAGES

Xu, Ben; Li, Peiwen; Waller, P.

2014-07-31

A novel flow field for algae raceways has been proposed, which is fundamentally different from traditional paddlewheel-driven raceways. To reduce freezing and heat loss in the raceway during cold time, the water is drained to a deep storage canal. The ground bed of the new raceway has a low slope so that water, lifted by propeller pump, can flow down in laterally-laid serpentine channels, relying on gravitational force. The flow rate of water is controlled so that it can overflow the lateral channel walls and mix with the main flow in the next lower channel, which thus creates a bettermore » mixing. In order to optimize the design parameters of the new flow field, methods including flow visualization, local point velocity measurement, and CFD analysis were employed to investigate the flow mixing features. Different combinations of channel geometries and water velocities were evaluated. An optimized flow field design and details of flow mixing are presented. The study offers an innovative design for large scale algae growth raceways which is of significance to the algae and biofuel industry.« less

Study of the flow mixing in a novel ARID raceway for algae production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Ben; Li, Peiwen; Waller, P.

A novel flow field for algae raceways has been proposed, which is fundamentally different from traditional paddlewheel-driven raceways. To reduce freezing and heat loss in the raceway during cold time, the water is drained to a deep storage canal. The ground bed of the new raceway has a low slope so that water, lifted by propeller pump, can flow down in laterally-laid serpentine channels, relying on gravitational force. The flow rate of water is controlled so that it can overflow the lateral channel walls and mix with the main flow in the next lower channel, which thus creates a bettermore » mixing. In order to optimize the design parameters of the new flow field, methods including flow visualization, local point velocity measurement, and CFD analysis were employed to investigate the flow mixing features. Different combinations of channel geometries and water velocities were evaluated. An optimized flow field design and details of flow mixing are presented. The study offers an innovative design for large scale algae growth raceways which is of significance to the algae and biofuel industry.« less

Enhanced mixing in polyacrylamide gels containing embedded silica nanoparticles as internal electroosmotic pumps.

PubMed

Matos, Marvi A; White, Lee R; Tilton, Robert D

2008-02-15

Many biosensors, including those based on sensing agents immobilized inside hydrogels, suffer from slow response dynamics due to mass transfer limitations. Here we present an internal pumping strategy to promote convective mixing inside crosslinked polymer gels. This is envisioned as a potential tool to enhance biosensor response dynamics. The method is based on electroosmotic flows driven by non-uniform, oscillating electric fields applied across a polyacrylamide gel that has been doped with charged colloidal silica inclusions. Evidence for enhanced mixing was obtained from florescence recovery after photobleaching (FRAP) measurements with fluorescein tracer dyes dissolved in the gel. Mixing rates in silica-laden gels under the action of the applied electric fields were more than an order of magnitude faster than either diffusion or electrophoretically driven mixing in gels that did not contain silica. The mixing enhancement was due in comparable parts to the electroosmotic pumping and to the increase in gel swelling caused by the presence of the silica inclusions. The latter had the effect of increasing tracer mobility in the silica-laden gels.

A proposed through-flow inverse method for the design of mixed-flow pumps

NASA Technical Reports Server (NTRS)

Borges, Joao Eduardo

1991-01-01

A through-flow (hub-to-shroud) truly inverse method is proposed and described. It uses an imposition of mean swirl, i.e., radius times mean tangential velocity, given throughout the meridional section of the turbomachine as an initial design specification. In the present implementation, it is assumed that the fluid is inviscid, incompressible, and irrotational at inlet and that the blades are supposed to have zero thickness. Only blade rows that impart to the fluid a constant work along the space are considered. An application of this procedure to design the rotor of a mixed-flow pump is described in detail. The strategy used to find a suitable mean swirl distribution and the other design inputs is also described. The final blade shape and pressure distributions on the blade surface are presented, showing that it is possible to obtain feasible designs using this technique. Another advantage of this technique is the fact that it does not require large amounts of CPU time.

Micromixer based on dielectric stack actuators for medical applications

NASA Astrophysics Data System (ADS)

Solano-Arana, Susana; Klug, Florian; Mößinger, Holger; Förster-Zügel, Florentine; Schlaak, Helmut F.

2017-04-01

Based on a previously developed microperistaltic pump, a micromixer made out of dielectric elastomer stack actuators (DESA) is proposed. The micromixer will be able to mix two fluids at the microscale, pumping both fluids in and out of the device. The device consists of three chambers. In the first and second chambers, fluids A and B are hosted, while in the third chamber, fluids A and B are mixed. The fluid flow regime is laminar. The application of voltage leads to an increase of the size of a gap in the z-axis direction, due to the actuators area expansion. This makes a channel open through which the fluid flows. The frequency of the actuation of the different actuators allows an increase of the flow rate. The micromixer can be used for applications such as drug delivery and synthesis of nucleic acids, the proposed device will be made of Polydimethylsiloxane (PDMS) as dielectric and graphite powder as electrode material. PDMS is a biocompatible material, widely used in the prosthesis field. Mixing fluids at a microscale is also in need in the lab-on-achip technology for complex chemical reactions.

An experimental investigation on fluid dynamics of an automotive torque converter

NASA Astrophysics Data System (ADS)

Dong, Yu

The objective of the automotive torque converter fluid dynamics experimental investigation is to understand the flow field inside the torque converter, improve the performance, and increase the fuel economy of vehicles. A high-frequency response five-hole probe was developed for the unsteady flow measurement. The dynamic performance of this probe was examined, and the corresponding data processing technique was also developed. The accuracy of this probe unsteady flow measurement was assessed using a hot-film sensor and a high-frequency response total pressure Pitot probe. The pump passage relative flow field was measured by a rotating five-hole probe system at three chord-wise locations. The rotating probe system is designed and developed for both pump and turbine flow measurement, and it was proved to be accurate and successful. A strong secondary flow is observed to dominate the flow structure at the pump mid-chord. At the pump 3/4 chord, the flow concentration on the pressure side is clearly observed. The secondary flow is found to change direction of rotation between the 3/4 chord and the 4/4 chord. High losses are found in the core-suction corner "wake" flow. The pump exit and turbine exit unsteady flow fields were measured by a high-frequency response five-hole probe in the stationary frame. At the pump exit, the flow is concentrated on the pressure side due to the strong secondary flow in the pump passage. A strong secondary flow is observed. At the turbine exit, a fully developed flow is found caused by the turbulent mixing. The stator exit steady flow was measured by a conventional five-hole probe. A strong secondary flow is found due to the inlet vorticity and axial velocity deficit near the core. The radially inward velocity and the secondary flow produce a large radial transport of mass flow in the stator passage. The stator passage flow is found to be turbulent at the normal operating condition by the measurement using the surface hot-film sensors mounted on the stator blade surface. Based on the experimental data and analysis, recommendations are proposed for the hydraulic design and the fluid dynamics research of the torque converter.

CFD simulation of gas and non-Newtonian fluid two-phase flow in anaerobic digesters.

PubMed

Wu, Binxin

2010-07-01

This paper presents an Eulerian multiphase flow model that characterizes gas mixing in anaerobic digesters. In the model development, liquid manure is assumed to be water or a non-Newtonian fluid that is dependent on total solids (TS) concentration. To establish the appropriate models for different TS levels, twelve turbulence models are evaluated by comparing the frictional pressure drops of gas and non-Newtonian fluid two-phase flow in a horizontal pipe obtained from computational fluid dynamics (CFD) with those from a correlation analysis. The commercial CFD software, Fluent12.0, is employed to simulate the multiphase flow in the digesters. The simulation results in a small-sized digester are validated against the experimental data from literature. Comparison of two gas mixing designs in a medium-sized digester demonstrates that mixing intensity is insensitive to the TS in confined gas mixing, whereas there are significant decreases with increases of TS in unconfined gas mixing. Moreover, comparison of three mixing methods indicates that gas mixing is more efficient than mixing by pumped circulation while it is less efficient than mechanical mixing.

Interchangeability of gas detection tubes and hand pumps.

PubMed

Haag, W R

2001-01-01

Users of gas detection tubes occasionally seek the convenience of using a single hand pump with different brands of tubes, to avoid the need to carry more than one pump. Several professional organizations recommend against such interchange. However, these recommendations appear to be based on a single study of pump designs that mostly are no longer in use. The present study was undertaken to determine if current hand pumps are interchangeable. Both piston-type and bellows-type hand pumps were evaluated by comparing pump flow profiles and test gas measurements with a variety of tubes. The results demonstrate that three piston hand pumps in common use (Sensidyne/Gastec GV/100, RAE Systems LP-1200, and Matheson-Kitagawa 8104-400A) are fully interchangeable. Two bellows pumps (Draeger Accuro and MSA Kwik-Draw) also are interchangeable with each other. Mixing of bellows and piston systems is often possible, but there are enough exceptions to conclude that such practice should be discouraged because it can give inaccurate readings. It is recommended that technical standards be adopted, such as total volume and an initial pump vacuum or a pump flow curve, to assess hand pump interchangeability. When two manufacturers' pumps meet the same standard and routine leak tests are conducted, interchangeability is scientifically valid and poses no risk to the end user while offering greater convenience.

Afterload-dependent flow fluctuation of centrifugal pump: should it be actively fixed?

PubMed

Nishida, H; Akazawa, T; Nishinaka, T; Aomi, S; Endo, M; Koyanagi, H

1998-05-01

To evaluate the clinical meaning and effects of afterload-dependent flow fluctuation in a centrifugal pump, concomitant measurement of flow rate and mixed venous oxygen saturation (SVO2) was performed in 5 cases of open heart surgery in which the patients underwent cardiopulmonary bypass (CPB) with the Terumo Capiox centrifugal pump. Continuous measurement of SVO2 using the 3M CDI System 100 was performed with a disposable cuvette incorporated into the drainage circuit. After the target flow rate of 2.4 L/min/m2 was obtained under a nonbeating condition, the pump rotational speed was fixed. During the cooling and low temperature period, SVO2 decreased as the flow rate spontaneously decreased but still stayed around 80% even with a 15-20% decrease in blood flow rate. This indicates that a luxury perfusion condition is ensured as long as the body temperature is kept low. In contrast, during the rewarming period, SVO2 decreased to around 70-75% despite a 15-25% spontaneous increase in flow rate. Although this level of SVO2 still indicates adequate systemic perfusion, there is a possibility of regional hypoperfusion in patients with such conditions as cerebrovascular disease. In conclusion, although diligent adjustment of the physiological fluctuating flow rate in the centrifugal pump seems unnecessary during conventional open heart surgery, manual control may be necessary especially during the rewarming period, normothermic surgery, or circulatory assist for shocked patients. From this study, we also conclude that the major benefit of the afterload-independent autoflow control system of the centrifugal pump is the improvement of safety in terms of the fixed reservoir level and the handling of cardiopulmonary bypass.

Dual-Pump CARS Development and Application to Supersonic Combustion

NASA Technical Reports Server (NTRS)

Magnotti, Gaetano; Cutler, Andrew D.

2012-01-01

A dual-pump Coherent Anti-Stokes Raman Spectroscopy (CARS) instrument has been developed to obtain simultaneous measurements of temperature and absolute mole fractions of N2, O2 and H2 in supersonic combustion and generate databases for validation and development of CFD codes. Issues that compromised previous attempts, such as beam steering and high irradiance perturbation effects, have been alleviated or avoided. Improvements in instrument precision and accuracy have been achieved. An axis-symmetric supersonic combusting coaxial jet facility has been developed to provide a simple, yet suitable flow to CFD modelers. Approximately one million dual-pump CARS single shots have been collected in the supersonic jet for varying values of flight and exit Mach numbers at several locations. Data have been acquired with a H2 co-flow (combustion case) or a N2 co-flow (mixing case). Results are presented and the effects of the compressibility and of the heat release are discussed.

Aeroacoustic Characteristics of a Rectangular Multi-Element Supersonic Jet Mixer-Ejector Nozzle

NASA Technical Reports Server (NTRS)

Raman, Ganesh; Taghavi, Ray

1996-01-01

This paper provides a unique, detailed evaluation of the acoustics and aerodynamics of a rectangular multi-element supersonic jet mixer-ejector noise suppressor. The performance of such mixer-ejectors is important in aircraft engine application for noise suppression and thrust augmentation. In contrast to most prior experimental studies on ejectors that reported either aerodynamic or acoustic data, our work documents both types of data. We present information on the mixing, pumping, ejector wall pressure distribution, thrust augmentation and noise suppression characteristics of four simple, multi-element, jet mixer-ejector configurations. The four configurations included the effect of ejector area ratio (AR = ejector area/primary jet area) and the effect of non-parallel ejector walls. We also studied in detail the configuration that produced the best noise suppression characteristics. Our results show that ejector configurations that produced the maximum maximum pumping (entrained flow per secondary inlet area) also exhibited the lowest wall pressures in the inlet region, and the maximum thrust augmentation. When cases having the same total mass flow were compared, we found that noise suppression trends corresponded with those for pumping. Surprisingly, the mixing (quantified by the peak Mach number, and flow uniformity) at the ejector exit exhibited no relationship to the noise suppression at moderate primary jet fully expanded Mach numbers (Mj is less than 1.4). However, the noise suppression dependence on the mixing was apparent at higher Mj. The above observations are justified by noting that the mixing at the ejector exit is ot a strong factor in determining the radiated noise when noise produced internal to the ejector dominates the noise field outside the ejector.

High density 3D printed microfluidic valves, pumps, and multiplexers.

PubMed

Gong, Hua; Woolley, Adam T; Nordin, Gregory P

2016-07-07

In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day.

Modeling of a Two-Phase Jet Pump with Phase Change, Shocks and Temperature-Dependent Properties

NASA Technical Reports Server (NTRS)

Sherif, S. A.

1998-01-01

One of the primary motivations behind this work is the attempt to understand the physics of a two-phase jet pump which constitutes part of a flow boiling test facility at NASA-Marshall. The flow boiling apparatus is intended to provide data necessary to design highly efficient two-phase thermal control systems for aerospace applications. The facility will also be capable of testing alternative refrigerants and evaluate their performance using various heat exchangers with enhanced surfaces. The test facility is also intended for use in evaluating single-phase performance of systems currently using CFC refrigerants. Literature dealing with jet pumps is abundant and covers a very wide array of application areas. Example application areas include vacuum pumps which are used in the food industry, power station work, and the chemical industry; ejector systems which have applications in the aircraft industry as cabin ventilators and for purposes of jet thrust augmentation; jet pumps which are used in the oil industry for oil well pumping; and steam-jet ejector refrigeration, to just name a few. Examples of work relevant to this investigation includes those of Fairuzov and Bredikhin (1995). While past researchers have been able to model the two-phase flow jet pump using the one-dimensional assumption with no shock waves and no phase change, there is no research known to the author apart from that of Anand (1992) who was able to account for condensation shocks. Thus, one of the objectives of this work is to model the dynamics of fluid interaction between a two-phase primary fluid and a subcooled liquid secondary fluid which is being injected employing atomizing spray injectors. The model developed accounts for phase transformations due to expansion, compression, and mixing. It also accounts for shock waves developing in the different parts of the jet pump as well as temperature and pressure dependencies of the fluid properties for both the primary two-phase mixture and the secondary subcooled liquid. The research effort on which this document partly reports described a relatively simple model capable of describing the performance of a two-phase flow jet pump. The model is based on the isentropic homogeneous expansion/compression hypothesis and is capable of fully incorporating the effects of shocks in both the mixing chamber and the throat/diffuser parts of the pump. The physical system chosen is identical to that experimentally tested by Fairuzov and Bredikhin (1995) and should therefore be relatively easy to validate.

Mixed Convection Flow of Nanofluid in Presence of an Inclined Magnetic Field

PubMed Central

Noreen, Saima; Ahmed, Bashir; Hayat, Tasawar

2013-01-01

This research is concerned with the mixed convection peristaltic flow of nanofluid in an inclined asymmetric channel. The fluid is conducting in the presence of inclined magnetic field. The governing equations are modelled. Mathematical formulation is completed through long wavelength and low Reynolds number approach. Numerical solution to the nonlinear analysis is made by shooting technique. Attention is mainly focused to the effects of Brownian motion and thermophoretic diffusion of nanoparticle. Results for velocity, temperature, concentration, pumping and trapping are obtained and analyzed in detail. PMID:24086276

Atmospheric pressure flow reactor: Gas phase chemical kinetics under tropospheric conditions without wall effects

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor); Davis, Dennis D. (Inventor)

1991-01-01

A flow reactor for simulating the interaction in the troposphere is set forth. A first reactant mixed with a carrier gas is delivered from a pump and flows through a duct having louvers therein. The louvers straighten out the flow, reduce turbulence and provide laminar flow discharge from the duct. A second reactant delivered from a source through a pump is input into the flowing stream, the second reactant being diffused through a plurality of small diffusion tubes to avoid disturbing the laminar flow. The commingled first and second reactants in the carrier gas are then directed along an elongated duct where the walls are spaced away from the flow of reactants to avoid wall interference, disturbance or turbulence arising from the walls. A probe connected with a measuring device can be inserted through various sampling ports in the second duct to complete measurements of the first and second reactants and the product of their reaction at selected XYZ locations relative to the flowing system.

Fluid channeling system

NASA Technical Reports Server (NTRS)

Davis, Donald Y. (Inventor); Hitch, Bradley D. (Inventor)

1994-01-01

A fluid channeling system includes a fluid ejector, a heat exchanger, and a fluid pump disposed in series flow communication The ejector includes a primary inlet for receiving a primary fluid, and a secondary inlet for receiving a secondary fluid which is mixed with the primary fluid and discharged therefrom as ejector discharge. Heat is removed from the ejector discharge in the heat exchanger, and the heat exchanger discharge is compressed in the fluid pump and channeled to the ejector secondary inlet as the secondary fluid In an exemplary embodiment, the temperature of the primary fluid is greater than the maximum operating temperature of a fluid motor powering the fluid pump using a portion of the ejector discharge, with the secondary fluid being mixed with the primary fluid so that the ejector discharge temperature is equal to about the maximum operating temperature of the fluid motor.

Tribology of hydraulic pumps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamaguchi, A.

To obtain much higher performance than that of alternative power transmission systems, hydraulic systems have been continuously evolving to use high-pressure. Adoption of positive displacement pumps and motors is based on this reason. Therefore, tribology is a key terminology for hydraulic pumps and motors to obtain excellent performance and durability. In this paper the following topics are investigated: (1) the special feature of tribology of hydraulic pumps and motors; (2) indication of the important bearing/sealing parts in piston pumps and effects of the frictional force and leakage flow to performance; (3) the methods to break through the tribological limitation ofmore » hydraulic equipment; and (4) optimum design of the bearing/sealing parts used in the fluid to mixed lubrication regions.« less

Generation of a medium vacuum pressure by using two different pumping methods in the KRISS dynamic flow-control system

NASA Astrophysics Data System (ADS)

Hong, S. S.; Lim, J. Y.; Khan, W.

2014-02-01

Pumping systems with large vacuum chambers have numerous applications in the process industry: for example, mixing of various types of gases as in the semiconductor industry, the calibration of vacuum gauges, the measurement of outgassing rates of various materials in the field of space technology, etc. Most often, these systems are used in the medium vacuum range (10-1 Pa-102 Pa) and in the dynamically-generated pressure mode. We have designed and developed a new dynamic flow system at the KRISS (Korea Research Institute of Standards and Science) that can be used for such applications with reliability in the range from 0.1 Pa - 133 Pa. In this report, the design philosophy, operational procedure and experimental data for the generated stable pressure points in the chamber of the system are discussed. The data consist the pressure points generated in the medium vacuum range while pumping the chamber of the system by using two different methods: first by using a dry scroll pump and then by using a combination of a turbomolecular pump backed by the same scroll pump. The relative standard deviations in the pressure points were calculated and were found to be greater than 1.5% for the scroll pump and less than 0.5% for the turbomolecular pump.

BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2012-05-10

Savannah River National Laboratory (SRNL) evaluated methods to mix and blend the contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank such as Tank 21 and Tank 24 to the Salt Waste Processing Facility (SWPF) feed tank. The tank contents consist of three forms: dissolved salt solution, other waste salt solutions, and sludge containing settled solids. This paper focuses on developing the computational model and estimating the operation time of submersible slurry pump when the tank contents are adequately blended prior to their transfer to the SWPF facility. Amore » three-dimensional computational fluid dynamics approach was taken by using the full scale configuration of SRS Type-IV tank, Tank 21H. Major solid obstructions such as the tank wall boundary, the transfer pump column, and three slurry pump housings including one active and two inactive pumps were included in the mixing performance model. Basic flow pattern results predicted by the computational model were benchmarked against the SRNL test results and literature data. Tank 21 is a waste tank that is used to prepare batches of salt feed for SWPF. The salt feed must be a homogeneous solution satisfying the acceptance criterion of the solids entrainment during transfer operation. The work scope described here consists of two modeling areas. They are the steady state flow pattern calculations before the addition of acid solution for tank blending operation and the transient mixing analysis during miscible liquid blending operation. The transient blending calculations were performed by using the 95% homogeneity criterion for the entire liquid domain of the tank. The initial conditions for the entire modeling domain were based on the steady-state flow pattern results with zero second phase concentration. The performance model was also benchmarked against the SRNL test results and literature data.« less

Use of Buckling Instabilities in Micro Pumps, Valves, and Mixers

NASA Astrophysics Data System (ADS)

Tavakol, Behrouz; Chawan, Aschvin; Holmes, Douglas

2014-03-01

We use the buckling of thin, flexible plates for pumping fluids, controlling the flow rate, and mixing different media within a microfluidic channel. A dielectric elastomeric film with a confined geometry buckles out of the plane when exposed to an electric field. Solid or grease electrodes have traditionally been used as conductive materials to aid in voltage application to both sides of the film. In this work, we use an electrolytic fluid solution as the electrode to enable buckling at relatively low voltages, and to enhance the rate of deformation. We show that this mechanism can be implemented as a microvalve that controls flow rate, or as a micropump that operates over a range of frequencies. A similar mechanism can be used to aid diffusion between two adjacent laminar streams and improve mixing. These low-cost micropumps, microvalves, and micromixers rely on the reversible buckling of thin plates, are easily embeddable in a microfluidic chip, and can potentially be used in variety of applications to accurately control and manipulate fluid flow in a microchannel.

Microfluidic Injector Models Based on Artificial Neural Networks

DTIC Science & Technology

2005-06-15

medicine, and chemistry [1], [2]. They generally perform chemical analysis involving sample preparation, mixing , reaction, injection, separation analysis...algorithms have been validated against many ex- periments found in the literature demonstrating microfluidic mixing , joule heating, injection, and...385 [7] K. Seiler, Z. H. Fan, K. Fluri, and D. J. Harrison, “ Electroosmotic pump- ing and valveless control of fluid flow within a manifold of

Microfluidic circuit designs for performing fluidic manipulations that reduce the number of pumping sources and fluid reservoirs

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN

2001-01-01

A microfabricated device and method for proportioning and mixing biological or chemical materials by pressure- or vacuum-driven flow is disclosed. The microfabricated device mixes a plurality of materials in volumetric proportions controlled by the flow resistances of tributary reagent channels through which the materials are transported. The microchip includes two or more tributary reagent channels combining at one or more junctions to form one or more mixing channels. By varying the geometries of the channels (length, cross section, etc.), a plurality of reagent materials can be mixed at a junction such that the proportions of the reagent materials in the mixing channel depend on a ratio of the channel geometries and material properties. Such an approach facilitates flow division on the microchip without relying on techniques external to the microchip. Microchannel designs that provide the necessary flow division to accomplish valving operations using a minimum of pressure or vacuum sources are also described. In addition, microchannel designs that accomplish fluidic operation utilizing a minimal number of fluidic reservoirs are disclosed.

Influence of infusion pump operation and flow rate on hemodynamic stability during epinephrine infusion.

PubMed

Klem, S A; Farrington, J M; Leff, R D

1993-08-01

To determine whether variations in the flow rate of epinephrine solutions administered via commonly available infusion pumps lead to significant variations in blood pressure (BP) in vivo. Prospective, randomized, crossover study with factorial design, using infusion pumps with four different operating mechanisms (pulsatile diaphragm, linear piston/syringe, cyclic piston-valve, and linear peristaltic) and three drug delivery rates (1, 5, and 10 mL/hr). Two healthy, mixed-breed dogs (12 to 16 kg). Dogs were made hypotensive with methohexital bolus and continuous infusion. BP was restored to normal with constant-dose epinephrine infusion via two pumps at each rate. Femoral mean arterial pressure (MAP) was recorded every 10 secs. Pump-flow continuity was quantitated in vitro using a digital gravimetric technique. Variations in MAP and flow continuity were expressed by the coefficient of variation; analysis of variance was used for comparisons. The mean coefficients of variations for MAP varied from 3.8 +/- 3.1% (linear piston/syringe) to 6.1 +/- 6.6% (linear peristaltic), and from 3.4 +/- 2.2% (10 mL/hr) to 7.9 +/- 6.6% (1 mL/hr). The coefficients of variation for in vitro flow continuity ranged from 9 +/- 8% (linear piston-syringe) to 250 +/- 162% (pulsatile diaphragm), and from 35 +/- 44% (10 mL/hr) to 138 +/- 196% (1 mL/hr). Both the type of pump and infusion rate significantly (p < .001) influenced variation in drug delivery rate. The 1 mL/hr infusion rate significantly (p < .01) influenced MAP variation. Cyclic fluctuations in MAP of < or = 30 mm Hg were observed using the pulsatile diaphragm pump at 1 mL/hr. Factors inherent in the operating mechanisms of infusion pumps may result in clinically important hemodynamic fluctuations when administering a concentrated short-acting vasoactive medication at slow infusion rates.

Heavy liquid metals: Research programs at PSI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeda, Y.

1996-06-01

The author describes work at PSI on thermohydraulics, thermal shock, and material tests for mechnical properties. In the presentation, the focus is on two main programs. (1) SINQ LBE target: The phase II study program for SINQ is planned. A new LBE loop is being constructed. The study has the following three objectives: (a) Pump study - design work on an electromagnetic pump to be integrated into the target. (b) Heat pipe performance test - the use of heat pipes as an additional component of the target cooling system is being considered, and it may be a way to futhermore » decouple the liquid metal and water coolant loops. (c) Mixed convection experiment - in order to find an optimal configuration of the additional flow guide for window cooling, mixed convection around the window is to be studied. The experiment will be started using water and then with LBE. (2) ESS Mercury target: For ESS target study, the following experimental studies are planned, some of which are exampled by trial experiments. (a) Flow around the window: Flow mapping around the hemi-cylindrical window will be made for optimising the flow channels and structures, (b) Geometry optimisation for minimizing a recirculation zone behind the edge of the flow separator, (c) Flow induced vibration and buckling problem for a optimised structure of the flow separator and (d) Gas-liquid two-phase flow will be studied by starting to establish the new experimental method of measuring various kinds of two-phase flow characteristics.« less

Temporal evolution of age data under transient pumping conditions

NASA Astrophysics Data System (ADS)

Leray, S.; De Dreuzy, J.; Aquilina, L.; Vergnaud, V.; Labasque, T.; Bour, O.; Le Borgne, T.

2013-12-01

While most age data derived from tracers have been analyzed in steady-state flow conditions, we determine their temporal evolution under transient pumping conditions. Starting pumping in a well modifies the natural flow patterns induced by the topographical gradient to a mainly convergent flow to the well. Our study is based on a set of models made up of a shallowly dipping aquifer overlain by a less permeable aquitard. These settings are characteristic of the crystalline aquifer of Plœmeur (Brittany, France) located in a highly fractured zone at the contact between a granite and micaschists. Under a pseudo steady-state flow assumption (instantaneous shift between two steady-state flow fields), we solve the transport equation with a backward particle-tracking method and determine the temporal evolution of the concentrations at the pumping well of the four atmospheric tracers CFC 11, CFC 12, CFC 113 and SF6. We show that apparent ages deduced from these concentrations evolve both because of the flow patterns modifications and because of the non-linear evolution of the atmospheric tracer concentrations. Flow patterns modifications only intervene just after the start of pumping, when the initially piston-like residence time distribution is transformed to a broader distribution mixing residence times from a wide variety of flow lines. Later, while flow patterns and the supplying volume of the pumping well still evolve, the residence time distributions are hardly modified and apparent ages are solely altered by the non-linear atmospheric tracer concentrations that progressively modifies the weighting of the residence time distribution. These results are confirmed by the observations at the site of Plœmeur in the pumping area. First, long term chloride observations confirm the quick evolution of the flow patterns after the start of pumping. Second, posterior and more recent evolutions of apparent ages derived from CFCs are consistent with the modeling results revealing in turn the marginal effect of the 20-year pumping on the first 70 years of the residence time distribution. We conclude that the temporal evolution of apparent ages should be used with great care for identifying the temporal evolution of the flow patterns as the apparent age evolution can have two sources - the transient flow patterns and transient tracer atmospheric concentrations. We argue that both evolutions either controlled by transient flow patterns or by transient tracer atmospheric concentrations provide key information that can be further used for the characterization of the hydrogeological system. This study illustrates that the temporal evolution of apparent ages could be used for models segregation and slightly compensate for the small number of tracers.

Microfluidic "Pouch" Chips for Immunoassays and Nucleic Acid Amplification Tests.

PubMed

Mauk, Michael G; Liu, Changchun; Qiu, Xianbo; Chen, Dafeng; Song, Jinzhao; Bau, Haim H

2017-01-01

Microfluidic cassettes ("chips") for processing and analysis of clinical specimens and other sample types facilitate point-of-care (POC) immunoassays and nucleic acid based amplification tests. These single-use test chips can be self-contained and made amenable to autonomous operation-reducing or eliminating supporting instrumentation-by incorporating laminated, pliable "pouch" and membrane structures for fluid storage, pumping, mixing, and flow control. Materials and methods for integrating flexible pouch compartments and diaphragm valves into hard plastic (e.g., acrylic and polycarbonate) microfluidic "chips" for reagent storage, fluid actuation, and flow control are described. We review several versions of these pouch chips for immunoassay and nucleic acid amplification tests, and describe related fabrication techniques. These protocols thus offer a "toolbox" of methods for storage, pumping, and flow control functions in microfluidic devices.

Dual-pump CARS measurements in a hydrogen diffusion flame in cross-flow with AC dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Nishihara, Munetake; Freund, Jonathan B.; Glumac, Nick G.; Elliott, Gregory S.

2018-03-01

This paper presents dual-pump coherent anti-Stokes Raman scattering (CARS) measurements for simultaneous detection of flow temperature and relative concentration, applied to the characterization of a discharge-coupled reacting jet in a cross flow. The diagnostic is hydrogen Q-branch based, providing a much wider dynamic range compared to detection in the S-branch. For a previously developed dielectric barrier discharge, aligned co-axially with the fuel jet, OH planar laser induced fluorescence measurements show that the disturbance in the flame boundary leads to mixing enhancement. The H2-N2 dual-pump CARS measurement was used to map two-dimensional temperature distributions. The increase of the maximum temperature was up to 300 K, with 50% more H2 consumption, providing the reason for the decrease in the flame length by 25%. The increase of the relative H2O-H2 fraction was accompanied with a temperature increase, which indicates local equivalence ratios of below 1. The H2-O2 dual-pump measurements confirmed that the fuel-oxidizer ratios remain in the fuel-lean side at most of the probed locations.

Microfluidic device and methods for focusing fluid streams using electroosmotically induced pressures

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2010-06-01

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either electric current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to electrokinetically inducing fluid flow to confine a selected material in a region of a microchannel that is not influenced by an electric field. Other structures for inducing fluid flow in accordance with this invention include nanochannel bridging membranes and alternating current fluid pumping devices. Applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Simultaneous injection effective mixing flow analysis of urinary albumin using dye-binding reaction.

PubMed

Ratanawimarnwong, Nuanlaor; Ponhong, Kraingkrai; Teshima, Norio; Nacapricha, Duangjai; Grudpan, Kate; Sakai, Tadao; Motomizu, Shoji

2012-07-15

A new four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for the determination of urinary albumin. The SIEMA system consisted of a syringe pump, two 5-way cross connectors, four holding coils, five 3-way solenoid valves, a 50-cm long mixing coil and a spectrophotometer. Tetrabromophenol blue anion (TBPB) in Triton X-100 micelle reacted with albumin at pH 3.2 to form a blue ion complex with a λ(max) 625nm. TBPB, Triton X-100, acetate buffer and albumin standard solutions were aspirated into four individual holding coils by a syringe pump and then the aspirated zones were simultaneously pushed in the reverse direction to the detector flow cell. Baseline drift, due to adsorption of TBPB-albumin complex on the wall of the hydrophobic PTFE tubing, was minimized by aspiration of Triton X-100 and acetate buffer solutions between samples. The calibration graph was linear in the range of 10-50μg/mL and the detection limit for albumin (3σ) was 0.53μg/mL. The RSD (n=11) at 30μg/mL was 1.35%. The sample throughput was 37/h. With a 10-fold dilution, interference from urine matrix was removed. The proposed method has advantages in terms of simple automation operation and short analysis time. Copyright © 2012 Elsevier B.V. All rights reserved.

Considerations when using variable frequency drive technology for pond aquculture

USDA-ARS?s Scientific Manuscript database

Some farmers have decided to use variable frequency drives (VFDs) to control pump speed and water flow rate to reduce operational cost and costs associated with repairs and maintenance. Mixed performance issues with VFDs and electric motors have been reported. Examples include frequent drive failure...

On controlling the flow behavior driven by induction electrohydrodynamics in microfluidic channels.

PubMed

Li, Yanbo; Ren, Yukun; Liu, Weiyu; Chen, Xiaoming; Tao, Ye; Jiang, Hongyuan

2017-04-01

In this study, we develop a nondimensional physical model to demonstrate fluid flow at the micrometer dimension driven by traveling-wave induction electrohydrodynamics (EHD) through direct numerical simulation. In order to realize an enhancement in the pump flow rate as well as a flexible adjustment of anisotropy of flow behavior generated by induction EHD in microchannels, while not adding the risk of causing dielectric breakdown of working solution and material for insulation, a pair of synchronized traveling-wave voltage signals are imposed on double-sided electrode arrays that are mounted on the top and bottom insulating substrate, respectively. Accordingly, we present a model evidence, that not only the pump performance is improved evidently, but a variety of flow profiles, including the symmetrical and parabolic curve, plug-like shape and even biased flow behavior of quite high anisotropy are produced by the device design of "mix-type", "superimposition-type" and "adjustable-type" proposed herein as well, with the resulting controllable fluid motion being able to greatly facilitate an on-demand transportation mode of on-chip bio-microfluidic samples. Besides, automatic conversion in the direction of pump flow is achievable by switching on and off a second voltage wave. Our results provide utilitarian guidelines for constructing flexible electrokinetic framework useful in controllable transportation of particle and fluid samples in modern microfluidic systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A highly reliable cryogenic mixing pump with no mechanical moving parts

NASA Astrophysics Data System (ADS)

Chen, W.; Niblick, A. L.

2017-12-01

This paper presents the design and preliminary test results of a novel cryogenic mixing pump based on magnetocaloric effect. The mixing pump is developed to enable long-term cryogenic propellant storage in space by preventing thermal stratification of cryogens in storage tanks. The mixing pump uses an innovative thermodynamic process to generate fluid jets to promote fluid mixing, eliminating the need for mechanical pumps. Its innovative mechanism uses a solid magnetocaloric material to alternately vaporize and condense the cryogen in the pumping chamber, and thus control the volume of the fluid inside the pumping chamber to produce pumping action. The pump is capable of self-priming and can generate a high-pressure rise. This paper discusses operating mechanism and design consideration of the pump, introduces the configuration of a brassboard cryogenic pump, and presents the preliminary test results of the pump with liquid nitrogen.

Groundwater withdrawal in randomly heterogeneous coastal aquifers

NASA Astrophysics Data System (ADS)

Siena, Martina; Riva, Monica

2018-05-01

We analyze the combined effects of aquifer heterogeneity and pumping operations on seawater intrusion (SWI), a phenomenon which is threatening coastal aquifers worldwide. Our investigation is set within a probabilistic framework and relies on a numerical Monte Carlo approach targeting transient variable-density flow and solute transport in a three-dimensional randomly heterogeneous porous domain. The geological setting is patterned after the Argentona river basin, in the Maresme region of Catalonia (Spain). Our numerical study is concerned with exploring the effects of (a) random heterogeneity of the domain on SWI in combination with (b) a variety of groundwater withdrawal schemes. The latter have been designed by varying the screen location along the vertical direction and the distance of the wellbore from the coastline and from the location of the freshwater-saltwater mixing zone which is in place prior to pumping. For each random realization of the aquifer permeability field and for each pumping scheme, a quantitative depiction of SWI phenomena is inferred from an original set of metrics characterizing (a) the inland penetration of the saltwater wedge and (b) the width of the mixing zone across the whole three-dimensional system. Our results indicate that the stochastic nature of the system heterogeneity significantly affects the statistical description of the main features of the seawater wedge either in the presence or in the absence of pumping, yielding a general reduction of toe penetration and an increase of the width of the mixing zone. Simultaneous extraction of fresh and saltwater from two screens along the same wellbore located, prior to pumping, within the freshwater-saltwater mixing zone is effective in limiting SWI in the context of groundwater resources exploitation.

Passive micromixer using by convection and surface tension effects with air-liquid interface.

PubMed

Ju, Jongil; Warrick, Jay

2013-12-01

This article describes a passive micromixer that utilizes an air-liquid interface and surface tension effects to enhance fluid mixing via convection and Marangoni effects. Performance of the microfluidic component is tested within a passive-pumping-based device that consists of three microchannels connected in succession using passive micro-mixers. Mixing was quantified at 5 key points along the length of the device using microscope images of patterned streams of Alexa 488 fluorescent-dyed water and pure DI water flowing through the device. The passive micro-mixer mixed fluid 15-20 times more effectively than diffusion between laminar flow streams alone and is a novel micro-mixer embodiment that provides an additional strategy for removing external components from microscale devices for simpler, autonomous operation.

Passive micromixer using by convection and surface tension effects with air-liquid interface

PubMed Central

Ju, Jongil; Warrick, Jay

2014-01-01

This article describes a passive micromixer that utilizes an air-liquid interface and surface tension effects to enhance fluid mixing via convection and Marangoni effects. Performance of the microfluidic component is tested within a passive-pumping-based device that consists of three microchannels connected in succession using passive micro-mixers. Mixing was quantified at 5 key points along the length of the device using microscope images of patterned streams of Alexa 488 fluorescent-dyed water and pure DI water flowing through the device. The passive micro-mixer mixed fluid 15–20 times more effectively than diffusion between laminar flow streams alone and is a novel micro-mixer embodiment that provides an additional strategy for removing external components from microscale devices for simpler, autonomous operation. PMID:25104979

A novel micromixer based on the alternating current-flow field effect transistor.

PubMed

Wu, Yupan; Ren, Yukun; Tao, Ye; Hou, Likai; Hu, Qingming; Jiang, Hongyuan

2016-12-20

Induced-charge electroosmosis (ICEO) phenomena have been attracting considerable attention as a means for pumping and mixing in microfluidic systems with the advantage of simple structures and low-energy consumption. We propose the first effort to exploit a fixed-potential ICEO flow around a floating electrode for microfluidic mixing. In analogy with the field effect transistor (FET) in microelectronics, the floating electrode act as a "gate" electrode for generating asymmetric ICEO flow and thus the device is called an AC-flow FET (AC-FFET). We take advantage of a tandem electrode configuration containing two biased center metal strips arranged in sequence at the bottom of the channel to generate asymmetric vortexes. The current device is manufactured on low-cost glass substrates via an easy and reliable process. Mixing experiments were conducted in the proposed device and the comparison between simulation and experimental results was also carried out, which indicates that the micromixer permits an efficient mixing effect. The mixing performance can be further enhanced by the application of a suitable phase difference between the driving electrode and the gate electrode or a square wave signal. Finally, we performed a critical analysis of the proposed micromixer in comparison with different mixer designs using a comparative mixing index (CMI). The novel methods put forward here offer a simple solution to mixing issues in microfluidic systems.

Increase of economy of torque flow pump with high specific speed

NASA Astrophysics Data System (ADS)

Gusak, A. G.; Krishtop, I. V.; German, V. F.; Baga, V. N.

2017-08-01

Torque flow pumps are widely spread types of energy machines, which are used in majority of modern branches of industry for pumping of dirty media. The main task of researchers of torque flow pumps is increase of such pumps effectiveness for higher feed. Hydraulic losses for torque flow pumps are caused by working process of such pumps and are inevitable. Decrease of losses can be obtained by means of optimization of hydraulic flow part geometry. Modern approach to design of pump outlet introduces new constructive solutions which can increase economy of torque flow pumps. The aim of this research is increase of economy of torque flow pumps by means of application of spatial outlet and investigation of its geometry on pump characteristics. Analytical and numerical methods of liquid flow research for hydraulic flow part of torque flow pump were used in this paper. Moreover, influence of hydraulic flow part geometry of different designs of “Turo” type torque flow pumps outlets on pump characteristics was investigated. Numerical research enabled to study process of energy transfer of torque flow pump and evaluate influence of geometrical dimensions of spatial spiral outlet on its characteristics. Besides numerical research confirmed introduced regularity of peripheral velocity distribution in outlet. Velocity moment distribution in outlet was obtained during implementation of numerical research. Implemented bench tests of torque flow pump prototypes enabled to obtain real characteristics of pump and confirm effectiveness of spatial geometry of outlet application for such pump.

Aerodynamic Design and Numerical Analysis of Supersonic Turbine for Turbo Pump

NASA Astrophysics Data System (ADS)

Fu, Chao; Zou, Zhengping; Kong, Qingguo; Cheng, Honggui; Zhang, Weihao

2016-09-01

Supersonic turbine is widely used in the turbo pump of modern rocket. A preliminary design method for supersonic turbine has been developed considering the coupling effects of turbine and nozzle. Numerical simulation has been proceeded to validate the feasibility of the design method. As the strong shockwave reflected on the mixing plane, additional numerical simulated error would be produced by the mixing plane model in the steady CFD. So unsteady CFD is employed to investigate the aerodynamic performance of the turbine and flow field in passage. Results showed that the preliminary design method developed in this paper is suitable for designing supersonic turbine. This periodical variation of complex shockwave system influences the development of secondary flow, wake and shock-boundary layer interaction, which obviously affect the secondary loss in vane passage. The periodical variation also influences the strength of reflecting shockwave, which affects the profile loss in vane passage. Besides, high circumferential velocity at vane outlet and short blade lead to high radial pressure gradient, which makes the low kinetic energy fluid moves towards hub region and produces additional loss.

Flow characterization and patch clamp dose responses using jet microfluidics in a tubeless microfluidic device.

PubMed

Resto, Pedro J; Bhat, Abhishek; Stava, Eric; Lor, Chong; Merriam, Elliot; Diaz-Rivera, Ruben E; Pearce, Robert; Blick, Robert; Williams, Justin C

2017-11-01

Surface tension passive pumping is a way to actuate flow without the need for pumps, tubing or valves by using the pressure inside small drop to move liquid via a microfluidic channel. These types of tubeless devices have typically been used in cell biology. Herein we present the use of tubeless devices as a fluid exchange platform for patch clamp electrophysiology. Inertia from high-speed droplets and jets is used to create flow and perform on-the-fly mixing of solutions. These are then flowed over GABA transfected HEK cells under patch in order to perform a dose response analysis. TIRF imaging and electrical recordings are used to study the fluid exchange properties of the microfluidic device, resulting in 0-90% fluid exchange times of hundreds of milliseconds. COMSOL is used to model flow and fluid exchange within the device. Patch-clamping experiments show the ability to use high-speed passive pumping and its derivatives for studying peak dose responses, but not for studying ion channel kinetics. Our system results in fluid exchange times slower than when using a standard 12-barrel application system and is not as stable as traditional methods, but it offers a new platform with added functionality. Surface tension passive pumping and tubeless devices can be used in a limited fashion for electrophysiology. Users may obtain peak dose responses but the system, in its current form, is not capable of fluid exchange fast enough to study the kinetics of most ion channels. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical simulation on the cavitation of waterjet propulsion pump

NASA Astrophysics Data System (ADS)

Xia, C. Z.; Cheng, L.; Shang, Y. N.; Zhou, J. R.; Yang, F.; Jin, Y.

2016-05-01

Waterjet propulsion system is widely used in high speed vessels with advantages of simple transmission mechanism, low noise underwater and good manoeuvrability. Compared with the propeller, waterjet propulsion can be used flow stamping to increasing cavitation resistance at high speed. But under certain conditions, such as low ship speed or high ship speed, cavitation problem still exists. If water-jet propulsion pump is run in cavitation condition for a long time, then the cavitation will cause a great deal of noise CFD is applied to analysis and predict the process of production and development of cavitation in waterjet propulsion pump. Based on the cavitation model of Zwart-Gerber-Belamri and a mixture of homogeneous flow model, commercial CFD software CFX was taken for characteristics of cavitation under the three operating conditions. Commercial software ANSYS 14.0 is used to build entity model, mesh and numerical simulation. The grid independence analysis determine the grid number of mixed flow pump model is about 1.6 million and the grid number of water-jet pump system unit is about 2.7 million. The cavitation characteristics of waterjet pump under three operating conditions are studied. The results show that the cavitation development trend is similar design and small rate of flow condition .Under the design conditions Cavitation bubbles are mainly gathered in suction surface of blade near the inlet side of the hub under the primary stage, and gradually extended to the water side in the direction of the rim with the loss of the inlet total pressure. Cavitation appears in hub before the blade rim, but the maximum value of gas content in blade rim is bigger than that in hub. Under large flow conditions, bubble along the direction of wheel hub extends to the rim gradually. Cavitation is found in the pressure surface of blade near the hub region under the critical point of cavitation nearby. When NPSHa is lower than critical point, the area covering by bubbles is about 40% in the suction surface of blade. It means that the critical point of cavitation of pump system is not the accrue point of install cavitation but cavitation has been developed to a certain stage.

Conversion of blackbody radiation into laser energy

NASA Technical Reports Server (NTRS)

Mcinville, R. M.; Hassan, H. A.

1982-01-01

By employing detailed kinetic models, three concepts which utilize a blackbody cavity for the conversion of solar energy into laser energy using a CO2 lasant are analyzed and compared. In the first, the blackbody radiation is used to excite flowing CO2 directly. The second and third employ a mixing laser concept with CO and N2 being the donor gases. The CO is optically pumped while thermal heating excites the N2. Blackbody temperatures ranging from 1500 deg K - 2500 deg K are considered. Based on calculated laser power output per unit flow rate of CO2, it appears that the N2-CO2 mixing laser is the most attractive system.

Method and system to directly produce electrical power within the lithium blanket region of a magnetically confined, deuterium-tritium (DT) fueled, thermonuclear fusion reactor

DOEpatents

Woolley, Robert D.

1999-01-01

A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

Analytical Solution for Interface Flow to a Sink With an Upconed Saline Water Lens: Strack's Regimes Revisited

NASA Astrophysics Data System (ADS)

Kacimov, A. R.; Obnosov, Y. V.

2018-01-01

A study is made of a steady, two-dimensional groundwater flow with a horizontal well (drain), which pumps out freshwater from an aquifer sandwiched between a horizontal bedrock and ponded soil surface, and containing a lens-shaped static volume of a heavier saline water (DNAPL-dense nonaqueous phase liquid) as a free surface. For flow toward a line sink, an explicit analytical solution is obtained by a conformal mapping of the hexagon in the complex potential plane onto a reference plane and the Keldysh-Sedov integral representation of a mixed boundary-value problem for a complex physical coordinate. The interface is found as a function of the pumping rate, the well locus, the ratio of liquid densities, and the hydraulic heads at the soil surface and in the well. The shape with two inflexion points and fronts varies from a small-thickness bedrock-spread pancake to a critical curvilinear triangle, which cusps toward the sink. The problem is mathematically solvable in a relatively narrow band of geometric and hydraulic parameters. A similar analytic solution for a static heavy bubble confined by a closed-curve interface (no contact with the bedrock) is outlined as an illustration of the method to solve a mixed boundary-value problem.

Strategy Plan A Methodology to Predict the Uniformity of Double-Shell Tank Waste Slurries Based on Mixing Pump Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

J.A. Bamberger; L.M. Liljegren; P.S. Lowery

This document presents an analysis of the mechanisms influencing mixing within double-shell slurry tanks. A research program to characterize mixing of slurries within tanks has been proposed. The research program presents a combined experimental and computational approach to produce correlations describing the tank slurry concentration profile (and therefore uniformity) as a function of mixer pump operating conditions. The TEMPEST computer code was used to simulate both a full-scale (prototype) and scaled (model) double-shell waste tank to predict flow patterns resulting from a stationary jet centered in the tank. The simulation results were used to evaluate flow patterns in the tankmore » and to determine whether flow patterns are similar between the full-scale prototype and an existing 1/12-scale model tank. The flow patterns were sufficiently similar to recommend conducting scoping experiments at 1/12-scale. Also, TEMPEST modeled velocity profiles of the near-floor jet were compared to experimental measurements of the near-floor jet with good agreement. Reported values of physical properties of double-shell tank slurries were analyzed to evaluate the range of properties appropriate for conducting scaled experiments. One-twelfth scale scoping experiments are recommended to confirm the prioritization of the dimensionless groups (gravitational settling, Froude, and Reynolds numbers) that affect slurry suspension in the tank. Two of the proposed 1/12-scale test conditions were modeled using the TEMPEST computer code to observe the anticipated flow fields. This information will be used to guide selection of sampling probe locations. Additional computer modeling is being conducted to model a particulate laden, rotating jet centered in the tank. The results of this modeling effort will be compared to the scaled experimental data to quantify the agreement between the code and the 1/12-scale experiment. The scoping experiment results will guide selection of parameters to be varied in the follow-on experiments. Data from the follow-on experiments will be used to develop correlations to describe slurry concentration profile as a function of mixing pump operating conditions. This data will also be used to further evaluate the computer model applications. If the agreement between the experimental data and the code predictions is good, the computer code will be recommended for use to predict slurry uniformity in the tanks under various operating conditions. If the agreement between the code predictions and experimental results is not good, the experimental data correlations will be used to predict slurry uniformity in the tanks within the range of correlation applicability.« less

Three-dimensional Diffusive Strip Method

NASA Astrophysics Data System (ADS)

Martinez-Ruiz, Daniel; Meunier, Patrice; Duchemin, Laurent; Villermaux, Emmanuel

2016-11-01

The Diffusive Strip Method (DSM) is a near-exact numerical method developed for mixing computations at large Péclet number in two-dimensions. The method consists in following stretched material lines to compute a-posteriori the resulting scalar field is extended here to three-dimensional flows, following surfaces. We describe its 3D peculiarities, and show how it applies to a simple Taylor-Couette configuration with non-rotating boundary conditions at the top end, bottom and outer cylinder. This flow produces an elaborate, although controlled, steady 3D flow which relies on the Ekman pumping arising from the rotation of the inner cylinder is both studied experimentally, and numerically modeled. A recurrent two-cells structure appears formed by stream tubes shaped as nested tori. A scalar blob in the flow experiences a Lagrangian oscillating dynamics with stretchings and compressions, driving the mixing process, and yielding both rapidly-mixed and nearly pure-diffusive regions. A triangulated-surface method is developed to calculate the blob elongation and scalar concentration PDFs through a single variable computation along the advected blob surface, capturing the rich evolution observed in the experiments.

A multiple disk centrifugal pump as a blood flow device.

PubMed

Miller, G E; Etter, B D; Dorsi, J M

1990-02-01

A multiple disk, shear force, valveless centrifugal pump was studied to determine its suitability as a blood flow device. A pulsatile version of the Tesla viscous flow turbine was designed by modifying the original steady flow pump concept to produce physiological pressures and flows with the aid of controlling circuitry. Pressures and flows from this pump were compared to a Harvard Apparatus pulsatile piston pump. Both pumps were connected to an artificial circulatory system. Frequency and systolic duration were varied over a range of physiological conditions for both pumps. The results indicated that the Tesla pump, operating in a pulsatile mode, is capable of producing physiologic pressures and flows similar to the Harvard pump and other pulsatile blood pumps.

Dual-Pump CARS Development and Application to Supersonic Combustion

NASA Astrophysics Data System (ADS)

Magnotti, Gaetano

Successful design of hypersonic air-breathing engines requires new computational fluid dynamics (CFD) models for turbulence and turbulence-chemistry interaction in supersonic combustion. Unfortunately, not enough data are available to the modelers to develop and validate their codes, due to difficulties in taking measurements in such a harsh environment. Dual-pump coherent anti-Stokes Raman spectroscopy (CARS) is a non-intrusive, non-linear, laser-based technique that provides temporally and spatially resolved measurements of temperature and absolute mole fractions of N2, O2 and H2 in H2-air flames. A dual-pump CARS instrument has been developed to obtain measurements in supersonic combustion and generate databases for the CFD community. Issues that compromised previous attempts, such as beam steering and high irradiance perturbation effects, have been alleviated or avoided. Improvements in instrument precision and accuracy have been achieved. An axis-symmetric supersonic combusting coaxial jet facility has been developed to provide a simple, yet suitable flow to CFD modelers. The facility provides a central jet of hot "vitiated air" simulating the hot air entering the engine of a hypersonic vehicle flying at Mach numbers between 5 and 7. Three different silicon carbide nozzles, with exit Mach number 1, 1.6 and 2, are used to provide flows with the effects of varying compressibility. H2 co-flow is available in order to generate a supersonic combusting free jet. Dual-pump CARS measurements have been obtained for varying values of flight and exit Mach numbers at several locations. Approximately one million Dual-pump CARS single shots have been collected in the supersonic jet for varying values of flight and exit Mach numbers at several locations. Data have been acquired with a H2 co-flow (combustion case) or a N 2 co-flow (mixing case). Results are presented and the effects of the compressibility and of the heat release are discussed.

Maintenance Free Fluidic Transfer and Mixing Devices for Highly Radioactive Applications - Design, Development, Deployment and Operational Experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, C.; Richardson, J. E.; Fallows, P.

2006-07-01

Power Fluidics is the generic name for a range of maintenance-free fluid transfer and mixing devices, capable of handling a wide range of highly radioactive fluids, jointly developed by British Nuclear Group, its US-based subsidiary BNG America, and AEA Technology. Power Fluidic devices include Reverse Flow Diverters (RFDs), Vacuum Operated Slug Lifts (VOSLs), and Air Lifts, all of which have an excellent proven record for pumping radioactive liquids and sludges. Variants of the RFD, termed Pulse Jet Mixers (PJMs) are used to agitate and mix tank contents, where maintenance-free equipment is desirable, and where a high degree of homogenization ismore » necessary. The equipment is designed around the common principle of using compressed air to provide the motive force to transfer liquids and sludges. These devices have no moving parts in contact with the radioactive medium and therefore require no maintenance in radioactive areas of processing plants. Once commissioned, Power Fluidic equipment has been demonstrated to operate for the life of the facility. Over 800 fluidic devices continue to operate safely and reliably in British Nuclear Group's nuclear facilities at the Sellafield site in the United Kingdom, and some of these have done so for almost 40 years. More than 400 devices are being supplied by AEA Technology and BNG America for the Waste Treatment Plant (WTP) at the Hanford Site in southeastern Washington State, USA. This paper discusses: - Principles of operation of fluidic pumps and mixers. - Selection criteria and design of fluidic pumps and mixers. - Operational experience of fluidic pumps and mixers in the United Kingdom. - Applications of fluidic pumps and mixers at the U.S. Department of Energy nuclear sites. (authors)« less

Novel design and fabrication of a geometrical obstacle-embedded micromixer with notched wall

NASA Astrophysics Data System (ADS)

Wu, Shih-Jeh; Hsu, Hsiang-Chen; Feng, Wen-Jui

2014-09-01

A microfluidic embedded MEMS mixer with a Y-junction type channel and cylindrical obstructions was designed and fabricated for improving the fluid mixing mechanism under low Reynolds number (\\mathit{Re}) condition. The flow field was simulated numerically by software (COMSOL multiphysics®) first. The design was then realized through casting the device in PDMS by lithographed SU-8 photo-resistive mold on silicon wafer. Parametric experimental studies were conducted for optimal design. Two different fluids were pumped into the two legs of the Y-junction channel, and the fluids were broken-up by an embedded cylindrical obstacle in the middle of the tapered micro-channel. The chaotic convection took place in the mixing channel behind the embedded cylindrical obstacles. The flow motion was observed under CCD camera and analyzed by grey level. The developed micromixer in this study can enhance the fluid mixing by the interaction of diffusion and convection for wide range of Reynolds numbers (0.01 < \\mathit{Re} < 100). Experimental results showed that the mixing index reached the required value at 0.1 within 0.024 seconds when the inlet fluid velocity is 0.499 m/s (i.e., at 1200 µl/min flow rate) for merely four cylindrical obstacles. A shorter mixing distance can be accomplished compared to the current devices reported due to faster mixing and shorter mixing time.

Preliminary design of turbopumps and related machinery

NASA Technical Reports Server (NTRS)

Wislicenus, George F.

1986-01-01

Pumps used in large liquid-fuel rocket engines are examined. The term preliminary design denotes the initial, creative phases of design, where the general shape and characteristics of the machine are determined. This compendium is intended to provide the design engineer responsible for these initial phases with a physical understanding and background knowledge of the numerous special fields involved in the design process. Primary attention is directed to the pumping part of the turbopump and hence is concerned with essentially incompressible fluids. However, compressible flow principles are developed. As much as possible, the simplicity and reliability of incompressible flow considerations are retained by treating the mechanics of compressible fluids as a departure from the theory of incompressible fluids. Five areas are discussed: a survey of the field of turbomachinery in dimensionless form; the theoretical principles of the hydrodynamic design of turbomachinery; the hydrodynamic and gas dynamic design of axial flow turbomachinery; the hydrodynamic and gas dynamic design of radial and mixed flow turbomachinery; and some mechanical design considerations of turbomachinery. Theoretical considerations are presented with a relatively elementary mathematical treatment.

Centaur Propellant Thermal Conditioning Study

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Pleasant, R. L.; Erickson, R. C.

1976-01-01

A wicking investigation revealed that passive thermal conditioning was feasible and provided considerable weight advantage over active systems using throttled vent fluid in a Centaur D-1s launch vehicle. Experimental wicking correlations were obtained using empirical revisions to the analytical flow model. Thermal subcoolers were evaluated parametrically as a function of tank pressure and NPSP. Results showed that the RL10 category I engine was the best candidate for boost pump replacement and the option showing the lowest weight penalty employed passively cooled acquisition devices, thermal subcoolers, dry ducts between burns and pumping of subcooler coolant back into the tank. A mixing correlation was identified for sizing the thermodynamic vent system mixer. Worst case mixing requirements were determined by surveying Centaur D-1T, D-1S, IUS, and space tug vehicles. Vent system sizing was based upon worst case requirements. Thermodynamic vent system/mixer weights were determined for each vehicle.

The effects of pumpage, irrigation return, and regional ground-water flow on the water quality at Waiawa water tunnel, Oahu, Hawaii

USGS Publications Warehouse

Eyre, P.R.

1983-01-01

Waiawa shaft is a 1,700-foot long water tunnel which draws water from the top of the Pearl Harbor Ghyben-Herzberg ground-water lens, Oahu, Hawaii. The application of brackish irrigation water to sugarcane fields overlying Waiawa shaft, combined with relatively low pumping rates at the shaft from 1978 to 1980, caused the chloride concentration of water produced by Waiawa shaft to rise to 290 milligrams per liter. Time-series analyses, pumping tests and analyses of water samples show that a zone of degraded water lies at the top of the lens. This zone is mixed in significantly different proportions with the underlying fresher water depending on the pumping rate at Waiawa shaft. The chloride concentration of water in the Waiawa shaft can generally be kept below 250 milligrams per liter for the next few years, if pumping rates of about 15 million gallons per day are maintained. The use of managed pumping to control the chloride problem over the long term is uncertain owing to the possible increase in chloride concentration of the irrigation water. Based on ground-water flow rates and analogy to nearby wells, the chloride concentration of Waiawa shaft 's water will decrease to less than 100 milligrams per liter in 2 to 3 years if the use of brackish irrigation water is discontinued. (USGS)

AnalyzeHOLE - An Integrated Wellbore Flow Analysis Tool

USGS Publications Warehouse

Halford, Keith

2009-01-01

Conventional interpretation of flow logs assumes that hydraulic conductivity is directly proportional to flow change with depth. However, well construction can significantly alter the expected relation between changes in fluid velocity and hydraulic conductivity. Strong hydraulic conductivity contrasts between lithologic intervals can be masked in continuously screened wells. Alternating intervals of screen and blank casing also can greatly complicate the relation between flow and hydraulic properties. More permeable units are not necessarily associated with rapid fluid-velocity increases. Thin, highly permeable units can be misinterpreted as thick and less permeable intervals or not identified at all. These conditions compromise standard flow-log interpretation because vertical flow fields are induced near the wellbore. AnalyzeHOLE, an integrated wellbore analysis tool for simulating flow and transport in wells and aquifer systems, provides a better alternative for simulating and evaluating complex well-aquifer system interaction. A pumping well and adjacent aquifer system are simulated with an axisymmetric, radial geometry in a two-dimensional MODFLOW model. Hydraulic conductivities are distributed by depth and estimated with PEST by minimizing squared differences between simulated and measured flows and drawdowns. Hydraulic conductivity can vary within a lithology but variance is limited with regularization. Transmissivity of the simulated system also can be constrained to estimates from single-well, pumping tests. Water-quality changes in the pumping well are simulated with simple mixing models between zones of differing water quality. These zones are differentiated by backtracking thousands of particles from the well screens with MODPATH. An Excel spreadsheet is used to interface the various components of AnalyzeHOLE by (1) creating model input files, (2) executing MODFLOW, MODPATH, PEST, and supporting FORTRAN routines, and (3) importing and graphically displaying pertinent results.

Fuel pumping system and method

DOEpatents

Shafer, Scott F [Morton, IL; Wang, Lifeng ,

2006-12-19

A fuel pumping system that includes a pump drive is provided. A first pumping element is operatively connected to the pump drive and is operable to generate a first flow of pressurized fuel. A second pumping element is operatively connected to the pump drive and is operable to generate a second flow of pressurized fuel. A first solenoid is operatively connected to the first pumping element and is operable to vary at least one of a fuel pressure and a fuel flow rate of the first flow of pressurized fuel. A second solenoid is operatively connected to the second pumping element and is operable to vary at least one of a fuel pressure and a fuel flow rate of the second flow of pressurized fuel.

Fuel Pumping System And Method

DOEpatents

Shafer, Scott F.; Wang, Lifeng

2005-12-13

A fuel pumping system that includes a pump drive is provided. A first pumping element is operatively connected to the pump drive and is operable to generate a first flow of pressurized fuel. A second pumping element is operatively connected to the pump drive and is operable to generate a second flow of pressurized fuel. A first solenoid is operatively connected to the first pumping element and is operable to vary at least one of a fuel pressure and a fuel flow rate of the first flow of pressurized fuel. A second solenoid is operatively connected to the second pumping element and is operable to vary at least one of a fuel pressure and a fuel flow rate of the second flow of pressurized fuel.

Two-Year Outcomes with a Magnetically Levitated Cardiac Pump in Heart Failure.

PubMed

Mehra, Mandeep R; Goldstein, Daniel J; Uriel, Nir; Cleveland, Joseph C; Yuzefpolskaya, Melana; Salerno, Christopher; Walsh, Mary N; Milano, Carmelo A; Patel, Chetan B; Ewald, Gregory A; Itoh, Akinobu; Dean, David; Krishnamoorthy, Arun; Cotts, William G; Tatooles, Antone J; Jorde, Ulrich P; Bruckner, Brian A; Estep, Jerry D; Jeevanandam, Valluvan; Sayer, Gabriel; Horstmanshof, Douglas; Long, James W; Gulati, Sanjeev; Skipper, Eric R; O'Connell, John B; Heatley, Gerald; Sood, Poornima; Naka, Yoshifumi

2018-04-12

In an early analysis of this trial, use of a magnetically levitated centrifugal continuous-flow circulatory pump was found to improve clinical outcomes, as compared with a mechanical-bearing axial continuous-flow pump, at 6 months in patients with advanced heart failure. In a randomized noninferiority and superiority trial, we compared the centrifugal-flow pump with the axial-flow pump in patients with advanced heart failure, irrespective of the intended goal of support (bridge to transplantation or destination therapy). The composite primary end point was survival at 2 years free of disabling stroke (with disabling stroke indicated by a modified Rankin score of >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove a malfunctioning device. The noninferiority margin for the risk difference (centrifugal-flow pump group minus axial-flow pump group) was -10 percentage points. Of 366 patients, 190 were assigned to the centrifugal-flow pump group and 176 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 151 patients (79.5%) in the centrifugal-flow pump group, as compared with 106 (60.2%) in the axial-flow pump group (absolute difference, 19.2 percentage points; 95% lower confidence boundary, 9.8 percentage points [P<0.001 for noninferiority]; hazard ratio, 0.46; 95% confidence interval [CI], 0.31 to 0.69 [P<0.001 for superiority]). Reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (3 patients [1.6%] vs. 30 patients [17.0%]; hazard ratio, 0.08; 95% CI, 0.03 to 0.27; P<0.001). The rates of death and disabling stroke were similar in the two groups, but the overall rate of stroke was lower in the centrifugal-flow pump group than in the axial-flow pump group (10.1% vs. 19.2%; hazard ratio, 0.47; 95% CI, 0.27 to 0.84, P=0.02). In patients with advanced heart failure, a fully magnetically levitated centrifugal-flow pump was superior to a mechanical-bearing axial-flow pump with regard to survival free of disabling stroke or reoperation to replace or remove a malfunctioning device. (Funded by Abbott; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Computerized microfluidic cell culture using elastomeric channels and Braille displays.

PubMed

Gu, Wei; Zhu, Xiaoyue; Futai, Nobuyuki; Cho, Brenda S; Takayama, Shuichi

2004-11-09

Computer-controlled microfluidics would advance many types of cellular assays and microscale tissue engineering studies wherever spatiotemporal changes in fluidics need to be defined. However, this goal has been elusive because of the limited availability of integrated, programmable pumps and valves. This paper demonstrates how a refreshable Braille display, with its grid of 320 vertically moving pins, can power integrated pumps and valves through localized deformations of channel networks within elastic silicone rubber. The resulting computerized fluidic control is able to switch among: (i) rapid and efficient mixing between streams, (ii) multiple laminar flows with minimal mixing between streams, and (iii) segmented plug-flow of immiscible fluids within the same channel architecture. The same control method is used to precisely seed cells, compartmentalize them into distinct subpopulations through channel reconfiguration, and culture each cell subpopulation for up to 3 weeks under perfusion. These reliable microscale cell cultures showed gradients of cellular behavior from C2C12 myoblasts along channel lengths, as well as differences in cell density of undifferentiated myoblasts and differentiation patterns, both programmable through different flow rates of serum-containing media. This technology will allow future microscale tissue or cell studies to be more accessible, especially for high-throughput, complex, and long-term experiments. The microfluidic actuation method described is versatile and computer programmable, yet simple, well packaged, and portable enough for personal use.

Computerized microfluidic cell culture using elastomeric channels and Braille displays

PubMed Central

Gu, Wei; Zhu, Xiaoyue; Futai, Nobuyuki; Cho, Brenda S.; Takayama, Shuichi

2004-01-01

Computer-controlled microfluidics would advance many types of cellular assays and microscale tissue engineering studies wherever spatiotemporal changes in fluidics need to be defined. However, this goal has been elusive because of the limited availability of integrated, programmable pumps and valves. This paper demonstrates how a refreshable Braille display, with its grid of 320 vertically moving pins, can power integrated pumps and valves through localized deformations of channel networks within elastic silicone rubber. The resulting computerized fluidic control is able to switch among: (i) rapid and efficient mixing between streams, (ii) multiple laminar flows with minimal mixing between streams, and (iii) segmented plug-flow of immiscible fluids within the same channel architecture. The same control method is used to precisely seed cells, compartmentalize them into distinct subpopulations through channel reconfiguration, and culture each cell subpopulation for up to 3 weeks under perfusion. These reliable microscale cell cultures showed gradients of cellular behavior from C2C12 myoblasts along channel lengths, as well as differences in cell density of undifferentiated myoblasts and differentiation patterns, both programmable through different flow rates of serum-containing media. This technology will allow future microscale tissue or cell studies to be more accessible, especially for high-throughput, complex, and long-term experiments. The microfluidic actuation method described is versatile and computer programmable, yet simple, well packaged, and portable enough for personal use. PMID:15514025

Joint Calibration of Submarine Groundwater Discharge (SGD) with Tidal Pumping: Modeling Variable-density Groundwater Flow in Unconfined Coastal Aquifer of Apalachee Bay, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Li, X.; Hu, B.; Burnett, W.; Santos, I.

2008-05-01

Submarine Groundwater Discharge (SGD) as an unseen phenomenon is now recognized as an important pathway between land and sea. These discharges typically display significant spatial and temporal variability making quantification difficult. Groundwater seepage is patchy, diffuse, and temporally variable, and thus makes the estimation of its magnitude and components is a challenging enterprise. A two-dimensional hydrogeological model is developed to the near-shore environment of an unconfined aquifer at a Florida coastal area in the northeastern Gulf of Mexico. Intense geological survey and slug tests are set to investigate the heterogeneity of this layered aquifer. By applying SEAWAT2000, considering the uncertainties caused by changes of boundary conditions, a series of variable-density-flow models incorporates the tidal-influenced seawater recirculation and the freshwater-saltwater mixing zone under the dynamics of tidal pattern, tidal amplitude and variation of water table. These are thought as the contributing factors of tidal pumping and hydraulic gradient which are the driven forces of SGD. A tidal-influenced mixing zone in the near-shore aquifer shows the importance of tidal mechanism to flow and salt transport in the process of submarine pore water exchange. Freshwater ratio in SGD is also analyzed through the comparison of Submarine Groundwater Recharge and freshwater inflow. The joint calibration with other methods (natural tracer model and seepage meter) is also discussed.

Dispersion in deep polar firn driven by synoptic-scale surface pressure variability

NASA Astrophysics Data System (ADS)

Buizert, Christo; Severinghaus, Jeffrey P.

2016-09-01

Commonly, three mechanisms of firn air transport are distinguished: molecular diffusion, advection, and near-surface convective mixing. Here we identify and describe a fourth mechanism, namely dispersion driven by synoptic-scale surface pressure variability (or barometric pumping). We use published gas chromatography experiments on firn samples to derive the along-flow dispersivity of firn, and combine this dispersivity with a dynamical air pressure propagation model forced by surface air pressure time series to estimate the magnitude of dispersive mixing in the firn. We show that dispersion dominates mixing within the firn lock-in zone. Trace gas concentrations measured in firn air samples from various polar sites confirm that dispersive mixing occurs. Including dispersive mixing in a firn air transport model suggests that our theoretical estimates have the correct order of magnitude, yet may overestimate the true dispersion. We further show that strong barometric pumping, such as at the Law Dome site, may reduce the gravitational enrichment of δ15N-N2 and other tracers below gravitational equilibrium, questioning the traditional definition of the lock-in depth as the depth where δ15N enrichment ceases. Last, we propose that 86Kr excess may act as a proxy for past synoptic activity (or paleo-storminess) at the site.

Incompressible viscous flow computations for the pump components and the artificial heart

NASA Technical Reports Server (NTRS)

Kiris, Cetin

1992-01-01

A finite difference, three dimensional incompressible Navier-Stokes formulation to calculate the flow through turbopump components is utilized. The solution method is based on the pseudo compressibility approach and uses an implicit upwind differencing scheme together with the Gauss-Seidel line relaxation method. Both steady and unsteady flow calculations can be performed using the current algorithm. Here, equations are solved in steadily rotating reference frames by using the steady state formulation in order to simulate the flow through a turbopump inducer. Eddy viscosity is computed by using an algebraic mixing-length turbulence model. Numerical results are compared with experimental measurements and a good agreement is found between the two.

A Fully Magnetically Levitated Circulatory Pump for Advanced Heart Failure.

PubMed

Mehra, Mandeep R; Naka, Yoshifumi; Uriel, Nir; Goldstein, Daniel J; Cleveland, Joseph C; Colombo, Paolo C; Walsh, Mary N; Milano, Carmelo A; Patel, Chetan B; Jorde, Ulrich P; Pagani, Francis D; Aaronson, Keith D; Dean, David A; McCants, Kelly; Itoh, Akinobu; Ewald, Gregory A; Horstmanshof, Douglas; Long, James W; Salerno, Christopher

2017-02-02

Continuous-flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous-flow pump that was engineered to avert thrombosis. We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous-flow pump or a commercially available axial continuous-flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, -10 percentage points). Of 294 patients, 152 were assigned to the centrifugal-flow pump group and 142 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal-flow pump group and in 109 (76.8%) in the axial-flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, -2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two-tailed P=0.04 for superiority]). There were no significant between-group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal-flow pump group and in 14 patients (10.1%) in the axial-flow pump group. Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal-flow pump was associated with better outcomes at 6 months than was implantation of an axial-flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Method and apparatus to characterize ultrasonically reflective contrast agents

NASA Technical Reports Server (NTRS)

Pretlow, Robert A., III (Inventor)

1993-01-01

A method and apparatus for characterizing the time and frequency response of an ultrasonically reflective contrast agent is disclosed. An ultrasonically reflective contrast agent is injected, under constant pressure, into a fluid flowing through a pump flow circuit. The fluid and the ultrasonically reflective contrast agent are uniformly mixed in a mixing chamber, and the uniform mixture is passed through a contrast agent chamber. The contrast agent chamber is acoustically and axially interposed between an ultrasonic transducer chamber and an acoustic isolation chamber. A pulse of ultrasonic energy is transmitted into the contrast agent chamber from the ultrasonic transducer chamber. An echo waveform is received from the ultrasonically reflective contrast agent, and it is analyzed to determine the time and frequency response of the ultrasonically reflective contrast agent.

Using Mortar Mixing Pump for Magnesia Mortars Preparing and Transporting

NASA Astrophysics Data System (ADS)

Kiyanets, A. V.

2017-11-01

The article is devoted to the problem of preparation and transportation of magnesia mortars with the help of screw mortar mixing pumps. The urgency of the wide use of mortars on magnesia binders (Sorel’s cement) in construction is substantiated due to their high characteristics: strength, hardening speed, wear resistance, possibility of using organic and mineral aggregates, ecological purity and economic efficiency. The necessity for the development of a technique for calculating the main parameters of a mortar mixing pump for its application in the technology of preparation and transportation of magnesia mortars is demonstrated. The analysis of various types of modern mortar mixing pumps is given. The conclusions are drawn about the advantages and disadvantages of standard schemes. The description of the experiment for determination of the productivity of a mortar mixing pump is described depending on the plasticity (mobility) of the used magnesia mortar. The graph and description of the mathematical dependency of the productivity of the mortar mixing pump on the magnesia mortar plasticity are given. On the basis of the obtained dependency, as well as the already known formulas given in the article, a new method is proposed for calculating the main parameters of the screw mortar mixing pump in preparation and transportation of magnesia mortar: productivity, feed range, supply pressure, drive power.

A durable, non power consumptive, simple seal for rotary blood pumps.

PubMed

Mitamura, Y; Sekine, K; Asakawa, M; Yozu, R; Kawada, S; Okamoto, E

2001-01-01

One of the key technologic requirements for rotary blood pumps is the sealing of the motor shaft. A mechanical seal, a journal bearing, magnetic coupling, and magnetic suspension have been developed, but they have drawbacks such as wear, thrombus formation, and power consumption. A magnetic fluid seal was developed for an axial flow pump. A magnetic fluid seal is durable, simple, and non power consumptive. Long-term experiments and finite element modeling (FEM) analyses confirmed these advantages. The seal body was composed of a Ned-Fe magnet and two pole pieces; the seal was formed by injecting ferrofluid into the gap (50 microm) between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was attached to the pole piece. While submerged in blood, the sealing pressure of the seal was measured and found to be 188 mm Hg with ferrofluid LS-40 (saturated magnetization, 24.3 kA/m) at a motor speed of 10,000 rpm and 225 mm Hg under static conditions. The magnetic fluid seals performed perfectly at a pressure of 100 mm Hg for 594 + days in a static condition, and 51, 39+, and 34+ days at a motor speed of 8,000 rpm. FEM analyses indicated a theoretical sealing pressure of 260 mm Hg. The state of the magnetic fluid in the seal in water was observed with a microscope. Neither splashing of magnetic fluid nor mixing of the magnetic fluid and water was observed. The specially designed magnetic fluid seal for keeping liquids out is useful for axial flow blood pumps. The magnetic fluid seal was incorporated into an intracardiac axial flow pump.

Rotary magnetic heat pump

DOEpatents

Kirol, Lance D.

1988-01-01

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

Rotary magnetic heat pump

DOEpatents

Kirol, L.D.

1987-02-11

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

Effects of Pump Pulsation on Hydrodynamic Properties and Dissolution Profiles in Flow-Through Dissolution Systems (USP 4).

PubMed

Yoshida, Hiroyuki; Kuwana, Akemi; Shibata, Hiroko; Izutsu, Ken-Ichi; Goda, Yukihiro

2016-06-01

To clarify the effects of pump pulsation and flow-through cell (FTC) dissolution system settings on the hydrodynamic properties and dissolution profiles of model formulations. Two FTC systems with different cell temperature control mechanisms were used. Particle image velocimetry (PIV) was used to analyze the hydrodynamic properties of test solutions in the flow-through dissolution test cell. Two pulsation pumps (semi-sine, full-sine) and a non-pulsatile pump were used to study the effects of varied flows on the dissolution profiles of United States Pharmacopeia standard tablets. PIV analysis showed periodic changes in the aligned upward fluid flow throughout the dissolution cell that was designed to reduce the temperature gradient during pump pulsation (0.5 s/pulse). The maximum instantaneous flow from the semi-sine pump was higher than that of the full-sine pump under all conditions. The flow from the semi-sine wave pump showed faster dissolution of salicylic acid and prednisone tablets than those from other pumps. The semi-sine wave pump flow showed similar dissolution profiles in the two FTC systems. Variations in instantaneous fluid flow caused by pump pulsation that meets the requirements of pharmacopoeias are a factor that affects the dissolution profiles of tablets in FTC systems.

Detail, Unit 4, Worthington MixFlo Pump, Harrison, New Jersey, USA. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail, Unit 4, Worthington Mix-Flo Pump, Harrison, New Jersey, USA. All six pump units are of the same size, make, and model - Wellton-Mohawk Irrigation System, Pumping Plant No. 1, Bounded by Gila River & Union Pacific Railroad, Wellton, Yuma County, AZ

Hele-Shaw Experiments on Plume Stretching and Folding

NASA Astrophysics Data System (ADS)

Foster, M.; Mays, D. C.; Neupauer, R. M.

2013-12-01

Fluid mixing in laminar flow is important in a number of practical applications, including remediation of contaminated groundwater. Recent modeling studies have shown that mixing can be accelerated and amplified by imposing a flow that generates stretching and folding of an injected plume of treatment solution. Stretching and folding, in turn, results from engineered injection and extraction of clean water through an array of wells surrounding the treatment solution. This poster describes a series of experiments whose goal is to demonstrate plume stretching and folding in a Hele-Shaw apparatus. An initial plume of treatment solution is injected into the center of the Hele-Shaw apparatus, which is assumed to represent a zone of contaminated groundwater, with four wells spaced evenly around the treatment solution. In order to spread the treatment solution into the groundwater, the four wells perform a series of infusions and withdrawals that push and pull apart the plume of treatment solution. With the proper steps, it will be shown that the plume can be stretched and folded to greatly increase the reactive interface area between the treatment solution and the contaminated groundwater. Consideration is given to two qualitative differences with respect to previous modeling studies. First, constant volume is required by the no-flow boundary used at the edge of the Hele-Shaw cell; any pump that is withdrawing water must have a complementary pump adding water at the same rate. Second, in these experiments, mixing results from a physical process, namely Taylor dispersion, eliminating the uncertainty resulting from the need to assume dispersion mechanisms in numerical models. Therefore, these experiments further elucidate the benefits and challenges of imposing plume stretching and folding in systems (like aquifers) where dispersion is unavoidable, providing new insight into the required logistics of using this approach in groundwater treatment.

Flow pumping system for physiological waveforms.

PubMed

Tsai, William; Savaş, Omer

2010-02-01

A pulsatile flow pumping system is developed to replicate flow waveforms with reasonable accuracy for experiments simulating physiological blood flows at numerous points in the body. The system divides the task of flow waveform generation between two pumps: a gear pump generates the mean component and a piston pump generates the oscillatory component. The system is driven by two programmable servo controllers. The frequency response of the system is used to characterize its operation. The system has been successfully tested in vascular flow experiments where sinusoidal, carotid, and coronary flow waveforms are replicated.

The dependency of expiratory airway collapse on pump system and flow rate in liquid ventilated rabbits.

PubMed

Meinhardt, J P; Ashton, B A; Annich, G M; Quintel, M; Hirschl, R B

2003-05-30

To evaluate the influence of pump system and flow pattern on expiratory airway collapse (EAC) in total perfluorocarbon ventilation. - Prospective, controlled, randomized animal trial for determination of (1) post-mortem changes by repeated expiration procedures (EP) with a constant flow piston pump (PP) before and after sacrifice (n = 8 rabbits), (2) differences between pump systems by subjecting animals to both PP and roller pump (RP) circuits for expiration (n = 16 rabbits). EP were performed using a servo-controlled shut-off at airway pressures < 25 cm H subset 2O randomly with either pump at different flows. - Expired volumes before and after sacrifice were not significantly different. PP and RP revealed identical mean flows, while significantly more liquid was drained using PP (p<0.05). Increasing differences towards higher flow rates indicated profound flow pulsatility in RP. - (1) post-mortem changes in expired volumes are not significant, (2) EAC is related to flow rate and pump system; (3) relationship between expiratory flow rate and drainable liquid volume is linear inverse; (4) PP provides higher drainage than RP. - Expiratory airway collapse is related to flow rate and pump system, post mortem changes in expirable volumes are not significant. Relationship between expiratory flow rate and drainable liquid volume is linear inverse, piston pump expiration provides higher drainage volumes than roller pump expiration.

The effect of balance holes to centrifugal pump performance

NASA Astrophysics Data System (ADS)

Babayigit, O.; Ozgoren, M.; Aksoy, M. H.; Kocaaslan, O.

2017-07-01

The aim of this study is to analyze of a centrifugal pump with and without balance holes by using ANSYS-Fluent software. The pump used in the study is a commercial centrifugal pump consisting of two stages that is a model of Sempa Pump Company. Firstly, models of impeller, diffuser, suction and discharge sections of the centrifugal pump were separately drawn using Ansys and Solidworks software. Later, grid structures were generated on the flow volume of the pump. Turbulent flow volume was numerically solved by realizable k-є turbulence model. The flow analyses were focused on the centrifugal pump performance and the flow characteristics under different operational conditions with/without balance holes. Distributions of flow characteristics such as velocity and pressure distributions in the flow volume were also determined, numerically. The results of Computational Fluid Dynamics (CFD) with/without balance holes for the pump head and hydraulic efficiency on the design flow rate of 80 m3/h were found to be 81.5/91.3 m and 51.9/65.3%, respectively.

No drive line, no seal, no bearing and no wear: magnetics for impeller suspension and flow assessment in a new VAD.

PubMed

Huber, Christoph H; Tozzi, Piergiorgio; Hurni, Michel; von Segesser, Ludwig K

2004-06-01

The new magnetically suspended axial pump is free of seals, bearings, mechanical friction and wear. In the absence of a drive shaft or flow meter, pump flow assessment is made with an algorithm based on currents required for impeller rotation and stabilization. The aim of this study is to validate pump performance, algorithm-based flow and effective flow. A series of bovine experiments was realized after equipment with pressure transducers, continuous-cardiac-output-catheter, intracardiac ultrasound (AcuNav) over 6 h. Pump implantation was through a median sternotomy (LV-->VAD-->calibrated transonic-flow-probe-->aorta). A transonic-HT311-flow-probe was fixed onto the outflow cannula for flow comparison. Animals were electively sacrificed and at necropsy systematic pump inspection and renal embolus score was realized. Observation period was 340+/-62.4 min. The axial pump generated a mean arterial pressure of 58.8+/-14.3 mmHg (max 117 mmHg) running at a speed of 6591.3+/-1395.4 rev./min (min 5000/max 8500 rev./min) and generating 2.5+/-1.0 l/min (min 1.4/max 6.0 l/min) of flow. Correlation between the results of the pump flow algorithm and measured pump flow was linear (y=1.0339x, R2=0.9357). VAD explants were free of macroscopic thrombi. Renal embolus score was 0+/-0. The magnetically suspended axial flow pump provides excellent left ventricular support. The pump flow algorithm used is accurate and reliable. Therefore, there is no need for direct flow measurement.

Jet pump-drive system for heat removal

NASA Technical Reports Server (NTRS)

French, J. R. (Inventor)

1985-01-01

A jet pump, in combination with a TEMP, is employed to assure safe cooling of a nuclear reactor after shutdown. A TEMP, responsive to the heat from the coolant in the secondary flow path, automatically pumps the withdrawn coolant to a higher pressure and thus higher velocity compared to the main flow. The high velocity coolant is applied as a driver flow for the jet pump which has a main flow chamber located in the main flow circulation pump. Upon nuclear shutdown and loss of power for the main reactor pumping system, the TEMP/jet pump combination continues to boost the coolant flow in the direction it is already circulating. During the decay time for the nuclear reactor, the jet pump keeps running until the coolant temperature drops to a lower and safe temperature. At this lower temperature, the TEMP/jet jump combination ceases its circulation boosting operation. The TEMP/jet pump combination is automatic, self-regulating and provides an emergency pumping system free of moving parts.

Fluid pumping using magnetic cilia

NASA Astrophysics Data System (ADS)

Hanasoge, Srinivas; Ballard, Matt; Alexeev, Alexander; Hesketh, Peter; Woodruff School of Mechanical Engineering Team

2016-11-01

Using experiments and computer simulations, we examine fluid pumping by artificial magnetic cilia fabricated using surface micromachining techniques. An asymmetry in forward and recovery strokes of the elastic cilia causes the net pumping in a creeping flow regime. We show this asymmetry in the ciliary strokes is due to the change in magnetization of the elastic cilia combined with viscous force due to the fluid. Specifically, the time scale for forward stroke is mostly governed by the magnetic forces, whereas the time scale for the recovery stroke is determined by the elastic and viscous forces. These different time scales result in different cilia deformation during forward and backward strokes which in turn lead to the asymmetry in the ciliary motion. To disclose the physics of magnetic cilia pumping we use a hybrid lattice Boltzmann and lattice spring method. We validate our model by comparing the simulation results with the experimental data. The results of our study will be useful to design microfluidic systems for fluid mixing and particle manipulation including different biological particles. USDA and NSF.

Jet pump-drive system for heat removal

NASA Technical Reports Server (NTRS)

French, James R. (Inventor)

1987-01-01

The invention does away with the necessity of moving parts such as a check valve in a nuclear reactor cooling system. Instead, a jet pump, in combination with a TEMP, is employed to assure safe cooling of a nuclear reactor after shutdown. A main flow exists for a reactor coolant. A point of withdrawal is provided for a secondary flow. A TEMP, responsive to the heat from said coolant in the secondary flow path, automatically pumps said withdrawn coolant to a higher pressure and thus higher velocity compared to the main flow. The high velocity coolant is applied as a driver flow for the jet pump which has a main flow chamber located in the main flow circulation pump. Upon nuclear shutdown and loss of power for the main reactor pumping system, the TEMP/jet pump combination continues to boost the coolant flow in the direction it is already circulating. During the decay time for the nuclear reactor, the jet pump keeps running until the coolant temperature drops to a lower and safe temperature where the heat is no longer a problem. At this lower temperature, the TEMP/jet pump combination ceases its circulation boosting operation. When the nuclear reactor is restarted and the coolant again exceeds the lower temperature setting, the TEMP/jet pump automatically resumes operation. The TEMP/jet pump combination is thus automatic, self-regulating and provides an emergency pumping system free of moving parts.

Inhibition of the active lymph pump by flow in rat mesenteric lymphatics and thoracic duct

NASA Technical Reports Server (NTRS)

Gashev, Anatoliy A.; Davis, Michael J.; Zawieja, David C.; Delp, M. D. (Principal Investigator)

2002-01-01

There are only a few reports of the influence of imposed flow on an active lymph pump under conditions of controlled intraluminal pressure. Thus, the mechanisms are not clearly defined. Rat mesenteric lymphatics and thoracic ducts were isolated, cannulated and pressurized. Input and output pressures were adjusted to impose various flows. Lymphatic systolic and diastolic diameters were measured and used to determine contraction frequency and pump flow indices. Imposed flow inhibited the active lymph pump in both mesenteric lymphatics and in the thoracic duct. The active pump of the thoracic duct appeared more sensitive to flow than did the active pump of the mesenteric lymphatics. Imposed flow reduced the frequency and amplitude of the contractions and accordingly the active pump flow. Flow-induced inhibition of the active lymph pump followed two temporal patterns. The first pattern was a rapidly developing inhibition of contraction frequency. Upon imposition of flow, the contraction frequency immediately fell and then partially recovered over time during continued flow. This effect was dependent on the magnitude of imposed flow, but did not depend on the direction of flow. The effect also depended upon the rate of change in the direction of flow. The second pattern was a slowly developing reduction of the amplitude of the lymphatic contractions, which increased over time during continued flow. The inhibition of contraction amplitude was dependent on the direction of the imposed flow, but independent of the magnitude of flow. Nitric oxide was partly but not completely responsible for the influence of flow on the mesenteric lymph pump. Exposure to NO mimicked the effects of flow, and inhibition of the NO synthase by N (G)-monomethyl-L-arginine attenuated but did not completely abolish the effects of flow.

Mechanical performance comparison between RotaFlow and CentriMag centrifugal blood pumps in an adult ECLS model.

PubMed

Yulong Guan; Xiaowei Su; McCoach, Robert; Kunselman, Allen; El-Banayosy, Aly; Undar, Akif

2010-03-01

Centrifugal blood pumps have been widely adopted in conventional adult cardiopulmonary bypass and circulatory assist procedures. Different brands of centrifugal blood pumps incorporate distinct designs which affect pump performance. In this adult extracorporeal life support (ECLS) model, the performances of two brands of centrifugal blood pump (RotaFlow blood pump and CentriMag blood pump) were compared. The simulated adult ECLS circuit used in this study included a centrifugal blood pump, Quadrox D membrane oxygenator and Sorin adult ECLS tubing package. A Sorin Cardiovascular(R) VVR(R) 4000i venous reservoir (Sorin S.p.A., Milan, Italy) with a Hoffman clamp served as a pseudo-patient. The circuit was primed with 900ml heparinized human packed red blood cells and 300ml lactated Ringer's solution (total volume 1200 ml, corrected hematocrit 40%). Trials were conducted at normothermia (36 degrees C). Performance, including circuit pressure and flow rate, was measured for every setting analyzed. The shut-off pressure of the RotaFlow was higher than the CentriMag at all measurement points given the same rotation speed (p < 0.0001). The shut-off pressure differential between the two centrifugal blood pumps was significant and increased given higher rotation speeds (p < 0.0001). The RotaFlow blood pump has higher maximal flow rate (9.08 +/- 0.01L/min) compared with the CentriMag blood pump (8.37 +/- 0.02L/min) (p < 0.0001). The blood flow rate differential between the two pumps when measured at the same revolutions per minute (RPM) ranged from 1.64L/min to 1.73L/min. The results obtained in this experiment demonstrate that the RotaFlow has a higher shut-off pressure (less retrograde flow) and maximal blood flow rate than the CentriMag blood pump. Findings support the conclusion that the RotaFlow disposable pump head has a better mechanical performance than the CentriMag. In addition, the RotaFlow disposable pump is 20-30 times less expensive than the CentriMag.

77 FR 72433 - Buy America Waiver Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-05

... Submersible pumps (3 @ 3,000 gallons/minute), (1 Low Flow Submersible pump @ 1,000 gallons/minute), (1 Low Flow Sump Pump @ 20 gallons/minute) for rehabilitation of a pump station in the State of Illinois... appropriate to use non-domestic Main Submersible pumps (3 @ 3,000 gallons/minute), (1 Low Flow Submersible...

Blood warming, pump heating and haemolysis in low-flow extracorporeal life support; an in vitro study using freshly donated human blood.

PubMed

Kusters, R W J; Simons, A P; Lancé, M D; Ganushchak, Y M; Bekers, O; Weerwind, P W

2017-01-01

Low-flow extracorporeal life support can be used for cardiopulmonary support of paediatric and neonatal patients and is also emerging as a therapy for patients suffering from exacerbation of chronic obstructive pulmonary disease. However, pump heating and haemolysis have proven to negatively affect the system and outcome. This in vitro study aimed at gaining insight into blood warming, pump heating and haemolysis related to the performance of a new low-flow centrifugal pump. Pump performance in the 400-1,500 ml/min flow range was modulated using small-sized dual-lumen catheters and freshly donated human blood. Measurements included plasma free haemoglobin, blood temperature, pump speed, pump pressure, blood flow and thermographic imaging. Blood warming (ΔT max =0.5°C) had no relationship with pump performance or haemolysis (R 2 max =0.05). Pump performance-related parameters revealed no relevant relationships with haemolysis (R 2 max =0.36). Thermography showed no relevant heat zones in the pump (T max =36°C). Concerning blood warming, pump heating and haemolysis, we deem the centrifugal pump applicable for low-flow extracorporeal circulation.

Heat Transfer Characteristics of Mixed Electroosmotic and Pressure Driven Micro-Flows

NASA Astrophysics Data System (ADS)

Horiuchi, Keisuke; Dutta, Prashanta

We analyze heat transfer characteristics of steady electroosmotic flows with an arbitrary pressure gradient in two-dimensional straight microchannels considering the effects of Joule heating in electroosmotic pumping. Both the temperature distribution and local Nusselt number are mathematically derived in this study. The thermal analysis takes into consideration of the interaction among advective, diffusive, and Joule heating terms to obtain the thermally developing behavior. Unlike macro-scale pipes, axial conduction in micro-scale cannot be negligible, and the governing energy equation is not separable. Thus, a method that considers an extended Graetz problem is introduced. Analytical results show that the Nusselt number of pure electrooosmotic flow is higher than that of plane Poiseulle flow. Moreover, when the electroosmotic flow and pressure driven flow coexist, it is found that adverse pressure gradient to the electroosmotic flow makes the thermal entrance length smaller and the heat transfer ability stronger than pure electroosmotic flow case.

The effect of intra-wellbore head losses in a vertical well

NASA Astrophysics Data System (ADS)

Wang, Quanrong; Zhan, Hongbin

2017-05-01

Flow to a partially penetrating vertical well is made more complex by intra-wellbore losses. These are caused not only by the frictional effect, but also by the kinematic effect, which consists of the accelerational and fluid inflow effects inside a wellbore. Existing models of flow to a partially penetrating vertical well assume either a uniform-flux boundary condition (UFBC) or a uniform-head boundary condition (UHBC) for treating the flow into the wellbore. Neither approach considers intra-wellbore losses. In this study a new general solution, named the mixed-type boundary condition (MTBC) solution, is introduced to include intra-wellbore losses. It is developed from the existing solutions using a hybrid analytical-numerical method. The MTBC solution is capable of modeling various types of aquifer tests (constant-head tests, constant-rate tests, and slug tests) for partially or fully penetrating vertical wells in confined aquifers. Results show that intra-wellbore losses (both frictional and kinematic) can be significant in the early pumping stage. At later pumping times the UHBC solution is adequate because the difference between the MTBC and UHBC solutions becomes negligible.

On traveling-wave field-effect flow control for simultaneous induced-charge electroosmotic pumping and mixing in microfluidics: physical perspectives and theoretical analysis

NASA Astrophysics Data System (ADS)

Liu, Weiyu; Ren, Yukun; Tao, Ye; Li, Yanbo; Wu, Qisheng

2018-05-01

Since its first proposition at the end of the last century (Schasfoort et al 1999 Science 286 942-5), field-effect flow control at micrometer dimensions has attracted tremendous attention from the microfluidic community. Most previous research on this subject has mainly focused on enhancing the electroosmotic pump flow rate by introducing an additional in-phase counterionic charge across the diffusing screening cloud with external gate electrodes of static DC voltages. However, there is a flaw, namely that AC fields, which suppress undesirable electrochemical reactions, result in zero time-averaged flow. Starting from this point, we present herein a brand new approach to traveling-wave field-effect electroosmosis control from a theoretical point of view, in the context of a smart manipulation tool for the stratified liquid content of miniaturization systems. In the configuration of a traveling-wave flow field-effect transistor (TW-FFET), the field-induced out-of-phase Debye screening charge within the thin double layer originates from the forward propagation of a traveling potential wave along a discrete arrangement of external gating electrode arrays, which interacts actively with the horizontal standing-wave electric field imposed across the source-drain terminal. Since the voltage waves and induced free charge are all sinusoidal functions of the observation time, the net ICEO flow component can survive in a broad frequency range. Due to the action of the background AC electric field on the inhomogeneous counterionic charge induced at the solution/sidewall interface, asymmetric ICEO vortex patterns appear above the traveling-wave gate arrays, giving rise to simultaneous induced-charge electroosmotic pumping and mixing of fluidic samples. A mathematical model is then developed to numerically investigate the feasibility of TW-FFETs in electrokinetic microflow manipulation. A prototyping paradigm of fully electrokinetics-driven microfabricated fluidic networks in a cross shape is theoretically erected, with four sets of gating traveling-fields in perpendicular orientations, from which the resulting liquid mixture is obtainable at any one of the three outlet ports. Supported by mathematical analysis, our physical demonstration of the TW-FFET shows it has great potential to advance fully automated electroconvective sample treatment in modern micro total analytical systems.

Induced charge electroosmosis micropumps using arrays of Janus micropillars.

PubMed

Paustian, Joel S; Pascall, Andrew J; Wilson, Neil M; Squires, Todd M

2014-09-07

We report on a microfluidic AC-driven electrokinetic pump that uses Induced Charge Electro-Osmosis (ICEO) to generate on-chip pressures. ICEO flows occur when a bulk electric field polarizes a metal object to induce double layer formation, then drives electroosmotic flow. A microfabricated array of metal-dielectric Janus micropillars breaks the symmetry of ICEO flow, so that an AC electric field applied across the array drives ICEO flow along the length of the pump. When pumping against an external load, a pressure gradient forms along the pump length. The design was analyzed theoretically with the reciprocal theorem. The analysis reveals a maximum pressure and flow rate that depend on the ICEO slip velocity and micropillar geometry. We then fabricate and test the pump, validating our design concept by demonstrating non-local pressure driven flow using local ICEO slip flows. We varied the voltage, frequency, and electrolyte composition, measuring pump pressures of 15-150 Pa. We use the pump to drive flows through a high-resistance microfluidic channel. We conclude by discussing optimization routes suggested by our theoretical analysis to enhance the pump pressure.

Magneto-Hydrodynamics Based Microfluidics

PubMed Central

Qian, Shizhi; Bau, Haim H.

2009-01-01

In microfluidic devices, it is necessary to propel samples and reagents from one part of the device to another, stir fluids, and detect the presence of chemical and biological targets. Given the small size of these devices, the above tasks are far from trivial. Magnetohydrodynamics (MHD) offers an elegant means to control fluid flow in microdevices without a need for mechanical components. In this paper, we review the theory of MHD for low conductivity fluids and describe various applications of MHD such as fluid pumping, flow control in fluidic networks, fluid stirring and mixing, circular liquid chromatography, thermal reactors, and microcoolers. PMID:20046890

A new blood pump for cardiopulmonary bypass: the HiFlow centrifugal pump.

PubMed

Göbel, C; Eilers, R; Reul, H; Schwindke, P; Jörger, M; Rau, G

1997-07-01

Centrifugal blood pumps are considered to be generally superior to the traditionally used roller pumps in cardiopulmonary bypass. In our institute a new lightweight centrifugal sealless blood pump with a unique spherical thrust bearing and with a magnetic coupling was developed, the HiFlow. The small design makes the pump suitable for applications in complex devices or close to a patient. Hemolysis tests were carried out in which the BioMedicus pump BP-80 and a roller pump were used as reference. The centrifugal pump HiFlow showed the least blood trauma within the group of investigated pumps. In summary, the HiFlow pump concept with its low priming volume and limited contact surfaces shows great potential for clinical applications in cardiopulmonary bypass. Also, the possibility of using the pump as a short-term assist device with an option of a pulsatile driving mode was demonstrated.

Magnetic design for the PediaFlow ventricular assist device.

PubMed

Noh, Myounggyu D; Antaki, James F; Ricci, Michael; Gardiner, Jeff; Paden, Dave; Wu, Jingchun; Prem, Ed; Borovetz, Harvey; Paden, Bradley E

2008-02-01

This article describes a design process for a new pediatric ventricular assist device, the PediaFlow. The pump is embodied in a magnetically levitated turbodynamic design that was developed explicitly based on the requirements for chronic support of infants and small children. The procedure entailed the consideration of multiple pump topologies, from which an axial mixed-flow configuration was chosen for further development. The magnetic design includes permanent-magnet (PM) passive bearings for radial support of the rotor, an actively controlled thrust actuator for axial support, and a brushless direct current (DC) motor for rotation. These components are closely coupled both geometrically and magnetically, and were therefore optimized in parallel, using electromagnetic, rotordynamic models and fluid models, and in consideration of hydrodynamic requirements. Multiple design objectives were considered, including efficiency, size, and margin between critical speeds to operating speed. The former depends upon the radial and yaw stiffnesses of the PM bearings. Analytical expressions for the stiffnesses were derived and verified through finite element analysis (FEA). A toroidally wound motor was designed for high efficiency and minimal additional negative radial stiffness. The design process relies heavily on optimization at the component level and system level. The results of this preliminary design optimization yielded a pump design with an overall stability margin of 15%, based on a pressure rise of 100 mm Hg at 0.5 lpm running at 16,000 rpm.

Tank 241-AZ-101 criticality assessment resulting from pump jet mixing: Sludge mixing simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Y.; Recknagle, K.

Tank 241-AZ-101 (AZ-101) is one of 28 double-shell tanks located in the AZ farm in the Hanford Site`s 200 East Area. The tank contains a significant quantity of fissile materials, including an estimated 9.782 kg of plutonium. Before beginning jet pump mixing for mitigative purposes, the operations must be evaluated to demonstrate that they will be subcritical under both normal and credible abnormal conditions. The main objective of this study was to address a concern about whether two 300-hp pumps with four rotating 18.3-m/s (60-ft/s) jets can concentrate plutonium in their pump housings during mixer pump operation and cause amore » criticality. The three-dimensional simulation was performed with the time-varying TEMPEST code to determine how much the pump jet mixing of Tank AZ-101 will concentrate plutonium in the pump housing. The AZ-101 model predicted that the total amount of plutonium within the pump housing peaks at 75 g at 10 simulation seconds and decreases to less than 10 g at four minutes. The plutonium concentration in the entire pump housing peaks at 0.60 g/L at 10 simulation seconds and is reduced to below 0.1 g/L after four minutes. Since the minimum critical concentration of plutonium is 2.6 g/L, and the minimum critical plutonium mass under idealized plutonium-water conditions is 520 g, these predicted maximums in the pump housing are much lower than the minimum plutonium conditions needed to reach a criticality level. The initial plutonium maximum of 1.88 g/L still results in safety factor of 4.3 in the pump housing during the pump jet mixing operation.« less

Method to produce American Thoracic Society flow-time waveforms using a mechanical pump.

PubMed

Hankinson, J L; Reynolds, J S; Das, M K; Viola, J O

1997-03-01

The American Thoracic Society (ATS) recently adopted a new set of 26 standard flow-time waveforms for use in testing both diagnostic and monitoring devices. Some of these waveforms have a higher frequency content than present in the ATS-24 standard volume-time waveforms, which, when produced by a mechanical pump, may result in a pump flow output that is less than the desired flow due to gas compression losses within the pump. To investigate the effects of gas compression, a mechanical pump was used to generate the necessary flows to test mini-Wright and Assess peak expiratory flow (PEF) meters. Flow output from the pump was measured by two different independent methods, a pneumotachometer and a method based on piston displacement and pressure measured within the pump. Measuring output flow based on piston displacement and pressure has been validated using a pneumotachometer and mini-Wright PEF meter, and found to accurately measure pump output. This method introduces less resistance (lower back-pressure) and dead space volume than using a pneumotachometer in series with the meter under test. Pump output flow was found to be lower than the desired flow both with the mini-Wright and Assess meters (for waveform No. 26, PEFs 7.1 and 10.9% lower, respectively). To compensate for losses due to gas compression, we have developed a method of deriving new input waveforms, which, when used to drive a commercially available mechanical pump, accurately and reliably produces the 26 ATS flow-time waveforms, even those with the fastest rise-times.

Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohne, Thomas; Kliem, Soren; Rohde, Ulrich

2006-07-01

Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shiftedmore » towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)« less

LeRC NATR Free-Jet Development

NASA Technical Reports Server (NTRS)

Long-Davis, M.; Cooper, B. A.

1999-01-01

The Nozzle Acoustic Test Rig (NATR) was developed to provide additional test capabilities at Lewis needed to meet HSR program goals. The NATR is a large f ree-jet facility (free-jet diameter = 53 in.) with a design Mach number of 0.3. It is located inside a geodesic dome, adjacent to the existing Powered Lift Facility (PLF). The NATR allows nozzle concepts to be acoustically assessed for far-field (approximately 50 feet) noise characteristics under conditions simulating forward flight. An ejector concept was identified as a means of supplying the required airflow for this free-jet facility. The primary stream is supplied through a circular array of choked nozzles and the resulting low pressure in the constant, annular- area mixing section causes a "pumping" action that entrains the secondary stream. The mixed flow expands through an annular diffuser and into a plenum chamber. Once inside the plenum, the flow passes over a honeycomb/screen combination intended to remove large disturbances and provide uniform flow. The flow accelerates through an elliptical contraction section where it achieves a free-jet Mach number of up to 0.3.

Simulations of groundwater flow, transport, and age in Albuquerque, New Mexico, for a study of transport of anthropogenic and natural contaminants (TANC) to public-supply wells

USGS Publications Warehouse

Heywood, Charles E.

2013-01-01

Vulnerability to contamination from manmade and natural sources can be characterized by the groundwater-age distribution measured in a supply well and the associated implications for the source depths of the withdrawn water. Coupled groundwater flow and transport models were developed to simulate the transport of the geochemical age-tracers carbon-14, tritium, and three chlorofluorocarbon species to public-supply wells in Albuquerque, New Mexico. A separate, regional-scale simulation of transport of carbon-14 that used the flow-field computed by a previously documented regional groundwater flow model was calibrated and used to specify the initial concentrations of carbon-14 in the local-scale transport model. Observations of the concentrations of each of the five chemical species, in addition to water-level observations and measurements of intra-borehole flow within a public-supply well, were used to calibrate parameters of the local-scale groundwater flow and transport models. The calibrated groundwater flow model simulates the mixing of “young” groundwater, which entered the groundwater flow system after 1950 as recharge at the water table, with older resident groundwater that is more likely associated with natural contaminants. Complexity of the aquifer system in the zone of transport between the water table and public-supply well screens was simulated with a geostatistically generated stratigraphic realization based upon observed lithologic transitions at borehole control locations. Because effective porosity was simulated as spatially uniform, the simulated age tracers are more efficiently transported through the portions of the simulated aquifer with relatively higher simulated hydraulic conductivity. Non-pumping groundwater wells with long screens that connect aquifer intervals having different hydraulic heads can provide alternate pathways for contaminant transport that are faster than the advective transport through the aquifer material. Simulation of flow and transport through these wells requires time discretization that adequately represents periods of pumping and non-pumping. The effects of intra-borehole flow are not fully represented in the simulation because it employs seasonal stress periods, which are longer than periods of pumping and non-pumping. Further simulations utilizing daily pumpage data and model stress periods may help quantify the relative effects of intra-borehole versus advective aquifer flow on the transport of contaminants near the public-supply wells. The fraction of young water withdrawn from the studied supply well varies with simulated pumping rates due to changes in the relative contributions to flow from different aquifer intervals. The advective transport of dissolved solutes from a known contaminant source to the public-supply wells was simulated by using particle-tracking. Because of the transient groundwater flow field, scenarios with alternative contaminant release times result in different simulated-particle fates, most of which are withdrawn from the aquifer at wells that are between the source and the studied supply well. The relatively small effective porosity required to simulate advective transport from the simulated contaminant source to the studied supply well is representative of a preferential pathway and not the predominant aquifer effective porosity that was estimated by the calibration of the model to observed chemical-tracer concentrations.

Blood flow/pump rotation ratio as an artificial lung performance monitoring tool during extracorporeal respiratory support using centrifugal pumps.

PubMed

Park, Marcelo; Mendes, Pedro Vitale; Hirota, Adriana Sayuri; dos Santos, Edzangela Vasconcelos; Costa, Eduardo Leite Vieira; Azevedo, Luciano Cesar Pontes

2015-01-01

To analyze the correlations of the blood flow/pump rotation ratio and the transmembrane pressure, CO2 and O2 transfer during the extracorporeal respiratory support. Five animals were instrumented and submitted to extracorporeal membrane oxygenation in a five-step protocol, including abdominal sepsis and lung injury. This study showed that blood flow/pump rotations ratio variations are dependent on extracorporeal membrane oxygenation blood flow in a positive logarithmic fashion. Blood flow/pump rotation ratio variations are negatively associated with transmembrane pressure (R2 = 0.5 for blood flow = 1500mL/minute and R2 = 0.4 for blood flow = 3500mL/minute, both with p < 0.001) and positively associated with CO2 transfer variations (R2 = 0.2 for sweep gas flow ≤ 6L/minute, p < 0.001, and R2 = 0.1 for sweep gas flow > 6L/minute, p = 0.006), and the blood flow/pump rotation ratio is not associated with O2 transfer variations (R2 = 0.01 for blood flow = 1500mL/minute, p = 0.19, and R2 = - 0.01 for blood flow = 3500 mL/minute, p = 0.46). Blood flow/pump rotation ratio variation is negatively associated with transmembrane pressure and positively associated with CO2 transfer in this animal model. According to the clinical situation, a decrease in the blood flow/pump rotation ratio can indicate artificial lung dysfunction without the occurrence of hypoxemia.

Neutron radiography experiments for verification of soluble boron mixing and transport modeling under natural circulation conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feltus, M.A.; Morlang, G.M.

1996-06-01

The use of neutron radiography for visualization of fluid flow through flow visualization modules has been very successful. Current experiments at the Penn State Breazeale Reactor serve to verify the mixing and transport of soluble boron under natural flow conditions as would be experienced in a pressurized water reactor. Different flow geometries have been modeled including holes, slots, and baffles. Flow modules are constructed of aluminum box material 1 1/2 inches by 4 inches in varying lengths. An experimental flow system was built which pumps fluid to a head tank and natural circulation flow occurs from the head tank throughmore » the flow visualization module to be radiographed. The entire flow system is mounted on a portable assembly to allow placement of the flow visualization module in front of the neutron beam port. A neutron-transparent fluorinert fluid is used to simulate water at different densities. Boron is modeled by gadolinium oxide powder as a tracer element, which is placed in a mixing assembly and injected into the system by remote operated electric valve, once the reactor is at power. The entire sequence is recorded on real-time video. Still photographs are made frame-by-frame from the video tape. Computers are used to digitally enhance the video and still photographs. The data obtained from the enhancement will be used for verification of simple geometry predictions using the TRAC and RELAP thermal-hydraulic codes. A detailed model of a reactor vessel inlet plenum, downcomer region, flow distribution area and core inlet is being constructed to model the AP600 plenum. Successive radiography experiments of each section of the model under identical conditions will provide a complete vessel/core model for comparison with the thermal-hydraulic codes.« less

Geochemical evolution of groundwater in southern Bengal Basin: The example of Rajarhat and adjoining areas, West Bengal, India

NASA Astrophysics Data System (ADS)

Sahu, Paulami; Sikdar, P. K.; Chakraborty, Surajit

2016-02-01

Detailed geochemical analysis of groundwater beneath 1223 km2 area in southern Bengal Basin along with statistical analysis on the chemical data was attempted, to develop a better understanding of the geochemical processes that control the groundwater evolution in the deltaic aquifer of the region. Groundwater is categorized into three types: `excellent', `good' and `poor' and seven hydrochemical facies are assigned to three broad types: `fresh', `mixed' and `brackish' waters. The `fresh' water type dominated with sodium indicates active flushing of the aquifer, whereas chloride-rich `brackish' groundwater represents freshening of modified connate water. The `mixed' type groundwater has possibly evolved due to hydraulic mixing of `fresh' and `brackish' waters. Enrichment of major ions in groundwater is due to weathering of feldspathic and ferro-magnesian minerals by percolating water. The groundwater of Rajarhat New Town (RNT) and adjacent areas in the north and southeast is contaminated with arsenic. Current-pumping may induce more arsenic to flow into the aquifers of RNT and Kolkata cities. Future large-scale pumping of groundwater beneath RNT can modify the hydrological system, which may transport arsenic and low quality water from adjacent aquifers to presently unpolluted aquifer.

Four-wave-mixing suppression in Er 3+-fiber amplifiers by backward pumping

NASA Astrophysics Data System (ADS)

Adel, P.; Engelbrecht, M.; Wandt, D.; Fallnich, C.

2007-03-01

Amplification of chirped fs-pulses in an Erbium doped fiber amplifier upto 0.8 μJ resulted in an additional peak in the spectrum at 1584 nm. This peak, attributable to four-wave-mixing between the signal centered at 1559 nm and amplified spontaneous emission at 1534 nm, hinders the temporal recompression of the amplified chirped pulse. Compared to the forward pumping configuration, this four-wave-mixing in the amplifier was largely reduced in a backward pumping configuration. Based on simulations, explanations for the observed influence of the pump direction on the four-wave-mixing efficiency are presented. The results pointed out that the gain spectrum distribution along the fiber strongly influences four-wave-mixing effects in fiber amplifiers even for constant overall gain spectrum.

The Solution to Pollution is Distribution: Design Your Own Chaotic Flow

NASA Astrophysics Data System (ADS)

Tigera, R. G.; Roth, E. J.; Neupauer, R.; Mays, D. C.

2015-12-01

Plume spreading promotes the molecular mixing that drives chemical reactions in porous media in general, and remediation reactions in groundwater aquifers in particular. Theoretical analysis suggests that engineered injection and extraction, a specific sequence of pumping through wells surrounding a contaminant plume, can improve groundwater remediation through chaotic advection. Selection of an engineered injection and extraction scheme is difficult, however, because the engineer is faced with the difficulty of recommending a pumping scheme for a contaminated site without having any previous knowledge of how the scheme will perform. To address this difficulty, this presentation describes a Graphical User Interface (GUI) designed to help engineers develop, test, and observe pumping schemes as described in previous research (Mays, D.C. and Neupauer, R.M., 2012, Plume spreading in groundwater by stretching and folding, Water Resour. Res., 48, W07501, doi:10.1029/2011WR011567). The inputs allow the user to manipulate the model conditions such as number of wells, plume size, and pumping scheme. Plume evolution is modeled, assuming no diffusion or dispersion, using analytical solutions for injection or extraction through individual wells or pairs or wells (i.e., dipoles). Using the GUI, an engineered injection and extraction scheme can be determined that best fits the remediation needs of the contaminated site. By creating multiple injection and extraction schemes, the user can learn about the plume shapes created from different schemes and, ultimately, recommend a pumping scheme based on some experience of fluid flow as shown in the GUI. The pumping schemes developed through this GUI are expected to guide more advanced modeling and laboratory studies that account for the crucial role of dispersion in groundwater remediation.

Peak expiratory flow profiles delivered by pump systems. Limitations due to wave action.

PubMed

Miller, M R; Jones, B; Xu, Y; Pedersen, O F; Quanjer, P H

2000-06-01

Pump systems are currently used to test the performance of both spirometers and peak expiratory flow (PEF) meters, but for certain flow profiles the input signal (i.e., requested profile) and the output profile can differ. We developed a mathematical model of wave action within a pump and compared the recorded flow profiles with both the input profiles and the output predicted by the model. Three American Thoracic Society (ATS) flow profiles and four artificial flow-versus-time profiles were delivered by a pump, first to a pneumotachograph (PT) on its own, then to the PT with a 32-cm upstream extension tube (which would favor wave action), and lastly with the PT in series with and immediately downstream to a mini-Wright peak flow meter. With the PT on its own, recorded flow for the seven profiles was 2.4 +/- 1.9% (mean +/- SD) higher than the pump's input flow, and similarly was 2.3 +/- 2.3% higher than the pump's output flow as predicted by the model. With the extension tube in place, the recorded flow was 6.6 +/- 6.4% higher than the input flow (range: 0.1 to 18.4%), but was only 1.2 +/- 2.5% higher than the output flow predicted by the model (range: -0.8 to 5.2%). With the mini-Wright meter in series, the flow recorded by the PT was on average 6.1 +/- 9.1% below the input flow (range: -23.8 to 2. 5%), but was only 0.6 +/- 3.3% above the pump's output flow predicted by the model (range: -5.5 to 3.9%). The mini-Wright meter's reading (corrected for its nonlinearity) was on average 1.3 +/- 3.6% below the model's predicted output flow (range: -9.0 to 1. 5%). The mini-Wright meter would be deemed outside ATS limits for accuracy for three of the seven profiles when compared with the pump's input PEF, but this would be true for only one profile when compared with the pump's output PEF as predicted by the model. Our study shows that the output flow from pump systems can differ from the input waveform depending on the operating configuration. This effect can be predicted with reasonable accuracy using a model based on nonsteady flow analysis that takes account of pressure wave reflections within pump systems.

Integrated aquitard-aquifer flow with a mixed-type well-face boundary and skin effect

NASA Astrophysics Data System (ADS)

Feng, Qinggao; Zhan, Hongbin

2016-03-01

A general analytical model describing groundwater flow to a partially penetrating well pumped at a constant rate in a leaky confined aquifer is developed. The model incorporates the effects of aquitard storage, aquifer anisotropy, wellbore storage and a finite well skin by treating the aquitard leakage as an aquitard-aquifer interface flow problem, and considers the well-face as a mixed-type or non-uniform flux (NUF) rather than a uniform flux (UF) boundary condition, which is novel. The solution is obtained using the Laplace transform coupled with separation of variables and discretization methods, followed by the numerical inverse Laplace transform. Moreover, the solution unifies some cases for flow to a partially penetrating well in a leaky confined aquifer including Perina and Lee (2006), Feng and Zhan (2015) and Hunt (2005) or confined aquifer including Chiu et al. (2007), Yang et al. (2006) and Hantush (1964). The newly developed NUF solution is compared with the UF solution. The NUF drawdown is larger than the UF drawdown at early time, while the NUF drawdown is smaller than the UF drawdown at intermediate and late times. The non-uniform flux along the well-face has significant impact on drawdown in the skin zone, while the UF solution can completely replace the NUF solution at a radial distance from the pumped well equaling to or greater than the aquifer thickness. The NUF and UF drawdowns for no skin case are remarkably smaller than that for the positive skin case and larger than that for the negative skin case. A thicker well skin results in a smaller drawdown in the skin zone.

Gain and temperature in a slit nozzle supersonic chemical oxygen-iodine laser with transonic and supersonic injection of iodine

NASA Astrophysics Data System (ADS)

Rosenwaks, Salman; Barmashenko, Boris D.; Bruins, Esther; Furman, Dov; Rybalkin, Victor; Katz, Arje

2002-05-01

Spatial distributions of the gain and temperament across the flow were studied for transonic and supersonic schemes of the iodine injection in a slit nozzle supersonic chemical oxygen-iodine laser as a function of the iodine and secondary nitrogen flow rate, jet penetration parameter and gas pumping rate. The mixing efficiency for supersonic injection of iodine is found to be much larger than for transonic injection, the maximum values of the gain being approximately 0.65 percent/cm for both injection schemes. Measurements of the gain distribution as a function of the iodine molar flow rate nI2 were carried out. For transonic injection the optimal value of nI2 at the flow centerline is smaller than that at the off axis location. The temperature is distributed homogeneously across the flow, increasing only in the narrow boundary layers near the walls. Opening a leak downstream of the cavity in order to decease the Mach number results in a decrease of the gain and increase of the temperature. The mixing efficiency in this case is much larger than for closed leak.

Manipulating low-Reynolds-number flow by a watermill

NASA Astrophysics Data System (ADS)

Zhu, Lailai; Stone, Howard

2017-11-01

Cilia and filaments have evolved in nature to achieve swimming, mixing and pumping at low Reynolds number. Their unique capacity has inspired a variety of biomimetic strategies employing artificial slender structures to manipulate flows in microfluidic devices. Most of them have to rely on an external field, such as magnetic or electric fields to actuate the slender structures actively. In this talk, we will present a new approach of utilizing the underlying flow alone to drive these structures passively. We investigate theoretically and numerically a watermill composing several rigid slender rods in simple flows. Slender body theory with and without considering hydrodynamic interactions is adopted. The theoretical predictions agree qualitatively with the numerical results and quantitatively in certain configurations. A VR International Postdoc Grant from Swedish Research Council ``2015-06334'' (L.Z.) is gratefully acknowledged.

Recirculating rotary gas compressor

DOEpatents

Weinbrecht, John F.

1992-01-01

A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

Recirculating rotary gas compressor

DOEpatents

Weinbrecht, J.F.

1992-02-25

A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor. 12 figs.

Blood flow/pump rotation ratio as an artificial lung performance monitoring tool during extracorporeal respiratory support using centrifugal pumps

PubMed Central

Park, Marcelo; Mendes, Pedro Vitale; Hirota, Adriana Sayuri; dos Santos, Edzangela Vasconcelos; Costa, Eduardo Leite Vieira; Azevedo, Luciano Cesar Pontes

2015-01-01

Objective To analyze the correlations of the blood flow/pump rotation ratio and the transmembrane pressure, CO2 and O2 transfer during the extracorporeal respiratory support. Methods Five animals were instrumented and submitted to extracorporeal membrane oxygenation in a five-step protocol, including abdominal sepsis and lung injury. Results This study showed that blood flow/pump rotations ratio variations are dependent on extracorporeal membrane oxygenation blood flow in a positive logarithmic fashion. Blood flow/pump rotation ratio variations are negatively associated with transmembrane pressure (R2 = 0.5 for blood flow = 1500mL/minute and R2 = 0.4 for blood flow = 3500mL/minute, both with p < 0.001) and positively associated with CO2 transfer variations (R2 = 0.2 for sweep gas flow ≤ 6L/minute, p < 0.001, and R2 = 0.1 for sweep gas flow > 6L/minute, p = 0.006), and the blood flow/pump rotation ratio is not associated with O2 transfer variations (R2 = 0.01 for blood flow = 1500mL/minute, p = 0.19, and R2 = - 0.01 for blood flow = 3500 mL/minute, p = 0.46). Conclusion Blood flow/pump rotation ratio variation is negatively associated with transmembrane pressure and positively associated with CO2 transfer in this animal model. According to the clinical situation, a decrease in the blood flow/pump rotation ratio can indicate artificial lung dysfunction without the occurrence of hypoxemia. PMID:26340159

Pre-compression volume on flow ripple reduction of a piston pump

NASA Astrophysics Data System (ADS)

Xu, Bing; Song, Yuechao; Yang, Huayong

2013-11-01

Axial piston pump with pre-compression volume(PCV) has lower flow ripple in large scale of operating condition than the traditional one. However, there is lack of precise simulation model of the axial piston pump with PCV, so the parameters of PCV are difficult to be determined. A finite element simulation model for piston pump with PCV is built by considering the piston movement, the fluid characteristic(including fluid compressibility and viscosity) and the leakage flow rate. Then a test of the pump flow ripple called the secondary source method is implemented to validate the simulation model. Thirdly, by comparing results among the simulation results, test results and results from other publications at the same operating condition, the simulation model is validated and used in optimizing the axial piston pump with PCV. According to the pump flow ripples obtained by the simulation model with different PCV parameters, the flow ripple is the smallest when the PCV angle is 13°, the PCV volume is 1.3×10-4 m3 at such operating condition that the pump suction pressure is 2 MPa, the pump delivery pressure 15 MPa, the pump speed 1 000 r/min, the swash plate angle 13°. At the same time, the flow ripple can be reduced when the pump suction pressure is 2 MPa, the pump delivery pressure is 5 MPa,15 MPa, 22 MPa, pump speed is 400 r/min, 1 000 r/min, 1 500 r/min, the swash plate angle is 11°, 13°, 15° and 17°, respectively. The finite element simulation model proposed provides a method for optimizing the PCV structure and guiding for designing a quieter axial piston pump.

Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

USGS Publications Warehouse

Ayotte, J.D.; Szabo, Z.; Focazio, M.J.; Eberts, S.M.

2011-01-01

The effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes and artificial connection of aquifers by well screens can mix chemically distinct groundwater. Chemical reactions between these mixed groundwaters and solid aquifer materials can result in the mobilization of trace elements such as U, As and Ra, with subsequent transport to water-supply wells. For example, in the High Plains aquifer near York, Nebraska, mixing of shallow, oxygenated, lower-pH water from an unconfined aquifer with deeper, confined, anoxic, higher-pH water is facilitated by wells screened across both aquifers. The resulting higher-O2, lower-pH mixed groundwater facilitated the mobilization of U from solid aquifer materials, and dissolved U concentrations were observed to increase significantly in nearby supply wells. Similar instances of trace element mobilization due to human-induced mixing of groundwaters were documented in: (1) the Floridan aquifer system near Tampa, Florida (As and U), (2) Paleozoic sedimentary aquifers in eastern Wisconsin (As), (3) the basin-fill aquifer underlying the California Central Valley near Modesto (U), and (4) Coastal Plain aquifers of New Jersey (Ra). Adverse water-quality impacts attributed to human activities are commonly assumed to be related solely to the release of the various anthropogenic contaminants to the environment. The results show that human activities including various land uses, well drilling, and pumping rates and volumes can adversely impact the quality of water in supply wells, when associated with naturally-occurring trace elements in aquifer materials. This occurs by causing subtle but significant changes in geochemistry and associated trace element mobilization as well as enhancing advective transport processes.

NASA Advanced Radiator Technology Development

NASA Astrophysics Data System (ADS)

Koester, J. Kent; Juhasz, Albert J.

1994-07-01

A practical implementation of the two-phase working fluid of lithium and NaK has been developed experimentally for pumped loop radiator designs. The benefits of the high heat capacity and low mass of lithium have been integrated with the shutdown capability enabled by the low freezing temperature of NaK by mixing these liquid metals directly. The stable and reliable start up and shutdown of a lithium/NaK pumped loop has been demonstrated through the development of a novel lithium freeze-separation technique within the flowing header ducts. The results of a highly instrumented liquid metal test loop are presented in which both lithium fraction as well as loop gravitational effects were varied over a wide range of values. Diagnostics based on dual electric probes are presented in which the convective behavior of the lithium component is directly measured during loop operation. The uniform distribution of the lithium after a freeze separation is verified by neutron radiography. The operating regime for reliable freeze/thaw flow behavior is described in terms of correlations based on dimensional analysis.

Design flow factors for sewerage systems in small arid communities.

PubMed

Imam, Emad H; Elnakar, Haitham Y

2014-09-01

Reliable estimation of sewage flow rates is essential for the proper design of sewers, pumping stations, and treatment plants. The design of the various components of the sewerage system should be based on the most critical flow rates with a focus on extremely low and peak flow rates that would be sustained for a duration related to the acceptable limits of behavior of the components under consideration. The extreme flow conditions and to what extent they differ from the average values are closely related to the size of the community or network, and the socioeconomic conditions. A single pumping station is usually sufficient to pump flow from small community in either flat or non-undulating topography. Therefore, the hydraulic loading on the wastewater treatment plant (WWTP) results from the pumped flow from the pumping station rather than the trunk sewer flow. The intermittent operation of the pumping units further accentuates the sewage hydrograph in the final trunk sewer. Accordingly, the design flow for the various components of the WWTP should be determined based on their relevant flow factors. In this study, analysis of one representative small community out of five monitored small communities in Egypt and the Kingdom of Saudi Arabia is presented. Pumped sewage flow rates were measured and the sewer incoming flows were hydraulically derived. The hourly and daily sewer and pumped flow records were analyzed to derive the relationship between the flow factors that would be sustained for various durations (instantaneously, 1 h, 2 h, etc.) and their probability of non-exceedance. The resulting peaking factors with a consideration for their sustained flow duration and specified probability would permit the design of the various components of the treatment plant using more accurate critical flows.

Design flow factors for sewerage systems in small arid communities

PubMed Central

Imam, Emad H.; Elnakar, Haitham Y.

2013-01-01

Reliable estimation of sewage flow rates is essential for the proper design of sewers, pumping stations, and treatment plants. The design of the various components of the sewerage system should be based on the most critical flow rates with a focus on extremely low and peak flow rates that would be sustained for a duration related to the acceptable limits of behavior of the components under consideration. The extreme flow conditions and to what extent they differ from the average values are closely related to the size of the community or network, and the socioeconomic conditions. A single pumping station is usually sufficient to pump flow from small community in either flat or non-undulating topography. Therefore, the hydraulic loading on the wastewater treatment plant (WWTP) results from the pumped flow from the pumping station rather than the trunk sewer flow. The intermittent operation of the pumping units further accentuates the sewage hydrograph in the final trunk sewer. Accordingly, the design flow for the various components of the WWTP should be determined based on their relevant flow factors. In this study, analysis of one representative small community out of five monitored small communities in Egypt and the Kingdom of Saudi Arabia is presented. Pumped sewage flow rates were measured and the sewer incoming flows were hydraulically derived. The hourly and daily sewer and pumped flow records were analyzed to derive the relationship between the flow factors that would be sustained for various durations (instantaneously, 1 h, 2 h, etc.) and their probability of non-exceedance. The resulting peaking factors with a consideration for their sustained flow duration and specified probability would permit the design of the various components of the treatment plant using more accurate critical flows. PMID:25685521

STEAM CARRYUNDER MEASUREMENT BY MEANS OF TWO-PHASE PUMP PERFORMANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemi, R.O.; Steamer, A.G.

1960-10-01

Pump tests were conducted at the Moss Landing Steam Separation Facility at operating pressures of 600 and 1000 psig to provide a method for determining the rate of steam carryunder. Pump power input and head were measured as functions of water flow and steam flow to the pump suction. The pump tested had a rated flow of 1700 gpm and a rated head of 148 feet. It was found that in this facility, steam carryander can be measured to 0.1% by measuring the recirculating water pump input power and Pump head. (auth)

Evaluation of contrast-enhanced power Doppler imaging for measuring blood flow

NASA Astrophysics Data System (ADS)

Ansaloni, Sara; Arger, Peter H.; Cary, Ted W.; Sehgal, Chandra M.

2005-04-01

Power Doppler ultrasound enhanced by microbubble contrast agent has been used to image tissue vascularity and blood flow for the assessment of antivascular therapies. We have proposed a multigating technique that measures bubble concentration as a function of ultrasound exposure for deriving tumor blood flow and vascularity.1 Techniques using ultrasound contrast agent are known to be sensitive to the choice of imaging parameters like mechanical index and tissue attenuation. In this paper, the roles of mechanical index (MI) and tissue attenuation were evaluated experimentally in a rubber tubing flow phantom connected to a mixing chamber and a variable speed pump. The contrast was injected in the mixing chamber and the flow rate was measured using power Doppler imaging. The measurements were repeated at different MIs (0.1 to 1.3), and at different levels of attenuation, obtained with solutions of glycerol-water (10-20%). True flow was measured by collecting liquid flowing out of the phantom over a fixed duration. At low MI (<0.5), the grayscale and Doppler signal were weak, making these images unsuitable for analysis. At higher MI (> 0.8), there was a well-defined enhancement by contrast agent resulting in reproducible flow measurements at variable MIs. A balance between the number of bubbles destroyed and the echo they generate must be achieved for optimal imaging. The increased attenuation of ultrasound by the overlying medium did not influence the flow measurements.

Field experiment and numerical simulation of coupling non-Darcy flow caused by curtain and pumping well in foundation pit dewatering

NASA Astrophysics Data System (ADS)

Wang, Jianxiu; Liu, Xiaotian; Wu, Yuanbin; Liu, Shaoli; Wu, Lingao; Lou, Rongxiang; Lu, Jiansheng; Yin, Yao

2017-06-01

High-velocity non-Darcy flow produced larger drawdown than Darcy flow under the same pumping rate. When the non-Darcy flow caused by curtain met non-Darcy flow caused by pumping wells, superposition and amplification effect occurred in the coupling area, the non-Darcy flow was defined as coupling non-Darcy flow. The coupling non-Darcy flow can be produced and controlled using different combination of curtain and pumping wells in foundation pit dewatering to obtain the maximum drawdown using the minimum pumping rate. The Qianjiang Century City Station foundation pit of Hangzhou subway, China, was selected as background. Field experiments were performed to observe the coupling non-Darcy flow in round gravel. A generalized conceptual model was established to study the coupling effect under different combination of curtain and pumping wells. Numerical simulations of the coupling non-Darcy flow in foundation pit dewatering were carried out based on the Forchheimer equation. The non-Darcy flow area and flow velocity were influenced by the coupling effect. Short filter tube, large pumping rate, small horizontal distance between filter tube and diaphragm wall, and small vertical distance between the filter tube and confined aquifer roof effectively strengthened the coupling effect and obtained a large drawdown. The pumping wells installed close to a curtain was an intentional choice designed to create coupling non-Darcy flow and obtain the maximize drawdown. It can be used in the dewatering of a long and narrow foundation pit, such as a subway foundation pit.

Modeling and simulation of flow field in giant magnetostrictive pump

NASA Astrophysics Data System (ADS)

Zhao, Yapeng; Ren, Shiyong; Lu, Quanguo

2017-09-01

Recent years, there has been significant research in the design and analysis of giant magnetostrictive pump. In this paper, the flow field model of giant magnetostrictive pump was established and the relationship between pressure loss and working frequency of piston was studied by numerical simulation method. Then, the influence of different pump chamber height on pressure loss in giant magnetostrictive pump was studied by means of flow field simulation. Finally, the fluid pressure and velocity vector distribution in giant magnetostrictive pump chamber were simulated.

The use of groundwater age as a calibration target

USGS Publications Warehouse

Konikow, Leonard F.; Hornberger, G.Z.; Putnam, L.D.; Shapiro, A.M.; Zinn, B.A.

2008-01-01

Groundwater age (or residence time), as estimated on the basis of concentrations of one or more environmental tracers, can provide a useful and independent calibration target for groundwater models. However, concentrations of environmental tracers are affected by the complexities and mixing inherent in groundwater flow through heterogeneous media, especially in the presence of pumping wells. An analysis of flow and age distribution in the Madison aquifer in South Dakota, USA, illustrates the additional benefits and difficulties of using age as a calibration target. Alternative numerical approaches to estimating travel time and age with backward particle tracking are assessed, and the resulting estimates are used to refine estimates of effective porosity and to help assess the adequacy and credibility of the flow model.

Pump tank divider plate for sump suction sodium pumps

DOEpatents

George, John A.; Nixon, Donald R.

1977-01-01

A circular plate extends across the diameter of "sump suction" pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level.

The numerical simulation based on CFD of hydraulic turbine pump

NASA Astrophysics Data System (ADS)

Duan, X. H.; Kong, F. Y.; Liu, Y. Y.; Zhao, R. J.; Hu, Q. L.

2016-05-01

As the functions of hydraulic turbine pump including self-adjusting and compensation with each other, it is far-reaching to analyze its internal flow by the numerical simulation based on CFD, mainly including the pressure field and the velocity field in hydraulic turbine and pump.The three-dimensional models of hydraulic turbine pump are made by Pro/Engineer software;the internal flow fields in hydraulic turbine and pump are simulated numerically by CFX ANSYS software. According to the results of the numerical simulation in design condition, the pressure field and the velocity field in hydraulic turbine and pump are analyzed respectively .The findings show that the static pressure decreases systematically and the pressure gradient is obvious in flow area of hydraulic turbine; the static pressure increases gradually in pump. The flow trace is regular in suction chamber and flume without spiral trace. However, there are irregular traces in the turbine runner channels which contrary to that in flow area of impeller. Most of traces in the flow area of draft tube are spiral.

MEMS Technology for Space Applications

NASA Technical Reports Server (NTRS)

vandenBerg, A.; Spiering, V. L.; Lammerink, T. S. J.; Elwenspoek, M.; Bergveld, P.

1995-01-01

Micro-technology enables the manufacturing of all kinds of components for miniature systems or micro-systems, such as sensors, pumps, valves, and channels. The integration of these components into a micro-electro-mechanical system (MEMS) drastically decreases the total system volume and mass. These properties, combined with the increasing need for monitoring and control of small flows in (bio)chemical experiments, makes MEMS attractive for space applications. The level of integration and applied technology depends on the product demands and the market. The ultimate integration is process integration, which results in a one-chip system. An example of process integration is a dosing system of pump, flow sensor, micromixer, and hybrid feedback electronics to regulate the flow. However, for many applications, a hybrid integration of components is sufficient and offers the advantages of design flexibility and even the exchange of components in the case of a modular set up. Currently, we are working on hybrid integration of all kinds of sensors (physical and chemical) and flow system modules towards a modular system; the micro total analysis system (micro TAS). The substrate contains electrical connections as in a printed circuit board (PCB) as well as fluid channels for a circuit channel board (CCB) which, when integrated, form a mixed circuit board (MCB).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xiaobing; Zheng, O'Neill; Niu, Fuxin

Most commercial ground source heat pump systems (GSHP) in the United States are in a distributed configuration. These systems circulate water or an anti-freeze solution through multiple heat pump units via a central pumping system, which usually uses variable speed pump(s). Variable speed pumps have potential to significantly reduce pumping energy use; however, the energy savings in reality could be far away from its potential due to improper pumping system design and controls. In this paper, a simplified hydronic pumping system was simulated with the dynamic Modelica models to evaluate three different pumping control strategies. This includes two conventional controlmore » strategies, which are to maintain a constant differential pressure across either the supply and return mains, or at the most hydraulically remote heat pump; and an innovative control strategy, which adjusts system flow rate based on the demand of each heat pump. The simulation results indicate that a significant overflow occurs at part load conditions when the variable speed pump is controlled to main a constant differential pressure across the supply and return mains of the piping system. On the other hand, an underflow occurs at part load conditions when the variable speed pump is controlled to maintain a constant differential pressure across the furthest heat pump. The flow-demand-based control can provide needed flow rate to each heat pump at any given time, and with less pumping energy use than the two conventional controls. Finally, a typical distributed GSHP system was studied to evaluate the energy saving potential of applying the flow-demand-based pumping control strategy. This case study shows that the annual pumping energy consumption can be reduced by 62% using the flow-demand-based control compared with that using the conventional pressure-based control to maintain a constant differential pressure a cross the supply and return mains.« less

Numerical investigation of the effect of number of blades on centrifugal pump performance

NASA Astrophysics Data System (ADS)

Kocaaslan, O.; Ozgoren, M.; Babayigit, O.; Aksoy, M. H.

2017-07-01

In this study, the flow structure in a centrifugal pump was numerically investigated for the different blade numbers in the impeller between 5 and 9. The pump used in the study is a single-stage horizontal shafted centrifugal pump. The original pump impeller was designed as 7 blades for the parameters of flow rate Q=100 mł/h, head Hm=180 kPa and revolution n=1480 rpm. First, models of impellers with the different blade numbers between 5 and 9 and the volute section of the centrifugal pump were separately drawn using Solidworks software. Later, grid structures were generated on the flow volume of the pump. Last, the flow analyses were performed and the flow characteristics under different operational conditions were determined numerically. In the numerical analyses, k-ɛ turbulence model and standard wall functions were used to solve turbulent flow. Balance holes and surface roughness, which adversely affect the hydraulic efficiency of pumps, were also considered. The obtained results of the analyses show that the hydraulic torque and head values have increased with the application of higher number of the impeller blades. For the impellers with 5 and 9 blades on the design flow rate of 100 mł/h (Q/Qd=1), the hydraulic torque and head were found 49/59.1 Nm and 153.1/184.4 kPa, respectively. Subsequently the hydraulic efficiencies of each pump were calculated. As a result, the highest hydraulic efficiency on the design flow rate was calculated as 54.16% for the pump impeller having 8 blades.

Experimental study on hydraulic characteristic around trash rack of a pumping station

NASA Astrophysics Data System (ADS)

Zhou, MinZhe; Li, TongChun; Lin, XiangYang; Liu, XiaoQing; Ding, Yuan; Liu, GuangYuan

2017-11-01

This paper focuses on flow pattern around trash rack of intake of a pumping station project. This pumping station undertake the task of supplying up to 3,500,000 m3 water per day for a megacity. Considering the large flow rate, high lift, multi-pipe supply and long-time operation in this water conveyance pumping station, we built a physical model test to measure the flow velocity and observe the flow pattern to verify the reasonability of preliminary design. In this test, we set 3 layers of current meters around each trash rack of intake in reservoir to collect the flow velocity. Furthermore, we design 2 operating conditions of 9 pumps to observe the change of flow pattern. Finally, we found the velocity data were in a normal range under 2 different operating conditions of the 9 pump units.

In Situ Local Fracture Flow Measurement by the Double Packer Dilution Test

NASA Astrophysics Data System (ADS)

Englert, A.; Le Borgne, T.; Bour, O.; Klepikova, M.; Lavenant, N.

2011-12-01

For prediction of flow and transport in fractured media, prior estimation of the fracture network is essential, but challenging. Recent developments in hydraulic tomography have shown promising results for understanding connectivities between boreholes. However, as the hydraulic tomographic survey is typically based on the propagation of head only, it becomes a strongly non unique problem. To reduce the non uniqueness of tomographic surveys point conditioning has been found beneficial. Just as well, measurement of local flow in a fracture can serve as point conditioning for hydraulic and tracer tomographic surveys. Nevertheless, only few measurements of local fracture flow have been performed since this type of measurements implies several important technical issues. Dilution test in a packed off interval is a possible method for measuring fracture flow (e.g. Drost et al. 1968, Novakowski et al., 2005). However, a key issue for estimating flow with dilution tests is to ensure a full mixing of the tracer in the packed interval. This is typically done by including a mixing system within the packer. The design of such system can be challenging for deep wells and small diameters. Here, we propose a method where mixing is ensured by a recirculation loop including a surface tank. This method is adapted from the design proposed by Brouyere et al. (2008), who measured dilution in open wells. Dilution is quantified by measuring the concentration in the surface barrel as function of time. Together with the measurement of the circulating flow and the water filled volume in the surface barrel, the measured tracer dilution allows for calculation of the fracture flow. Since the method can be applied using a classical double packer system, it may provide a broader application of local flow measurements in heterogeneous media. We tested the approach on the Ploemeur fractured crystalline rock site. A one meter interval at depth 80 m with a single flowing fracture was isolated with a double packer dilution system. We performed a pumping test in the adjacent well. Different flow rates were estimated from the dilution curves for the different pumping rates in the adjacent well, showing a linear response. The obtained fracture flow rates provide important information on the flow geometry and connectivity between the two wells. Future joint interpretation of flow measurements, hydraulic head and tracer test data is expected to provide detailed insights in the flow and transport processes at the Ploemeur site. Drost, W., Klotz, D., Koch, A., Moser, H., Neumaier, F., Rauert, W.: Point dilution methods of investigating ground water flow by means of radioisotopes, Water. Resour. Res., 4(1), 1968. Novakowski, K., Bickerton, G., Lapcevic, P., Voralek, J., Ross, N.: Measurements of groundwater velocity in discrete rock fractures: Jour. Cont. Hydr., 82(1-2), 2006. Brouyere, S., Batlle-Aguilar, J., Goderniaux, P., Dassargues, A.: A new tracer technique for monitoring groundwater fluxes: The Finite Volume Point Dilution Method, Jour. Cont. Hydr., 95(3-4), 121-140, 2008.

Hydrodynamic performance and heat generation by centrifugal pumps.

PubMed

Ganushchak, Y; van Marken Lichtenbelt, W; van der Nagel, T; de Jong, D S

2006-11-01

For over a century, centrifugal pumps (CP) have been used in various applications, from large industrial pumps to flow pumps for aquariums. However, the use of CP as blood pumps has a rather short history. Consequently, the hydraulic performance data for a blood CP are limited. The aim of our investigation was to study the hydraulic performance and the heat generation of three commercially available CP: Bio-Medicus Bio-Pump BP80 (Medtronic), Rotaflow (Jostra Medizintechnik), and DeltaStream DP2 (MEDOS Medizintechnik AQ). The study was performed using a circuit primed with a water-glycerin mixture with a dynamic viscosity of 0.00272 pa/s. Pressure-flow curves were obtained by a stepwise stagnation of the pump outlet or inlet. The temperature changes were observed using ThermaCAM SC2000 (Flir Systems). The pumps' performance in close to clinical conditions ('operating region') was analysed in this report. The 'operating region' in the case of the BP80 is positioned around the pressure-flow curve at a pump speed of 3000 rpm. In the case of the Rotaflow, the 'operating region' was between the pump pressure-flow curves at a speed of 3000 and 4000 rpm, and the DP2 was found between 7000 and 8000 rpm. The standard deviation of mean pressure through the pump was used to characterise the stability of the pump. In experiments with outlet stagnation, the BP80 demonstrated high negative association between flow and pressure variability (r = -0.68, p < 0.001). In experiments with the DP2, this association was positive (r = 0.68, p < 0.001). All pumps demonstrated significantly higher variability of pressure in experiments with inlet stagnation in comparison to the experiments with outlet stagnation. The rise of relative temperature in the inlet of a pump was closely related to the flow rate. The heating of fluid was more pronounced in the 'zero-flow' mode, especially in experiments with inlet stagnation. In summary, (1) the 'zero-flow' regime, which is described in the manuals of some commercially-available pumps, is the use of the pump outside the allowable operating region. It is potentially dangerous and should, therefore, never be used in clinical settings. (2) Using centrifugal pumps for kinetic-assisted venous return can only be performed safely when the negative pressure at the inlet of the pump is monitored continuously. The maximum allowable negative pressure has to be defined for each type of pump, and must be based on pump performance.

SHINE Vacuum Pump Test Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, Gregg A; Peters, Brent

2013-09-30

Normetex pumps used world-wide for tritium service are no longer available. DOE and other researchers worldwide have spent significant funds characterizing this pump. Identification of alternate pumps is required for performance and compatibility with tritium gas. Many of the pumps that could be used to meet the functional performance requirements (e.g. pressure and flow conditions) of the Normetex pump have features that include the use of polymers or oils and greases that are not directly compatible with tritium service. This study assembles a test system to determine the flow characteristics for candidate alternate pumps. These tests are critical to themore » movement of tritium through the SHINE Tritium Purification System (TPS). The purpose of the pump testing is two-fold: (1) obtain baseline vacuum pump characteristics for an alternate (i.e. ''Normetex replacement'') pump intended for use in tritium service; and (2) verify that low pressure hydrogen gas can be transported over distances up to 300 feet by the candidate pumps. Flow rates and nominal system pressures have been identified for the SHINE Mo-99 production process Tritium Purification System (TPS). To minimize the line sizes for the transfer of low pressure tritium from the Neutron Driver Accelerator System (NDAS) to the primary processing systems in the TPS, a ''booster'' pump has been located near the accelerator in the design. A series of pump tests were performed at various configurations using hydrogen gas (no tritium) to ensure that this concept is practical and maintains adequate flow rates and required pressures. This report summarizes the results of the tests that have been performed using various pump configurations. The current design of the Tritium Purification System requires the ''booster'' pump to discharge to or to be backed by another vacuum pump. Since Normetex pumps are no longer manufactured, a commercially available Edwards scroll pump will be used to back the booster pump. In this case the ''booster pump'' is an Adixen Molecular Drag Pump (MDP 5011) and the backing pump is an Edwards (nXDS15iC) scroll pump. Various configurations of the two pumps and associated lengths of 3/4 inch tubing (0 feet to 300 feet) were used in combination with hydrogen and nitrogen flow rates ranging from 25-400 standard cubic centimeters per minute (sccm) to determine whether the proposed pump configuration meets the design criteria for SHINE. The results of this study indicate that even under the most severe conditions (300 feet of tubing and 400 sccm flow rate) the Adixen 5011 MDP can serve as a booster pump to transport gases from the accelerator (NDAS) to the TPS. The Target Gas Receiving System pump (Edwards nXDS15iC) located approximately 300 feet from the accelerator can effectively back the Adixen MDP. The molecular drag pump was able to maintain its full rotational speed even when the flow rate was 400 sccm hydrogen or nitrogen and 300 feet of tubing was installed between the drag pump and the Edwards scroll pump. In addition to maintaining adequate rotation, the pressure in the system was maintained below the target pressure of 30 torr for all flow rates, lengths of tubing, and process gases. This configuration is therefore adequate to meet the SHINE design requirements in terms of flow and pressure.« less

In vivo study of flow-rate accuracy of the MedStream Programmable Infusion System.

PubMed

Venugopalan, Ramakrishna; Ginggen, Alec; Bork, Toralf; Anderson, William; Buffen, Elaine

2011-01-01

  Flow-rate accuracy and precision are important parameters to optimizing the efficacy of programmable intrathecal (IT) infusion pump delivery systems. Current programmable IT pumps are accurate within ±14.5% of their programmed infusion rate when assessed under ideal environmental conditions and specific flow-rate settings in vitro. We assessed the flow-rate accuracy of a novel programmable pump system across its entire flow-rate range under typical conditions in sheep (in vivo) and nominal conditions in vitro.   The flow-rate accuracy of the MedStream Programmable Pump was assessed in both the in vivo and in vitro settings. In vivo flow-rate accuracy was assessed in 16 sheep at various flow-rates (producing 90 flow intervals) more than 90 ± 3 days. Pumps were then explanted, re-sterilized and in vitro flow-rate accuracy was assessed at 37°C and 1013 mBar (80 flow intervals).   In vivo (sheep body temperatures 38.1°C-39.8°C), mean ± SD flow-rate error was 9.32% ± 9.27% and mean ± SD leak-rate was 0.028 ± 0.08 mL/day. Following explantation, mean in vitro flow-rate error and leak-rate were -1.05% ± 2.55% and 0.003 ± 0.004 mL/day (37°C, 1013 mBar), respectively.   The MedStream Programmable Pump demonstrated high flow-rate accuracy when tested in vivo and in vitro at normal body temperature and environmental pressure as well as when tested in vivo at variable sheep body temperature. The flow-rate accuracy of the MedStream Programmable Pump across its flow-rate range, compares favorably to the accuracy of current clinically utilized programmable IT infusion pumps reported at specific flow-rate settings and conditions. © 2011 International Neuromodulation Society.

Electroosmotic pumps for microflow analysis

PubMed Central

Wang, Xiayan; Wang, Shili; Gendhar, Brina; Cheng, Chang; Byun, Chang Kyu; Li, Guanbin; Zhao, Meiping; Liu, Shaorong

2009-01-01

With rapid development in microflow analysis, electroosmotic pumps are receiving increasing attention. Compared to other micropumps, electroosmotic pumps have several unique features. For example, they are bi-directional, can generate constant and pulse-free flows with flow rates well suited to microanalytical systems, and can be readily integrated with lab-on-chip devices. The magnitude and the direction of flow of an electroosmotic pump can be changed instantly. In addition, electroosmotic pumps have no moving parts. In this article, we discuss common features, introduce fabrication technologies and highlight applications of electroosmotic pumps. PMID:20047021

Porous glass electroosmotic pumps: design and experiments.

PubMed

Yao, Shuhuai; Hertzog, David E; Zeng, Shulin; Mikkelsen, James C; Santiago, Juan G

2003-12-01

An analytical model for electroosmotic flow rate, total pump current, and thermodynamic efficiency reported in a previous paper has been applied as a design guideline to fabricate porous-structure EO pumps. We have fabricated sintered-glass EO pumps that provide maximum flow rates and pressure capacities of 33 ml/min and 1.3 atm, respectively, at applied potential 100 V. These pumps are designed to be integrated with two-phase microchannel heat exchangers with load capacities of order 100 W and greater. Experiments were conducted with pumps of various geometries and using a relevant, practical range of working electrolyte ionic concentration. Characterization of the pumping performance are discussed in the terms of porosity, tortuosity, pore size, and the dependence of zeta potential on bulk ion density of the working solution. The effects of pressure and flow rate on pump current and thermodynamic efficiency are analyzed and compared to the model prediction. In particular, we explore the important tradeoff between increasing flow rate capacity and obtaining adequate thermodynamic efficiency. This research aims to demonstrate the performance of EOF pump systems and to investigate optimal and practical pump designs. We also present a gas recombination device that makes possible the implementation of this pumping technology into a closed-flow loop where electrolytic gases are converted into water and reclaimed by the system.

Microfluidic perfusion system for automated delivery of temporal gradients to islets of Langerhans.

PubMed

Zhang, Xinyu; Roper, Michael G

2009-02-01

A microfluidic perfusion system was developed for automated delivery of stimulant waveforms to cells within the device. The 3-layer glass/polymer device contained two pneumatic pumps, a 12 cm mixing channel, and a 0.2 microL cell chamber. By altering the flow rate ratio of the pumps, a series of output concentrations could be produced while a constant 1.43 +/- 0.07 microL/min flow rate was maintained. The output concentrations could be changed in time producing step gradients and other waveforms, such as sine and triangle waves, at different amplitudes and frequencies. Waveforms were analyzed by comparing the amplitude of output waveforms to the amplitude of theoretical waveforms. Below a frequency of 0.0098 Hz, the output waveforms had less than 20% difference than input waveforms. To reduce backflow of solutions into the pumps, the operational sequence of the valving program was modified, as well as differential etching of the valve seat depths. These modifications reduced backflow to the point that it was not detected. Gradients in glucose levels were applied in this work to stimulate single islets of Langerhans. Glucose gradients between 3 and 20 mM brought clear and intense oscillations of intracellular [Ca(2+)] indicating the system will be useful in future studies of cellular physiology.

Sealing properties of mechanical seals for an axial flow blood pump.

PubMed

Tomioka, J; Mori, T; Yamazaki, K; Koyanagi, H

1999-08-01

A miniature intraventricular axial flow blood pump for left ventricular support is under development. One of the key technologies required for such pumps is sealing of the motor shaft. In this study, to prevent blood backflow into the motor side, mechanical seals were developed and their sealing properties investigated. In the experimental apparatus, the mechanical seal separated the bovine blood on the chamber side from the cooling water on the motor side. A leakage of the blood was measured by inductively coupled plasma (ICP) light emission analysis. The rate of hemolysis was measured by the cyanmethemoglobin method. Frictional torque acting on the shaft was measured by a torque transducer. In the experiments, the rotational speed of the shaft was changed from 1,000 to 10,000 rpm, and the contact force of the seal faces was changed from 1.96 to 4.31 N. To estimate lubrication regimes, the Stribeck curve, a diagram of the coefficient of friction against the bearing characteristic G number, was drawn. The results of the experiments showed that both the leakage of blood and the rate of hemolysis were very small. The friction loss was also very small. The mechanical seal was operated in various lubrication regimes, from a fluid lubrication regime to a mixed lubrication regime.

PediaFlow™ Maglev Ventricular Assist Device: A Prescriptive Design Approach.

PubMed

Antaki, James F; Ricci, Michael R; Verkaik, Josiah E; Snyder, Shaun T; Maul, Timothy M; Kim, Jeongho; Paden, Dave B; Kameneva, Marina V; Paden, Bradley E; Wearden, Peter D; Borovetz, Harvey S

2010-03-01

This report describes a multi-disciplinary program to develop a pediatric blood pump, motivated by the critical need to treat infants and young children with congenital and acquired heart diseases. The unique challenges of this patient population require a device with exceptional biocompatibility, miniaturized for implantation up to 6 months. This program implemented a collaborative, prescriptive design process, whereby mathematical models of the governing physics were coupled with numerical optimization to achieve a favorable compromise among several competing design objectives. Computational simulations of fluid dynamics, electromagnetics, and rotordynamics were performed in two stages: first using reduced-order formulations to permit rapid optimization of the key design parameters; followed by rigorous CFD and FEA simulations for calibration, validation, and detailed optimization. Over 20 design configurations were initially considered, leading to three pump topologies, judged on the basis of a multi-component analysis including criteria for anatomic fit, performance, biocompatibility, reliability, and manufacturability. This led to fabrication of a mixed-flow magnetically levitated pump, the PF3, having a displaced volume of 16.6 cc, approximating the size of a AA battery and producing a flow capacity of 0.3-1.5 L/min. Initial in vivo evaluation demonstrated excellent hemocompatibility after 72 days of implantation in an ovine. In summary, combination of prescriptive and heuristic design principles have proven effective in developing a miniature magnetically levitated blood pump with excellent performance and biocompatibility, suitable for integration into chronic circulatory support system for infants and young children; aiming for a clinical trial within 3 years.

Analytical study of mixed electroosmotic-pressure-driven flow in rectangular micro-channels

NASA Astrophysics Data System (ADS)

Movahed, Saeid; Kamali, Reza; Eghtesad, Mohammad; Khosravifard, Amir

2013-09-01

Operational state of many miniaturized devices deals with flow field in microchannels. Pressure-driven flow (PDF) and electroosmotic flow (EOF) can be recognized as the two most important types of the flow field in such channels. EOF has many advantages in comparison with PDF, such as being vibration free and not requiring any external mechanical pumps or moving parts. However, the disadvantages of this type of flow such as Joule heating, electrophoresis demixing, and not being suitable for mobile devices must be taken into consideration carefully. By using mixed electroosmotic/pressure-driven flow, the role of EOF in producing desired velocity profile will be reduced. In this way, the advantages of EOF can be exploited, and its disadvantages can be prevented. Induced pressure gradient can be utilized in order to control the separation in the system. Furthermore, in many complicated geometries such as T-shape microchannels, turns may induce pressure gradient to the electroosmotic velocity. While analytical formulas are completely essential for analysis and control of any industrial and laboratory microdevices, lack of such formulas in the literature for solving Poisson-Boltzmann equation and predicting electroosmotic velocity field in rectangular domains is evident. In the present study, first a novel method is proposed to solve Poisson-Boltzmann equation (PBE). Subsequently, this solution is utilized to find the electroosmotic and the mixed electroosmotic/pressure-driven velocity profile in a rectangular domain of the microchannels. To demonstrate the accuracy of the presented analytical method in solving PBE and finding electroosmotic velocity, a general nondimensional example is analyzed, and the results are compared with the solution of boundary element method. Additionally, the effects of different nondimensional parameters and also aspect ratio of channels on the electroosmotic part of the flow field will be investigated.

Oceanographic, Air-sea Interaction, and Environmental Aspects of Artificial Upwelling Produced by Wave-Inertia Pumps for Potential Hurricane Intensity Mitigation

NASA Astrophysics Data System (ADS)

Soloviev, A.; Dean, C.

2017-12-01

The artificial upwelling system consisting of the wave-inertia pumps driven by surface waves can produce flow of cold deep water to the surface. One of the recently proposed potential applications of the artificial upwelling system is the hurricane intensity mitigation. Even relatively small reduction of intensity may provide significant benefits. The ocean heat content (OHC) is the "fuel" for hurricanes. The OHC can be reduced by mixing of the surface layer with the cold water produced by wave-inertia pumps. Implementation of this system for hurricane mitigation has several oceanographic and air-sea interaction aspects. The cold water brought to the surface from a deeper layer has higher density than the surface water and, therefore, tends to sink back down. The mixing of the cold water produced by artificial upwelling depends on environmental conditions such as stratification, regional ocean circulation, and vertical shear. Another aspect is that as the sea surface temperature drops below the air temperature, the stable stratification develops in the atmospheric boundary layer. The stable atmospheric stratification suppresses sensible and latent heat air-sea fluxes and reduces the net longwave irradiance from the sea surface. As a result, the artificial upwelling may start increasing the OHC (though still reducing the sea surface temperature). In this work, the fate of the cold water in the stratified environment with vertical shear has been studied using computational fluid dynamics (CFD) tools. A 3D large eddy simulation model is initialized with observational temperature, salinity, and current velocity data from a sample location in the Straits of Florida. A periodic boundary condition is set along the direction of the current, which allows us to simulate infinite fetch. The model results indicate that the cold water brought to the sea surface by a wave-inertia pump forms a convective jet. This jet plunges into the upper ocean mixed layer and penetrates the thermocline. On the way down, the jet partially mixes with the surrounding water reducing the temperature of the upper ocean. The OHC thus can either reduce or increase, depending on the wave-inertia pump parameters. Based on the model results, we discuss feasibility of the implementation of the artificial upwelling system for hurricane intensity mitigation.

Incompressible viscous flow computations for the pump components and the artificial heart

NASA Technical Reports Server (NTRS)

Kiris, Cetin

1992-01-01

A finite-difference, three-dimensional incompressible Navier-Stokes formulation to calculate the flow through turbopump components is utilized. The solution method is based on the pseudocompressibility approach and uses an implicit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. Both steady and unsteady flow calculations can be performed using the current algorithm. In this work, the equations are solved in steadily rotating reference frames by using the steady-state formulation in order to simulate the flow through a turbopump inducer. Eddy viscosity is computed by using an algebraic mixing-length turbulence model. Numerical results are compared with experimental measurements and a good agreement is found between the two. Included in the appendix is a paper on incompressible viscous flow through artificial heart devices with moving boundaries. Time-accurate calculations, such as impeller and diffusor interaction, will be reported in future work.

Electric analog of three-dimensional flow to wells and its application to unconfined aquifers

USGS Publications Warehouse

Stallman, Robert W.

1963-01-01

Electric-analog design criteria are established from the differential equations of ground-water flow for analyzing pumping-test data. A convenient analog design was obtained by transforming the cylindrical equation of flow to a rectilinear form. The design criteria were applied in the construction of an electric analog, which was used for studying pumping-test data collected near Grand Island, Nebr. Data analysis indicated (1) vertical flow components near pumping wells in unconfined aquifers may be much more significant in the control of water-table decline than radial flow components for as much as a day of pumping; (2) the specific yield during the first few minutes of pumping appears to be a very small fraction of that observed after pumping for more than 1 day; and (3) estimates of specific yield made from model studies seem much more sensitive to variations in assumed flow conditions than are estimates of permeability. Analysis of pumping-test data where vertical flow components are important requires that the degree of anisotropy be known. A procedure for computing anisotropy directly from drawdowns observed at five points was developed. Results obtained in the analog study emphasize the futility of calculating unconfined aquifer properties from pumping tests of short duration by means of equations based on the assumptions that vertical flow components are negligible and specific yield is constant.

Experimental analysis of flow structure in contra-rotating axial flow pump designed with different rotational speed concept

NASA Astrophysics Data System (ADS)

Cao, Linlin; Watanabe, Satoshi; Imanishi, Toshiki; Yoshimura, Hiroaki; Furukawa, Akinori

2013-08-01

As a high specific speed pump, the contra-rotating axial flow pump distinguishes itself in a rear rotor rotating in the opposite direction of the front rotor, which remarkably contributes to the energy conversion, the reduction of the pump size, better hydraulic and cavitation performances. However, with two rotors rotating reversely, the significant interaction between blade rows was observed in our prototype contra-rotating rotors, which highly affected the pump performance compared with the conventional axial flow pumps. Consequently, a new type of rear rotor was designed by the rotational speed optimization methodology with some additional considerations, aiming at better cavitation performance, the reduction of blade rows interaction and the secondary flow suppression. The new rear rotor showed a satisfactory performance at the design flow rate but an unfavorable positive slope of the head — flow rate curve in the partial flow rate range less than 40% of the design flow rate, which should be avoided for the reliability of pump-pipe systems. In the present research, to understand the internal flow field of new rear rotor and its relation to the performances at the partial flow rates, the velocity distributions at the inlets and outlets of the rotors are firstly investigated. Then, the boundary layer flows on rotor surfaces, which clearly reflect the secondary flow inside the rotors, are analyzed through the limiting streamline observations using the multi-color oil-film method. Finally, the unsteady numerical simulations are carried out to understand the complicated internal flow structures in the rotors.

Design and Construction of Aquaculture Facilities in Dredged Material Containment Areas

DTIC Science & Technology

1993-07-01

detail. The following discussion of centrifugal and axial flow pumps is adapted from Wheaton (1977), Baker (1987), and Baker and Bankston (1988...at a right angle to the impeller shaft. Axial flow propeller pumps are also used, especially in high-volume low-lift situations. The propeller may look...horizontal centrifugal pump or the axial flow pump may be used. Both of these pumps provide large volumes of water under low head conditions. Many

Experimental and numerical investigation of a scaled-up passive micromixer using fluorescence technique

NASA Astrophysics Data System (ADS)

Fan, Yanfeng; Hassan, Ibrahim

2010-09-01

The present paper investigates experimentally and numerically a scaled-up micromixer that combines the mixing principles of focusing/diverging and flow split-and-recombine. The micromixer consists of two units called “cross” and “omega”, which are similar to a zigzag structure. The total length is 199.5 mm with a depth of 3 mm. Fluorescence technique is used in the present study for local quantitative measurements of concentration. Two syringe pumps are used to supply the working fluids at two inlets. The testing range of Reynolds number is at 1 ≤ Re ≤ 50. The results of the experiment, obtained by fluorescence technique, are supported by the mixing visualization. The experimental results show that the mixing efficiency decreases at Re ≤ 10 and increases at Re ≥ 10. This is caused by the change in mixing mechanism from mass-diffusion domination to mass-convection domination. After five cells, the mixing efficiency reaches to 70% at Re = 50. The computational fluid dynamics is applied to assist in the understanding of fluid characteristics in channels. The simulation has a good agreement with the experiment. Based on the simulation results, vortices are observed in the channels at high Re, which could stretch and fold the fluids to enhance the effect of mass-convection on mixing. This design has the potential to be developed for micromixers with high flow rates.

Field emission microplasma actuation for microchannel flows

NASA Astrophysics Data System (ADS)

Sashank Tholeti, Siva; Shivkumar, Gayathri; Alexeenko, Alina A.

2016-06-01

Microplasmas offer attractive flow control methodology for gas transport in microsystems where large viscous losses make conventional pumping methods highly inefficient. We study microscale flow actuation by dielectric-barrier discharge (DBD) with field emission (FE) of electrons, which allows lowering the operational voltage from kV to a few hundred volts and below. A feasibility study of FE-DBD for flow actuation is performed using 2D particle-in-cell method with Monte Carlo collisions (PIC/MCC) at 10 MHz in nitrogen at atmospheric pressure. The free diffusion dominated, high velocity field emission electrons create a large positive space charge and a body force on the order of 106 N m-3. The body force and Joule heat decrease with increase in dielectric thickness and electrode thickness. The body force also decreases at lower pressures. The plasma body force distribution along with the Joule heating is then used in the Navier-Stokes simulations to quantify the flow actuation in a microchannel. Theoretical analysis and simulations for plasma actuated planar Poiseuille flow show that the gain in flow rate is inversely proportional to Reynolds number. This theoretical analysis is in good agreement with the simulations for a microchannel with closely placed actuators under incompressible conditions. Flow rate of FE-DBD driven 2D microchannel is around 100 ml min-1 mm-1 for an input power of 64 μW mm-1. The gas temperature rises by 1500 K due to the Joule heating, indicating FE-DBD’s potential for microcombustion, micropropulsion and chemical sensing in addition to microscale pumping and mixing applications.

Differential atmospheric tritium sampler

DOEpatents

Griesbach, O.A.; Stencel, J.R.

1987-10-02

An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The moisture then passes through a combustion chamber where hydrogen gas in the form of H/sub 2/ or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

Differential atmospheric tritium sampler

DOEpatents

Griesbach, Otto A.; Stencel, Joseph R.

1990-01-01

An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The mixture then passes through a combustion chamber where hydrogen gas in the form of H.sub.2 or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

Three-dimensional flow in the Florida platform: Theoretical analysis of Kohout convection at its type locality

USGS Publications Warehouse

Hughes, J.D.; Vacher, H. Leonard; Sanford, W.E.

2007-01-01

Kohout convection is the name given to the circulation of saline groundwater deep within carbonate platforms, first proposed by F.A. Kohout in the 1960s for south Florida. It is now seen as an Mg pump for dolomitization by seawater. As proposed by Kohout, cold seawater is drawn into the Florida platform from the deep Straits of Florida as part of a geothermally driven circulation in which the seawater then rises in the interior of the platform to mix and exit with the discharging meteoric water of the Floridan aquifer system. Simulation of the asymmetrically emergent Florida platform with the new three-dimensional (3-D), finite-element groundwater flow and transport model SUTRA-MS, which couples salinity- and temperature-dependent density variations, allows analysis of how much of the cyclic flow is due to geothermal heating (free convection) as opposed to mixing with meteoric water discharging to the shoreline (forced convection). Simulation of the system with and without geothermal heating reveals that the inflow of seawater from the Straits of Florida would be similar without the heat flow, but the distribution would differ significantly. The addition of heat flow reduces the asymmetry of the circulation: it decreases seawater inflows on the Atlantic side by 8% and on the Guff of Mexico side by half. The study illustrates the complex interplay of freshwater-saltwater mixing, geothermal heat flow, and projected dolomitization in complicated 3-D settings with asymmetric boundary conditions and realistic horizontal and vertical variations in hydraulic properties. ?? 2007 The Geological Society of America.

A simulation-based study on different control strategies for variable speed pump in distributed ground source heat pump systems

DOE PAGES

Liu, Xiaobing; Zheng, O'Neill; Niu, Fuxin

2016-01-01

Most commercial ground source heat pump systems (GSHP) in the United States are in a distributed configuration. These systems circulate water or an anti-freeze solution through multiple heat pump units via a central pumping system, which usually uses variable speed pump(s). Variable speed pumps have potential to significantly reduce pumping energy use; however, the energy savings in reality could be far away from its potential due to improper pumping system design and controls. In this paper, a simplified hydronic pumping system was simulated with the dynamic Modelica models to evaluate three different pumping control strategies. This includes two conventional controlmore » strategies, which are to maintain a constant differential pressure across either the supply and return mains, or at the most hydraulically remote heat pump; and an innovative control strategy, which adjusts system flow rate based on the demand of each heat pump. The simulation results indicate that a significant overflow occurs at part load conditions when the variable speed pump is controlled to main a constant differential pressure across the supply and return mains of the piping system. On the other hand, an underflow occurs at part load conditions when the variable speed pump is controlled to maintain a constant differential pressure across the furthest heat pump. The flow-demand-based control can provide needed flow rate to each heat pump at any given time, and with less pumping energy use than the two conventional controls. Finally, a typical distributed GSHP system was studied to evaluate the energy saving potential of applying the flow-demand-based pumping control strategy. This case study shows that the annual pumping energy consumption can be reduced by 62% using the flow-demand-based control compared with that using the conventional pressure-based control to maintain a constant differential pressure a cross the supply and return mains.« less

Engine lubrication circuit including two pumps

DOEpatents

Lane, William H.

2006-10-03

A lubrication pump coupled to the engine is sized such that the it can supply the engine with a predetermined flow volume as soon as the engine reaches a peak torque engine speed. In engines that operate predominately at speeds above the peak torque engine speed, the lubrication pump is often producing lubrication fluid in excess of the predetermined flow volume that is bypassed back to a lubrication fluid source. This arguably results in wasted power. In order to more efficiently lubricate an engine, a lubrication circuit includes a lubrication pump and a variable delivery pump. The lubrication pump is operably coupled to the engine, and the variable delivery pump is in communication with a pump output controller that is operable to vary a lubrication fluid output from the variable delivery pump as a function of at least one of engine speed and lubrication flow volume or system pressure. Thus, the lubrication pump can be sized to produce the predetermined flow volume at a speed range at which the engine predominately operates while the variable delivery pump can supplement lubrication fluid delivery from the lubrication pump at engine speeds below the predominant engine speed range.

Numerical Investigation of Transient Flow in a Prototype Centrifugal Pump during Startup Period

NASA Astrophysics Data System (ADS)

Zhang, Yu-Liang; Zhu, Zu-Chao; Dou, Hua-Shu; Cui, Bao-Ling; Li, Yi; Zhou, Zhao-Zhong

2017-05-01

Transient performance of pumps during transient operating periods, such as startup and stopping, has drawn more and more attentions recently due to the growing engineering needs. During the startup period of a pump, the performance parameters such as the flow rate and head would vary significantly in a broad range. Therefore, it is very difficult to accurately specify the unsteady boundary conditions for a pump alone to solve the transient flow in the absence of experimental results. The closed-loop pipe system including a centrifugal pump is built to accomplish the self-coupling calculation. The three-dimensional unsteady incompressible viscous flow inside the passage of the pump during startup period is numerically simulated using the dynamic mesh method. Simulation results show that there are tiny fluctuations in the flow rate even under stable operating conditions and this can be attributed to influence of the rotor-stator interaction. At the very beginning of the startup, the rising speed of the flow rate is lower than that of the rotational speed. It is also found that it is not suitable to predict the transient performance of pumps using the calculation method of quasi-steady flow, especially at the earlier period of the startup.

A microfluidic direct formate fuel cell on paper.

PubMed

Copenhaver, Thomas S; Purohit, Krutarth H; Domalaon, Kryls; Pham, Linda; Burgess, Brianna J; Manorothkul, Natalie; Galvan, Vicente; Sotez, Samantha; Gomez, Frank A; Haan, John L

2015-08-01

We describe the first direct formate fuel cell on a paper microfluidic platform. In traditional membrane-less microfluidic fuel cells (MFCs), external pumping consumes power produced by the fuel cell in order to maintain co-laminar flow of the anode stream and oxidant stream to prevent mixing. However, in paper microfluidics, capillary action drives flow while minimizing stream mixing. In this work, we demonstrate a paper MFC that uses formate and hydrogen peroxide as the anode fuel and cathode oxidant, respectively. Using these materials we achieve a maximum power density of nearly 2.5 mW/mg Pd. In a series configuration, our MFC achieves an open circuit voltage just over 1 V, and in a parallel configuration, short circuit of 20 mA absolute current. We also demonstrate that the MFC does not require continuous flow of fuel and oxidant to produce power. We found that we can pre-saturate the materials on the paper, stop the electrolyte flow, and still produce approximately 0.5 V for 15 min. This type of paper MFC has potential applications in point-of-care diagnostic devices and other electrochemical sensors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flow determination of a pump-turbine at zero discharge

NASA Astrophysics Data System (ADS)

Edinger, G.; Erne, S.; Doujak, E.; Bauer, C.

2014-03-01

When starting up a reversible Francis pump-turbine in pump mode, the machine may operate at zero flow at a given gate opening. Besides reversal flow and prerotation in the draft tube cone, the onset of a fully separated flow in the vaned diffuser is observable at zero- discharge condition. In this paper, the occurrence of prerotation and reversal flow in the conical draft tube and the flow in one stay vane channel of a pump-turbine are examined experimentally and compared to numerical simulations. In order to assess the strongly three-dimensional flow in the stay vane channel, measurements with a 2D laser doppler velocimeter (LDV) were performed at various positions. The inlet flow in the draft tube cone, which becomes significantly at zero discharge in pump mode, is investigated by velocity measurements at two different positions. Pressure fluctuations in the draft tube cone induced by complex flow patterns are also recorded and analyzed. It is found that the swirl number at zero discharge does not significant differ from the values obtained at very low load pumping. Experimental investigations combined with CFD have shown that in the stay vane channel flow velocity components different from zero occur even at no discharge. Streamline plots show the fully separated flow structure.

Observation of motion of colloidal particles undergoing flowing Brownian motion using self-mixing laser velocimetry with a thin-slice solid-state laser.

PubMed

Sudo, S; Ohtomo, T; Otsuka, K

2015-08-01

We achieved a highly sensitive method for observing the motion of colloidal particles in a flowing suspension using a self-mixing laser Doppler velocimeter (LDV) comprising a laser-diode-pumped thin-slice solid-state laser and a simple photodiode. We describe the measurement method and the optical system of the self-mixing LDV for real-time measurements of the motion of colloidal particles. For a condensed solution, when the light scattered from the particles is reinjected into the solid-state laser, the laser output is modulated in intensity by the reinjected laser light. Thus, we can capture the motion of colloidal particles from the spectrum of the modulated laser output. For a diluted solution, when the relaxation oscillation frequency coincides with the Doppler shift frequency, f_d, which is related to the average velocity of the particles, the spectrum reflecting the motion of the colloidal particles is enhanced by the resonant excitation of relaxation oscillations. Then, the spectral peak reflecting the motion of colloidal particles appears at 2×f_d. The spectrum reflecting the motion of colloidal particles in a flowing diluted solution can be measured with high sensitivity, owing to the enhancement of the spectrum by the thin-slice solid-state laser.

Experimental and analytical study of loss-of-flow transients in EBR-II occurring at decay power levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, L.K.; Mohr, D.; Feldman, E.E.

A series of eight loss-of-flow (LOF) tests have been conducted in EBR-II to study the transition between forced and natural convective flows following a variety of loss-of-primary-pumping power conditions from decay heat levels. Comparisons of measurements and pretest/posttest predictions were made on a selected test. Good agreements between measurements and predictions was found prior to and just after the flow reaching its minimum, but the agreement is not as good after that point. The temperatures are consistent with the flow response and the assumed decay power. The measured results indicate that the flows of driver and the instrumented subassemblies aremore » too much in the analytical model in the natural convective region. Although a parametric study on secondary flow, turbulent-laminar flow transition, heat transfer ability of the intermediate heat exchange at low flow and flow mixing in the primary tank has been performed to determine their effects on the flow, the cause of the discrepancy at very low flow level is still unknown.« less

Laser and thermal properties of Nd:YGd2Sc2Al2GaO12 garnet ceramic Laser and thermal properties of Nd:YSGG garnet ceramic

NASA Astrophysics Data System (ADS)

Brenier, A.; Alombert-Goget, G.; Guyot, Y.; Boulon, G.

2012-10-01

The absorption and fluorescence properties of the Nd-doped YGd2Sc2Al2GaO12 mixed garnet ceramics have been measured at different temperatures. Under laser diode pumping an efficient laser emission has been demonstrated with 45% slope efficiency. The emission is constituted by two lines at 1058.6 and 1061.3 nm, subjected to a red shift and a variable relative intensity versus pump power. The role of the temperature has been investigated playing with the cavity parameters. The thermal conductivity of the 1% Nd-doped material has been determined (3.2 W/m/K) measuring the radial temperature distribution of the exit face of the sample including the axial heat flow in the analysis. The M2 beam quality factor and the dioptric power of the thermal lens have been investigated versus the pump power. The thermo-optic coefficient χ was determined as 44.4×10-6 K-1.

Numerical analysis of rotating stall instabilities of a pump- turbine in pump mode

NASA Astrophysics Data System (ADS)

Xia, L. S.; Cheng, Y. G.; Zhang, X. X.; Yang, J. D.

2014-03-01

Rotating stall may occur at part load flow of a pump-turbine in pump mode. Unstable flow structures developing under stall condition can lead to a sudden drop of efficiency, high dynamic load and even cavitation. CFD simulations on a pump-turbine model in pump mode were carried out to reveal the onset and developed mechanisms of these unstable flow phenomena at part load. The simulation results of energy-discharge and efficiency characteristics are in good agreement with those obtained by experiments. The more deviate from design conditions with decreasing flow rate, the more flow separations within the vanes. Under specific conditions, four stationary separation zones begin to progress on the circumference, rotating at a fraction of the impeller rotation rate. Rotating stalls lead to the flow in the vane diffuser channels alternating between outward jet flow and blockage. Strong jets impact the spiral casing wall causing high pressure pulsations. Severe separations of the stall cells disturb the flow inducing periodical large amplitude pressure fluctuations, of which the intensity at different span wise of the guide vanes is different. The enforced rotating nonuniform pressure distributions on the circumference lead to dynamic uniform forces on the impeller and guide vanes. The results show that the CFD simulations are capable to gain the complicated flow structure information for analysing the unstable characteristics of the pump mode at part load.

Method, system and computer program product for monitoring and optimizing fluid extraction from geologic strata

DOEpatents

Medizade, Masoud [San Luis Obispo, CA; Ridgely, John Robert [Los Osos, CA

2009-12-15

An arrangement which utilizes an inexpensive flap valve/flow transducer combination and a simple local supervisory control system to monitor and/or control the operation of a positive displacement pump used to extract petroleum from geologic strata. The local supervisory control system controls the operation of an electric motor which drives a reciprocating positive displacement pump so as to maximize the volume of petroleum extracted from the well per pump stroke while minimizing electricity usage and pump-off situations. By reducing the electrical demand and pump-off (i.e., "pounding" or "fluid pound") occurrences, operating and maintenance costs should be reduced sufficiently to allow petroleum recovery from marginally productive petroleum fields. The local supervisory control system includes one or more applications to at least collect flow signal data generated during operation of the positive displacement pump. No flow, low flow and flow duration are easily evaluated using the flap valve/flow transducer arrangement.

Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

PubMed

Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

Control of reactor coolant flow path during reactor decay heat removal

DOEpatents

Hunsbedt, Anstein N.

1988-01-01

An improved reactor vessel auxiliary cooling system for a sodium cooled nuclear reactor is disclosed. The sodium cooled nuclear reactor is of the type having a reactor vessel liner separating the reactor hot pool on the upstream side of an intermediate heat exchanger and the reactor cold pool on the downstream side of the intermediate heat exchanger. The improvement includes a flow path across the reactor vessel liner flow gap which dissipates core heat across the reactor vessel and containment vessel responsive to a casualty including the loss of normal heat removal paths and associated shutdown of the main coolant liquid sodium pumps. In normal operation, the reactor vessel cold pool is inlet to the suction side of coolant liquid sodium pumps, these pumps being of the electromagnetic variety. The pumps discharge through the core into the reactor hot pool and then through an intermediate heat exchanger where the heat generated in the reactor core is discharged. Upon outlet from the heat exchanger, the sodium is returned to the reactor cold pool. The improvement includes placing a jet pump across the reactor vessel liner flow gap, pumping a small flow of liquid sodium from the lower pressure cold pool into the hot pool. The jet pump has a small high pressure driving stream diverted from the high pressure side of the reactor pumps. During normal operation, the jet pumps supplement the normal reactor pressure differential from the lower pressure cold pool to the hot pool. Upon the occurrence of a casualty involving loss of coolant pump pressure, and immediate cooling circuit is established by the back flow of sodium through the jet pumps from the reactor vessel hot pool to the reactor vessel cold pool. The cooling circuit includes flow into the reactor vessel liner flow gap immediate the reactor vessel wall and containment vessel where optimum and immediate discharge of residual reactor heat occurs.

Assessment of performing an MST strike in Tank 21H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, Michael R.

2014-09-29

Previous Savannah River National Laboratory (SRNL) tank mixing studies performed for the Small Column Ion Exchange (SCIX) project have shown that 3 Submersible Mixer Pumps (SMPs) installed in Tank 41 are sufficient to support actinide removal by MST sorption as well as subsequent resuspension and removal of settled solids. Savannah River Remediation (SRR) is pursuing MST addition into Tank 21 as part of the Large Tank Strike (LTS) project. The preliminary scope for LTS involves the use of three standard slurry pumps (installed in N, SE, and SW risers) in a Type IV tank. Due to the differences in tankmore » size, internal interferences, and pump design, a separate mixing evaluation is required to determine if the proposed configuration will allow for MST suspension and strontium and actinide sorption. The author performed the analysis by reviewing drawings for Tank 21 [W231023] and determining the required cleaning radius or zone of influence for the pumps. This requirement was compared with previous pilot-scale MST suspension data collected for SCIX that determined the cleaning radius, or zone of influence, as a function of pump operating parameters. The author also reviewed a previous Tank 50 mixing analysis that examined the ability of standard slurry pumps to suspend sludge particles. Based on a review of the pilot-scale SCIX mixing tests and Tank 50 pump operating experience, three standard slurry pumps should be able to suspend sludge and MST to effectively sorb strontium and actinides onto the MST. Using the SCIX data requires an assumption about the impact of cooling coils on slurry pump mixing. The basis for this assumption is described in this report. Using the Tank 50 operating experience shows three standard slurry pumps should be able to suspend solids if the shear strength of the settled solids is less than 160 Pa. Because Tank 21 does not contain cooling coils, the shear strength could be larger.« less

Simulation analysis and experimental verification of spiral-tube-type valveless piezoelectric pump with gyroscopic effect

NASA Astrophysics Data System (ADS)

Leng, Xuefei; Zhang, Jianhui; Jiang, Yan; Wang, Shouyin; Zhao, Chunsheng

2014-07-01

The current research of the valveless piezoelectric pump focuses on increasing the flow rate and pressure differential. Compared with the valve piezoelectric pump, the valveless one has excellent performances in simple structure, low cost, and easy miniaturization. So, their important development trend is the mitigation of their weakness, and the multi-function integration. The flow in a spiral tube element is sensitive to the element attitude caused by the Coriolis force, and that a valveless piezoelectric pump is designed by applying this phenomenon. The pump has gyroscopic effect, and has both the actuator function of fluid transfer and the sensor function, which can obtain the angular velocity when its attitude changes. First, the present paper analyzes the flow characteristics in the tube, obtains the calculation formula for the pump flow, and identifies the relationship between pump attitude and flow, which clarifies the impact of flow and driving voltage, frequency, spiral line type and element attitude, and verifies the gyroscopic effect of the pump. Then, the finite element simulation is used to verify the theory. Finally, a pump is fabricated for experimental testing of the relationship between pump attitude and pressure differential. Experimental results show that when Archimedes spiral θ=4π is selected for the tube design, and the rotation speed of the plate is 70 r/min, the pressure differential is 88.2 Pa, which is 1.5 times that of 0 r/min rotation speed. The spiral-tube-type valveless piezoelectric pump proposed can turn the element attitude into a form of pressure output, which is important for the multi-function integration of the valveless piezoelectric pump and for the development of civil gyroscope in the future.

Investigation of an ejector heat pump by analytical methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, C.T.

1984-07-01

Using existing theories of ejector design, the optimum geometry of a high-efficiency ejector - including mixing section cross-sectional area, mass flow entrainment rate, ejector efficiency, and overall COP - for a heat pump cycle was determined. A parametric study was performed to evaluate the COP values for different operating conditions. A sensitivity study determined th effects of nozzle efficiency and diffuser efficiency on the overall ejector heat pump COP. The off-design study estimated the COP for an ejector heat pump operating at off-design conditions. Refrigerants 11, 113, and 114 are three of the halocarbons which best satisfy the criteria formore » an ejector heat pump system. The estimated COPs were 0.3 for the cooling mode and 1.3 for the heating mode at standard operating conditions: a boiler temperature of 93.3/sup 0/C (200/sup 0/F), a condenser temperature of 43.3/sup 0/C (110/sup 0/F), and an evaporator temperature of 10/sup 0/C (50/sup 0/F). Based on the same operating conditions, an optimum ejector geometry was estimated for each of the refrigerants R-11 and R-113. Since the COP values for heating obtained in this analysis are greater than unity, the performance of an ejector heat pump operating in the heating mode should be competitive with that of oil- or gas-fired furnaces or electrical resistance heaters.« less

Investigation of the Flow Field and Performances of a Centrifugal Pump at Part Load

NASA Astrophysics Data System (ADS)

Prunières, R.; Inoue, Y.; Nagahara, T.

2016-11-01

Centrifugal pump performance curve instability, characterized by a local dent at part load, can be the consequence of flow instabilities in rotating or stationary parts. Such flow instabilities often result in abnormal operating conditions which can damage both the pump and the system. In order for the pump to have reliable operation over a wide flow rate range, it is necessary to achieve a design free of instability. The present paper focuses on performance curve instability of a centrifugal pump of mid specific speed (ωs = 0.65) for which instability was observed at part load during tests. The geometry used for this research consist of the first stage of a multi-stage centrifugal pump and is composed of a suction bend, a closed-type impeller, a vaned diffuser and return guide vanes. In order to analyse the instability phenomenon, PIV and CFD analysis were performed. Both methods qualitatively agree relatively well. It appears that the main difference before and after head drop is an increase of reverse flow rate at the diffuser passage inlet on the hub side. This reverse flow decreases the flow passing area at the diffuser passage inlet, disallowing effective flow deceleration and impairing static pressure recovery.

A survey of instabilities within centrifugal pumps and concepts for improving the flow range of pumps in rocket engines

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

1992-01-01

Design features and concepts that have primary influence on the stable operating flow range of propellant-feed centrifugal turbopumps in a rocket engine are discussed. One of the throttling limitations of a pump-fed rocket engine is the stable operating range of the pump. Several varieties of pump hydraulic instabilities are mentioned. Some pump design criteria are summarized and a qualitative correlation of key parameters to pump stall and surge are referenced. Some of the design criteria were taken from the literature on high pressure ratio centrifugal compressors. Therefore, these have yet to be validated for extending the stable operating flow range of high-head pumps. Casing treatment devices, dynamic fluid-damping plenums, backflow-stabilizing vanes and flow-reinjection techniques are summarized. A planned program was undertaken at LeRC to validate these concepts. Technologies developed by this program will be available for the design of turbopumps for advanced space rocket engines for use by NASA in future space missions where throttling is essential.

Efficacy and safety of strategies to preserve stable extracorporeal life support flow during simulated hypovolemia.

PubMed

Simons, A P; Lindelauf, A A M A; Ganushchak, Y M; Maessen, J G; Weerwind, P W

2014-01-01

Without volume-buffering capacity in extracorporeal life support (ELS) systems, hypovolemia can acutely reduce support flow. This study aims at evaluating efficacy and safety of strategies for preserving stable ELS during hypovolemia. Flow and/or pressure-guided servo pump control, a reserve-driven control strategy and a volume buffer capacity (VBC) device were evaluated with respect to pump flow, venous line pressure and arterial gaseous microemboli (GME) during simulated normovolemia and hypovolemia. Normovolemia resulted in a GME-free pump flow of 3.1 ± 0.0 L/min and a venous line pressure of -10 ± 1 mmHg. Hypovolemia without servo pump control resulted in a GME-loaded flow of 2.3 ± 0.4 L/min with a venous line pressure of -114 ± 52 mmHg. Servo control resulted in an unstable and GME-loaded flow of 1.5 ± 1.2 L/min. With and without servo pump control, the VBC device stabilised flow (SD = 0.2 and 0.0 L/min, respectively) and venous line pressure (SD=51 and 4 mmHg, respectively) with near-absent GME activity. Reserve-driven pump control combined with a VBC device restored a near GME-free flow of 2.7 ± 0.0 L/min with a venous line pressure of -9 ± 0 mmHg. In contrast to a reserve-driven pump control strategy combined with a VBC device, flow and pressure servo control for ELS show evident deficits in preserving stable and safe ELS flow during hypovolemia.

A handy liquid metal based electroosmotic flow pump.

PubMed

Gao, Meng; Gui, Lin

2014-06-07

A room temperature liquid metal based electroosmotic flow (EOF) pump has been proposed in this work. This low-cost EOF pump is convenient for both fabrication and integration. It utilizes polydimethylsiloxane (PDMS) microchannels filled with the liquid-metal as non-contact pump electrodes. The electrode channels are fabricated symmetrically to both sides of the pumping channel, having no contact with the pumping channel. To test the pumping performance of the EOF pump, the mean flow velocities of the fluid (DI water) in the EOF pumps were experimentally measured by tracing the fluorescent microparticles in the flow. To provide guidance for designing a low voltage EOF pump, parametric studies on dimensions of the electrode and pumping channels were performed in this work. According to the experimental results, the pumping speed can reach 5.93 μm s(-1) at a driving voltage of only 1.6 V, when the gap between the electrode and the pumping channel is 20 μm. Injecting a room temperature liquid metal into microchannels can provide a simple, rapid, low-cost but accurately self-aligned way to fabricate microelectrodes for EOF pumps, which is a promising method to achieve the miniaturization and integration of the EOF pump in microfluidic systems. The non-contact liquid electrodes have no influence on the fluid in the pumping channel when pumping, reducing Joule heat generation and preventing gas bubble formation at the surface of electrodes. The pump has great potential to drive a wide range of fluids, such as drug reagents, cell suspensions and biological macromolecule solutions.

Flow in water-intake pump bays: A guide for utility engineers. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ettema, R.

1998-09-01

This report is intended to serve as a guide for power-plant engineers facing problems with flow conditions in pump bays in water-intake structures, especially those located alongside rivers. The guide briefly introduces the typical prevailing flow field outside of a riverside water intake. That flow field often sets the inflow conditions for pump bays located within the water intake. The monograph then presents and discusses the main flow problems associated with pump bays. The problems usually revolve around the formation of troublesome vortices. A novel feature of this monograph is the use of numerical modeling to reveal diagnostically how themore » vortices form and their sensitivities to flow conditions, such as uniformity of approach flow entering the bay and water-surface elevation relative to pump-bell submergence. The modeling was carried out using a computer code developed specially for the present project. Pump-bay layouts are discussed next. The discussion begins with a summary of the main variables influencing bay flows. The numerical model is used to determine the sensitivities of the vortices to variations in the geometric parameters. The fixes include the use of flow-control vanes and suction scoops for ensuring satisfactory flow performance in severe flow conditions; notably flows with strong cross flow and shallow flows. The monograph ends with descriptions of modeling techniques. An extensive discussion is provided on the use of numerical model for illuminating bay flows. The model is used to show how fluid viscosity affects bay flow. The effect of fluid viscosity is an important consideration in hydraulic modeling of water intakes.« less

Forced convection in vertical Bridgman configuration with the submerged heater

NASA Astrophysics Data System (ADS)

Meyer, S.; Ostrogorsky, A. G.

1997-02-01

Ga-doped Ge single crystals were grown in vertical Bridgman configuration, using the submerged heater method (SHM). When used without rotation, the submerged heater drastically reduces convection at the solid-liquid interface. When the submerged heater is set in to rotation or oscillatory rotation, it acts as a centrifugal viscous pump, inducing forced convection (radial-inward flow) along the interface. The flow produced by a rotation and oscillatory rotation of the submerged heater was visualized using a 1 : 1 scale model. The vigorous mixing produced by the oscillatory rotation creates a nearly perfectly stirred melt, and yields a uniform lateral distribution of the dopant. The crystals were free of unintentionally produced striae.

Simulation of the effects of seasonally varying pumping on intraborehole flow and the vulnerability of public-supply wells to contamination

USGS Publications Warehouse

Yager, Richard M.; Heywood, Charles E.

2014-01-01

Public-supply wells with long screens in alluvial aquifers can produce waters of differing quality from different depths. Seasonal changes in quality are linked to seasonal changes in pumping rates that influence the distribution of flow into the well screens under pumping conditions and the magnitude and direction of intraborehole flow within the wells under ambient conditions. Groundwater flow and transport simulations with MODFLOW and MT3DMS were developed to quantify the effects of changes in average seasonal pumping rates on intraborehole flow and water quality at two long-screened, public-supply wells, in Albuquerque, New Mexico and Modesto, California, where widespread pumping has altered groundwater flow patterns. Simulation results indicate that both wells produce water requiring additional treatment to maintain potable quality in winter when groundwater withdrawals are reduced because less water is derived from parts of the aquifer that contain water requiring less treatment. Simulation results indicate that the water quality at both wells could be improved by increasing average winter-pumping rates to induce more lateral flow from parts of the aquifer that contain better quality water. Arsenic-bearing water produced by the Albuquerque well could be reduced from 55% to 45% by doubling average winter-pumping rate, while nitrate- and uranium-bearing water produced by the Modesto well could be reduced from 95% to 65% by nearly tripling the average winter-pumping rate. Higher average winter-pumping rates would also reduce the volume of intraborehole flow within both wells and prevent the exchange of poor quality water between shallow and deep parts of both aquifers.

The influence of Reynolds numbers on resistance properties of jet pumps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Q.; Graduate University of Chinese Academy of Sciences, Beijing 100049; Zhou, G.

2014-01-29

Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structuresmore » and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.« less

The influence of Reynolds numbers on resistance properties of jet pumps

NASA Astrophysics Data System (ADS)

Geng, Q.; Zhou, G.; Li, Q.

2014-01-01

Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structures and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.

Rotary blood pump

NASA Technical Reports Server (NTRS)

Benkowski, Robert J. (Inventor); Kiris, Cetin (Inventor); Kwak, Dochan (Inventor); Rosenbaum, Bernard J. (Inventor); Bacak, James W. (Inventor); DeBakey, Michael E. (Inventor)

1999-01-01

A blood pump that comprises a pump housing having a blood flow path therethrough, a blood inlet, and a blood outlet; a stator mounted to the pump housing, the stator having a stator field winding for producing a stator magnetic field; a flow straightener located within the pump housing, and comprising a flow straightener hub and at least one flow straightener blade attached to the flow straightener hub; a rotor mounted within the pump housing for rotation in response to the stator magnetic field, the rotor comprising an inducer and an impeller; the inducer being located downstream of the flow straightener, and comprising an inducer hub and at least one inducer blade attached to the inducer hub; the impeller being located downstream of the inducer, and comprising an impeller hub and at least one impeller blade attached to the impeller hub; and preferably also comprising a diffuser downstream of the impeller, the diffuser comprising a diffuser hub and at least one diffuser blade. Blood flow stagnation and clot formation within the pump are minimized by, among other things, providing the inducer hub with a diameter greater than the diameter of the flow straightener hub; by optimizing the axial spacing between the flow straightener hub and the inducer hub, and between the impeller hub and the diffuser hub; by optimizing the inlet angle of the diffuser blades; and by providing fillets or curved transitions between the upstream end of the inducer hub and the shaft mounted therein, and between the impeller hub and the shaft mounted therein.

NASA Goddard Space Flight Center Cooperative Enterprise

NASA Technical Reports Server (NTRS)

Fredley, Joseph E.; Lysak, Daniel B.

2004-01-01

The viability of a Capillary Heat Pump (CHP) concept using a Loop Heat Pipe evaporator and an eductor in a closed loop to reject heat at a higher temperature than it is acquired at with the goal of reducing spacecraft radiator area is examined. Eductor inefficiency resulting from the mixing of high velocity motive flow with low velocity suction flow may preclude spacecraft radiator area savings. The utility of a CHP for thermal management may be limited to those missions where system mass is of secondary concern compared to system reliability, or where a heat pump is required to accommodate relatively high thermal rejection temperatures. Shearography techniques for nondestructive inspection and evaluation were examined for two unique applications. Shearography is shown to give good results in evaluating the quality of bonds holding lead tiles to the SWIFT spacecraft BAT gamma ray mask. Also, a novel technique was developed allowing specular objects to be inspected using shearography to evaluate bonding between the skin and core of a specular surface honeycomb structure. Large-scale bond failures are readily identified.

Portable Intravenous Fluid Production Device For Ground Use Project

NASA Technical Reports Server (NTRS)

Oliva-Buisson, Yvette J.

2014-01-01

Several medical conditions require the administration of intravenous (IV) fluids,but limitations of mass, volume, shelf-life, transportation, and local resources can restrict the availability of these important fluids. Such limitations are expected in long-duration space exploration missions and in remote or austere places on Earth. This design uses regular drinking water that is pumped through two filters to produce, in minutes, sterile, ultrapure water that meets the stringent quality standards of the United States Pharmacopeia for Water for Injection (Total Bacteria, Conductivity, Endo - toxins, Total Organic Carbon). The device weighs 2.2 lb (1 kg) and is 10 in. long, 5 in. wide, and 3 in. high (˜25, 13, and 7.5 cm, respectively) in its storage configuration. This handheld device produces one liter of medical-grade water in 21 minutes. Total production capacity for this innovation is expected to be in the hundreds of liters. The device contains one battery powered electric mini-pump. Alternatively, a manually powered pump can be attached and used. Drinking water enters the device from a source water bag, flows through two filters, and final sterile production water exits into a sealed, medical-grade collection bag. The collection bag contains pre-placed crystalline salts to mix with product water to form isotonic intravenous medical solutions. Alternatively, a hypertonic salt solution can be injected into a filled bag. The filled collection bag is detached from the device and is ready for use or storage. This device currently contains one collection bag, but a manifold of several pre-attached bags or replacement of single collection bags under sterile needle technique is possible for the production of multiple liters. The entire system will be flushed, sealed, and radiation-sterilized. Operation of the device is easy and requires minimal training. Drinking water is placed into the collection bag. Inline stopcock flow valves at the source and collection bags are opened, and the mini-pump is turned on by a switch to begin fluid flow. When the collection bag is completely filled with the medical- grade water, the pump can be turned off. The pump is designed so it cannot pump air, and overfilling of the collection bag with fluid is avoided by placing an equal amount of water in the source bag. Backflow is avoided by inline check valves. The filled collection bag is disconnected from its tubing and is ready for use. The source bag can be refilled for production of multiple liters, or the source bag can be replaced with an input tube that can be placed in a larger potable water source if the device is attended. The device functions in all orientations independent of any gravity fields. In addition to creating IV fluids, the device produces medical-grade water, which can be used for mixing with medications for injection, reconstituting freeze-dried blood products for injection, or for wound hydration or irrigation. Potential worldwide use is expected with medical activities in environments that have limited resources, storage, or resupply such as in military field operations, humanitarian relief efforts, submarines, commercial cruise ships, etc.

Do Europa's Mountains Have Roots? Erosion of Topography at the Ice-Water Interface via the "Ice Pump"

NASA Astrophysics Data System (ADS)

Goodman, J. C.

2016-12-01

Are topographic features on the surface of Europa and other icy worlds isostatically compensated by variations in shell thickness (Airy isostasy)? This is only possible if variations in shell thickness can remain stable over geologic time. Here we show that melting and freezing driven by the pressure dependence of the melting point of water - the "ice pump" - can rapidly erase topography at the ice/water interface. We consider ice pumps driven by both tidal action and buoyancy-driven flow. We first show that as tidal action drives the ocean up and down along a sloping interface, ice will be melted from areas where it's thickest and deposited where the ice is thinnest. We show that this process causes the ice interface topography to relax according to a simple "diffusion" linear partial differential equation. We estimate that a 10-km-wide topographic feature would be erased by the tidal ice pump in 3000 years if Europa's tidal current amplitude is 1 cm/s; however, this timescale is inversely proportional to the cube of the tidal velocity! Next, we consider an ice pump powered by ascent of meltwater along a sloping ice-water interface. We consider layer-averaged budgets for heat, mass, and momentum, along with turbulent mixing of the meltwater layer with underlying seawater via a Richardson number dependent entrainment process, and use these to estimate the thickness and mass flux of the meltwater layer. From this we estimate the rate of melting and freezing at the interface. These two ice pump processes combine with the glacial flow of warm basal ice to rapidly flatten out any variations in the height of the ice-water interface: Europa's ice/water interface may be perfectly flat! If so, topography at Europa's surface can only be supported by variations in density of the shell or the strength of the brittle surface ice.

Development of a Mechatronic Syringe Pump to Control Fluid Flow in a Microfluidic Device Based on Polyimide Film

NASA Astrophysics Data System (ADS)

Sek Tee, Kian; Sharil Saripan, Muhammad; Yap, Hiung Yin; Fhong Soon, Chin

2017-08-01

With the advancement in microfluidic technology, fluid flow control for syringe pump is always essential. In this paper, a mechatronic syringe pump will be developed and customized to control the fluid flow in a poly-dimethylsiloxane (PDMS) microfluidic device based on a polyimide laminating film. The syringe pump is designed to drive fluid with flow rates of 100 and 1000 μl/min which intended to drive continuous fluid in a polyimide based microfluidic device. The electronic system consists of an Arduino microcontroller board and a uni-polar stepper motor. In the system, the uni-polar stepper motor was coupled to a linear slider attached to the plunger of a syringe pump. As the motor rotates, the plunger pumps the liquid out of the syringe. The accuracy of the fluid flow rate was determined by adjusting the number of micro-step/revolution to drive the stepper motor to infuse fluid into the microfluidic device. With the precise control of the electronic system, the syringe pump could accurately inject fluid volume at 100 and 1000 μl/min into a microfluidic device.

Pump Thrombosis following HeartMate II Left Ventricular Assist Device Implantation in a Patient with Aspirin and Plavix Resistance.

PubMed

Ghodsizad, Ali; Badiye, A; Zeriouh, M; Pae, W; Koerner, M M; Loebe, M

2016-12-14

Despite advances in pump technology, thromboembolic events and pump thrombosis are potentially life-threatening complications in patients with continuous flow ventricular assist devices. Here we describe a patient with pump thrombosis following LVAD HeartMate II implantation presenting with Aspirin and Plavix resistance and signs of acute hemolysis as manifested by high LDH, changing pump power, pulse index and reduced pump flows.

Improvement of centrifugal pump performance through addition of splitter blades on impeller pump

NASA Astrophysics Data System (ADS)

Kurniawan, Krisna Eka; Santoso, Budi; Tjahjana, Dominicus Danardono Dwi Prija

2018-02-01

The workable way to improve pump performance is to redesign or modify the impellers of centrifugal pump. The purpose of impeller pump modification is to improve pump efficiency, reduce cross flow, reduce secondary incidence flows, and decrease backflow areas at impeller outlets. Number blades and splitter blades in the impeller are three. The outlet blade angle is 20°, and the rotating speed of impeller is 2400 rpm. The added splitter blades variations are 0.25, 0.375, and 0.5 of the original blade length. The splitter blade placements are on the outer side of the impeller. The addition of splitter blades on the outer side of the impeller with 0.5L increases the pump head until 22% and the pump has 38.66% hydraulic efficiency. The best efficiency point of water flow rate pump (Qbep) was 3.02 × 10-3 m3/s.

Liquid metal enabled pump

PubMed Central

Tang, Shi-Yang; Khoshmanesh, Khashayar; Sivan, Vijay; Petersen, Phred; O’Mullane, Anthony P.; Abbott, Derek; Mitchell, Arnan; Kalantar-zadeh, Kourosh

2014-01-01

Small-scale pumps will be the heartbeat of many future micro/nanoscale platforms. However, the integration of small-scale pumps is presently hampered by limited flow rate with respect to the input power, and their rather complicated fabrication processes. These issues arise as many conventional pumping effects require intricate moving elements. Here, we demonstrate a system that we call the liquid metal enabled pump, for driving a range of liquids without mechanical moving parts, upon the application of modest electric field. This pump incorporates a droplet of liquid metal, which induces liquid flow at high flow rates, yet with exceptionally low power consumption by electrowetting/deelectrowetting at the metal surface. We present theory explaining this pumping mechanism and show that the operation is fundamentally different from other existing pumps. The presented liquid metal enabled pump is both efficient and simple, and thus has the potential to fundamentally advance the field of microfluidics. PMID:24550485

Investigation of pumping mechanism for non-Newtonian blood flow with AC electrothermal forces in a microchannel by hybrid boundary element method and immersed boundary-lattice Boltzmann method.

PubMed

Ren, Qinlong

2018-02-10

Efficient pumping of blood flow in a microfluidic device is essential for rapid detection of bacterial bloodstream infections (BSI) using alternating current (AC) electrokinetics. Compared with AC electro-osmosis (ACEO) phenomenon, the advantage of AC electrothermal (ACET) mechanism is its capability of pumping biofluids with high electrical conductivities at a relatively high AC voltage frequency. In the current work, the microfluidic pumping of non-Newtonian blood flow using ACET forces is investigated in detail by modeling its multi-physics process with hybrid boundary element method (BEM) and immersed boundary-lattice Boltzmann method (IB-LBM). The Carreau-Yasuda model is used to simulate the realistic rheological behavior of blood flow. The ACET pumping efficiency of blood flow is studied in terms of different AC voltage magnitudes and frequencies, thermal boundary conditions of electrodes, electrode configurations, channel height, and the channel length per electrode pair. Besides, the effect of rheological behavior on the blood flow velocity is theoretically analyzed by comparing with the Newtonian fluid flow using scaling law analysis under the same physical conditions. The results indicate that the rheological behavior of blood flow and its frequency-dependent dielectric property make the pumping phenomenon of blood flow different from that of the common Newtonian aqueous solutions. It is also demonstrated that using a thermally insulated electrode could enhance the pumping efficiency dramatically. Besides, the results conclude that increasing the AC voltage magnitude is a more economical pumping approach than adding the number of electrodes with the same energy consumption when the Joule heating effect is acceptable. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cavitation, Flow Structure and Turbulence in the Tip Region of a Rotor Blade

NASA Technical Reports Server (NTRS)

Wu, H.; Miorini, R.; Soranna, F.; Katz, J.; Michael, T.; Jessup, S.

2010-01-01

Objectives: Measure the flow structure and turbulence within a Naval, axial waterjet pump. Create a database for benchmarking and validation of parallel computational efforts. Address flow and turbulence modeling issues that are unique to this complex environment. Measure and model flow phenomena affecting cavitation within the pump and its effect on pump performance. This presentation focuses on cavitation phenomena and associated flow structure in the tip region of a rotor blade.

Convective flow reversal in self-powered enzyme micropumps.

PubMed

Ortiz-Rivera, Isamar; Shum, Henry; Agrawal, Arjun; Sen, Ayusman; Balazs, Anna C

2016-03-08

Surface-bound enzymes can act as pumps that drive large-scale fluid flows in the presence of their substrates or promoters. Thus, enzymatic catalysis can be harnessed for “on demand” pumping in nano- and microfluidic devices powered by an intrinsic energy source. The mechanisms controlling the pumping have not, however, been completely elucidated. Herein, we combine theory and experiments to demonstrate a previously unreported spatiotemporal variation in pumping behavior in urease-based pumps and uncover the mechanisms behind these dynamics. We developed a theoretical model for the transduction of chemical energy into mechanical fluid flow in these systems, capturing buoyancy effects due to the solution containing nonuniform concentrations of substrate and product. We find that the qualitative features of the flow depend on the ratios of diffusivities δ=D(P)/D(S) and expansion coefficients β=β(P)/β(S) of the reaction substrate (S) and product (P). If δ>1 and δ>β (or if δ<1 and δ<β ), an unexpected phenomenon arises: the flow direction reverses with time and distance from the pump. Our experimental results are in qualitative agreement with the model and show that both the speed and direction of fluid pumping (i) depend on the enzyme activity and coverage, (ii) vary with the distance from the pump, and (iii) evolve with time. These findings permit the rational design of enzymatic pumps that accurately control the direction and speed of fluid flow without external power sources, enabling effective, self-powered fluidic devices.

Convective flow reversal in self-powered enzyme micropumps

PubMed Central

Ortiz-Rivera, Isamar; Shum, Henry; Agrawal, Arjun; Sen, Ayusman; Balazs, Anna C.

2016-01-01

Surface-bound enzymes can act as pumps that drive large-scale fluid flows in the presence of their substrates or promoters. Thus, enzymatic catalysis can be harnessed for “on demand” pumping in nano- and microfluidic devices powered by an intrinsic energy source. The mechanisms controlling the pumping have not, however, been completely elucidated. Herein, we combine theory and experiments to demonstrate a previously unreported spatiotemporal variation in pumping behavior in urease-based pumps and uncover the mechanisms behind these dynamics. We developed a theoretical model for the transduction of chemical energy into mechanical fluid flow in these systems, capturing buoyancy effects due to the solution containing nonuniform concentrations of substrate and product. We find that the qualitative features of the flow depend on the ratios of diffusivities δ=DP/DS and expansion coefficients β=βP/βS of the reaction substrate (S) and product (P). If δ>1 and δ>β (or if δ<1 and δ<β), an unexpected phenomenon arises: the flow direction reverses with time and distance from the pump. Our experimental results are in qualitative agreement with the model and show that both the speed and direction of fluid pumping (i) depend on the enzyme activity and coverage, (ii) vary with the distance from the pump, and (iii) evolve with time. These findings permit the rational design of enzymatic pumps that accurately control the direction and speed of fluid flow without external power sources, enabling effective, self-powered fluidic devices. PMID:26903618

Diffusion sampler testing at Naval Air Station North Island, San Diego County, California, November 1999 to January 2000

USGS Publications Warehouse

Vroblesky, Don A.; Peters, Brian C.

2000-01-01

Volatile organic compound concentrations in water from diffusion samplers were compared to concentrations in water obtained by low-flow purging at 15 observation wells at the Naval Air Station North Island, San Diego, California. Multiple diffusion samplers were installed in the wells. In general, comparisons using bladder pumps and diffusion samplers showed similar volatile organic carbon concentrations. In some wells, sharp concentration gradients were observed, such as an increase in cis-1,2-dichloroethene concentration from 100 to 2,600 micrograms per liter over a vertical distance of only 3.4 feet. In areas where such sharp gradients were observed, concentrations in water obtained by low-flow sampling at times reflected an average concentration over the area of influence; however, concentrations obtained by using the diffusion sampler seemed to represent the immediate vicinity of the sampler. When peristaltic pumps were used to collect ground-water samples by low-flow purging, the volatile organic compound concentrations commonly were lower than concentrations obtained by using diffusion samplers. This difference may be due to loss of volatiles by degassing under negative pressures in the sampling lines induced while using the peristaltic pump, mixing in the well screen, or possible short-circuiting of water from an adjacent depth. Diffusion samplers placed in buckets of freephase jet fuel (JP-5) and Stoddard solvent from observation wells did not show evidence of structural integrity loss during the 2 months of equilibration, and volatile organic compounds detected in the free-phase fuel also were detected in the water from the diffusion samplers.

Suspended Sediment Dynamics in the Macrotidal Seine Estuary (France): 1. Numerical Modeling of Turbidity Maximum Dynamics

NASA Astrophysics Data System (ADS)

Grasso, F.; Verney, R.; Le Hir, P.; Thouvenin, B.; Schulz, E.; Kervella, Y.; Khojasteh Pour Fard, I.; Lemoine, J.-P.; Dumas, F.; Garnier, V.

2018-01-01

Tidal pumping, baroclinic circulation, and vertical mixing are known to be the main mechanisms responsible for the estuarine turbidity maximum (ETM) formation. However, the influence of hydro-meteorological conditions on ETM dynamics is still not properly grasped and requires further investigation to be quantified. Based on a realistic three-dimensional numerical model of the macrotidal Seine Estuary (France) that accounts for mud and sand transport processes, the objective of this study is to quantify the influence of the main forcing (river flow, tides, and waves) on the ETM location and mass changes. As expected, the ETM location is strongly modulated by semidiurnal tidal cycles and fortnightly time scales with a high sensitivity to river flow variations. The ETM mass is clearly driven by the tidal range, characteristic of the tidal pumping mechanism. However, it is not significantly affected by the river flow. Energetic wave conditions substantially influence the ETM mass by contributing up to 44% of the maximum mass observed during spring tides and by increasing the mass by a factor of 3 during mean tides compared to calm wave conditions. This means that neglecting wave forcing can result in significantly underestimating the ETM mass in estuarine environments. In addition, neap-to-spring phasing has a strong influence on ETM location and mass through a hysteresis response associated with the delay for tidal pumping and stratification to fully develop. Finally, simulations show that the uppermost limit of the Seine ETM location did not change notably during the last 35 years; however, the seaward limit migrated few kilometers upstream.

High power pumped MID-IR wavelength devices using nonlinear frequency mixing (NFM)

NASA Technical Reports Server (NTRS)

Sanders, Steven (Inventor); Lang, Robert J. (Inventor); Waarts, Robert G. (Inventor)

2001-01-01

Laser diode pumped mid-IR wavelength sources include at least one high power, near-IR wavelength, injection and/or sources wherein one or both of such sources may be tunable providing a pump wave output beam to a quasi-phase matched (QPM) nonlinear frequency mixing (NFM) device. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Wavelength tuning of at least one of the sources advantageously provides the ability for optimizing pump or injection wavelengths to match the QPM properties of the NFM device enabling a broad range of mid-IR wavelength selectivity. Also, pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.

High power pumped mid-IR wavelength systems using nonlinear frequency mixing (NFM) devices

NASA Technical Reports Server (NTRS)

Sanders, Steven (Inventor); Lang, Robert J. (Inventor); Waarts, Robert G. (Inventor)

1999-01-01

Laser diode pumped mid-IR wavelength systems include at least one high power, near-IR wavelength, injection and/or sources wherein one or both of such sources may be tunable providing a pump wave output beam to a quasi-phase matched (QPM) nonlinear frequency mixing (NFM) device. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Wavelength tuning of at least one of the sources advantageously provides the ability for optimizing pump or injection wavelengths to match the QPM properties of the NFM device enabling a broad range of mid-IR wavelength selectivity. Also, pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.

Chilldown study of the single stage inducer test rig

NASA Technical Reports Server (NTRS)

Kimura, L. A.

1972-01-01

Of the six chilldown tests, data from only one could be used for evaluation. During the rest of the chilldown tests, there was leakage hydrogen flow into the pump cavity prior to the initiation of the chilldown test. In all of the tests the hydrogen condition into the pump was probably 100% vapor. The data from this one test, therefore, can be used to compare only the single phase fluid correlation in the analytical pump chilldown model. In general, the actual pump chilled down much faster than predicted by the analytical pump model. There were insufficient data from the test to measure the pump flow rate and pump inlet fluid condition; therefore, these parameters were extrapolated based on related data which were available. However, even with the highest probable flow rate, the pump chilled faster than predicted.

PediaFlow™ Maglev Ventricular Assist Device: A Prescriptive Design Approach

PubMed Central

Antaki, James F.; Ricci, Michael R.; Verkaik, Josiah E.; Snyder, Shaun T.; Maul, Timothy M.; Kim, Jeongho; Paden, Dave B.; Kameneva, Marina V.; Paden, Bradley E.; Wearden, Peter D.; Borovetz, Harvey S.

2010-01-01

This report describes a multi-disciplinary program to develop a pediatric blood pump, motivated by the critical need to treat infants and young children with congenital and acquired heart diseases. The unique challenges of this patient population require a device with exceptional biocompatibility, miniaturized for implantation up to 6 months. This program implemented a collaborative, prescriptive design process, whereby mathematical models of the governing physics were coupled with numerical optimization to achieve a favorable compromise among several competing design objectives. Computational simulations of fluid dynamics, electromagnetics, and rotordynamics were performed in two stages: first using reduced-order formulations to permit rapid optimization of the key design parameters; followed by rigorous CFD and FEA simulations for calibration, validation, and detailed optimization. Over 20 design configurations were initially considered, leading to three pump topologies, judged on the basis of a multi-component analysis including criteria for anatomic fit, performance, biocompatibility, reliability, and manufacturability. This led to fabrication of a mixed-flow magnetically levitated pump, the PF3, having a displaced volume of 16.6 cc, approximating the size of a AA battery and producing a flow capacity of 0.3–1.5 L/min. Initial in vivo evaluation demonstrated excellent hemocompatibility after 72 days of implantation in an ovine. In summary, combination of prescriptive and heuristic design principles have proven effective in developing a miniature magnetically levitated blood pump with excellent performance and biocompatibility, suitable for integration into chronic circulatory support system for infants and young children; aiming for a clinical trial within 3 years. PMID:20544002

Method for eliminating gas blocking in electrokinetic pumping systems

DOEpatents

Arnold, Don W.; Paul, Phillip H.; Schoeniger, Joseph S.

2001-09-11

A method for eliminating gas bubble blockage of current flow during operation of an electrokinetic pump. By making use of the ability to modify the surface charge on the porous dielectric medium used in electrokinetic pumps, it becomes possible to place electrodes away from the pressurized region of the electrokinetic pump. While gas is still generated at the electrodes they are situated such that the generated gas can escape into a larger buffer reservoir and not into the high pressure region of the pump where the gas bubbles can interrupt current flow. Various combinations of porous dielectric materials and ionic conductors can be used to create pumps that have desirable electrical, material handling, and flow attributes.

CFD research on runaway transient of pumped storage power station caused by pumping power failure

NASA Astrophysics Data System (ADS)

Zhang, L. G.; Zhou, D. Q.

2013-12-01

To study runaway transient of pumped storage power station caused by pumping power failure, three dimensional unsteady numerical simulations were executed on geometrical model of the whole flow system. Through numerical calculation, the changeable flow configuration and variation law of some parameters such as unit rotate speed,flow rate and static pressure of measurement points were obtained and compared with experimental data. Numerical results show that runaway speed agrees well with experimental date and its error was 3.7%. The unit undergoes pump condition, brake condition, turbine condition and runaway condition with flow characteristic changing violently. In runaway condition, static pressure in passage pulses very strongly which frequency is related to runaway speed.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

2001-01-01

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

2003-06-03

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based system. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

The research on flow pulsation characteristics of axial piston pump

NASA Astrophysics Data System (ADS)

Wang, Bingchao; Wang, Yulin

2017-01-01

The flow pulsation is an important factor influencing the axial piston pump performance. In this paper we implement modeling and simulation of the axial piston pump with AMESim software to explore the flow pulsation characteristics under various factors . Theory analysis shows the loading pressure, angular speed, piston numbers and the accumulator impose evident influence on the flow pulsation characteristics. This simulation and analysis can be used for reducing the flow pulsation rate via properly setting the related factors.

Multimodal flow visualization and optimization of pneumatic blood pump for sorbent hemodialysis system.

PubMed

Shu, Fangjun; Parks, Robert; Maholtz, John; Ash, Steven; Antaki, James F

2009-04-01

Renal Solutions Allient Sorbent Hemodialysis System utilizes a two-chambered pneumatic pump (Pulsar Blood Pump, Renal Solutions, Inc., Warrendale, PA, USA) to avoid limitations associated with peristaltic pumping systems. Single-needle access is enabled by counter-pulsing the two pump chambers, thereby obviating compliance chambers or blood reservoirs. Each chamber propels 20 cc per pulse of 3 s (dual access) or 6 s (single access) duration, corresponding to a peak Reynolds number of approximately 8000 (based on inlet velocity and chamber diameter). A multimodal series of flow visualization studies (tracer particle, dye washout, and dye erosion) was conducted on a sequence of pump designs with varying port locations and diaphragms to improve the geometry with respect to risk of thrombogenesis. Experiments were conducted in a simplified flow loop using occluders to simulate flow resistance induced by tubing and dialyzer. Tracer visualization revealed flow patterns and qualitatively indicated turbulence intensity. Dye washout identified dwell volume and areas of flow stagnation for each design. Dye erosion results indicated the effectiveness and homogeneity of surface washing. Compared to a centered inlet which resulted in a fluid jet that produced two counter-rotating vortices, a tangential inlet introduced a single vortex, and kept the flow laminar. It also provided better surface washing on the pump inner surface. However, a tangential outlet did not present as much benefit as expected. On the contrary, it created a sharp defection to the flow when transiting from filling to ejection.

Satellite Propellant Pump Research

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Veres, Joseph P.; Hah, Chunill; Nerone, Anthony L.; Cunningham, Cameron C.; Kraft, Thomas G.; Tavernelli, Paul F.; Fraser, Bryan

2005-01-01

NASA Glenn initiated a satellite propellant pump technology demonstration program. The goal was to demonstrate the technologies for a 60 percent efficient pump at 1 gpm flow rate and 500 psia pressure rise. The pump design and analysis used the in-house developed computer codes named PUMPA and HPUMP3D. The requirements lead to a 4-stage impeller type pump design with a tip diameter of 0.54 inches and a rotational speed of 57,000 rpm. Analyses indicated that flow cavitation was not a problem in the design. Since the flow was incompressible, the stages were identical. Only the 2-stage pump was designed, fabricated, assembled, and tested for demonstration. Water was selected as the surrogate fluid for hydrazine in this program. Complete mechanical design including stress and dynamic analyses were conducted. The pump was driven by an electric motor directly coupled to the impellers. Runs up to 57,000 rpm were conducted, where a pressure rise of 200 psia at a flow rate of 0.8 gpm was measured to validate the design effort.

Modification of the BioMedicus centrifugal pump to provide continuous irrigation for neuroendoscopy: technical note.

PubMed

Koueik, Joyce; Rocque, Brandon G; Henry, Jordan; Bragg, Taryn; Paul, Jennifer; Iskandar, Bermans J

2018-02-01

Continuous irrigation is an important adjunct for successful intraventricular endoscopy, particularly for complex cases. It allows better visualization by washing out blood and debris, improves navigation by expanding the ventricles, and assists with tissue dissection. A method of irrigation delivery using a centrifugal pump designed originally for cardiac surgery is presented. The BioMedicus centrifugal pump has the desirable ability to deliver a continuous laminar flow of fluid that excludes air from the system. A series of modifications to the pump tubing was performed to adapt it to neuroendoscopy. Equipment testing determined flow and pressure responses at various settings and simulated clinical conditions. The pump was then studied clinically in 11 endoscopy cases and eventually used in 310 surgical cases. Modifications of the pump tubing allowed for integration with different endoscopy systems. Constant flow rates were achieved with and without surgical instruments through the working ports. Optimal flow rates ranged between 30 and 100 ml/min depending on endoscope size. Intraoperative use was well tolerated with no permanent morbidity and showed consistent flow rates, minimal air accumulation, and seamless irrigation bag replacement during prolonged surgery. Although the pump is equipped with an internal safety mechanism to protect against pressure buildup when outflow obstructions occur, equipment testing revealed that flow cessation is not instantaneous enough to protect against sudden intracranial pressure elevation. A commonly available cardiac pump system was modified to provide continuous irrigation for intraventricular endoscopy. The system alleviates the problems of inconsistent flow rates, air in the irrigation lines, and delays in changing irrigation bags, thereby optimizing patient safety and surgical efficiency. Safe use of the pump requires good ventricular outflow and, clearly, sound surgical judgment.

Choroidal microcirculation in patients with rotary cardiac assist device.

PubMed

Polska, Elzbieta; Schima, Heinrich; Wieselthaler, Georg; Schmetterer, Leopold

2007-06-01

In recent years, fully implanted rotary blood pumps have been used for long-term cardiac assist in patients with end-stage heart failure. With these pumps, the pulsatility of arterial blood flow and arterial pressure pulse is considerably reduced. Effects on end-organ perfusion, particularly microcirculation, have been assessed. The ocular choroid offers a unique opportunity to study the pulsatile component of blood flow by measurement of fundus pulsation amplitude (FPA) as well as the microcirculation by laser Doppler flowmetry. Both techniques were applied in three male patients with rotary pumps (MicroMed DeBakey VAD), in whom pump velocity was adjusted to four levels of flow between individual minimal need and maximal support. In addition, blood flow velocities in the ophthalmic artery (peak, end-diastolic and mean flow velocity--PSV, EDV and MFV, respectively) were measured using color Doppler imaging. Systolic blood pressure increased by 6 to 22 mm Hg with increasing support. At maximal support FPA was reduced by -60% to -52% as compared with minimal pump support. Blood flow in the choroidal microvasculature, however, did not show relevant changes. A reduction in PSV (-31%, range -47% to -21%) and a pronounced rise in EDV (+93%, range +28% to +147%) was observed, whereas MFV was independent of pump flow. Our data indicate that mean choroidal blood flow is maintained when pump support is varied within therapeutic values, whereas the ratio of pulsatile to non-pulsatile choroidal flow changes. This study shows that, in patients with ventricular assist devices, a normal perfusion rate in the ocular microcirculation is maintained over a wide range of support conditions.

Probable effects of the proposed Sulphur Gulch Reservoir on Colorado River quantity and quality near Grand Junction, Colorado

USGS Publications Warehouse

Friedel, M.J.

2004-01-01

A 16,000 acre-foot reservoir is proposed to be located about 25 miles east of Grand Junction, Colorado, on a tributary of the Colorado River that drains the Sulphur Gulch watershed between De Beque and Cameo, Colorado. The Sulphur Gulch Reservoir, which would be filled by pumping water from the Colorado River, is intended to provide the Colorado River with at least 5,412.5 acre-feet of water during low-flow conditions to meet the East Slopes portion of the 10,825 acre-feet of water required under the December 20, 1999, Final Programmatic Biological Opinion for the Upper Colorado River. The reservoir also may provide additional water in the low-flow period and as much as 10,000 acre-feet of water to supplement peak flows when flows in the Colorado River are between 12,900 and 26,600 cubic feet per second. For this study, an annual stochastic mixing model with a daily time step and 1,500 Monte Carlo trials were used to evaluate the probable effect that reservoir operations may have on water quality in the Colorado River at the Government Highline Canal and the Grand Valley Irrigation Canal. Simulations of the divertible flow (ambient background streamflow), after taking into account demands of downstream water rights, indicate that divertible flow will range from 621,860 acre-feet of water in the driest year to 4,822,732 acrefeet of water in the wettest year. Because of pumping limitations, pumpable flow (amount of streamflow available after considering divertible flow and subsequent pumping constraints) will be less than divertible flow. Assuming a pumping capacity of 150 cubic feet per second and year round pumping, except during reservoir release periods, the simulations indicate that there is sufficient streamflow to fill a 16,000 acre-feet reservoir 100 percent of the time. Simulated pumpable flows in the driest year are 91,669 acre-feet and 109,500 acre-feet in the wettest year. Simulations of carryover storage together with year-round pumping indicate that there is generally sufficient pumpable flow available to refill the reservoir to capacity each year following peak-flow releases of as much as 10,000 acrefeet and low-flow releases of 5,412.5 acre-feet of water. It is assumed that at least 5,412.5 acre-feet of stored water will be released during low-flow conditions irrespective of the hydrologic condition. Simulations indicate that peak-flow release conditions (flows between 12,900 and 26,600 cubic feet per second) to allow release of 10,000 acre-feet of stored water in the spring will occur only about 50 percent of the time. Under typical (5 of 10 years) to moderately dry (3 of 10 years) hydrologic conditions, the duration of the peak-flow conditions will not allow the full 10,000 acre-feet to be released from storage to supplement peak flows. During moderate to extremely dry (2 of 10 years) hydrologic conditions, the peak-flow release conditions will not occur, and there will be no opportunity to release water from storage to supplement peak flows. In general, the simulated daily background dissolved-solids concentrations (salinity) increase due to the reservoir releases as hydrologic conditions go from wet to dry at the Government Highline Canal. For example, the simulated median concentrations during the low-flow period range from 417 milligrams per liter (wet year) to 723 milligrams per liter (dry year), whereas the simulated median concentrations observed during the peak-flow period range from 114 milligrams per liter (wet year) to 698 milligrams per liter (dry year). Background concentration values at the Grand Valley Irrigation Canal are generally only a few percent less than those at the Government Highline Canal except during dry years. Low-flow reservoir releases of 5,412.5 acre-feet and 10,825 acre-feet were simulated for a 30-day period in September, and low-flow releases of 5,412.5 acre-feet were simulated for a 78-day period in the months of August through October. In general, these low-flo

33 CFR 155.780 - Emergency shutdown.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the vessel to stop the flow of oil or hazardous material. (b) The means to stop the flow may be a pump control, a quick-acting, power actuated valve, or an operating procedure. If an emergency pump control is... through the stopped pump. (c) The means to stop the flow must be operable from the cargo deck, cargo...

33 CFR 155.780 - Emergency shutdown.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the vessel to stop the flow of oil or hazardous material. (b) The means to stop the flow may be a pump control, a quick-acting, power actuated valve, or an operating procedure. If an emergency pump control is... through the stopped pump. (c) The means to stop the flow must be operable from the cargo deck, cargo...

33 CFR 155.780 - Emergency shutdown.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the vessel to stop the flow of oil or hazardous material. (b) The means to stop the flow may be a pump control, a quick-acting, power actuated valve, or an operating procedure. If an emergency pump control is... through the stopped pump. (c) The means to stop the flow must be operable from the cargo deck, cargo...

33 CFR 155.780 - Emergency shutdown.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the vessel to stop the flow of oil or hazardous material. (b) The means to stop the flow may be a pump control, a quick-acting, power actuated valve, or an operating procedure. If an emergency pump control is... through the stopped pump. (c) The means to stop the flow must be operable from the cargo deck, cargo...

33 CFR 155.780 - Emergency shutdown.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the vessel to stop the flow of oil or hazardous material. (b) The means to stop the flow may be a pump control, a quick-acting, power actuated valve, or an operating procedure. If an emergency pump control is... through the stopped pump. (c) The means to stop the flow must be operable from the cargo deck, cargo...

Design of a high-pressure circulating pump for viscous liquids.

PubMed

Seifried, Bernhard; Temelli, Feral

2009-07-01

The design of a reciprocating dual action piston pump capable of circulating viscous fluids at pressures of up to 34 MPa (5000 psi) and temperatures up to 80 degrees C is described. The piston of this pump is driven by a pair of solenoids energized alternatively by a 12 V direct current power supply controlled by an electronic controller facilitating continuously adjustable flow rates. The body of this seal-less pump is constructed using off-the-shelf parts eliminating the need for custom made parts. Both the electronic controller and the pump can be assembled relatively easily. Pump performance has been evaluated at room temperature (22 degrees C) and atmospheric pressure using liquids with low and moderately high viscosities, such as ethanol and corn oil, respectively. At ambient conditions, the pump delivered continuous flow of ethanol and corn oil at a flow rate of up to 170 and 17 cm3/min, respectively. For pumping viscous fluids comparable to corn oil, an optimum reciprocation frequency was ascertained to maximize flow rate. For low viscosity liquids such as ethanol, a linear relationship between the flow rate and reciprocation frequency was determined up to the maximum reciprocation frequency of the pump. Since its fabrication, the pump has been used in our laboratory for circulating triglycerides in contact with supercritical carbon dioxide at pressures of up to 25 MPa (3600 psi) and temperatures up to 70 degrees C on a daily basis for a total of more than 1500 h of operation functioning trouble free.

Redesigning flow injection after 40 years of development: Flow programming.

PubMed

Ruzicka, Jaromir Jarda

2018-01-01

Automation of reagent based assays, by means of Flow Injection (FI), is based on sample processing, in which a sample flows continuously towards and through a detector for quantification of the target analyte. The Achilles heel of this methodology, the legacy of Auto Analyzer®, is continuous reagent consumption, and continuous generation of chemical waste. However, flow programming, assisted by recent advances in precise pumping, combined with the lab-on-valve technique, allows the FI manifold to be designed around a single confluence point through which sample and reagents are sequentially directed by means of a series of flow reversals. This approach results in sample/reagent mixing analogous to the traditional FI, reduces sample and reagent consumption, and uses the stop flow technique for enhancement of the yield of chemical reactions. The feasibility of programmable Flow Injection (pFI) is documented by example of commonly used spectrophotometric assays of, phosphate, nitrate, nitrite and glucose. Experimental details and additional information are available in online tutorial http://www.flowinjectiontutorial.com/. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimating mechanical blood trauma in a centrifugal blood pump: laser Doppler anemometer measurements of the mean velocity field.

PubMed

Pinotti, M; Paone, N

1996-06-01

A laser Doppler anemometer (LDA) was used to obtain the mean velocity and the Reynolds stress fields in the inner channels of a well-known centrifugal vaneless pump (Bio-pump). Effects of the excessive flow resistance against which an occlusive pump operates in some surgical situations, such as cardiopulmonary bypass, are illustrated. The velocity vector field obtained from LDA measurements reveals that the constraint-forced vortex provides pumping action in a restricted area in the core of the pump. In such situations, recirculating zones dominate the flow and consequently increase the damage to blood cells and raise the risk of thrombus formation in the device. Reynolds normal and shear stress fields were obtained in the entry flow for the channel formed by two rotating cones to illustrate the effects of flow disturbances on the potential for blood cell damage.

Estimating Mechanical Blood Trauma in a Centrifugal Blood Pump: Laser Doppler Anemometer Measurements of the Mean Velocity Field.

PubMed

Pinotti, Marcos; Paone, Nicola

1996-05-01

A laser Doppler anemometer (LDA) was used to obtain the mean velocity and the Reynolds stress fields in the inner channels of a well-known centrifugal vaneless pump (Bio-pump). Effects of the excessive flow resistance against which an occlusive pump operates in some surgical situations, such as cardiopulmonary bypass, are illustrated. The velocity vector field obtained from LDA measurements reveals that the constraint-forced vortex provides pumping action in a restricted area in the core of the pump. In such situations, recirculating zones dominate the flow and consequently increase the damage to blood cells and raise the risk of thrombus formation in the device. Reynolds normal and shear stress fields were obtained in the entry flow for the channel formed by two rotating cones to illustrate the effects of flow disturbances on the potential for blood cell damage. © 1996 International Society for Artificial Organs.

Using Self Potential and Multiphase Flow Modeling to Optimize Groundwater Pumping

NASA Astrophysics Data System (ADS)

Gasperikova, E.; Zhang, Y.; Hubbard, S.

2008-12-01

Numerical and field hydrological and geophysical studies have been conducted to investigate the impact of groundwater pumping on near-river hydrology for a segment of the Russian River at the Wohler Site, California, which is a riverbed filtration system managed by the Sonoma County Water Agency. Groundwater pumping near streams can cause a creation of unsaturated regions and hence reduce the pumping capacity and change the flow paths. A three-dimensional multiphase flow and transport model can be calibrated to the temperature, and water levels at monitoring wells based on known pumping rates, and the river stage. Streaming (self) potential (SP) is one of the electrokinetic processes that describes the coupled behavior of hydraulic and electrical flow within a porous medium, and is easily measured on the surface or in boreholes. Observing temporal and spatial variations in geophysical signatures provides a powerful approach for monitoring changes in the natural systems due to natural or forced (pumping) system perturbations. Geophysical and hydrological data were collected before, during and after a pumping experiment at the Wohler Site. Using this monitoring dataset, we illustrate how loose coupling between hydrogeological and geophysical (SP) processes and data can be used to calibrate the flow model and to optimize pumping schedules as needed to guide sustainable water resource development.

Classification of Unsteady Flow Patterns in a Rotodynamic Blood Pump: Introduction of Non-Dimensional Regime Map.

PubMed

Shu, Fangjun; Vandenberghe, Stijn; Brackett, Jaclyn; Antaki, James F

2015-09-01

Rotodynamic blood pumps (also known as rotary or continuous flow blood pumps) are commonly evaluated in vitro under steady flow conditions. However, when these devices are used clinically as ventricular assist devices (VADs), the flow is pulsatile due to the contribution of the native heart. This study investigated the influence of this unsteady flow upon the internal hemodynamics of a centrifugal blood pump. The flow field within the median axial plane of the flow path was visualized with particle image velocimetry (PIV) using a transparent replica of the Levacor VAD. The replica was inserted in a dynamic cardiovascular simulator that synchronized the image acquisition to the cardiac cycle. As compared to steady flow, pulsatile conditions produced periodic, transient recirculation regions within the impeller and separation in the outlet diffuser. Dimensional analysis revealed that the flow characteristics could be uniquely described by the non-dimensional flow coefficient (Φ) and its time derivative ([Formula: see text]), thereby eliminating impeller speed from the experimental matrix. Four regimes within the Φ-[Formula: see text] plane were found to classify the flow patterns, well-attached or disturbed. These results and methods can be generalized to provide insights for both design and operation of rotodynamic blood pumps for safety and efficacy.

Design and optimization of a Holweck pump via linear kinetic theory

NASA Astrophysics Data System (ADS)

Naris, Steryios; Koutandou, Eirini; Valougeorgis, Dimitris

2012-05-01

The Holweck pump is widely used in the vacuum pumping industry. It can be a self standing apparatus or it can be part of a more advanced pumping system. It is composed by an inner rotating cylinder (rotor) and an outer stationary cylinder (stator). One of them, has spiral guided grooves resulting to a gas motion from the high towards the low vacuum port. Vacuum pumps may be simulated by the DSMC method but due to the involved high computational cost in many cases manufactures commonly resort to empirical formulas and experimental data. Recently a computationally efficient simulation of the Holweck pump via linear kinetic theory has been proposed by Sharipov et al [1]. Neglecting curvature and end effects the gas flow configuration through the helicoidal channels is decomposed into four basic flows. They correspond to pressure and boundary driven flows through a grooved channel and through a long channel with a T shape cross section. Although the formulation and the methodology are explained in detail, results are very limited and more important they are presented in a normalized way which does not provide the needed information about the pump performance in terms of the involved geometrical and flow parameters. In the present work the four basic flows are solved numerically based on the linearized BGK model equation subjected to diffuse boundary conditions. The results obtained are combined in order to create a database of the flow characteristics for a large spectrum of the rarefaction parameter and various geometrical configurations. Based on this database the performance characteristics which are critical in the design of the Holweck pump are computed and the design parameters such as the angle of the pump and the rotational speed, are optimized. This modeling may be extended to other vacuum pumps.

Analytical Solution for Flow to a Partially Penetrating Well with Storage in a Confined Aquifer

NASA Astrophysics Data System (ADS)

Vesselinov, V. V.; Mishra, P. K.; Neuman, S. P.

2009-12-01

Analytical solutions for radial flow toward a pumping well are commonly applied to analyze pumping tests conducted in confined aquifers. However, the existing analytical solutions are not capable to simultaneously take into account aquifer anisotropy, partial penetration, and wellbore storage capacity of pumping well. Ignoring these effects may have important impact on the estimated aquifer properties. We present a new analytical solution for three-dimensional, axially symmetric flow to a pumping well in confined aquifer that accouts for aquifer anisotropy, partial penetration and wellbore storage capacity of pumping well. Our analytical reduces to that of Papadopulos et.al. [1967] when the pumping well is fully penetrating, Hantush [1964] when the pumping well has no wellbore storage, and Theis [1935] when both conditions are fulfilled. The solution is evaluated through numerical inversion of its Laplace transform. We use our new solution to analyze data from synthetic and real pumping tests.

Modeling of flowing gas diode pumped alkali lasers: dependence of the operation on the gas velocity and on the nature of the buffer gas.

PubMed

Barmashenko, B D; Rosenwaks, S

2012-09-01

A simple, semi-analytical model of flowing gas diode pumped alkali lasers (DPALs) is presented. The model takes into account the rise of temperature in the lasing medium with increasing pump power, resulting in decreasing pump absorption and slope efficiency. The model predicts the dependence of power on the flow velocity in flowing gas DPALs and checks the effect of using a buffer gas with high molar heat capacity and large relaxation rate constant between the 2P3/2 and 2P1/2 fine-structure levels of the alkali atom. It is found that the power strongly increases with flow velocity and that by replacing, e.g., ethane by propane as a buffer gas the power may be further increased by up to 30%. Eight kilowatt is achievable for 20 kW pump at flow velocity of 20  m/s.

Development and Characterization a Single-Active-Chamber Piezoelectric Membrane Pump with Multiple Passive Check Valves.

PubMed

Zhang, Ronghui; You, Feng; Lv, Zhihan; He, Zhaocheng; Wang, Haiwei; Huang, Ling

2016-12-12

In order to prevent the backward flow of piezoelectric pumps, this paper presents a single-active-chamber piezoelectric membrane pump with multiple passive check valves. Under the condition of a fixed total number of passive check valves, by means of changing the inlet valves and outlet valves' configuration, the pumping characteristics in terms of flow rate and backpressure are experimentally investigated. Like the maximum flow rate and backpressure, the testing results show that the optimal frequencies are significantly affected by changes in the number inlet valves and outlet valves. The variation ratios of the maximum flow rate and the maximum backpressure are up to 66% and less than 20%, respectively. Furthermore, the piezoelectric pump generally demonstrates very similar flow rate and backpressure characteristics when the number of inlet valves in one kind of configuration is the same as that of outlet valves in another configuration. The comparison indicates that the backflow from the pumping chamber to inlet is basically the same as the backflow from the outlet to the pumping chamber. No matter whether the number of inlet valves or the number of outlet valves is increased, the backflow can be effectively reduced. In addition, the backpressure fluctuation can be significantly suppressed with an increase of either inlet valves or outlet valves. It also means that the pump can prevent the backflow more effectively at the cost of power consumption. The pump is very suitable for conditions where more accurate flow rates are needed and wear and fatigue of check valves often occur.

Integrated Analysis of Flow, Temperature, and Specific-Conductance Logs and Depth-Dependent Water-Quality Samples from Three Deep Wells in a Fractured-Sandstone Aquifer, Ventura County, California

USGS Publications Warehouse

Williams, John H.; Knutson, Kevin D.

2009-01-01

Analysis of flow, temperature, and specific-conductance logs and depth-dependent water-quality samples collected under ambient and pumped conditions provided a preliminary delineation of flow zones and water quality in three deep abandoned water-supply wells. The integrated analysis was completed as part of the characterization of a fractured-sandstone aquifer in the mountainous setting of the Santa Susana Field Laboratory in southern Ventura County, California. In the deepest well, which was 1,768 feet deep and had the highest specific capacity (120 gallons per minute per foot), flow zones were detected at 380 feet (base of casing) and at 440, 595, and 770 feet in the open hole. Under ambient conditions, measured flow was downward from the 380- and 440-foot zones to the 595- and 770-foot zones. Under pumped conditions, most of flow was contributed by the 595-foot zone. Flow from the 380- and 440-foot zones appeared to have lower specific conductance and higher trichloroethylene concentrations than that from the 595-foot zone. In the shallowest well, which was reportedly 940 feet deep but only logged to 915 feet due to blockage, flow zones were detected behind the perforated casing and at 867 feet in the open hole. Under ambient conditions, downward and upward flows appeared to exit at a zone behind the perforated casing at 708 feet. Most of the pumped flow was contributed from zones behind the perforated casing between 565 and 708 feet. Pumped flow also was contributed by zones at 867 feet and below the logged depth. Volatile organic compounds were not detected in the ambient and pumped flows. In the third well, which was 1,272 feet deep and had the lowest specific capacity (3.6 gallons per minute per foot), flow zones were detected in the open hole above and just below the water level near 337 feet and at 615, 785, 995, and 1,070 feet. Under ambient conditions, measured flow in well was downward from the shallowmost zones to the 995-foot zone. Fracture zones at 615, 785, and 995 feet each contributed about one-third of the pumped flow measured below the pump. Volatile organic compounds were not detected in the ambient and pumped flows.

Rotary piston blood pumps: past developments and future potential of a unique pump type.

PubMed

Wappenschmidt, Johannes; Autschbach, Rüdiger; Steinseifer, Ulrich; Schmitz-Rode, Thomas; Margreiter, Raimund; Klima, Günter; Goetzenich, Andreas

2016-08-01

The design of implantable blood pumps is either based on displacement pumps with membranes or rotary pumps. Both pump types have limitations to meet the clinical requirements. Rotary piston blood pumps have the potential to overcome these limitations and to merge the benefits. Compared to membrane pumps, they are smaller and with no need for wear-affected membranes and valves. Compared to rotary pumps, the blood flow is pulsatile instead of a non-physiological continuous flow. Furthermore, the risk of flow-induced blood damage and platelet activation may be reduced due to low shear stress to the blood. The past developments of rotary piston blood pumps are summarized and the main problem for long-term application is identified: insufficient seals. A new approach with seal-less drives is proposed and current research on a simplified rotary piston design is presented. Expert commentary: The development of blood pumps focuses mainly on the improvement of rotary pumps. However, medical complications indicate that inherent limitations of this pump type remain and restrict the next substantial step forward in the therapy of heart failure patients. Thus, research on different pump types is reasonable. If the development of reliable drives and bearings succeeds, rotary piston blood pumps become a promising alternative.

Computational fluid dynamics investigation of turbulence models for non-newtonian fluid flow in anaerobic digesters.

PubMed

Wu, Binxin

2010-12-01

In this paper, 12 turbulence models for single-phase non-newtonian fluid flow in a pipe are evaluated by comparing the frictional pressure drops obtained from computational fluid dynamics (CFD) with those from three friction factor correlations. The turbulence models studied are (1) three high-Reynolds-number k-ε models, (2) six low-Reynolds-number k-ε models, (3) two k-ω models, and (4) the Reynolds stress model. The simulation results indicate that the Chang-Hsieh-Chen version of the low-Reynolds-number k-ε model performs better than the other models in predicting the frictional pressure drops while the standard k-ω model has an acceptable accuracy and a low computing cost. In the model applications, CFD simulation of mixing in a full-scale anaerobic digester with pumped circulation is performed to propose an improvement in the effective mixing standards recommended by the U.S. EPA based on the effect of rheology on the flow fields. Characterization of the velocity gradient is conducted to quantify the growth or breakage of an assumed floc size. Placement of two discharge nozzles in the digester is analyzed to show that spacing two nozzles 180° apart with each one discharging at an angle of 45° off the wall is the most efficient. Moreover, the similarity rules of geometry and mixing energy are checked for scaling up the digester.

SCALE-MODEL STUDIES OF MIXING IN DRINKING WATER STORAGE TANKS

EPA Science Inventory

Storage tanks and reservoirs are commonly used in drinking water distribution systems to equalize pumping requirements and operating pressures, and to provide emergency water for fire-fighting and pumping outages. Poor mixing in these structures can create pockets of older water...

Zero Gravity Cryogenic Vent System Concepts for Upper Stages

NASA Astrophysics Data System (ADS)

Ravex, Alain; Flachbart, Robin; Holt, Barney

The capability to vent in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray bar system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses. TVS performance testing demonstrated that the spray bar was effective in providing tank pressure control within a 6.89 kPa (1psi) band for fill levels of 90%, 50%, and 25%. Complete destratification of the liquid and ullage was achieved at these fill levels. The axial jet was effective in providing tank pressure control within the same pressure control band at the 90% fill level. However, at the 50% level, the system reached a point at which it was unable to extract enough energy to keep up with the heat leak into the tank. Due to a hardware problem, the recirculation pump operated well below the axial jet design flow rate. Therefore, it is likely that the performance of the axial jet would have improved had the pump operated at the proper flow rate. A CFD model is being used to determine if the desired axial jet performance would be achieved if a higher pump flow rate were available. Testing conducted thus far has demonstrated that both TVS concepts can be effective in destratifying a propellant tank, rejecting stored heat energy, and thus, controlling tank pressure.

Characterization of interactions between sub-surface compartments and a deep sub-vertical aquifer in crystalline basement (St-Brice en Coglès, French Brittany)

NASA Astrophysics Data System (ADS)

Roques, C.; Bour, O.; Aquilina, L.; Longuevergne, L.; Dewandel, B.; Hochreutener, R.; Schroetter, J.; Labasque, T.; Lavenant, N.

2012-12-01

Hard-rock aquifers constitute in general a limited groundwater resource whose upper part is particularly sensitive to anthropogenic activities. Locally, some high production aquifers can be encountered, typically near regional tectonic discontinuities which may constitute preferential flow paths. However, this kind of aquifer, in particular their interactions with sub-surface, is often very difficult to characterize. We investigated the hydrogeological functioning of a deep vertical conductive fractured zone, focusing on the interactions between hydrologic compartments, thanks to a multidisciplinary approach and a variety of field experiments. A specific field site located in north east of French Brittany, in crystalline bedrock, was selected because of high measured yields during drilling (100 m3/h), essentially related to permeable fractures at 120 m depth and deeper. Three deep boreholes 80 to 250 deep were drilled at relatively short distances (typically 30 meters); one of them has been cored for detailed geological information. Shallower boreholes were also drilled (7 to 20 m deep) to characterize the upper weathered compartment and the hydraulic connections with the deep compartment. The system was characterized both in natural conditions and during a 9-week large scale pumping test carried out at a pumping rate of 45 m3/h. To describe the hydraulic properties and the functioning of the deep hydraulic structure, we used a multidisciplinary approach: (a) well head variations and traditional pumping test interpretations, (b) high-resolution flow loggings to identify fracture connectivity, (c) tracer tests to estimate transfer times and groundwater fluxes between main compartments and (d) multi-parameters fluid logging, geochemistry and groundwater dating to identify water origin and mixing processes between different reservoirs. The geometry of the main permeable structure has been identified combining geological information and hydraulic interpretations. It shows a clear compartmentalization of the aquifer with a strong spatial heterogeneity in permeability. Although using a packer to force the pumping to be deeper than 80 meters, a very fast reaction of the upper aquifer during pumping with clear leaky effects was observed. Heat-Pulse Flowmeter logs also show the interconnections between compartments. During the pumping, we also monitored a high decrease of groundwater ages of the water pumped. Combination of all these methods allowed the flow connections between compartments to be identified and the fluxes between the different compartments to be quantified. We show in particular how the deep groundwater resource is strongly dependent of shallower compartments. Identifying flow properties and origin of water in a deep aquifer is an important issue to optimize the management of such groundwater resources. In particular the estimation of the groundwater capacity, and also to predict groundwater quality changes are essential. This study allows quantifying fluxes between compartments both in natural and pumping conditions. Such a characterization is crucial to assess the sustainability of deep hard-rock aquifers for groundwater supply.

The relationship between dynamic and average flow rates of the coolant in the channels of complex shape

NASA Astrophysics Data System (ADS)

Fedoseev, V. N.; Pisarevsky, M. I.; Balberkina, Y. N.

2018-01-01

This paper presents interconnection of dynamic and average flow rates of the coolant in a channel of complex geometry that is a basis for a generalization model of experimental data on heat transfer in various porous structures. Formulas for calculation of heat transfer of fuel rods in transversal fluid flow are acquired with the use of the abovementioned model. It is shown that the model describes a marginal case of separated flows in twisting channels where coolant constantly changes its flow direction and mixes in the communicating channels with large intensity. Dynamic speed is suggested to be identified by power for pumping. The coefficient of proportionality in general case depends on the geometry of the channel and the Reynolds number (Re). A calculation formula of the coefficient of proportionality for the narrow line rod packages is provided. The paper presents a comparison of experimental data and calculated values, which shows usability of the suggested models and calculation formulas.

A High Performance Pulsatile Pump for Aortic Flow Experiments in 3-Dimensional Models.

PubMed

Chaudhury, Rafeed A; Atlasman, Victor; Pathangey, Girish; Pracht, Nicholas; Adrian, Ronald J; Frakes, David H

2016-06-01

Aortic pathologies such as coarctation, dissection, and aneurysm represent a particularly emergent class of cardiovascular diseases. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies, as well as for planning their surgical repair. In vitro experiments are required to validate the simulations against real world data, and the experiments require a pulsatile flow pump system that can provide physiologic flow conditions characteristic of the aorta. We designed a newly capable piston-based pulsatile flow pump system that can generate high volume flow rates (850 mL/s), replicate physiologic waveforms, and pump high viscosity fluids against large impedances. The system is also compatible with a broad range of fluid types, and is operable in magnetic resonance imaging environments. Performance of the system was validated using image processing-based analysis of piston motion as well as particle image velocimetry. The new system represents a more capable pumping solution for aortic flow experiments than other available designs, and can be manufactured at a relatively low cost.

Theoretical prediction of fast 3D AC electro-osmotic pumps.

PubMed

Bazant, Martin Z; Ben, Yuxing

2006-11-01

AC electro-osmotic (ACEO) pumps in microfluidics currently involve planar electrode arrays, but recent work on the underlying phenomenon of induced-charge electro-osmosis (ICEO) suggests that three-dimensional (3D) geometries may be exploited to achieve faster flows. In this paper, we present some new design principles for periodic 3D ACEO pumps, such as the "fluid conveyor belt" of ICEO flow over a stepped electrode array. Numerical simulations of these designs (using the standard low-voltage model) predict flow rates almost twenty times faster than existing planar ACEO pumps, for the same applied voltage and minimum feature size. These pumps may enable new portable or implantable lab-on-a-chip devices, since rather fast (mm s(-1)), tuneable flows should be attainable with battery voltages (<10 V).

Development of a flow feedback pulse duplicator system with rhesus monkey arterial input impedance characteristics

NASA Technical Reports Server (NTRS)

Schaub, J. D.; Koenig, S. C.; Schroeder, M. J.; Ewert, D. L.; Drew, G. A.; Swope, R. D.; Convertino, V. A. (Principal Investigator)

1999-01-01

An in vitro pulsatile pump flow system that is capable of producing physiologic pressures and flows in a mock circulatory system tuned to reproduce the first nine harmonics of the input impedance of a rhesus monkey was developed and tested. The system was created as a research tool for evaluating cardiovascular function and for the design, testing, and evaluation of electrical-mechanical cardiovascular models and chronically implanted sensors. The system possesses a computerized user interface for controlling a linear displacement pulsatile pump in a controlled flow loop format to emulate in vivo cardiovascular characteristics. Evaluation of the pump system consisted of comparing its aortic pressure and flow profiles with in vivo rhesus hemodynamic waveforms in the time and frequency domains. Comparison of aortic pressure and flow data between the pump system and in vivo data showed good agreement in the time and frequency domains, however, the pump system produced a larger pulse pressure. The pump system can be used for comparing cardiovascular parameters with predicted cardiovascular model values and for evaluating such items as vascular grafts, heart valves, biomaterials, and sensors. This article describes the development and evaluation of this feedback controlled cardiovascular dynamics simulation modeling system.

Estimating Hyrdologic Properties of Groundwater Wells Using Tracer Pulse Dynamic Flow Profiling

NASA Astrophysics Data System (ADS)

Miles, K. A.; Heller, N.

2016-12-01

Traditional groundwater well design places the pump intake above the top of the well screen. It is common in this case to design the well screen for uniform entrance velocity along the profile of the well screen, even though non-uniform flow may occur. Particularly in the case where the pump is set near the very top or bottom of the well, there are instances where the zonal testing with a test pump indicates favorable water quality at one pump depth of the groundwater production well, and the water quality results yielded from the well at another depth are not compliant with federal and state regulatory limits for various naturally occurring and anthropogenic compounds. Well bore flow velocity and chemistry were determined using the USGS Tracer Pulse Dynamic Flow Profiling method along the length of well screens, while varying the pump depth. The information was then used to perform a flow and chemical mass balance to characterize the distribution of flow and chemical contribution, groundwater well screen entrance velocities, and hydrologic parameters. The presented results show pump placement affecting the average chemical discharge, and entrance velocities along the length of well screens.

Acoustically and Electrokinetically Driven Transport in Microfluidic Devices

NASA Astrophysics Data System (ADS)

Sayar, Ersin

Electrokinetically driven flows are widely employed as a primary method for liquid pumping in micro-electromechanical systems. Mixing of analytes and reagents is limited in microfluidic devices due to the low Reynolds number of the flows. Acoustic excitations have recently been suggested to promote mixing in the microscale flow systems. Electrokinetic flows through straight microchannels were investigated using the Poisson-Boltzmann and Nernst-Planck models. The acoustic wave/fluid flow interactions in a microchannel were investigated via the development of two and three-dimensional dynamic predictive models for flows with field couplings of the electrical, mechanical and fluid flow quantities. The effectiveness and applicability of electrokinetic augmentation in flexural plate wave micropumps for enhanced capabilities were explored. The proposed concept can be exploited to integrate micropumps into complex microfluidic chips improving the portability of micro-total-analysis systems along with the capabilities of actively controlling acoustics and electrokinetics for micro-mixer applications. Acoustically excited flows in microchannels consisting of flexural plate wave devices and thin film resonators were considered. Compressible flow fields were considered to accommodate the acoustic excitations produced by a vibrating wall. The velocity and pressure profiles for different parameters including frequency, channel height, wave amplitude and length were investigated. Coupled electrokinetics and acoustics cases were investigated while the electric field intensity of the electrokinetic body forces and actuation frequency of acoustic excitations were varied. Multifield analysis of a piezoelectrically actuated valveless micropump was also presented. The effect of voltage and frequency on membrane deflection and flow rate were investigated. Detailed fluid/solid deformation coupled simulations of piezoelectric valveless micropump have been conducted to predict the generated time averaged flow rates. Developed coupled solid and fluid mechanics models can be utilized to integrate flow-through sensors with microfluidic chips.

Experimental measurements of energy augmentation for mechanical circulatory assistance in a patient-specific Fontan model.

PubMed

Chopski, Steven G; Rangus, Owen M; Moskowitz, William B; Throckmorton, Amy L

2014-09-01

A mechanical blood pump specifically designed to increase pressure in the great veins would improve hemodynamic stability in adolescent and adult Fontan patients having dysfunctional cavopulmonary circulation. This study investigates the impact of axial-flow blood pumps on pressure, flow rate, and energy augmentation in the total cavopulmonary circulation (TCPC) using a patient-specific Fontan model. The experiments were conducted for three mechanical support configurations, which included an axial-flow impeller alone in the inferior vena cava (IVC) and an impeller with one of two different protective stent designs. All of the pump configurations led to an increase in pressure generation and flow in the Fontan circuit. The increase in IVC flow was found to augment pulmonary arterial flow, having only a small impact on the pressure and flow in the superior vena cava (SVC). Retrograde flow was neither observed nor measured from the TCPC junction into the SVC. All of the pump configurations enhanced the rate of power gain of the cavopulmonary circulation by adding energy and rotational force to the fluid flow. We measured an enhancement of forward flow into the TCPC junction, reduction in IVC pressure, and only minimally increased pulmonary arterial pressure under conditions of pump support. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Effects of atmospheric pressure conditions on flow rate of an elastomeric infusion pump.

PubMed

Wang, Jong; Moeller, Anna; Ding, Yuanpang Samuel

2012-04-01

The effects of pressure conditions, both hyperbaric and hypobaric, on the flow rate of an elastomeric infusion pump were investigated. The altered pressure conditions were tested with the restrictor outlet at two different conditions: (1) at the same pressure condition as the Infusor elastomeric balloon and (2) with the outlet exposed to ambient conditions. Five different pressure conditions were tested. These included ambient pressure (98-101 kilopascals [kPa]) and test pressures controlled to be 10 or 20 kPa below or 75 or 150 kPa above the ambient pressure. A theoretical calculation based on the principles of fluid mechanics was also used to predict the pump's flow rate at various ambient conditions. The conditions in which the Infusor elastomeric pump and restrictor outlet were at the same pressure gave rise to average flow rates within the ±10% tolerance of the calculated target flow rate of 11 mL/hr. The flow rate of the Infusor pump decreased when the pressure conditions changed from hypobaric to ambient. The flow rate increased when the pressure conditions changed from hyperbaric to ambient. The flow rate of the Infusor elastomeric pump was not affected when the balloon reservoir and restrictor outlet were at the same pressure. The flow rate varied from 58.54% to 377.04% of the labeled flow rate when the pressure applied to the reservoir varied from 20 kPa below to 150 kPa above the pressure applied to the restrictor outlet, respectively. The maximum difference between observed flow rates and those calculated by applying fluid mechanics was 4.9%.

Microcapillary-Based Flow-Through Immunosensor and Displacement Immunoassay Using the Same.

DTIC Science & Technology

1997-04-28

an antibody. If desired, an electroosmotic 24 pump may be used to flow fluid through the microcapillary or 25 microcapillaries in the chip...8 for field use. 9 Fig. 1C shows a flow immunosensor chip 100. Buffer flow 10 through microcapillary passage 102 by virtue of an electroosmotic ...Power for an 23 electroosmotic pump or other fluid pump, as well as any other on- 24 chip components, may be provided by a battery incorporated into

Turbine-Driven Pipe-Cleaning Brush

NASA Technical Reports Server (NTRS)

Werlink, Rudy J.; Rowell, David E.

1994-01-01

Simple pipe-cleaning device includes small turbine wheel axially connected, by standoff, to circular brush. Turbine wheel turns on hub bearing attached to end of upstream cable. Turbine-and-brush assembly inserted in pipe with cable trailing upstream and brush facing downstream. Water or cleaning solution pumped through pipe. Cable held at upstream end, so it holds turbine and brush in pipe at location to be cleaned. Flow in pipe turns turbine, which turns wheel, producing desired cleaning action. In addition to brushing action, device provides even mixing of cleaning solution in pipe.

Estimating Vibrational Powers Of Parts In Fluid Machinery

NASA Technical Reports Server (NTRS)

Harvey, S. A.; Kwok, L. C.

1995-01-01

In new method of estimating vibrational power associated with component of fluid-machinery system, physics of flow through (or in vicinity of) component regarded as governing vibrations. Devised to generate scaling estimates for design of new parts of rocket engines (e.g., pumps, combustors, nozzles) but applicable to terrestrial pumps, turbines, and other machinery in which turbulent flows and vibrations caused by such flows are significant. Validity of method depends on assumption that fluid flows quasi-steadily and that flow gives rise to uncorrelated acoustic powers in different parts of pump.

An efficient continuous-wave 591 nm light source based on sum-frequency mixing of a diode pumped Nd:GdVO4-Nd:CNGG laser

NASA Astrophysics Data System (ADS)

Zhao, Y. D.; Liu, J. H.

2013-08-01

We report a laser architecture to obtain continuous-wave (CW) yellow-orange light sources at the 591 nm wavelength. An 808 nm diode pumped a Nd:GdVO4 crystal emitting at 1063 nm. A part of the pump power was then absorbed by the Nd:CNGG crystal. The remaining pump power was used to pump a Nd:CNGG crystal emitting at 1329 nm. Intracavity sum-frequency mixing at 1063 and 1329 nm was then realized in a LiB3O5 (LBO) crystal to reach the yellow-orange radiation. We obtained a CW output power of 494 mW at 591 nm with a pump laser diode emitting 17.8 W at 808 nm.

Characterization of a membrane-based, electrochemically driven pumping system using aqueous electrolyte solutions.

PubMed

Norman, Mya A; Evans, Christine E; Fuoco, Anthony R; Noble, Richard D; Koval, Carl A

2005-10-01

Electrokinetic flow provides a mechanism for a variety of fluid pumping schemes. The design and characterization of an electrochemically driven pump that utilizes porous carbon electrodes, iodide/triiodide redox electrolytes, and Nafion membranes is described. Fluid pumping by the cell is reversible and controlled by the cell current. Chronopotentiometry experiments indicate that the total available fluid that can be pumped in a single electrolysis without gas evolution is determined solely by the initial concentration of electrolyte and the applied current. The magnitude of the fluid flow at a given current is determined by the nature of the cation in the electrolyte and by the water absorption properties of the Nafion membrane. For 1 M aqueous electrolytes, pumping rates ranging from 1 to 14 microL/min were obtained for current densities of 10-30 mA/cm2 of membrane area. Molar volume changes for the I3-/I- redox couple and for the alkali cation migration contribute little to the observed volumetric flow rates; the magnitude of the flow is dominated by the migration-induced flow of water.

Performance analysis of axial flow pump on gap changing between impeller and guide vane

NASA Astrophysics Data System (ADS)

Wang, W. J.; Liang, Q. H.; Wang, Y.; Yang, Y.; Yin, G.; Shi, X. X.

2013-12-01

In order to study the influence on gap changing of the static and dynamic components in axial flow pump, the axial flow pump model (TJ04-ZL-06) that used in the eastern of south-to-north water diversion project was selected. Steady turbulence field with different gaps was simulated by standard κ-ε turbulence model and double-time stepping methods. Information on the pressure distribution and velocity distribution of impeller surfaces were obtained. Then, calculated results were compared with the test results and analyzed. The results show that the performance of pump is not sensitive with the axial gap width under design conditions and the large flow rate condition. With increasing gap width, it will be improved in low flow rate condition. The attack angle of impeller inlet in small flow rate condition become small and the flow separation phenomenon can be observed in this condition. The axial velocity distribution of impeller outlet is nonlinear and to increase the axial gap is to improve the flow pattern near the hub effectively. The trend of calculating results is identical with test. It will play a guiding role to the axial pump operation and design in south-to-north water diversion project.

Hazardous Chemical Pump Tests.

DTIC Science & Technology

1980-07-01

hydraulic flow rate is the product of the pump speed and the pump displacement. The pump displacement for each respective pump was constant throughout...speed - rpm T - torque - ft lbs 7= 3.1416 By substituting the product of pump speed and pump displacement for the hydraulic flow rate (Q=NO) in the above...FF:iipr’: iL 40 H FLUID F-’UMPED; FPl H FVIi T’E1l ’HJO I...S Lu FL: H KFITE C F~~:ri FIGURE 2 CC E MT 2, Fi C F . c ;E’C F11 *:;_cl PF fog O ~ \\ 4 1

The mechanism performance of improved oil pump with micro-structured vanes

NASA Astrophysics Data System (ADS)

Li, Ping; Xie, Jin; Qi, Dongtao; Li, Houbu

2017-09-01

The wear of oil pump vanes easily leads to the noise and vibration, even results the decrease of volume efficiency and total efficiency. In order to reduce the friction and improve the lubrication between the vane and the pump inner wall, the micro-machining of micro-structure on the oil pump vanes is proposed. First, the micro-V-grooves with the depth ranging from 500μm to 50μm were micro-grinding on the top of the vanes by a diamond grinding wheel. Secondly, the experiments were conducted to test the actual flow rate, the output power and the overall efficiency of the oil pump with and without the micro-groove vanes. Then, the computational fluid dynamics (CFD) method was adopted to simulate the pump internal flow field. Finally, the micro-flow field between the internal wall of the oil pump and the top of micro-grooved vanes was analyzed. The results shows that the pump overall efficiency increased as the decrease of micro-groove depth from 500 μm to 50μm and not be affected by the rotate speed and working frequency of the pump rotator. Especially the micro-groove with depth of 50μm, the actual flow rate, the output power and the overall efficiency reached to the maximum. From CFD simulation, the velocity of the micro-flow between the surfaces of the vane and inner wall was larger than the pump linear velocity when the microstructure depth is larger than 50μm, leading to an internal leakage. When the micro-groove depth is between10-50μm, the velocity of the micro-flow was less than the pump linear velocity and no internal leakage was found, but the oil film thickness is too small to be beneficial to lubrication according to the fluid dynamic characteristics. Thus, for the oil pump equipping with micro-grooved vane with the depth of 50 μm, the internal leakage not only is avoided but the lubrication efficiency is improved and the oil pump efficiency is also enhanced.

Design and evaluation of a single-pivot supported centrifugal blood pump.

PubMed

Yoshino, M; Uemura, M; Takahashi, K; Watanabe, N; Hoshi, H; Ohuchi, K; Nakamura, M; Fujita, H; Sakamoto, T; Takatani, S

2001-09-01

In order to develop a centrifugal blood pump that meets the requirements of a long-term, implantable circulatory support device, in this study a single-pivot bearing supported centrifugal blood pump was designed to evaluate its basic performance. The single-pivot structure consisted of a ceramic ball male pivot mounted on the bottom surface of the impeller and a polyethylene female pivot incorporated in the bottom pump casing. The follower magnet mounted inside the impeller was magnetically coupled to the driver magnet mounted on the shaft of the direct current brushless motor. As the motor rotated, the impeller rotated supported entirely by a single-pivot bearing system. The static pump performance obtained in the mock circulatory loop revealed an acceptable performance as a left ventricular assist device in terms of flow and head pressure. The pump flow of 5 L/min against the head pressure of 100 mm Hg was obtained at rotational speeds of 2,000 to 2,200 rpm. The maximum pump flow was 9 L/min with 2,200 rpm. The maximum electrical-to-hydraulic power conversion efficiency was around 14% at pump flows of 4 to 5 L/min. The stability of the impeller was demonstrated at the pump rpm higher than 1,400 with a single-pivot bearing without an additional support at its top. The single-pivot supported centrifugal pump can provide adequate flow and pressure as a ventricular assist device, but its mechanical stability and hemolytic as well as thrombotic performances must be tested prior to clinical use.

Experimental and Numerical Analysis of Performance Discontinuity of a Pump-Turbine under Pumping Mode

NASA Astrophysics Data System (ADS)

Zhang, X.; Burgstaller, R.; Lai, X.; Gehrer, A.; Kefalas, A.; Pang, Y.

2016-11-01

The performance discontinuity of a pump-turbine under pumping mode is harmful to stable operation of units in hydropower station. In this paper, the performance discontinuity phenomenon of the pump-turbine was studied by means of experiment and numerical simulation. In the experiment, characteristics of the pump-turbine with different diffuser vane openings were tested in order to investigate the effect of pumping casing to the performance discontinuity. While other effects such as flow separation and rotating stall are known to have an effect on the discontinuity, the present studied test cases show that prerotation is the dominating effect for the instability, positions of the positive slope of characteristics are almost the same in different diffuser vane opening conditions. The impeller has principal effect to the performance discontinuity. In the numerical simulation, CFD analysis of tested pump-turbine has been done with k-ω and SST turbulence model. It is found that the position of performance curve discontinuity corresponds to flow recirculation at impeller inlet. Flow recirculation at impeller inlet is the cause of the discontinuity of characteristics curve. It is also found that the operating condition of occurrence of flow recirculation at impeller inlet is misestimated with k-ω and SST turbulence model. Furthermore, the original SST model has been modified. We predict the occurrence position of flow recirculation at impeller inlet correctly with the modified SST turbulence model, and it also can improve the prediction accuracy of the pump- turbine performance at the same time.

Effects of groundwater pumping on agricultural drains in the Tule Lake subbasin, Oregon and California

USGS Publications Warehouse

Pischel, Esther M.; Gannett, Marshall W.

2015-07-24

To better define the effect of increased pumping on drain flow and on the water balance of the groundwater system, the annual water volume pumped from drains in three subareas of the Tule Lake subbasin was estimated and a fine-grid, local groundwater model of the Tule Lake subbasin was constructed. Results of the agricultural-drain flow analysis indicate that groundwater discharge to drains has decreased such that flows in 2012 were approximately 32,400 acre-ft less than the 1997–2000 average flow. This decrease was concentrated in the northern and southeastern parts of the subbasin, which corresponds with the areas of greatest groundwater pumping. Model simulation results of the Tule Lake subbasin groundwater model indicate that increased supplemental pumping is the dominant stress to the groundwater system in the subbasin. Simulated supplemental pumping and decreased recharge from irrigation between 2000 and 2010 totaled 323,573 acre-ft, 234,800 acre-ft (73 percent) of which was from supplemental pumping. The response of the groundwater system to this change in stress included about 180,500 acre-ft (56 percent) of decreased groundwater discharge to drains and a 126,000 acre-ft (39 percent) reduction in aquifer storage. The remaining 5 percent came from reduced groundwater flow to other model boundaries, including the Lost River, the Tule Lake sumps, and interbasin flow.

Total heart replacement using dual intracorporeal continuous-flow pumps in a chronic bovine model: a feasibility study.

PubMed

Frazier, O H; Tuzun, Egemen; Cohn, William E; Conger, Jeffrey L; Kadipasaoglu, Kamuran A

2006-01-01

Continuous-flow pumps are small, simple, and respond physiologically to input variations, making them potentially ideal for total heart replacement. However, the physiological effects of complete pulseless flow during long-term circulatory support without a cardiac interface or with complete cardiac exclusion have not been well studied. We evaluated the feasibility of dual continuous-flow pumps as a total artificial heart (TAH) in a chronic bovine model. Both ventricles of a 6-month-old Corriente crossbred calf were excised and sewing rings attached to the reinforced atrioventricular junctions. The inlet portions of 2 Jarvik 2000 pumps were positioned through their respective sewing rings at the mid-atrial level and the pulseless atrial reservoir connected end-to-end to the pulmonary artery and aorta. Pulseless systemic and pulmonary circulations were thereby achieved. Volume status was controlled, and systemic and pulmonary resistance were managed pharmacologically to keep mean arterial pressures at 100+/-10 mmHg (systemic) and 20+/-5 mmHg (pulmonary) and both left and right atrial pressures at 15+/-5 mmHg. The left pump speed was maintained at 14,000 rpm and its output autoregulated in response to variations in right pump flow, systemic and pulmonary pressures, fluid status, and activity level. Hemodynamics, end-organ function, and neurohormonal status remained normal. These results suggest the feasibility of using dual continuous-flow pumps as a TAH.

Experimental and numerical investigation of centrifugal pumps with asymmetric inflow conditions

NASA Astrophysics Data System (ADS)

Mittag, Sten; Gabi, Martin

2015-11-01

Most of the times pumps operate off best point states. Reasons are changes of operating conditions, modifications, pollution and wearout or erosion. As consequences non-rotational symmetric flows, transient operational conditions, increased risk of cavitation, decrease of efficiency and unpredictable wearout can appear. Especially construction components of centrifugal pumps, in particular intake elbows, contribute to this matter. Intake elbows causes additional losses and secondary flows, hence non-rotational velocity distributions as intake profile to the centrifugal pump. As a result the impeller vanes experience permanent changes of the intake flow angle and with it transient flow conditions in the blade channels. This paper presents the first results of a project, experimentally and numerically investigating the consequences of non-rotational inflow to leading edge flow conditions of a centrifugal pump. Therefore two pumpintake- elbow systems are compared, by only altering the intake elbow geometry: a common single bended 90° elbow and a numerically optimized elbow (improved regarding rotational symmetric inflow conditions and friction coefficient). The experiments are carried out, using time resolved stereoscopic PIV on a full acrylic pump with refractions index matched (RIM) working fluid. This allows transient investigations of the flow field simultaneously for all blade leading edges. Additional CFD results are validated and used to further support the investigation i.e. for comparing an analog pump system with ideal inflow conditions.

Power consumption of rotary blood pumps: pulsatile versus constant-speed mode.

PubMed

Pirbodaghi, Tohid; Cotter, Chris; Bourque, Kevin

2014-12-01

We investigated the power consumption of a HeartMate III rotary blood pump based on in vitro experiments performed in a cardiovascular simulator. To create artificial-pulse mode, we modulated the pump speed by decreasing the mean speed by 2000 rpm for 200 ms and then increasing speed by 4000 rpm (mean speeds plus 2000 rpm) for another 200 ms, creating a square waveform shape. The HeartMate III was connected to a cardiovascular simulator consisting of a hydraulic pump system to simulate left ventricle pumping action, arterial and venous compliance chambers, and an adjustable valve for peripheral resistance to facilitate the desired aortic pressure. The simulator operated based on Suga's elastance model to mimic the Starling response of the heart, thereby reproducing physiological blood flow and pressure conditions. We measured the instantaneous total electrical current and voltage of the pump to evaluate its power consumption. The aim was to answer these fundamental questions: (i) How does pump speed modulation affect pump power consumption? (ii) How does the power consumption vary in relation to external pulsatile flow? The results indicate that speed modulation and external pulsatile flow both moderately increase the power consumption. Increasing the pump speed reduces the impact of external pulsatile flow. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Limiting pumping from the Edwards Aquifer: An economic investigation of proposals, water markets, and spring flow guarantees

NASA Astrophysics Data System (ADS)

McCarl, Bruce A.; Dillon, Carl R.; Keplinger, Keith O.; Williams, R. Lynn

1999-04-01

The Edwards Aquifer, near San Antonio, Texas, is an important water source for both pumping and spring flow, which in turn provides water for recreation and habitat for several endangered species. A management authority is charged with aquifer management and is mandated to reduce pumping, facilitate water markets, protect agricultural rights, and protect the species habitat. This paper examines the economic dimensions of authority duties. A combined hydrologic-economic model is used in the investigation. The results indicate that proposed pumping limits are shown to have large consequences for agricultural usage and to decrease the welfare of current aquifer pumping users. However, the spring flow habitat is found to be protected, and the gains from that protection would have to exceed pumping user losses in order for the protection measures to increase regional economic welfare. Agricultural guarantees are shown to cause use value differences, indicating the opportunity for emergence of an active water market. Fixed quantity pumping limits are found to be an expensive way of insuring adequate spring flow.

A novel miniature dynamic microfluidic cell culture platform using electro-osmosis diode pumping.

PubMed

Chang, Jen-Yung; Wang, Shuo; Allen, Jeffrey S; Lee, Seong Hyuk; Chang, Suk Tai; Choi, Young-Ki; Friedrich, Craig; Choi, Chang Kyoung

2014-07-01

An electro-osmosis (EOS) diode pumping platform capable of culturing cells in fluidic cellular micro-environments particularly at low volume flow rates has been developed. Diode pumps have been shown to be a viable alternative to mechanically driven pumps. Typically electrokinetic micro-pumps were limited to low-concentration solutions (≤10 mM). In our approach, surface mount diodes were embedded along the sidewalls of a microchannel to rectify externally applied alternating current into pulsed direct current power across the diodes in order to generate EOS flows. This approach has for the first time generated flows at ultra-low flow rates (from 2.0 nl/s to 12.3 nl/s) in aqueous solutions with concentrations greater than 100 mM. The range of flow was generated by changing the electric field strength applied to the diodes from 0.5 Vpp/cm to 10 Vpp/cm. Embedding an additional diode on the upper surface of the enclosed microchannel increased flow rates further. We characterized the diode pump-driven fluidics in terms of intensities and frequencies of electric inputs, pH values of solutions, and solution types. As part of this study, we found that the growth of A549 human lung cancer cells was positively affected in the microfluidic diode pumping system. Though the chemical reaction compromised the fluidic control overtime, the system could be maintained fully functional over a long time if the solution was changed every hour. In conclusion, the advantage of miniature size and ability to accurately control fluids at ultra-low volume flow rates can make this diode pumping system attractive to lab-on-a-chip applications and biomedical engineering in vitro studies.

A novel miniature dynamic microfluidic cell culture platform using electro-osmosis diode pumping

PubMed Central

Chang, Jen-Yung; Wang, Shuo; Allen, Jeffrey S.; Lee, Seong Hyuk; Chang, Suk Tai; Choi, Young-Ki; Friedrich, Craig; Choi, Chang Kyoung

2014-01-01

An electro-osmosis (EOS) diode pumping platform capable of culturing cells in fluidic cellular micro-environments particularly at low volume flow rates has been developed. Diode pumps have been shown to be a viable alternative to mechanically driven pumps. Typically electrokinetic micro-pumps were limited to low-concentration solutions (≤10 mM). In our approach, surface mount diodes were embedded along the sidewalls of a microchannel to rectify externally applied alternating current into pulsed direct current power across the diodes in order to generate EOS flows. This approach has for the first time generated flows at ultra-low flow rates (from 2.0 nl/s to 12.3 nl/s) in aqueous solutions with concentrations greater than 100 mM. The range of flow was generated by changing the electric field strength applied to the diodes from 0.5 Vpp/cm to 10 Vpp/cm. Embedding an additional diode on the upper surface of the enclosed microchannel increased flow rates further. We characterized the diode pump-driven fluidics in terms of intensities and frequencies of electric inputs, pH values of solutions, and solution types. As part of this study, we found that the growth of A549 human lung cancer cells was positively affected in the microfluidic diode pumping system. Though the chemical reaction compromised the fluidic control overtime, the system could be maintained fully functional over a long time if the solution was changed every hour. In conclusion, the advantage of miniature size and ability to accurately control fluids at ultra-low volume flow rates can make this diode pumping system attractive to lab-on-a-chip applications and biomedical engineering in vitro studies. PMID:25379101

A two-stage rotary blood pump design with potentially lower blood trauma: a computational study.

PubMed

Thamsen, Bente; Mevert, Ricardo; Lommel, Michael; Preikschat, Philip; Gaebler, Julia; Krabatsch, Thomas; Kertzscher, Ulrich; Hennig, Ewald; Affeld, Klaus

2016-06-15

In current rotary blood pumps, complications related to blood trauma due to shear stresses are still frequently observed clinically. Reducing the rotor tip speed might decrease blood trauma. Therefore, the aim of this project was to design a two-stage rotary blood pump leading to lower shear stresses. Using the principles of centrifugal pumps, two diagonal rotor stages were designed with an outer diameter of 22 mm. The first stage begins with a flow straightener and terminates with a diffusor, while a volute casing behind the second stage is utilized to guide fluid to the outlet. Both stages are combined into one rotating part which is pivoted by cup-socket ruby bearings. Details of the flow field were analyzed employing computational fluid dynamics (CFD). A functional model of the pump was fabricated and the pressure-flow dependency was experimentally assessed. Measured pressure-flow performance of the developed pump indicated its ability to generate adequate pressure heads and flows with characteristic curves similar to centrifugal pumps. According to the CFD results, a pressure of 70 mmHg was produced at a flow rate of 5 L/min and a rotational speed of 3200 rpm. Circumferential velocities could be reduced to 3.7 m/s as compared to 6.2 m/s in a clinically used axial rotary blood pump. Flow fields were smooth with well-distributed pressure fields and comparatively few recirculation or vortices. Substantially smaller volumes were exposed to high shear stresses >150 Pa. Hence, blood trauma might be reduced with this design. Based on these encouraging results, future in vitro investigations to investigate actual blood damage are intended.

The noncavitating performance and life of a small vane-type positive displacement pump in liquid hydrogen

NASA Technical Reports Server (NTRS)

Ulbricht, T. E.; Hemminger, J. A.

1986-01-01

The low flow rate and high head rise requirements of hydrogen/oxygen auxiliary propulsion systems make the application of centrifugal pumps difficult. Positive displacement pumps are well-suited for these flow conditions, but little is known about their performance and life characteristics in liquid hydrogen. An experimental and analytical investigation was conducted to determine the performance and life characteristics of a vane-type, positive displacement pump. In the experimental part of this effort, mass flow rate and shaft torque were determined as functions of shaft speed and pump pressure rise. Since liquid hydrogen offers little lubrication in a rubbing situation, pump life is an issue. During the life test, the pump was operated intermittently for 10 hr at the steady-state point of 0.074 lbm/sec (0.03 kg/sec) flow rate, 3000 psid (2.07 MPa) pressure rise, and 8000 rpm (838 rad/sec) shaft speed. Pump performance was monitored during the life test series and the results indicated no loss in performance. Material loss from the vanes was recorded and wear of the other components was documented. In the analytical part of this effort, a comprehensive pump performance analysis computer code, developed in-house, was used to predict pump performance. The results of the experimental investigation are presented and compared with the results of the analysis. Results of the life test are also presented.

A miniature, nongassing electroosmotic pump operating at 0.5 V.

PubMed

Shin, Woonsup; Lee, Jong Myung; Nagarale, Rajaram Krishna; Shin, Samuel Jaeho; Heller, Adam

2011-03-02

Electroosmotic pumps are arguably the simplest of all pumps, consisting merely of two flow-through electrodes separated by a porous membrane. Most use platinum electrodes and operate at high voltages, electrolyzing water. Because evolved gas bubbles adhere and block parts of the electrodes and the membrane, steady pumping rates are difficult to sustain. Here we show that when the platinum electrodes are replaced by consumed Ag/Ag(2)O electrodes, the pumps operate well below 1.23 V, the thermodynamic threshold for electrolysis of water at 25 °C, where neither H(2) nor O(2) is produced. The pumping of water is efficient: 13 000 water molecules are pumped per reacted electron and 4.8 mL of water are pumped per joule at a flow rate of 0.13 mL min(-1) V(-1) cm(-2), and a flow rate per unit of power is 290 mL min(-1) W(-1). The water is driven by protons produced in the anode reaction 2Ag(s) + H(2)O → Ag(2)O(s) + 2H(+) + 2e(-), traveling through the porous membrane, consumed by hydroxide ions generated in the cathode reaction Ag(2)O(s) + 2 H(2)O + 2e(-) → 2Ag(s) + 2 OH(-). A pump of 2 mm thickness and 0.3 cm(2) cross-sectional area produces flow of 5-30 μL min(-1) when operating at 0.2-0.8 V and 0.04-0.2 mA. Its flow rate can be either voltage or current controlled. The flow rate suffices for the delivery of drugs, such as a meal-associated boli of insulin.

An approach to reducing hemolysis in an axial-flow blood pump.

PubMed

Anai, H; Nakatani, T; Wakisaka, Y; Araki, K; Taenaka, Y; Tatsumi, E; Masuzawa, T; Baba, Y; Eya, K; Toda, K

1995-01-01

In an attempt to decrease hemolysis caused by an axial-flow blood pump, we studied whether specific speed (Ns) at a design point (determined by flow in m3/min, pump head in m, and pump speeds in rpm), should be kept within the existing engineering standard range (1000 < Ns < 2500) or whether pump speed should be reduced to a minimum (Ns < 1000). Four pumps (A: 14,000 rpm, B: 18,000 rpm, C: 22,000 rpm, and D: 26,000 rpm), each with an impeller 11.8 mm in diameter, were designed to accommodate a flow rate of 5 L/min and a pressure head of 100 mmHg. At this design point, the Ns of each pump was calculated as A:758, B:974, C:1191, and D:1407. Pump performance was observed, and the total efficiency of each pump was calculated. The hemolysis index (HI) was calculated after simultaneous testing in duplicate of all four pumps using fresh goat blood (anticoagulated with citrate-dextrose solution) in a closed mock-loop circuit. Total efficiency of each pump was calculated as A:49%, B:50%, C:45%, and D:22%. In the first hemolytic test, HIs were measured as A:0.066, B:0.18, and C:0.13; a water seal failed in pump D. In the second test, HIs were B:0.077, C:0.0499, and D:0.12; a bearing failed in pump A. It is concluded that a lower level of hemolysis is associated with a pump speed in the minimum range at the design point, even though Ns is outside the standard range.

Substantial energy input to the mesopelagic ecosystem from the seasonal mixed-layer pump

PubMed Central

Dall’Olmo, Giorgio; Dingle, James; Polimene, Luca; Brewin, Robert J.W.; Claustre, Hervé

2016-01-01

The “mesopelagic” is the region of the ocean between about 100 and 1000 m that harbours one of the largest ecosystems and fish stocks on the planet1,2. This vastly unexplored ecosystem is believed to be mostly sustained by chemical energy, in the form of fast-sinking particulate organic carbon, supplied by the biological carbon pump3. Yet, this supply appears insufficient to match mesopelagic metabolic demands4–6. The mixed-layer pump is a physically-driven biogeochemical process7–11 that could further contribute to meet these energetic requirements. However, little is known about the magnitude and spatial distribution of this process at the global scale. Here we show that the mixed-layer pump supplies an important seasonal flux of organic carbon to the mesopelagic. By combining mixed-layer depths from Argo floats with satellite retrievals of particulate organic carbon, we estimate that this pump exports a global flux of about 0.3 Pg C yr−1 (range 0.1 – 0.5 Pg C yr−1). In high-latitude regions where mixed-layers are deep, this flux is on average 23%, but can be greater than 100% of the carbon supplied by fast sinking particles. Our results imply that a relatively large flux of organic carbon is missing from current energy budgets of the mesopelagic. PMID:27857779

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing.

PubMed

Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

2016-11-23

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.

Water Flow Performance of a Superscale Model of the Fastrac Liquid Oxygen Pump

NASA Technical Reports Server (NTRS)

Skelley, Stephen; Zoladz, Thomas

2001-01-01

As part of the National Aeronautics and Space Administration's ongoing effort to lower the cost of access to space, the Marshall Space Flight Center has developed a rocket engine with 60,000 pounds of thrust for use on the Reusable Launch Vehicle technology demonstrator slated for launch in 2000. This gas generator cycle engine, known as the Fastrac engine, uses liquid oxygen and RP-1 for propellants and includes single stage liquid oxygen and RP-1 pumps and a single stage supersonic turbine on a common shaft. The turbopump design effort included the first use and application of new suction capability prediction codes and three-dimensional blade generation codes in an attempt to reduce the turbomachinery design and certification costs typically associated with rocket engine development. To verify the pump's predicted cavitation performance, a water flow test of a superscale model of the Fastrac liquid oxygen pump was conducted to experimentally evaluate the liquid oxygen pump's performance at and around the design point. The water flow test article replicated the flow path of the Fastrac liquid oxygen pump in a 1.582x scale model, including scaled seal clearances for correct leakage flow at a model operating speed of 5000 revolutions per minute. Flow entered the 3-blade axial-flow inducer, transitioned to a shrouded, 6- blade radial impeller, and discharged into a vaneless radial diffuser and collection volute. The test article included approximately 50 total and static pressure measurement locations as well as flush-mounted, high frequency pressure transducers for complete mapping of the pressure environment. The primary objectives of the water flow test were to measure the steady-state and dynamic pressure environment of the liquid oxygen pump versus flow coefficient, suction specific speed, and back face leakage flow rate. Initial results showed acceptable correlation between the predicted and experimentally measured pump head rise at low suction specific speeds. Likewise, only small circumferential variations in steady-state were observed from 80% to 120% of the design flow coefficient, matching the computational predictions and confirming that the integrated design approach has minimized any exit volute-induced distortions. The test article exhibited suction performance trends typically observed in inducer designs with virtually constant head rise with decreasing inlet pressure until complete pump head breakdown. Unfortunately, the net positive suction head at 3% head fall-off occurred far below that predicted at all tested flow coefficients, resulting in a negative net positive suction head margin at the design point in water. Additional testing to map the unsteady pressure environment was conducted and cavitation-induced flow disturbances at the inducer inlet were observed. Two distinct disturbances were identified, one rotating and one stationary relative to the fixed frame of reference, while the transition from one regime to the next produced significant effects on the steady state pump performance. The impact of the unsteady phenomena and the corresponding energy losses on the unexpectedly poor pump performance is also discussed.

Heart Pump Design for Cleveland Clinic Foundation

NASA Technical Reports Server (NTRS)

2005-01-01

Through a Lewis CommTech Program project with the Cleveland Clinic Foundation, the NASA Lewis Research Center is playing a key role in the design and development of a permanently implantable, artificial heart pump assist device. Known as the Innovative Ventricular Assist System (IVAS), this device will take on the pumping role of the damaged left ventricle of the heart. The key part of the IVAS is a nonpulsatile (continuous flow) artificial heart pump with centrifugal impeller blades, driven by an electric motor. Lewis is part of an industry and academia team, led by the Ohio Aerospace Institute (OAI), that is working with the Cleveland Clinic Foundation to make IVAS a reality. This device has the potential to save tens of thousands of lives each year, since 80 percent of heart attack victims suffer irreversible damage to the left ventricle, the part of the heart that does most of the pumping. Impeller blade design codes and flow-modeling analytical codes will be used in the project. These codes were developed at Lewis for the aerospace industry but will be applicable to the IVAS design project. The analytical codes, which currently simulate the flow through the compressor and pump systems, will be used to simulate the flow within the blood pump in the artificial heart assist device. The Interdisciplinary Technology Office heads up Lewis' efforts in the IVAS project. With the aid of numerical modeling, the blood pump will address many design issues, including some fluid-dynamic design considerations that are unique to the properties of blood. Some of the issues that will be addressed in the design process include hemolysis, deposition, recirculation, pump efficiency, rotor thrust balance, and bearing lubrication. Optimum pumping system performance will be achieved by modeling all the interactions between the pump components. The interactions can be multidisciplinary and, therefore, are influenced not only by the fluid dynamics of adjacent components but also by thermal and structural effects. Lewis-developed flow-modeling codes to be used in the pump simulations will include a one-dimensional code and an incompressible three-dimensional Navier-Stokes flow code. These codes will analyze the prototype pump designed by the Cleveland Clinic Foundation. With an improved understanding of the flow phenomena within the prototype pump, design changes to improve the performance of the pump system can be verified by computer prior to fabrication in order to reduce risks. The use of Lewis flow modeling codes during the design and development process will improve pump system performance and reduce the number of prototypes built in the development phase. The first phase of the IVAS project is to fully develop the prototype in a laboratory environment that uses a water/glycerin mixture as the surrogate fluid to simulate blood. A later phase of the project will include testing in animals for final validation. Lewis will be involved in the IVAS project for 3 to 5 years.

Paper pump for passive and programmable transport

PubMed Central

Wang, Xiao; Hagen, Joshua A.; Papautsky, Ian

2013-01-01

In microfluidic systems, a pump for fluid-driving is often necessary. To keep the size of microfluidic systems small, a pump that is small in size, light-weight and needs no external power source is advantageous. In this work, we present a passive, simple, ultra-low-cost, and easily controlled pumping method based on capillary action of paper that pumps fluid through conventional polymer-based microfluidic channels with steady flow rate. By using inexpensive cutting tools, paper can be shaped and placed at the outlet port of a conventional microfluidic channel, providing a wide range of pumping rates. A theoretical model was developed to describe the pumping mechanism and aid in the design of paper pumps. As we show, paper pumps can provide steady flow rates from 0.3 μl/s to 1.7 μl/s and can be cascaded to achieve programmable flow-rate tuning during the pumping process. We also successfully demonstrate transport of the most common biofluids (urine, serum, and blood). With these capabilities, the paper pump has the potential to become a powerful fluid-driving approach that will benefit the fielding of microfluidic systems for point-of-care applications. PMID:24403999

Commercial Submersible Mixing Pump For SRS Tank Waste Removal - 15223

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hubbard, Mike; Herbert, James E.; Scheele, Patrick W.

The Savannah River Site Tank Farms have 45 active underground waste tanks used to store and process nuclear waste materials. There are 4 different tank types, ranging in capacity from 2839 m 3 to 4921 m 3 (750,000 to 1,300,000 gallons). Eighteen of the tanks are older style and do not meet all current federal standards for secondary containment. The older style tanks are the initial focus of waste removal efforts for tank closure and are referred to as closure tanks. Of the original 51 underground waste tanks, six of the original 24 older style tanks have completed waste removalmore » and are filled with grout. The insoluble waste fraction that resides within most waste tanks at SRS requires vigorous agitation to suspend the solids within the waste liquid in order to transfer this material for eventual processing into glass filled canisters at the Defense Waste Processing Facility (DWPF). SRS suspends the solid waste by use of recirculating mixing pumps. Older style tanks generally have limited riser openings which will not support larger mixing pumps, since the riser access is typically 58.4 cm (23 inches) in diameter. Agitation for these tanks has been provided by four long shafted standard slurry pumps (SLP) powered by an above tank 112KW (150 HP) electric motor. The pump shaft is lubricated and cooled in a pressurized water column that is sealed from the surrounding waste in the tank. Closure of four waste tanks has been accomplished utilizing long shafted pump technology combined with heel removal using multiple technologies. Newer style waste tanks at SRS have larger riser openings, allowing the processing of waste solids to be accomplished with four large diameter SLPs equipped with 224KW (300 HP) motors. These tanks are used to process the waste from closure tanks for DWPF. In addition to the SLPs, a 224KW (300 HP) submersible mixer pump (SMP) has also been developed and deployed within older style tanks. The SMPs are product cooled and product lubricated canned motor pumps designed to fit within available risers and have significant agitation capabilities to suspend waste solids. Waste removal and closure of two tanks has been accomplished with agitation provided by 3 SMPs installed within the tanks. In 2012, a team was assembled to investigate alternative solids removal technologies to support waste removal for closing tanks. The goal of the team was to find a more cost effective approach that could be used to replace the current mixing pump technology. This team was unable to identify an alternative technology outside of mixing pumps to support waste agitation and removal from SRS waste tanks. However, the team did identify a potentially lower cost mixing pump compared to the baseline SLPs and SMPs. Rather than using the traditional procurement using an engineering specification, the team proposed to seek commercially available submersible mixer pumps (CSMP) as alternatives to SLPs and SMPs. SLPs and SMPs have a high procurement cost and the actual cost of moving pumps between tanks has shown to be significantly higher than the original estimates that justified the reuse of SMPs and SLPs. The team recommended procurement of “off-the-shelf” industry pumps which may be available for significant savings, but at an increased risk of failure and reduced operating life in the waste tank. The goal of the CSMP program is to obtain mixing pumps that could mix from bulk waste removal through tank closure and then be abandoned in place as part of tank closure. This paper will present the development, progress and relative advantages of the CSMP.« less

On Gravitational Radiation: A Nonlinear Wave Theory in a Viscoelastic Kerr-Lambda Spacetime

NASA Astrophysics Data System (ADS)

Gamble, Ronald

This project presents the experimental results concerning the mix design, fresh and hardened properties of an ultra-high strength concrete that has already been developed for high performance construction applications but now needs to be evaluated for a 3D printing process. The concrete is designed to be extruded through a nozzle and pump system, and have layers printed to analyze deformation within printed layers. The key factors for printable concrete are, the ability to be extruded through a pump and nozzle (flowability) and buildability. The flow of mortar will be studied by looking at the rheological properties of the mix and assessing the acceptable range of shear strength. Three different water to cement ratios and varying dosages of superplasticizers were incorporated to optimize a workable mortar/concrete mix to be applied for 3D printing. A Brookfield DV-III Ultra programmable rheometer was used to determine the viscosity and yield strength of the mortar mixes; these values were used to calculate the shear strength of the printable concrete. Compressive strengths of optimal mixtures were taken to assess the feasibility of 3D printed concrete as compared to traditional means. Compression test was conducted on a High Capacity Series Compression Testing Machine with 2" x 2" mortars cubes. The results indicated that the mortars that have shear ranges between of 0.3 - 0.9 kPa could be used in a 3D printer. The compressive strength of the concrete made with a 25% water/cement ratio and 10% superplasticizer dosage reached 62.8 MPa, which qualifies it as ultrahigh strength mortar. An optimum mix will be validated by printing the most filaments until deformation occurs. The end goal of this project is to develop an optimal concrete to produce the strength needed for 3D printed concrete. Using our predesigned ultra-high strength concrete mix ingredients, we will optimize that mix to have the same performance characteristics and be used in 3D printing applications.

Groundwater ages from the freshwater zone of the Edwards aquifer, Uvalde County, Texas—Insights into groundwater flow and recharge

USGS Publications Warehouse

Hunt, Andrew G.; Landis, Gary P.; Faith, Jason R.

2016-02-23

Tritium–helium-3 groundwater ages of the Edwards aquifer in south-central Texas were determined as part of a long-term study of groundwater flow and recharge in the Edwards and Trinity aquifers. These ages help to define groundwater residence times and to provide constraints for calibration of groundwater flow models. A suite of 17 samples from public and private supply wells within Uvalde County were collected for active and noble gases, and for tritium–helium-3 analyses from the confined and unconfined parts of the Edwards aquifer. Samples were collected from monitoring wells at discrete depths in open boreholes as well as from integrated pumped well-head samples. The data indicate a fairly uniform groundwater flow system within an otherwise structurally complex geologic environment comprised of regionally and locally faulted rock units, igneous intrusions, and karst features within carbonate rocks. Apparent ages show moderate, downward average, linear velocities in the Uvalde area with increasing age to the east along a regional groundwater flow path. Though the apparent age data show a fairly consistent distribution across the study area, many apparent ages indicate mixing of both modern (less than 60 years) and premodern (greater than 60 years) waters. This mixing is most evident along the “bad water” line, an arbitrary delineation of 1,000 milligrams per liter dissolved solids that separates the freshwater zone of the Edwards aquifer from the downdip saline water zone. Mixing of modern and premodern waters also is indicated within the unconfined zone of the aquifer by high excess helium concentrations in young waters. Excess helium anomalies in the unconfined aquifer are consistent with possible subsurface discharge of premodern groundwater from the underlying Trinity aquifer into the younger groundwater of the Edwards aquifer.

Effects of simulated ground-water pumping and recharge on ground-water flow in Cape Cod, Martha's Vineyard, and Nantucket Island basins, Massachusetts

USGS Publications Warehouse

Masterson, John P.; Barlow, Paul M.

1997-01-01

Three-dimensional transient ground-water-flow models that simulate both freshwater and saltwater flow were developed for the flow cells of the Cape Cod Basin to determine the effects of long-term pumping and recharge, seasonal fluctuations in pumping and recharge, and prolonged reductions of natural recharge, on the position of the freshwater-saltwater interface, water-table and pond altitudes, and streamflow and discharge to coastal marshes and embayments. Two-dimensional, finite-difference change models were developed for Martha's Vineyard and Nantucket Island basins to determine anticipated drawdowns in response to projected summer season pumping rates for 180 days of no recharge.

Study on the thermodynamical and mechanical conditions for the generation of high operating pressures with liquefied gases for low and very low flow rates

NASA Astrophysics Data System (ADS)

Nieratschker, Willi

1989-12-01

An investigation of the thermodynamical and mechanical conditions for extending the flow rate range in the direction of low flow rates with regard to the delivery of liquefied gases at high operating pressures is presented. For low flow rates, the especially critical cavitation problem connected with the pumping of liquefied gases becomes more acute, since with decreasing volume the ratio of heat losses to the hydraulic power becomes ever more unfavorable. A first prototype is designed, produced and investigated to evaluate design-related heat loss and piston seal problems. An approach to the solution is indicated for both problem areas with the application of a new and patented pump principle, and through investigation of a second prototype modified in several respects. By reducing the pump mass when designing the second pump prototype, the nonstationary cooling phase is greatly shortened, so that intermittent pump operation becomes possible when the pump is housed external to the storage tank.

An evaluation of a hubless inducer and a full flow hydraulic turbine driven inducer boost pump

NASA Technical Reports Server (NTRS)

Lindley, B. K.; Martinson, A. R.

1971-01-01

The purpose of the study was to compare the performance of several configurations of hubless inducers with a hydrodynamically similar conventional inducer and to demonstrate the performance of a full flow hydraulic turbine driven inducer boost pump using these inducers. A boost pump of this type consists of an inducer connected to a hydraulic turbine with a high speed rotor located in between. All the flow passes through the inducer, rotor, and hydraulic turbine, then into the main pump. The rotor, which is attached to the main pump shaft, provides the input power to drive the hydraulic turbine which, in turn, drives the inducer. The inducer, rotating at a lower speed, develops the necessary head to prevent rotor cavitation. The rotor speed is consistent with present main engine liquid hydrogen pump designs and the overall boost pump head rise is sufficient to provide adequate main pump suction head. This system would have the potential for operating at lower liquid hydrogen tank pressures.

Pulsating electrolyte flow in a full vanadium redox battery

NASA Astrophysics Data System (ADS)

Ling, C. Y.; Cao, H.; Chng, M. L.; Han, M.; Birgersson, E.

2015-10-01

Proper management of electrolyte flow in a vanadium redox battery (VRB) is crucial to achieve high overall system efficiency. On one hand, constant flow reduces concentration polarization and by extension, energy efficiency; on the other hand, it results in higher auxiliary pumping costs, which can consume around 10% of the discharge power. This work seeks to reduce the pumping cost by adopting a novel pulsing electrolyte flow strategy while retaining high energy efficiency. The results indicate that adopting a short flow period, followed by a long flow termination period, results in high energy efficiencies of 80.5% with a pumping cost reduction of over 50%.

Pipeline Optimization Program (PLOP)

DTIC Science & Technology

2006-08-01

the framework of the Dredging Operations Decision Support System (DODSS, https://dodss.wes.army.mil/wiki/0). PLOP compiles industry standards and...efficiency point ( BEP ). In the interest of acceptable wear rate on the pump, industrial standards dictate that the flow Figure 2. Pump class as a function of...percentage of the flow rate corresponding to the BEP . Pump Acceptability Rules. The facts for pump performance, industrial standards and pipeline and

Modification of ocean-estuary salt fluxes by density-driven advection of a headland eddy

NASA Astrophysics Data System (ADS)

Fram, J. P.; Stacey, M. T.

2005-05-01

Scalar exchange between San Francisco Bay and the coastal ocean is examined using shipboard observations made across the Golden Gate Channel. Ocean-estuary exchange is often described as a combination of two independent types of mechanisms: density-driven exchange such as gravitational circulation and tidal asymmetries such as tidal trapping. In this study we found that exchange is also governed by an interaction between these mechanisms. Tidally trapped eddies created in shallow shoals are mixed into the main channel earlier in the tidal cycle during the rainy season because the eddies are pushed seaward by gravitational circulation. This interaction increases the tidally averaged dispersive salt flux into the bay. The study consists of experiments during each of three 'seasons': winter/spring runoff (March 2002), summer upwelling (July 2003), and fall relaxation (October 2002). Within each experiment, transects across the channel were repeated approximately every 12 minutes for 25 hours during both spring tide and the following neap tide. Velocity was measured from a boat-mounted ADCP. Scalar concentrations were measured from a tow-yoed SeaSciences Acrobat. Salinity exchange over each spring-neap cycle is quantified with harmonic analysis. Harmonic results are decomposed into flux mechanisms using temporal and spatial correlations. The temporal correlation of cross-sectional averaged salinity and velocity (tidal pumping flux) is the largest part of the dispersive flux of salinity into the bay. From the tidal pumping portion of the dispersive flux, it is shown that there is less exchange than was found in earlier studies. Furthermore, tidal pumping flux scales strongly with flow due to density-driven movement of tidally trapped eddies and density-driven increases in ebb-flood frictional phasing. Complex bathymetry makes salinity exchange scale differently with flow than would be expected from simple tidal pumping and gravitational circulation models.

A flow-batch analyzer with piston propulsion applied to automatic preparation of calibration solutions for Mn determination in mineral waters by ET AAS.

PubMed

Almeida, Luciano F; Vale, Maria G R; Dessuy, Morgana B; Silva, Márcia M; Lima, Renato S; Santos, Vagner B; Diniz, Paulo H D; Araújo, Mário C U

2007-10-31

The increasing development of miniaturized flow systems and the continuous monitoring of chemical processes require dramatically simplified and cheap flow schemes and instrumentation with large potential for miniaturization and consequent portability. For these purposes, the development of systems based on flow and batch technologies may be a good alternative. Flow-batch analyzers (FBA) have been successfully applied to implement analytical procedures, such as: titrations, sample pre-treatment, analyte addition and screening analysis. In spite of its favourable characteristics, the previously proposed FBA uses peristaltic pumps to propel the fluids and this kind of propulsion presents high cost and large dimension, making unfeasible its miniaturization and portability. To overcome these drawbacks, a low cost, robust, compact and non-propelled by peristaltic pump FBA is proposed. It makes use of a lab-made piston coupled to a mixing chamber and a step motor controlled by a microcomputer. The piston-propelled FBA (PFBA) was applied for automatic preparation of calibration solutions for manganese determination in mineral waters by electrothermal atomic-absorption spectrometry (ET AAS). Comparing the results obtained with two sets of calibration curves (five by manual and five by PFBA preparations), no significant statistical differences at a 95% confidence level were observed by applying the paired t-test. The standard deviation of manual and PFBA procedures were always smaller than 0.2 and 0.1mugL(-1), respectively. By using PFBA it was possible to prepare about 80 calibration solutions per hour.

Particle motion in unsteady two-dimensional peristaltic flow with application to the ureter

NASA Astrophysics Data System (ADS)

Jiménez-Lozano, Joel; Sen, Mihir; Dunn, Patrick F.

2009-04-01

Particle motion in an unsteady peristaltic fluid flow is analyzed. The fluid is incompressible and Newtonian in a two-dimensional planar geometry. A perturbation method based on a small ratio of wave height to wavelength is used to obtain a closed-form solution for the fluid velocity field. This analytical solution is used in conjunction with an equation of motion for a small rigid sphere in nonuniform flow taking Stokes drag, virtual mass, Faxén, Basset, and gravity forces into account. Fluid streamlines and velocity profiles are calculated. Theoretical values for pumping rates are compared with available experimental data. An application to ureteral peristaltic flow is considered since fluid flow in the ureter is sometimes accompanied by particles such as stones or bacteriuria. Particle trajectories for parameters that correspond to calcium oxalates for calculosis and Escherichia coli type for bacteria are analyzed. The findings show that retrograde or reflux motion of the particles is possible and bacterial transport can occur in the upper urinary tract when there is a partial occlusion of the wave. Dilute particle mixing is also investigated, and it is found that some of the particles participate in the formation of a recirculating bolus, and some of them are delayed in transit and eventually reach the walls. This can explain the failure of clearing residuals from the upper urinary tract calculi after successful extracorporeal shock wave lithotripsy. The results may also be relevant to the transport of other physiological fluids and industrial applications in which peristaltic pumping is used.

Sixty-five-year old final clarifier performance rivals that of modern designs.

PubMed

Barnard, James L; Kunetz, Thomas E; Sobanski, Joseph P

2008-01-01

The Stickney plant of the Metropolitan Wastewater Reclamation District of Greater Chicago (MWRDGC), one of the largest wastewater treatment plants in the world, treats an average dry weather flow of 22 m3/s and a sustained wet weather flow of 52 m3/s that can peak to 63 m3/s. Most of the inner city of Chicago has combined sewers, and in order to reduce pollution through combined sewer overflows (CSO), the 175 km Tunnel and Reservoir Plan (TARP) tunnels, up to 9.1 m in diameter, were constructed to receive and convey CSO to a reservoir from where it will be pumped to the Stickney treatment plant. Pumping back storm flows will result in sustained wet weather flows over periods of weeks. Much of the success of the plant will depend on the ability of 96 circular final clarifiers to produce an effluent of acceptable quality. The nitrifying activated sludge plant is arranged in a plug-flow configuration, and some denitrification takes place as a result of the high oxygen demand in the first pass of the four-pass aeration basins that have a length to width ratio of 18:1. The SVI of the mixed liquor varies between 60 and 80 ml/g. The final clarifiers, which were designed by the District's design office in 1938, have functioned for more than 65 years without major changes and are still producing very high-quality effluent. This paper will discuss the design and operation of these final clarifiers and compare the design with more modern design practices. (c) IWA Publishing 2008.

Experimental analysis of the flow pattern of a pump turbine model in pump mode

NASA Astrophysics Data System (ADS)

Guggenberger, Mark; Senn, Florian; Jaberg, Helmut; Gehrer, Arno; Sallaberger, Manfred; Widmer, Christian

2016-11-01

Reversible pump turbines are the only means to store primary energy in an highly efficient way. Within a short time their operation can be switched between the different operational regimes thus enhancing the stabilization of the electric grid. These qualities in combination with the operation even at off-design conditions offer a high flexibility to the energy market. However, pump turbines pass through operational regimes where their behaviour becomes unstable. One of these effects occurs when the flowrate is decreased continuously down to a minimum. This point is the physical limitation of the pump operation and is very difficult to predict properly by numerical design without a model test. The purpose of the present study is to identify the fluid mechanical phenomena leading to the occurrence of instabilities of pump turbines in pump mode. A reduced scale model of a ANDRITZ pump turbine was installed on a 4-quadrant test rig for the experimental investigation of unstable conditions in pump mode. The performed measurements are based on the IEC60193-standard. Characteristic measurements at a single guide vane opening were carried out to get a detailed insight into the instabilities in pump mode. The interaction between runner and guide vane was analysed by Particle Image Velocimetry. Furthermore, high-speed visualizations of the suction side part load flow and the suction recirculation were performed. Like never before the flow pattern in the draft tube cone became visible with the help of a high-speed camera by intentionally caused cavitation effects which allow a qualitative view on the flow pattern in the draft tube cone. Suction recirculation is observed in form of single vortices separating from each runner blade and stretching into the draft tube against the main flow direction. To find an explanation for the flow phenomena responsible for the appearance of the unstable head curve also characteristic velocity distributions on the pressure side were combined with high-speed visualizations on the suction side of the pump turbine model. The results enhance the comprehension of the physical background leading to the instability and improve the numerical predictability of the instability in pump mode.

Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.

PubMed

Nalewajko-Sieliwoniuk, Edyta; Iwanowicz, Magdalena; Kalinowski, Sławomir; Kojło, Anatol

2016-03-10

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL(-1). The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL(-1)), high precision (RSD = 3.3%) and high sample throughput (144 samples h(-1)) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices). Copyright © 2016 Elsevier B.V. All rights reserved.

Research of working pulsation in closed angle based on rotating-sleeve distributing-flow system

NASA Astrophysics Data System (ADS)

Zhang, Yanjun; Zhang, Hongxin; Zhao, Qinghai; Jiang, Xiaotian; Cheng, Qianchang

2017-08-01

In order to reduce negative effects including hydraulic impact, noise and mechanical vibration, compression and expansion of piston pump in closed volume are used to optimize the angle between valve port and chamber. In addition, the mathematical model about pressurization and depressurization in pump chamber are analyzed based on distributing-flow characteristic, and it is necessary to use simulation software Fluent to simulate the distributing-flow fluid model so as to select the most suitable closed angle. As a result, when compression angle is 3°, the angle is closest to theoretical analysis and has the minimum influence on flow and pump pressure characteristic. Meanwhile, cavitation phenomenon appears in pump chamber in different closed angle on different degrees. Besides the flow pulsation is increasingly smaller with increasing expansion angle. Thus when expansion angle is 2°, the angle is more suitable for distributing-flow system.

Cooperative suction by vertical capillary array pump for controlling flow profiles of microfluidic sensor chips.

PubMed

Horiuchi, Tsutomu; Hayashi, Katsuyoshi; Seyama, Michiko; Inoue, Suzuyo; Tamechika, Emi

2012-10-18

A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.

Pumping power considerations in the designs of NASA-Redox flow cells

NASA Technical Reports Server (NTRS)

Hoberecht, M. A.

1981-01-01

Pressure drop data for six different cell geometries of various flow port, manifold, and cavity dimensions are presented. The redox/energy/storage system uses two fully soluble redox couples as anode and cathode fluids. Both fluids are pumped through a redox cell, or stack of cells, where the electrochemical reactions take place at porous carbon felt electrodes. Pressure drop losses are therefore associated with this system due to the continuous flow of reactant solutions. The exact pressure drop within a redox flow cell is directly dependent on the flow rate as well as the various cell dimensions. Pumping power requirements for a specific set of cell operating conditions are found for various cell geometries once the flow rate and pressure drop are determined. These pumping power requirements contribute to the overall system parasitic energy losses which must be minimized, the choice of cell geometry becomes critical.

Methods and apparatus of entangled photon generation using four-wave mixing

DOEpatents

Camacho, Ryan

2016-02-23

A non-linear optical device is provided. The device comprises an optical disk or ring microresonator fabricated from a material that exhibits an optical nonlinearity able to produce degenerate four-wave mixing (FWM) in response to a pump beam having a pump frequency in a specified effective range. The microresonator is conformed to exhibit an angular group velocity minimum at a pump frequency within the specified effective range such that there is zero angular group velocity dispersion at the pump frequency. We refer to such a pump frequency as the "zero dispersion frequency". In embodiments, excitation of the resonator by a pump beam of sufficient intensity at the zero-dispersion frequency causes the resonator to emit a frequency comb of entangled photon pairs wherein the respective frequencies in each pair are symmetrically placed about the zero-dispersion frequency.

Preparation of uniaxially aligned TiO2 ultrafine fibers by electrospinning.

PubMed

Nien, Yu-Hsun; Tsai, Yan-Sheng; Wang, Jia-Yi; Syu, Shu-Ping

2012-11-01

TiO2 nanofibers are often produced by electrospinning using a collector consisting of two parallel electrodes. In this work, a high speed rotating drum was used as a collector to produce uniaxially aligned TiO2 ultrafine fibers. The apparatus to manufacture uniaxially aligned TiO2 ultrafine fiber consisted of a high-speed roller, a high-voltage power supply, a controllable syringe pump and a syringe. Titanium (IV) isopropoxide and polyvinylpyrrolidone were used as precursor and auxiliary, respectively. Titanium (IV) isopropoxide and polyvinylpyrrolidone were well mixed with other essential reagents to form the polymer solution. The polymer solution was poured into the syringe and pumped at various flow rates. The electrospun ultrafine fibers collected on the roller were heat treated up to 600 degrees C and the uniaxially aligned TiO2 ultrafine fibers were formed and characterized using scanning electron microscope and X-ray diffraction.

Using hybrid magnetic bearings to completely suspend the impeller of a ventricular assist device.

PubMed

Khanwilkar, P; Olsen, D; Bearnson, G; Allaire, P; Maslen, E; Flack, R; Long, J

1996-06-01

Clinically available blood pumps and those under development suffer from poor mechanical reliability and poor biocompatibility related to anatomic fit, hemolysis, and thrombosis. To alleviate these problems concurrently in a long-term device is a substantial challenge. Based on testing the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist device, the CFVAD4, for long-term use. The design process and its outcome, the CFVAD4 system configuration, is described. To provide unprecedented reliability and biocompatibility, magnetic bearings completely suspend the rotating pump impeller. The CFVAD4 uses a combination of passive (permanent) and active (electric) magnetic bearings, a mixed flow impeller, and a slotless 3-phase brushless DC motor. These components are shaped, oriented, and integrated to provide a compact, implantable, pancake-shaped unit for placement in the left upper abdominal quadrant of adult humans.

Impact of Aquifer Heterogeneities on Autotrophic Denitrification.

NASA Astrophysics Data System (ADS)

McCarthy, A.; Roques, C.; Selker, J. S.; Istok, J. D.; Pett-Ridge, J. C.

2015-12-01

Nitrate contamination in groundwater is a big challenge that will need to be addressed by hydrogeologists throughout the world. With a drinking water standard of 10mg/L of NO3-, innovative techniques will need to be pursued to ensure a decrease in drinking water nitrate concentration. At the pumping site scale, the influence and relationship between heterogeneous flow, mixing, and reactivity is not well understood. The purpose of this project is to incorporate both physical and chemical modeling techniques to better understand the effect of aquifer heterogeneities on autotrophic denitrification. We will investigate the link between heterogeneous hydraulic properties, transport, and the rate of autotrophic denitrification. Data collected in previous studies in laboratory experiments and pumping site scale experiments will be used to validate the models. The ultimate objective of this project is to develop a model in which such coupled processes are better understood resulting in best management practices of groundwater.

Advances in Valveless Piezoelectric Pump with Cone-shaped Tubes

NASA Astrophysics Data System (ADS)

Zhang, Jian-Hui; Wang, Ying; Huang, Jun

2017-07-01

This paper reviews the development of valveless piezoelectric pump with cone-shaped tube chronologically, which have widely potential application in biomedicine and micro-electro-mechanical systems because of its novel principles and deduces the research direction in the future. Firstly, the history of valveless piezoelectric pumps with cone-shaped tubes is reviewed and these pumps are classified into the following types: single pump with solid structure or plane structure, and combined pump with parallel structure or series structure. Furthermore, the function of each type of cone-shaped tubes and pump structures are analyzed, and new directions of potential expansion of valveless piezoelectric pumps with cone-shaped tubes are summarized and deduced. The historical argument, which is provided by the literatures, that for a valveless piezoelectric pump with cone-shaped tubes, cone angle determines the flow resistance and the flow resistance determines the flow direction. The argument is discussed in the reviewed pumps one by one, and proved to be convincing. Finally, it is deduced that bionics is pivotal in the development of valveless piezoelectric pump with cone-shaped tubes from the perspective of evolution of biological structure. This paper summarizes the current valveless piezoelectric pumps with cone-shaped tubes and points out the future development, which may provide guidance for the research of piezoelectric actuators.

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Capillary pumping independent of the liquid surface energy and viscosity

NASA Astrophysics Data System (ADS)

Guo, Weijin; Hansson, Jonas; van der Wijngaart, Wouter

2018-03-01

Capillary pumping is an attractive means of liquid actuation because it is a passive mechanism, i.e., it does not rely on an external energy supply during operation. The capillary flow rate generally depends on the liquid sample viscosity and surface energy. This poses a problem for capillary-driven systems that rely on a predictable flow rate and for which the sample viscosity or surface energy are not precisely known. Here, we introduce the capillary pumping of sample liquids with a flow rate that is constant in time and independent of the sample viscosity and sample surface energy. These features are enabled by a design in which a well-characterized pump liquid is capillarily imbibed into the downstream section of the pump and thereby pulls the unknown sample liquid into the upstream pump section. The downstream pump geometry is designed to exert a Laplace pressure and fluidic resistance that are substantially larger than those exerted by the upstream pump geometry on the sample liquid. Hence, the influence of the unknown sample liquid on the flow rate is negligible. We experimentally tested pumps of the new design with a variety of sample liquids, including water, different samples of whole blood, different samples of urine, isopropanol, mineral oil, and glycerol. The capillary filling speeds of these liquids vary by more than a factor 1000 when imbibed to a standard constant cross-section glass capillary. In our new pump design, 20 filling tests involving these liquid samples with vastly different properties resulted in a constant volumetric flow rate in the range of 20.96-24.76 μL/min. We expect this novel capillary design to have immediate applications in lab-on-a-chip systems and diagnostic devices.

Effects of Cone-Shaped Bend Inlet Cannulas of an Axial Blood Pump on Thrombus Formation: An Experiment and Simulation Study.

PubMed

Liu, Guangmao; Zhou, Jianye; Sun, Hansong; Zhang, Yan; Chen, Haibo; Hu, Shengshou

2017-04-05

BACKGROUND Cannula shape and connection style influence the risk of thrombus formation in the blood pump by varying the blood flow characteristics inside the pump. Inlet cannulas should be designed based on the need for anatomical fit and reducing the risk of thrombus generation in the blood pump. The effects on thrombus formation of the cone-shaped bend inlet cannulas of axial blood pumps should be studied. MATERIAL AND METHODS The cannulas were designed as cone-shaped, with 1 bent section connecting 2 straight sections. Both the silicone tube and novel cone-shaped cannula were simulated for comparison. The flow fields of a blood pump with inlet cannula were simulated by computational fluid dynamics (CFD) at flows of 2.0, 2.5, and 3.0 liters per minute (lpm), with pump rotational speeds of 7500, 8000, and 8500 rpm, respectively. Then, 6 two-dimensional (2D) particle image velocimetry (PIV) tests were conducted and the velocity distributions were analyzed. RESULTS A low-velocity region was located inside the pump entrance when a soft silicone tube was used. At 8500 rpm and 3.0 lpm working condition, the minimum velocity inside the pump with cone-shaped cannulas was 2.5×10^-1 m/s. The cone-shaped cannulas eliminated the low-velocity region inside the pump. Both CFD and PIV results showed that the low-velocity region did not spread to the entrance of the blood pump within the flow range from 2.0 lpm to 7.0 lpm. CONCLUSIONS The designed cone-shaped bent cannulas can eliminate the low-velocity region inside the blood pump and reduce the risk of thrombus formation in the blood pump.

Microfluidic chemostat and turbidostat with flow rate, oxygen, and temperature control for dynamic continuous culture.

PubMed

Lee, Kevin S; Boccazzi, Paolo; Sinskey, Anthony J; Ram, Rajeev J

2011-05-21

This work reports on an instrument capable of supporting automated microscale continuous culture experiments. The instrument consists of a plastic-PDMS device capable of continuous flow without volume drift or evaporation. We apply direct computer controlled machining and chemical bonding fabrication for production of fluidic devices with a 1 mL working volume, high oxygen transfer rate (k(L)a≈0.025 s(-1)), fast mixing (2 s), accurate flow control (±18 nL), and closed loop control over temperature, cell density, dissolved oxygen, and pH. Integrated peristaltic pumps and valves provide control over input concentrations and allow the system to perform different types of cell culture on a single device, such as batch, chemostat, and turbidostat continuous cultures. Continuous cultures are demonstrated without contamination for 3 weeks in a single device and both steady state and dynamically controlled conditions are possible. © The Royal Society of Chemistry 2011

Methods for forming small-volume electrical contacts and material manipulations with fluid microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-12-27

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-04-26

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microehannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-03-22

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Photo-actuation of liquids for light-driven microfluidics: state of the art and perspectives.

PubMed

Baigl, Damien

2012-10-07

Using light to control liquid motion is a new paradigm for the actuation of microfluidic systems. We review here the different principles and strategies to induce or control liquid motion using light, which includes the use of radiation pressure, optical tweezers, light-induced wettability gradients, the thermocapillary effect, photosensitive surfactants, the chromocapillary effect, optoelectrowetting, photocontrolled electroosmotic flows and optical dielectrophoresis. We analyze the performance of these approaches to control using light many kinds of microfluidic operations involving discrete pL- to μL-sized droplets (generation, driving, mixing, reaction, sorting) or fluid flows in microchannels (valve operation, injection, pumping, flow rate control). We show that a complete toolbox is now available to control microfluidic systems by light. We finally discuss the perspectives of digital optofluidics as well as microfluidics based on all optical fluidic chips and optically reconfigurable devices.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2007-11-20

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael; Culbertson, Christopher T.; Whitten, William B.; Foote, Robert S.

2004-02-03

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Water Flow Performance of a Superscale Model of the Fastrac Liquid Oxygen Pump

NASA Technical Reports Server (NTRS)

Skelley, Stephen; Zoladz, Thomas

1999-01-01

As part of the National Aeronautics and Space Administration's ongoing effort to lower the cost of access to space, the Marshall Space Flight Center has developed a rocket engine with 60,000 pounds of thrust for use on the Reusable Launch Vehicle technology demonstrator slated for launch in 2000. This gas generator cycle engine, known as the Fastrac engine, uses liquid oxygen and RP-1 for propellants and includes single stage liquid oxygen and RP-1 pumps and a single stage supersonic turbine on a common shaft. The turbopump design effort included the first use and application of new suction capability prediction codes and three-dimensional blade generation codes in an attempt to reduce the turbomachinery design and certification costs typically associated with rocket engine development. To verify the pump's predicted cavitation performance, a water flow test of a superscale model of the Fastrac liquid oxygen pump was conducted to experimentally evaluate the liquid oxygen pump's performance at and around the design point. The water flow test article replicated the flow path of the Fastrac liquid oxygen pump in a 1.582x scale model, including scaled seal clearances for correct leakage flow at a model operating speed of 5000 revolutions per minute. Flow entered the 3-blade axial-flow inducer, transitioned to a shrouded, 6-blade radial impeller, and discharged into a vaneless radial diffuser and collection volute. The test article included approximately 50 total and static pressure measurement locations as well as flush-mounted, high frequency pressure transducers for complete mapping of the pressure environment. The primary objectives of the water flow test were to measure the steady-state and dynamic pressure environment of the liquid oxygen pump versus flow coefficient, suction specific speed, and back face leakage flow rate. Results showed excellent correlation between the predicted and experimentally measured pump head rise at low suction specific speeds. Likewise, only small circumferential variations in steady-state impeller exit and radial diffuser pressure distributions were observed from 80% to 120% of the design flow coefficient, matching the computational predictions and confirming that the integrated design approach has minimized any exit volute-induced distortions. The test article exhibited suction performance trends typically observed in inducer designs with virtually constant head rise with decreasing inlet pressure until complete pump head breakdown. Unfortunately, the net positive suction head at 3% head fall-off occurred far below that predicted at all tested flow coefficients, resulting in a negative net positive suction head margin at the design point in water. Additional testing to map the unsteady pressure environment was conducted and interesting rotating phenomena at the inducer inlet were observed. These rotating phenomena's cell numbers, direction, and speed were correlated with pump operating parameters. The impact of the unsteady phenomena and their corresponding energy losses on the unexpectedly poor pump performance is also discussed.

The Progress in the Novel Pediatric Rotary Blood Pump Sputnik Development.

PubMed

Telyshev, Dmitry; Denisov, Maxim; Pugovkin, Alexander; Selishchev, Sergey; Nesterenko, Igor

2018-04-01

In this work, the study results of an implantable pediatric rotary blood pump (PRBP) are presented. They show the results of the numerical simulation of fluid flow rates in the pump. The determination method of the backflows and stagnation regions is represented. The operating points corresponding to fluid flow rates of 1, 3, and 5 L/min for 75-80 mm Hg pressure head are investigated. The study results have shown that use of the pump in the 1 L/min operating point can potentially lead to the appearance of backflows and stagnation regions. In the case of using pumps in fluid flow rates ranging from 3 to 5 L/min, the number of stagnation regions decreases and the fluid flow rate changes marginally. Using the pump in this flow rate range is considered judicious. The study shows an increase in shear stress with an increase in fluid flow rates, while there is no increase in shear stress above the critical condition of 150 Pa (which does not allow us to reliably speak about the increased risk of blood cell damage). The aim of this work was to design, prototype, and study interaction of the Sputnik PRBP with the cardiovascular system. A three-dimensional model of Sputnik PRBP was designed with the following geometrical specifications: flow unit length of 51.5 mm, flow unit diameter of 10 mm, and spacing between the rotor and housing of 0.1 mm. Computational fluid dynamics studies were used to calculate head pressure-flow rate (H-Q) curves at rotor speeds ranging from 10 000 to 14 000 rpm (R 2  = 0.866 between numerical simulation and experiment) and comparing flow patterns at various points of the flow rate operating range (1, 3, and 5 L/min) for operating pressures ranging from 75 to 80 mm Hg. It is noted that when fluid flow rate changes from 1 L/min to 3 L/min, significant changes are observed in the distribution of zero flow zones. At the inlet and outlet of the pump, when going to the operating point of 3 L/min, zones of stagnation become minuscule. The shear stress distribution was calculated along the pump volume. The volume in which shear stress exceed 150 Pa is less than 0.38% of the total pump volume at flow rates of 1, 3, and 5 L/min. In this study, a mock circulatory system (MCS) allowing simulation of physiological cardiovascular characteristics was used to investigate the interaction of the Sputnik PRBP with the cardiovascular system. MCS allows reproducing the Frank-Starling autoregulation mechanism of the heart. PRBP behavior was tested in the speed range of 6 000 to 15 000 rpm. Decreased contractility can be expressed in a stroke volume decrease approximately from 18 to 4 mL and ventricle systolic pressure decrease approximately from 92 to 20 mm Hg. The left ventricle becomes fully supported at a pump speed of 10 000 rpm. At a pump speed of 14 000 rpm, the left ventricle goes into a suction state in which fluid almost does not accumulate in the ventricle and only passes through it to the pump. The proposed PRBP showed potential for improved clinical outcomes in pediatric patients with a body surface area greater than 0.6 m 2 and weight greater than 12 kg. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Theoretical investigation on exciplex pumped alkali vapor lasers with sonic-level gas flow

NASA Astrophysics Data System (ADS)

Xu, Xingqi; Shen, Binglin; Huang, Jinghua; Xia, Chunsheng; Pan, Bailiang

2017-07-01

Considering the effects of higher excited and ion energy states and utilizing the methodology in the fluid mechanics, a modified model of exciplex pumped alkali vapor lasers with sonic-level flowing gas is established. A comparison of output characters between subsonic flow and supersonic flow is made. In this model, higher excited and ion energy states are included as well, which modifies the analysis of the kinetic process and introduces larger heat loading in an operating CW exciplex-pumped alkali vapor laser. The results of our calculations predict that subsonic flow has an advantage over supersonic flow under the same fluid parameters, and stimulated emission in the supersonic flow would be quenched while the pump power reaching a threshold value of the fluid choking effect. However, by eliminating the influence of fluid characters, better thermal management and higher optical conversion efficiency can be obtained in supersonic flow. In addition, we make use of the "nozzle-diffuser" to build up the closed-circle flowing experimental device and gather some useful simulated results.

The effect of surface wettability on the performance of a piezoelectric membrane pump

NASA Astrophysics Data System (ADS)

Wang, Jiantao; Yang, Zhigang; Liu, Yong; Shen, Yanhu; Chen, Song; Yu, Jianqun

2018-04-01

In this paper, we studied the effect of surface wettability on the bubble tolerance of a piezoelectric membrane pump, by applying the super-hydrophilic or super-hydrophobic surface to the key elements on the pump. Wettability for the flow passage surface has a direct influence on the air bubbles flowing in the fluid. Based on the existing research results, we first analyzed the relationship between the flow passage surface of the piezoelectric pump and the bubbles in the fluid. Then we made three prototypes where pump chamber walls and valve plate surfaces were given different wettability treatments. After the output performance test, results demonstrate that giving super-hydrophilic treatment on the surface of key elements can improve the bubble tolerance of piezoelectric pump; in contrast, giving super-hydrophobic treatment will reduce the bubble tolerance.

Development of a solenoid actuated planar valveless micropump with single and multiple inlet-outlet arrangements

NASA Astrophysics Data System (ADS)

Kumar, N.; George, D.; Sajeesh, P.; Manivannan, P. V.; Sen, A. K.

2016-07-01

We report a planar solenoid actuated valveless micropump with multiple inlet-outlet configurations. The self-priming characteristics of the multiple inlet-multiple outlet micropump are studied. The filling dynamics of the micropump chamber during start-up and the effects of fluid viscosity, voltage and frequency on the dynamics are investigated. Numerical simulations for multiple inlet-multiple outlet micropumps are carried out using fluid structure algorithm. With DI water and at 5.0 Vp-p, 20 Hz frequency, the two inlet-two outlet micropump provides a maximum flow rate of 336 μl min-1 and maximum back pressure of 441 Pa. Performance characteristics of the two inlet-two outlet micropump are studied for aqueous fluids of different viscosity. Transport of biological cell lines and diluted blood samples are demonstrated; the flow rate-frequency characteristics are studied. Viability of cells during pumping with multiple inlet multiple outlet configuration is also studied in this work, which shows 100% of cells are viable. Application of the proposed micropump for simultaneous pumping, mixing and distribution of fluids is demonstrated. The proposed integrated, standalone and portable micropump is suitable for drug delivery, lab-on-chip and micro-total-analysis applications.

General well function for pumping from a confined, leaky, or unconfined aquifer

NASA Astrophysics Data System (ADS)

Perina, Tomas; Lee, Tien-Chang

2006-02-01

A general well function for groundwater flow toward an extraction well with non-uniform radial flux along the screen and finite-thickness skin, partially penetrating an unconfined, leaky-boundary flux, or confined aquifer is derived via the Laplace and generalized finite Fourier transforms. The mixed boundary condition at the well face is solved as the discretized Fredholm integral equation. The general well function reduces to a uniform radial flux solution as a special case. In the Laplace domain, the relation between the drawdown in the extraction well and flowrate is linear and the formulations for specified flowrate or specified drawdown pumping are interchangeable. The deviation in drawdown of the uniform from non-uniform radial flux solutions depends on the relative positions of the extraction and observation well screens, aquifer properties, and time of observation. In an unconfined aquifer the maximum deviation occurs during the period of delayed drawdown when the effect of vertical flow is most apparent. The skin and wellbore storage in an observation well are included as model parameters. A separate solution is developed for a fully penetrating well with the radial flux being a continuous function of depth.

AC electrothermal mixing for high conductive biofluids by arc-electrodes

NASA Astrophysics Data System (ADS)

Meng, Jiyu; Li, Shanshan; Li, Junwei; Yu, Chengzhuang; Wei, Chunyang; Dai, Shijie

2018-06-01

As a platform to mix the bioagents (i.e. serum, urine), we take advantage of the alternating current electrothermal (ACET) effect which is quite suitable for rapid pumping/mixing of high conductive biomicrofluids. Here we demonstrate the concept of a high-efficient mixing microfluidic chip as a basic unit to provide rapid mixing for lab-on-a-chip applications. As an active mixer, two streams are introduced into a ring-shape microchamber by a passive flow rate regulator, and then the microfluids in the chamber are actuated by a nonuniform electric field with a phase shift of 180°. It shows perfect mixing performance by arranging four arc-electrodes around the ring-shape microchamber subsequently. Taking the Joule heating and conductivity/permittivity changes into consideration, a temperature dependent fully coupled numerical model is presented. Then, the effects of applied voltages on mixing performance and temperature rise are provided to get an optimized design for ACET mixer. Moreover, the arrangement of the electrode array is analyzed to show the effects of electrode patterns on the swirls and mixing efficiencies. Since all the electrodes here are located along a ring-shape central microchamber, the ring-shape micromixer is quite suitable to function as a compact element modular for integrated microfluidic chips.

Another way of pumping blood with a rotary but noncentrifugal pump for an artificial heart.

PubMed

Monties, J R; Mesana, T; Havlik, P; Trinkl, J; Demunck, J L; Candelon, B

1990-01-01

This article describes an alternative mode of pumping blood inside the body. The device is a non centrifugal, valveless, low speed rotary pump, electrically powered, based on Wankel engine principle. The authors developed an implantable electrical actuator resulting in a compact, sealed motor-pump unit with electrical and magnetic components insulated from fluids. The results in the flow curve and in the pumping action show some common points but also some basic differences compared to classical pulsatile pumps or centrifugal pumps. The blood coming from the atrium follows a continuous movement without any stop flow but with variations creating pulsatility. Ejection and filling of the pump are simultaneous. It is always an active filling. Hydraulic efficiency depends on clearance in the pumping chamber and outlet port pressure. A 60 cc device allows flows up to 8-9 liters. The implantable motor is cyclindrical in shape, has a moderate weight (490 grams) and presents a good efficiency (32% for a rotary speed of 90 rpm against a mean aortic pressure of 150 mm of Hg). The authors conclude that their device could be proposed after further experimental studies, as an LVAD for shortterm assistance with a good promise for permanent application.

Research on the performance of low-lift diving tubular pumping system by CFD and Test

NASA Astrophysics Data System (ADS)

Xia, Chenzhi; Cheng, Li; Liu, Chao; Zhou, Jiren; Tang, Fangping; Jin, Yan

2016-11-01

Post-diving tubular pump is always used in large-discharge & low-head irrigation or storm drainage pumping station, its impeller and motor share the same shaft. Considering diving tubular pump system's excellent hydraulic performance, compact structure, good noise resistance and low operating cost, it is used in Chinese pump stations. To study the hydraulic performance and pressure fluctuation of inlet and outlet passage in diving tubular pump system, both of steady and unsteady full flow fields are numerically simulated at three flow rate conditions by using CFD commercial software. The asymmetry of the longitudinal structure of inlet passage affects the flow pattern on outlet. Especially at small flow rate condition, structural asymmetry will result in the uneven velocity distribution on the outlet of passage inlet. The axial velocity distribution uniformity increases as the flow rate increases on the inlet of passage inlet, and there is a positive correlation between hydraulic loss in the passage inlet and flow rate's quadratic. The axial velocity distribution uniformity on the outlet of passage inlet is 90% at design flow rate condition. The predicted result shows the same trend with test result, and the range of high efficiency area between predicted result and test result is almost identical. The dominant frequency of pressure pulsation is low frequency in inlet passage at design condition. The dominant frequency is high frequency in inlet passage at small and large flow rate condition. At large flow rate condition, the flow pattern is significantly affected by the rotation of impeller in inlet passage. At off-design condition, the pressure pulsation is strong at outlet passage. At design condition, the dominant frequency is 35.57Hz, which is double rotation frequency.

Field-effect Flow Control in Polymer Microchannel Networks

NASA Technical Reports Server (NTRS)

Sniadecki, Nathan; Lee, Cheng S.; Beamesderfer, Mike; DeVoe, Don L.

2003-01-01

A new Bio-MEMS electroosmotic flow (EOF) modulator for plastic microchannel networks has been developed. The EOF modulator uses field-effect flow control (FEFC) to adjust the zeta potential at the Parylene C microchannel wall. By setting a differential EOF pumping rate in two of the three microchannels at a T-intersection with EOF modulators, the induced pressure at the intersection generated pumping in the third, field-free microchannel. The EOF modulators are able to change the magnitude and direction of the pressure pumping by inducing either a negative or positive pressure at the intersection. The flow velocity is tracked by neutralized fluorescent microbeads in the microchannels. The proof-of-concept of the EOF modulator described here may be applied to complex plastic ,microchannel networks where individual microchannel flow rates are addressable by localized induced-pressure pumping.

Influence of different heating types on the pumping performance of a bubble pump

NASA Astrophysics Data System (ADS)

Bierling, Bernd; Schmid, Fabian; Spindler, Klaus

2017-11-01

This study presents an experimental investigation of the influence of different heating types on the pumping performance of a bubble pump. A test rig was set up at the Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart. The vertical lift tube is made of copper with an inner diameter of 8 mm and a length of 1.91 m. The working fluid is demineralized water. The test rig offers the possibility to vary the supplied heat flow (0 W - 750 W), the resulting supplied heat flux and the location of the heating. Investigations were carried out using spot heating, partial-length heating and full-length heating. A Coriolis mass flowmeter was successfully implemented which measures the vapor mass flow rate continuously. The improvement of the vapor mass flow rate measurement by using the continuous measurement method compared to a discontinuous one is discussed. Furthermore, the influence of an unstable inlet temperature of the working fluid entering the lift tube on the pumping performance is investigated. The focus of this publication lies on the build-up of the test rig with the measurement setup and the analysis of the pumping performance for the three heating types. The measurement results show a big influence of the heating type on the pumping performance. The lower the relative length of the heating, the higher is the pumping ratio which is defined as the lifted liquid mass flow rate in relation to the generated vapor mass flow rate.

Pilot Study Report, Cape Canaveral Air Station, Florida. Permeable Reactive Treatment (PeRT) Wall Pilot Study. Revision 2

DTIC Science & Technology

1999-11-01

slurry was made from mixing iron, guar gum , an enzyme and borax. The guar gum was Hercules Supercol™ food grade fine (200-mesh size) powder . It was...Florida The guar gum was mixed with water in batches in a stirred open top tank to form 2 to 3% solutions. The guar gum solution was pumped first to a...holding tank, then into a truck-mounted batch mixing plant. A positive displacement pump controlled the feed rate of guar gum to the batch mixing plant

[Comparison and Discussion of National/Military Standards Related to Flow Measurement of Medical Injection Pump].

PubMed

Zhang, Nan; Zhou, Juan; Yu, Jinlai; Hua, Ziyu; Li, Yongxue; Wu, Jiangang

2018-05-30

Medical injection pump is a commonly used clinical equipment with high risk. Accurate detection of flow is an important aspect to ensure its reliable operation. In this paper, we carefully studied and analyzed the flow detection methods of three standards being used in medical injection pump detection in our country. The three standards were compared from the aspects of standard device, flow test point selection, length of test time and accuracy judgment. The advantages and disadvantages of these standards were analyzed and suggestions for improvement were put forward.

A microfluidic two-pump system inspired by liquid feeding in mosquitoes

NASA Astrophysics Data System (ADS)

Marino, Andrew; Goad, Angela; Stremler, Mark; Socha, John; Jung, Sunghwan

Mosquitoes feed on nectar and blood using a two-pump system in the head-a smaller cibarial pump in line with a larger a pharyngeal pump, with a valve in between. To suck, mosquitoes transport the liquid (which may be a multi-component viscous fluid, blood) through a long micro-channel, the proboscis. In the engineering realm, microfluidic devices in biomedical applications, such as lab-on-a-chip technology, necessitate implementing a robust pump design to handle clogging and increase flow control compared to a single-pump system. In this talk, we introduce a microfluidic pump design inspired by the mosquito's two-pump system. The pumping performance (flow rate) in presence of impurities (air bubbles, soft clogs) is quantified as a function of phase difference and volume expansion of the pumps, and the elasticity of the valve.

Concept designs of nonrotating-type centrifugal blood pump and basic study on output characteristics of the oscillating disk-type centrifugal pump.

PubMed

Kabei, N; Tuichiya, K; Sakurai, Y

1994-09-01

When designing a turbo-type blood pump as an artificial heart, the gap between a rotating shaft and a pump housing should be perfectly sealed to prevent any leakage or contamination through a seal. In addition, blood coagulation in a blood chamber must be avoided. To overcome these problems, we proposed five different nonrotating-type turbo pumps: a caudal-fin-type axial-flow pump, a caudal-fin-type centrifugal pump, a nutating-column-type centrifugal pump, a nutating-collapsible-tube-type centrifugal pump, and an oscillating-disk-type centrifugal pump. We selected and developed the oscillating-disk-type centrifugal pump that consists of a disk, a driving rod, a seal, an oscillation mechanism, and a pump housing. The disk is mounted on the end of the rod, which is connected to a high-speed DC motor through an oscillation mechanism. The rod and the disk do not rotate, but they oscillate in the pump housing. This movement of the disk generates forward fluid flow around the axis (i.e., the rotational fluid flow). Centrifugal force due to fluid rotation supports the pressure difference between the outlet and the inlet. The diameter of the disk is 39 mm, the maximum inner diameter of the pump housing is 40 mm, and the volume of the blood chamber for 25 degrees' oscillation is 16.9 ml. The performance of the pump was tested in a mock circulatory system.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of abstraction regime and knowledge of hydrogeological conditions to control high-fluoride concentration in abstracted groundwater: San Luis Potosí basin, Mexico

NASA Astrophysics Data System (ADS)

Carrillo-Rivera, J. J.; Cardona, A.; Edmunds, W. M.

2002-04-01

Significant amounts of fluoride are found in the abstracted groundwater of San Luis Potosí. This groundwater withdrawal induces a cold, low-fluoride flow as well as deeper thermal fluoride-rich flow in various proportions. Flow mixing takes place depending on the abstraction regime, local hydrogeology, and borehole construction design and operation. Fluoride concentrations (≈3.7 mg l -1) could become higher still, in time and space, if the input of regional fluoride-rich water to the abstraction boreholes is enhanced. It is suggested that by controlling the abstraction well-head water temperature at 28-30 °C, a pumped water mixture with a fluoride content close to the maximum drinking water standard of 1.5 mg l -1 will be produced. Further, new boreholes and those already operating could take advantage of fluoride solubility controls to reduce the F concentration in the abstracted water by considering lithology and borehole construction design in order to regulate groundwater flow conditions.

A method for gear fatigue life prediction considering the internal flow field of the gear pump

NASA Astrophysics Data System (ADS)

Shen, Haidong; Li, Zhiqiang; Qi, Lele; Qiao, Liang

2018-01-01

Gear pump is the most widely used volume type hydraulic pump, and it is the main power source of the hydraulic system. Its performance is influenced by many factors, such as working environment, maintenance, fluid pressure and so on. It is different from the gear transmission system, the internal flow field of gear pump has a greater impact on the gear life, therefore it needs to consider the internal hydraulic system when predicting the gear fatigue life. In this paper, a certain aircraft gear pump as the research object, aim at the typical failure forms, gear contact fatigue, of gear pump, proposing the prediction method based on the virtual simulation. The method use CFD (Computational fluid dynamics) software to analyze pressure distribution of internal flow field of the gear pump, and constructed the unidirectional flow-solid coupling model of gear to acquire the contact stress of tooth surface on Ansys workbench software. Finally, employing nominal stress method and Miner cumulative damage theory to calculated the gear contact fatigue life based on modified material P-S-N curve. Engineering practice show that the method is feasible and efficient.

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrie, B. J.; Yang, Y.; Eaton, M.

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein- Podolsky-Rosen entanglement and intensity difference squeezing. Recently, diode-laser-pumped four-wave mixing processes have been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generatedmore » by a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. In conclusion, this robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrie, B. J., E-mail: lawriebj@ornl.gov; Pooser, R. C.; Yang, Y.

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein-Podolsky-Rosen entanglement and intensity difference squeezing. Diode-laser-pumped four-wave mixing processes have recently been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generated bymore » a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. This robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

Robust and compact entanglement generation from diode-laser-pumped four-wave mixing

DOE PAGES

Lawrie, B. J.; Yang, Y.; Eaton, M.; ...

2016-04-11

Four-wave-mixing processes are now routinely used to demonstrate multi-spatial-mode Einstein- Podolsky-Rosen entanglement and intensity difference squeezing. Recently, diode-laser-pumped four-wave mixing processes have been shown to provide an affordable, compact, and stable source for intensity difference squeezing, but it was unknown if excess phase noise present in power amplifier pump configurations would be an impediment to achieving quadrature entanglement. Here, we demonstrate the operating regimes under which these systems are capable of producing entanglement and under which excess phase noise produced by the amplifier contaminates the output state. We show that Einstein-Podolsky-Rosen entanglement in two mode squeezed states can be generatedmore » by a four-wave-mixing source deriving both the pump field and the local oscillators from a tapered-amplifier diode-laser. In conclusion, this robust continuous variable entanglement source is highly scalable and amenable to miniaturization, making it a critical step toward the development of integrated quantum sensors and scalable quantum information processors, such as spatial comb cluster states.« less

A Portable Analyzer for Pouch-Actuated, Immunoassay Cassettes

PubMed Central

Qiu, Xianbo; Liu, Changchun; Mauk, Michael G.; Hart, Robert W.; Chen, Dafeng; Qiu, Jing; Kientz, Terry; Fiene, Jonathan; Bau, Haim H.

2011-01-01

A portable, small footprint, light, general purpose analyzer (processor) to control the flow in immunoassay cassettes and to facilitate the detection of test results is described. The durable analyzer accepts disposable cassettes that contain pouches and reaction chambers for various unit operations such as hydration of dry reagents, stirring, and incubation. The analyzer includes individually controlled, linear actuators to compress the pouches in the cassette, which facilitates the pumping and mixing of sample and reagents, and to close diaphragm-based valves for flow control. The same types of actuators are used to compress pouches and actuate valves. The analyzer also houses a compact OEM scanner/reader to excite fluorescence and detect emission from labels. The analyzer is hydraulically isolated from the cassette, reducing the possibility of cross-contamination. The analyzer facilitates programmable, automated execution of a sequence of operations such as pumping and valving in a timely fashion, reducing the level of expertise required from the operator and the possibility for errors. The analyzer’s design is modular and expandable to accommodate cassettes of various complexities and additional functionalities. In this paper, the utility of the analyzer has been demonstrated with the execution of a simple, consecutive, lateral flow assay of a model biological system and the test results were detected with up converting phosphor labels that are excited at infrared frequencies and emit in the visible spectrum. PMID:22125359

Multi-reverse flow injection analysis integrated with multi-optical sensor for simultaneous determination of Mn(II), Fe(II), Cu(II) and Fe(III) in natural waters.

PubMed

Youngvises, Napaporn; Suwannasaroj, Kittigan; Jakmunee, Jaroon; AlSuhaimi, Awadh

2017-05-01

Multi-reverse flow injection analysis (Mr-FIA) integrated with multi-optical sensor was developed and optimized for the simultaneous determination of multi ions; Mn(II), Fe(II), Cu(II) and Fe(III) in water samples. The sample/standard solutions were propelled making use of a four channels peristaltic pump whereas 4 colorimetric reagents specific for the metal ions were separately injected in sample streams using multi-syringe pump. The color zones that formed in the individual mixing coils were then streamed into multi-channels spectrometer, which comprised of four flows through cell and four pairs of light emitting diode and photodiode, whereby signals were measured concurrently. The linearity range (along with detection limit, µgL -1 ) was 0.050-3.0(16), 0.30-2.0 (11), 0.050-1.0(12) and 0.10-1.0(50)mgL -1 , for Mn(II), Fe(II), Cu(II) and Fe(III), respectively. In the interim, the correlation coefficients were 0.9924-0.9942. The percentages relative standard deviation was less than 3. The proposed system was applied successfully to determine targeted metal ions simultaneously in natural water with high sample throughput and low reagent consumption, thus it satisfies the criteria of Green Analytical Chemistry (GAC) and its goals. Copyright © 2016 Elsevier B.V. All rights reserved.

Simulation of groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, east central Massachusetts

USGS Publications Warehouse

Eggleston, Jack R.; Carlson, Carl S.; Fairchild, Gillian M.; Zarriello, Phillip J.

2012-01-01

The effects of groundwater pumping on surface-water features were evaluated by use of a numerical groundwater model developed for a complex glacial-sediment aquifer in northeastern Framingham, Massachusetts, and parts of surrounding towns. The aquifer is composed of sand, gravel, silt, and clay glacial-fill sediments up to 270 feet thick over an irregular fractured bedrock surface. Surface-water bodies, including Cochituate Brook, the Sudbury River, Lake Cochituate, Dudley Pond, and adjoining wetlands, are in hydraulic connection with the aquifer and can be affected by groundwater withdrawals. Groundwater and surface-water interaction was simulated with MODFLOW-NWT under current conditions and a variety of hypothetical pumping conditions. Simulations of hypothetical pumping at reactivated water supply wells indicate that captured groundwater would decrease baseflow to the Sudbury River and induce recharge from Lake Cochituate. Under constant (steady-state) pumping, induced groundwater recharge from Lake Cochituate was equal to about 32 percent of the simulated pumping rate, and flow downstream in the Sudbury River decreased at the same rate as pumping. However, surface water responded quickly to pumping stresses. When pumping was simulated for 1 month and then stopped, streamflow depletions decreased by about 80 percent within 2 months and by about 90 percent within about 4 months. The fast surface water response to groundwater pumping offers the potential to substantially reduce streamflow depletions during periods of low flow, which are of greatest concern to the ecological integrity of the river. Results indicate that streamflow depletion during September, typically the month of lowest flow, can be reduced by 29 percent by lowering the maximum pumping rates to near zero during September. Lowering pumping rates for 3 months (July through September) reduces streamflow depletion during September by 79 percent as compared to constant pumping. These results demonstrate that a seasonal or streamflow-based groundwater pumping schedule can reduce the effects of pumping during periods of low flow.

Shaken, Not Stirred: How Tidal Advection and Dispersion Mechanisms Rather Than Turbulent Mixing Impact the Movement and Fate of Aquatic Constituents and Fish in the California Central Valley

NASA Astrophysics Data System (ADS)

Sridharan, V. K.; Fong, D.; Monismith, S. G.; Jackson, D.; Russel, P.; Pope, A.; Danner, E.; Lindley, S. T.

2016-12-01

River deltas worldwide - home to nearly a billion people, thousands of species of flora and fauna, and economies worth trillions of dollars - have experienced massive ecosystem decline caused by urbanization, pollution, and water withdrawals. Habitat restoration in these systems is imperative not only for preserving endangered biomes, but also in sustaining human demand for freshwater and long term commercial viability. The sustainable management of heavily engineered, multi-use, branched tidal estuaries such as the Sacramento-San Joaquin Delta (henceforth, the Delta) requires utilizing physical transport and mixing process models. These inform us about the movement and fate of water quality constituents and aquatic organisms. This study identifies and quantifies the effects of various hydrodynamic mechanisms in the Delta across multiple spatio-temporal scales. A particle tracking model with accurate channel junction physics and an agent based model with realistic biological hypotheses of fish behavior were developed to study the movement and fate of tracers (surrogates for water quality constituents) and fish in the Delta. Simulations performed with these models were used to (1) determine the transport pathways through the Delta, (2) quantify the magnitude of transport and mixing processes along those pathways, and (3) describe the effects of physical stressors on fates of juvenile salmon. The Delta is largely dominated by large spatial scale advection by river flows, tidal pumping, and significantly increased dispersion through chaos due to the interaction of tidal flows with channel junctions. The movement and fate of simulated tracers and juvenile salmon are governed largely by the water diversion and pumping operations, transport pathways and chaotic tidal mixing mechanisms along those pathways. There is also a significant effect of predation on fish. These transport pathway and mechanistic dependencies indicate that restoration efforts which are harmonious with human needs can be undertaken along the identified transport pathways by optimizing land and water use along these pathways, while facilitating transport of substances such as sediments and nutrients, and biota, between spatial regions to sustain populations of desired aquatic organisms.

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing

PubMed Central

Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

2016-01-01

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications. PMID:27886051

Development of a pump flow estimator for rotary blood pumps to enhance monitoring of ventricular function.

PubMed

Granegger, Marcus; Moscato, Francesco; Casas, Fernando; Wieselthaler, Georg; Schima, Heinrich

2012-08-01

Estimation of instantaneous flow in rotary blood pumps (RBPs) is important for monitoring the interaction between heart and pump and eventually the ventricular function. Our group has reported an algorithm to derive ventricular contractility based on the maximum time derivative (dQ/dt(max) as a substitute for ventricular dP/dt(max) ) and pulsatility of measured flow signals. However, in RBPs used clinically, flow is estimated with a bandwidth too low to determine dQ/dt(max) in the case of improving heart function. The aim of this study was to develop a flow estimator for a centrifugal pump with bandwidth sufficient to provide noninvasive cardiac diagnostics. The new estimator is based on both static and dynamic properties of the brushless DC motor. An in vitro setup was employed to identify the performance of pump and motor up to 20 Hz. The algorithm was validated using physiological ventricular and arterial pressure waveforms in a mock loop which simulated different contractilities (dP/dt(max) 600 to 2300 mm Hg/s), pump speeds (2 to 4 krpm), and fluid viscosities (2 to 4 mPa·s). The mathematically estimated pump flow data were then compared to the datasets measured in the mock loop for different variable combinations (flow ranging from 2.5 to 7 L/min, pulsatility from 3.5 to 6 L/min, dQ/dt(max) from 15 to 60 L/min/s). Transfer function analysis showed that the developed algorithm could estimate the flow waveform with a bandwidth up to 15 Hz (±2 dB). The mean difference between the estimated and measured average flows was +0.06 ± 0.31 L/min and for the flow pulsatilities -0.27 ± 0.2 L/min. Detection of dQ/dt(max) was possible up to a dP/dt(max) level of 2300 mm Hg/s. In conclusion, a flow estimator with sufficient frequency bandwidth and accuracy to allow determination of changes in ventricular contractility even in the case of improving heart function was developed. © 2012, Copyright the Authors. Artificial Organs © 2012, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Long-term animal experiments with an intraventricular axial flow blood pump.

PubMed

Yamazaki, K; Kormos, R L; Litwak, P; Tagusari, O; Mori, T; Antaki, J F; Kameneva, M; Watach, M; Gordon, L; Mukuo, H; Umezu, M; Tomioka, J; Outa, E; Griffith, B P; Koyanagai, H

1997-01-01

A miniature intraventricular axial flow blood pump (IVAP) is undergoing in vivo evaluation in calves. The IVAP system consists of a miniature (phi 13.9 mm) axial flow pump that resides within the left ventricular (LV) chamber and a brushless DC motor. The pump is fabricated from titanium alloy, and the pump weight is 170 g. It produces a flow rate of over 5 L/min against 100 mmHg pressure at 9,000 rpm with an 8 W total power consumption. The maximum total efficiency exceeds 17%. A purged lip seal system is used in prototype no. 8, and a newly developed "Cool-Seal" (a low temperature mechanical seal) is used in prototype no. 9. In the Cool-Seal system, a large amount of purge flow is introduced behind the seal faces to augment convective heat transfer, keeping the seal face temperature at a low level for prevention of heat denaturation of blood proteins. The Cool-Seal system consumes < 10 cc purge fluid per day and has greatly extended seal life. The pumps were implanted in three calves (26, 30, and 168 days of support). The pump was inserted through a left thoracotomy at the fifth intercostal space. Two pursestring sutures were placed on the LV apex, and the apex was cored with a myocardial punch. The pump was inserted into the LV with the outlet cannula smoothly passing through the aortic valve without any difficulty. Only 5 min elapsed between the time of chest opening and initiation of pumping. Pump function remained stable throughout in all experiments. No cardiac arrhythmias were detected, even at treadmill exercise tests. The plasma free hemoglobin level remained in the acceptable range. Post mortem examination did not reveal any interference between the pump and the mitral apparatus. No major thromboembolism was detected in the vital organs in Cases 1 or 2, but a few small renal infarcts were detected in Case 3.

Inducer analysis/pump model development

NASA Astrophysics Data System (ADS)

Cheng, Gary C.

1994-03-01

Current design of high performance turbopumps for rocket engines requires effective and robust analytical tools to provide design information in a productive manner. The main goal of this study was to develop a robust and effective computational fluid dynamics (CFD) pump model for general turbopump design and analysis applications. A finite difference Navier-Stokes flow solver, FDNS, which includes an extended k-epsilon turbulence model and appropriate moving zonal interface boundary conditions, was developed to analyze turbulent flows in turbomachinery devices. In the present study, three key components of the turbopump, the inducer, impeller, and diffuser, were investigated by the proposed pump model, and the numerical results were benchmarked by the experimental data provided by Rocketdyne. For the numerical calculation of inducer flows with tip clearance, the turbulence model and grid spacing are very important. Meanwhile, the development of the cross-stream secondary flow, generated by curved blade passage and the flow through tip leakage, has a strong effect on the inducer flow. Hence, the prediction of the inducer performance critically depends on whether the numerical scheme of the pump model can simulate the secondary flow pattern accurately or not. The impeller and diffuser, however, are dominated by pressure-driven flows such that the effects of turbulence model and grid spacing (except near leading and trailing edges of blades) are less sensitive. The present CFD pump model has been proved to be an efficient and robust analytical tool for pump design due to its very compact numerical structure (requiring small memory), fast turnaround computing time, and versatility for different geometries.

Inducer analysis/pump model development

NASA Technical Reports Server (NTRS)

Cheng, Gary C.

1994-01-01

Current design of high performance turbopumps for rocket engines requires effective and robust analytical tools to provide design information in a productive manner. The main goal of this study was to develop a robust and effective computational fluid dynamics (CFD) pump model for general turbopump design and analysis applications. A finite difference Navier-Stokes flow solver, FDNS, which includes an extended k-epsilon turbulence model and appropriate moving zonal interface boundary conditions, was developed to analyze turbulent flows in turbomachinery devices. In the present study, three key components of the turbopump, the inducer, impeller, and diffuser, were investigated by the proposed pump model, and the numerical results were benchmarked by the experimental data provided by Rocketdyne. For the numerical calculation of inducer flows with tip clearance, the turbulence model and grid spacing are very important. Meanwhile, the development of the cross-stream secondary flow, generated by curved blade passage and the flow through tip leakage, has a strong effect on the inducer flow. Hence, the prediction of the inducer performance critically depends on whether the numerical scheme of the pump model can simulate the secondary flow pattern accurately or not. The impeller and diffuser, however, are dominated by pressure-driven flows such that the effects of turbulence model and grid spacing (except near leading and trailing edges of blades) are less sensitive. The present CFD pump model has been proved to be an efficient and robust analytical tool for pump design due to its very compact numerical structure (requiring small memory), fast turnaround computing time, and versatility for different geometries.

An AC electroosmotic micropump for circular chromatographic applications.

PubMed

Debesset, S; Hayden, C J; Dalton, C; Eijkel, J C T; Manz, A

2004-08-01

Flow rates of up to 50 microm s(-1) have been successfully achieved in a closed-loop channel using an AC electroosmotic pump. The AC electroosmotic pump is made of an interdigitated array of unequal width electrodes located at the bottom of a channel, with an AC voltage applied between the small and the large electrodes. The flow rate was found to increase linearly with the applied voltage and to decrease linearly with the applied frequency. The pump is expected to be suitable for circular chromatography for the following reasons: the driving forces are distributed over the channel length and the pumping direction is set by the direction of the interdigitated electrodes. Pumping in a closed-loop channel can be achieved by arranging the electrode pattern in a circle. In addition the inherent working principle of AC electroosmotic pumping enables the independent optimisation of the channel height or the flow velocity.

2011 IEEE Visualization Contest winner: Visualizing unsteady vortical behavior of a centrifugal pump.

PubMed

Otto, Mathias; Kuhn, Alexander; Engelke, Wito; Theisel, Holger

2012-01-01

In the 2011 IEEE Visualization Contest, the dataset represented a high-resolution simulation of a centrifugal pump operating below optimal speed. The goal was to find suitable visualization techniques to identify regions of rotating stall that impede the pump's effectiveness. The winning entry split analysis of the pump into three parts based on the pump's functional behavior. It then applied local and integration-based methods to communicate the unsteady flow behavior in different regions of the dataset. This research formed the basis for a comparison of common vortex extractors and more recent methods. In particular, integration-based methods (separation measures, accumulated scalar fields, particle path lines, and advection textures) are well suited to capture the complex time-dependent flow behavior. This video (http://youtu.be/oD7QuabY0oU) shows simulations of unsteady flow in a centrifugal pump.

Low-cost fabrication and performance testing of Polydimethylsiloxane (PDMS) micromixers using an improved print-and-Peel (PAP) method

NASA Astrophysics Data System (ADS)

Abagon, Ma. Victoria; Buendia, Neil Daniel; Jasper Caracas, Corine; July Yap, Kristian

2018-03-01

The research presents different configurations of microfluidic mixers made from polydimethylsiloxane (PDMS) fabricated using an improved, low-cost print-and-peel (PAP) method. Processes, such as mixing, operated in the micro scale allow decreased equipment size-to-production capacity ratio and decreased energy consumption per unit product. In the study, saturated solutions of blue and yellow food dyes were introduced inside the channels using a LEGO® improvised microsyringe pump. Scanning Electron Microscopy (SEM) was used to determine the average depth of the fabricated micromixers which was found to be around 14 ¼m. The flows were observed and images were taken using a light microscope. The color intensities of the images were then measured using MATLAB®. From the relationship between color intensity and concentration, the mixing indices were calculated and found to be 0.9435 to 0.9941, which falls within the standard mixing index range (0.8 - 1.0) regardless of the flow rate and the configuration of the micromixer as verified through the two-way ANOVA. From the cost analysis, the cost of the device fabricated in this study is a hundred-fold less than expenses from standard fabrication procedures. Hence, the fabricated device provides an alternative for micromixers produced from expensive and conventional lithographic methods.

Characterization of an induced pressure pumping force for microfluidics

NASA Astrophysics Data System (ADS)

Jiang, Hai; Fan, Na; Peng, Bei; Weng, Xuan

2017-05-01

The electro-osmotic pumping and pressure-driven manipulation of fluids are considered as the most common strategies in microfluidic devices. However, both of them exhibit major disadvantages such as hard integration and high reagent consumption, and they are destructive methods for detection and photo bleaching. In this paper, an electric field-effect flow control approach, combining the electro-osmotic pumping force and the pressure-driven pumping force, was developed to generate the induced pressure-driven flow in a T-shaped microfluidic chip. Electro-osmotic flow between the T-intersection and two reservoirs was demonstrated, and it provided a stable, continuous, and electric field-free flow in the section of the microchannel without the electrodes. The velocity of the induced pressure-driven flow was linearly proportional to the applied voltages. Both numerical and experimental investigations were conducted to prove the concept, and the experimental results showed good agreement with the numerical simulations. In comparison to other induced pressure pumping methods, this approach can induce a high and controllable pressure drop in the electric field-free segment, subsequently causing an induced pressure-driven flow for transporting particles or biological cells. In addition, the generation of bubbles and the blocking of the microchannel are avoided.

IgG particle formation during filling pump operation: a case study of heterogeneous nucleation on stainless steel nanoparticles.

PubMed

Tyagi, Anil K; Randolph, Theodore W; Dong, Aichun; Maloney, Kevin M; Hitscherich, Carl; Carpenter, John F

2009-01-01

This study investigated factors associated with vial filling with a positive displacement piston pump leading to formation of protein particles in a formulation of an IgG. We hypothesized that nanoparticles shed from the pump's solution-contact surfaces nucleated protein aggregation and particle formation. Vials of IgG formulation filled at a clinical manufacturing site contained a few visible particles and about 100,000 particles (1.5-3 microm) per mL. In laboratory studies with the same model (National Instruments FUS-10) of pump, pumping of 20 mg/mL IgG formulation resulted in about 300,000 particles (1.5-3 microm) per mL. Pumping of protein-free formulation resulted in 13,000 particles (1.5-15 microm) per mL. More than 99% of the particles were 0.25-0.95 microm in size. Mixing of protein-free pumped solution with an equal volume of 40 mg/mL IgG resulted in 300,000 particles (1.5-15 microm) per mL. Also, mixing IgG formulation with 30,000/mL stainless steel nanoparticles resulted in formation of 30,000 protein microparticles (1.5-15 microm) per mL. Infrared spectroscopy showed that secondary structure of IgG in microparticles formed by pumping or mixing with steel nanoparticles was minimally perturbed. Our results document that nanoparticles of foreign materials shed by pumps can serve as heterogeneous nuclei for formation of protein microparticles. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

Recovery of injected freshwater to differentiate fracture flow in a low-permeability brackish aquifer

NASA Astrophysics Data System (ADS)

Miotliński, Konrad; Dillon, Peter J.; Pavelic, Paul; Cook, Peter G.; Page, Declan W.; Levett, Kerry

2011-10-01

SummaryA low-permeability weathered siltstone-sandstone aquifer containing brackish water was investigated to measure recoverability of injected freshwater with the aim of determining the significance of secondary porosity in contributing to groundwater flow and transport. Examination of the core, borehole geophysics, Radon-222, electromagnetic flowmeter (EMF) profiles and step-drawdown pumping tests did not identify whether fractures contribute to groundwater flow. A number of injection and recovery tests lasting from 3 days to 3 months using potable water showed a large degree of mixing with native groundwater. Withdrawal greater than 12-17% of the injected volume resulted in recovered water containing more native groundwater than injected water. A finite element solute transport model was set up to reproduce the observed salinity in recovered water. Without the inclusion of discrete fractures in the model it was not possible to get a fit between the observed and modelled salinity of recovered water within a realistic range of dispersivity values. The model was subsequently verified by using data from long-term injection and recovery trials. This evaluation of mixing conclusively demonstrated that the aquifer behaved as a fractured rock aquifer and not as an aquifer with primary porosity alone. Therefore, aquifer storage and recovery can be a very useful hydrogeological method to identify the occurrence of fracture flow in aquifers where there is a measurable concentration difference between the injected water and ambient groundwater.

Hydraulic pump with in-ground filtration and monitoring capability

DOEpatents

Hopkins, C.D.; Livingston, R.R.; Toole, W.R. Jr.

1995-01-01

A hydraulically operated pump is described for in-ground filtering and monitoring of wells or other fluid sources, including a hollow cylindrical pump housing with an inlet and an outlet, filtering devices positioned in the inlet and the outlet, a piston that fits slidably within the pump housing, and an optical cell in fluid communication with the pump housing. A conduit within the piston allows fluid communication between the exterior and one end of the piston. A pair of O-rings form a seal between the inside of the pump housing and the exterior of the piston. A flow valve positioned within the piston inside the conduit allows fluid to flow in a single direction. In operation, fluid enters the pump housing through the inlet, flows through the conduit and towards an end of the pump housing. The piston then makes a downward stroke closing the valve, thus forcing the fluid out from the pump housing into the optical cell, which then takes spectrophotometric measurements of the fluid. A spring helps return the piston back to its starting position, so that a new supply of fluid may enter the pump housing and the downward stroke can begin again. The pump may be used independently of the optical cell, as a sample pump to transport a sample fluid from a source to a container for later analysis.

Hydraulic pump with in-ground filtration and monitoring capability

DOEpatents

Hopkins, C.D.; Livingston, R.R.; Toole, W.R. Jr.

1996-10-29

A hydraulically operated pump is described for in-ground filtering and monitoring of waters or other fluid sources, includes a hollow cylindrical pump housing with an inlet and an outlet, filtering devices positioned in the inlet and the outlet, a piston that fits slidably within the pump housing, and an optical cell in fluid communication with the pump housing. A conduit within the piston allows fluid communication between the exterior and one end of the piston. A pair of o-rings form a seal between the inside of the pump housing and the exterior of the piston. A flow valve positioned within the piston inside the conduit allows fluid to flow in a single direction. In operation, fluid enters the pump housing through the inlet, flows through the conduit and towards an end of the pump housing. The piston then makes a downward stroke closing the valve, thus forcing the fluid out from the pump housing into the optical cell, which then takes spectrophotometric measurements of the fluid. A spring helps return the piston back to its starting position, so that a new supply of fluid may enter the pump housing and the downward stroke can begin again. The pump may be used independently of the optical cell, as a sample pump to transport a sample fluid from a source to a container for later analysis. 5 figs.

Hydraulic pump with in-ground filtration and monitoring capability

DOEpatents

Hopkins, Charles D.; Livingston, Ronald R.; Toole, Jr., William R.

1996-01-01

A hydraulically operated pump for in-ground filtering and monitoring of ws or other fluid sources, including a hollow cylindrical pump housing with an inlet and an outlet, filtering devices positioned in the inlet and the outlet, a piston that fits slidably within the pump housing, and an optical cell in fluid communication with the pump housing. A conduit within the piston allows fluid communication between the exterior and one end of the piston. A pair of o-rings form a seal between the inside of the pump housing and the exterior of the piston. A flow valve positioned within the piston inside the conduit allows fluid to flow in a single direction. In operation, fluid enters the pump housing through the inlet, flows through the conduit and towards an end of the pump housing. The piston then makes a downward stroke closing the valve, thus forcing the fluid out from the pump housing into the optical cell, which then takes spectrophotometric measurements of the fluid. A spring helps return the piston back to its starting position, so that a new supply of fluid may enter the pump housing and the downward stroke can begin again. The pump may be used independently of the optical cell, as a sample pump to transport a sample fluid from a source to a container for later analysis.

Computation of incompressible viscous flows through turbopump components

NASA Technical Reports Server (NTRS)

Kiris, Cetin; Chang, Leon

1993-01-01

Flow through pump components, such as an inducer and an impeller, is efficiently simulated by solving the incompressible Navier-Stokes equations. The solution method is based on the pseudocompressibility approach and uses an implicit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. the equations are solved in steadily rotating reference frames and the centrifugal force and the Coriolis force are added to the equation of motion. Current computations use a one-equation Baldwin-Barth turbulence model which is derived from a simplified form of the standard k-epsilon model equations. The resulting computer code is applied to the flow analysis inside a generic rocket engine pump inducer, a fuel pump impeller, and SSME high pressure fuel turbopump impeller. Numerical results of inducer flow are compared with experimental measurements. In the fuel pump impeller, the effect of downstream boundary conditions is investigated. Flow analyses at 80 percent, 100 percent, and 120 percent of design conditions are presented.

[Feasibility Study on Digital Signal Processor and Gear Pump of Uroflowmeter Calibration Device].

PubMed

Yuan, Qing; Ji, Jun; Gao, Jiashuo; Wang, Lixin; Xiao, Hong

2016-08-01

It will cause hidden trouble on clinical application if the uroflowmeter is out of control.This paper introduces a scheme of uroflowmeter calibration device based on digital signal processor(DSP)and gear pump and shows studies of its feasibility.According to the research plan,we analyzed its stability,repeatability and linearity by building a testing system and carried out experiments on it.The flow test system is composed of DSP,gear pump and other components.The test results showed that the system could produce a stable water flow with high precision of repeated measurement and different flow rate.The test system can calibrate the urine flow rate well within the range of 9~50mL/s which has clinical significance,and the flow error is less than 1%,which meets the technical requirements of the calibration apparatus.The research scheme of uroflowmeter calibration device on DSP and gear pump is feasible.

Feasibility of a miniature centrifugal rotary blood pump for low-flow circulation in children and infants.

PubMed

Takatani, Setsuo; Hoshi, Hideo; Tajima, Kennichi; Ohuchi, Katsuhiro; Nakamura, Makoto; Asama, Junichio; Shimshi, Tadahiko; Yoshikawa, Masaharu

2005-01-01

In this study, a seal-less, tiny centrifugal rotary blood pump was designed for low-flow circulatory support in children and infants. The design was targeted to yield a compact and priming volume of 5 ml with a flow rate of 0.5-4 l/min against a head pressure of 40-100 mm Hg. To meet the design requirements, the first prototype had an impeller diameter of 30 mm with six straight vanes. The impeller was supported with a needle-type hydrodynamic bearing and was driven with a six-pole radial magnetic driver. The external pump dimensions included a pump head height of 20 mm, diameter of 49 mm, and priming volume of 5 ml. The weight was 150 g, including the motor driver. In the mock circulatory loop, using fresh porcine blood, the pump yielded a flow of 0.5-4.0 l/min against a head pressure of 40-100 mm Hg at a rotational speed of 1800-4000 rpm using 1/4" inflow and outflow conduits. The maximum flow and head pressure of 5.25 l/min and 244 mm Hg, respectively, were obtained at a rotational speed of 4400 rpm. The maximum electrical-to-hydraulic efficiency occurred at a flow rate of 1.5-3.5 l/min and at a rotational speed of 2000-4400 rpm. The normalized index of hemolysis, which was evaluated using fresh porcine blood, was 0.0076 g/100 l with the impeller in the down-mode and a bearing clearance of 0.1 mm. Further refinement in the bearing and magnetic coupler are required to improve the hemolytic performance of the pump. The durability of the needle-type hydrodynamic bearing and antithrombotic performance of the pump will be performed before clinical applications. The tiny centrifugal blood pump meets the flow requirements necessary to support the circulation of pediatric patients.

Magnetohydrodynamic pump with a system for promoting flow of fluid in one direction

DOEpatents

Lemoff, Asuncion V [Union City, CA; Lee, Abraham P [Irvine, CA

2010-07-13

A magnetohydrodynamic pump for pumping a fluid. The pump includes a microfluidic channel for channeling the fluid, a MHD electrode/magnet system operatively connected to the microfluidic channel, and a system for promoting flow of the fluid in one direction in the microfluidic channel. The pump has uses in the medical and biotechnology industries for blood-cell-separation equipment, biochemical assays, chemical synthesis, genetic analysis, drug screening, an array of antigen-antibody reactions, combinatorial chemistry, drug testing, medical and biological diagnostics, and combinatorial chemistry. The pump also has uses in electrochromatography, surface micromachining, laser ablation, inkjet printers, and mechanical micromilling.

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, Ganapati Rao

1997-01-01

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

Hydraulic and Thermal Response to Intermittent Pumping in Unconfined Alluvial Aquifers along a Regulated Stream

NASA Astrophysics Data System (ADS)

Maharjan, Madan

Groundwater response to stream stage fluctuations was studied using a year-long time series of stream stage and well heads in Glen Dale and New Martinsville, WV. Stream stage fluctuations exerted primary control over groundwater levels, especially during high flows. The location and operation of river pools created by dams alter groundwater flow paths and velocities. Aquifers are more prone to surface water infiltration in the upper reaches of pools than in lower reaches. Aquifer diffusivity is heterogeneous within and between the two sites. Temperature fluctuations were observed for 2.5 years in 14 wells in three alluvial aquifers. Temperature signals have 2 components corresponding to pump-on and pump-off periods. Both components vary seasonality at different magnitudes. While pump-off temperatures fluctuated up to 3.8o C seasonally, short-term temperature shifts induced by turning the pump on were 0.2 to 2.5o C. Pumping-induced temperature shifts were highest in magnitude in summer and winter. Groundwater temperature lagged behind that of surface water by approximately six months. Pumping induced and seasonal temperature shifts were spatially and temporally complex but indicate stream exfiltration is a major driver for a number of these wells. Numerical simulation of aquifer response to pumping show different conditions before and after well-field development. During pre-development, the stream was losing at high flow and gaining at low flow. During post-development, however, the stream was losing at high flow and spatially variable at low flow. While bank storage gained only during high stage, stream exfiltration occurred year-round. Pumping induced stream exfiltration by creating an extensive cone of depression beneath the stream in both upstream and downstream directions. Spatially and temporally variable groundwater-surface water interaction next to a regulated stream were studied using analytical and numerical models, based on field observations. Seasonality plays an important role in these interactions, but human activity may also alter its intensity.

Atmospheric Carbon Dioxide Record from In Situ Measurements at Baring Head (1970 - 1993)

DOE Data Explorer

Manning, M. R. [National Institute of Water and Atmospheric Research, Ltd., Lower Hutt, New Zealand; Gomez, A. J. [National Institute of Water and Atmospheric Research, Ltd., Lower Hutt, New Zealand; Pohl, K. P. [National Institute of Water and Atmospheric Research, Ltd. Lower Hutt, New Zealand

1994-01-01

Determinations of atmospheric CO2 mixing ratios are made using a Siemens Ultramat-3 nondispersive infrared (NDIR) gas analyzer. The NDIR CO2 analyzer is connected via a gas manifold consisting of stainless steel tubing and computer-controlled solenoid switches to 12 gas cylinders and 2 sample air lines. The NDIR analyzer compares ambient air CO2 mixing ratios relative to known CO2 mixing ratios in tanks of compressed reference gases. The analyzer operates in a differential mode, with a "zero" reference gas of CO2 mixing ratio 20 to 30 parts per million (ppm) below ambient air CO2 levels flowing continuously through one cell of the analyzer at ~10 mL/min. When atmospheric CO2 is measured, a diaphragm pump pulls air through a sampling line at ~5 L/min. A small fraction of this (180 mL/min) is dried cryogenically to a temperature of approximately ¬70° Celsius and passed through the sample cell of the CO2 analyzer. Both the "zero" and sample gas are exhausted into the observatory building.

Fractional flow in fractured chalk; a flow and tracer test revisited.

PubMed

Odling, N E; West, L J; Hartmann, S; Kilpatrick, A

2013-04-01

A multi-borehole pumping and tracer test in fractured chalk is revisited and reinterpreted in the light of fractional flow. Pumping test data analyzed using a fractional flow model gives sub-spherical flow dimensions of 2.2-2.4 which are interpreted as due to the partially penetrating nature of the pumped borehole. The fractional flow model offers greater versatility than classical methods for interpreting pumping tests in fractured aquifers but its use has been hampered because the hydraulic parameters derived are hard to interpret. A method is developed to convert apparent transmissivity and storativity (L(4-n)/T and S(2-n)) to conventional transmissivity and storativity (L2/T and dimensionless) for the case where flow dimension, 2

Broadband multi-wavelength Brillouin lasers with an operating wavelength range of 1500–1600 nm generated by four-wave mixing in a dual wavelength Brillouin fiber laser cavity

NASA Astrophysics Data System (ADS)

Li, Q.; Jia, Z. X.; Weng, H. Z.; Li, Z. R.; Yang, Y. D.; Xiao, J. L.; Chen, S. W.; Huang, Y. Z.; Qin, W. P.; Qin, G. S.

2018-05-01

We demonstrate broadband multi-wavelength Brillouin lasers with an operating wavelength range of 1500–1600 nm and a frequency separation of ~9.28 GHz generated by four-wave mixing in a dual wavelength Brillouin fiber laser cavity. By using one continuous-wave laser as the pump source, multi-wavelength Brillouin lasers with an operating wavelength range of 1554–1574 nm were generated via cascaded Brillouin scattering and four-wave mixing. Interestingly, when pumped by two continuous-wave lasers with an appropriate frequency separation, the operating wavelength range of the multi-wavelength Brillouin lasers was increased to 1500–1600 nm due to cavity-enhanced cascaded four-wave mixing among the frequency components generated by two pump lasers in the dual wavelength Brillouin laser cavity.

Analysis of vertical flow during ambient and pumped conditions in four monitoring wells at the Pantex Plant, Carson County, Texas, July-September 2008

USGS Publications Warehouse

Stanton, Gregory P.; Thomas, Jonathan V.; Stoval, Jeffery

2009-01-01

Logs collected in monitoring well PTX06–1068 during ambient conditions indicate a static environment with no flow. During pumping there was upward vertical flow at rates ranging from 0.4 to 4.8 gallons per minute. During pumping, a gradual trend of more positive flowmeter values (upward flow) with distance up the well was observed. Estimated total transmissivity for four production zones identified from Flow–B numerical model results taken together was calculated to be about 200 feet squared per day.

Microscale electrokinetic transport and stability

NASA Astrophysics Data System (ADS)

Chen, Chuan-Hua

Electrokinetics is a leading mechanism for transport and separation of biochemical samples in microdevices due to its favorable scaling at small scales. However, electrokinetic systems can become highly unstable, and this instability adversely affects key processes such as sample stacking and electrophoretic separation. This dissertation deals with two major topics: a novel planar micropump exploiting the favorable scaling of electroosmosis at the microscale, and a fundamental study of electrokinetic flow instabilities induced by electrical conductivity gradients. Electroosmotic micropumps use field-induced ion drag to drive liquids and achieve high pressures in a compact design with no moving parts. An analytical model applicable to planar, etched-structure micropumps was developed to guide the geometrical design and working fluid selection. Standard microlithography and wet etching techniques were used to fabricate a pump 1 mm long along the flow direction and 0.9 mum by 38 mm in cross section. The pump produced a maximum pressure of 0.33 atm and a maximum flow rate of 15 mul/min at 1 kV applied potential with deionized water as working fluid. The pump performance agreed well with the theoretical model. Electrokinetic flow instabilities occur under high electric field in the presence of electrical conductivity gradients. In a microfluidic T-junction 11 mum by 155 mum in cross section, aqueous electrolytes of 10:1 conductivity ratio were electrokinetically driven into a common mixing channel. Convectively unstable waves were observed at 0.5 kV/cm, and upstream propagating waves at 1.5 kV/cm. A physical model for this instability has been developed. A linear stability analysis of the governing equations in the thin-layer limit predicts both qualitative trends and quantitative features that agree well with experimental data. Briggs-Bers criteria were applied to select physically unstable modes and determine the nature of instability. Conductivity gradients and bulk charge accumulation are a crucial factor in the instability. The role of electroosmotic flow is mainly as a convecting medium. The instability is governed by two key controlling parameters: the ratio of dynamic to dissipative forces which determines the onset of instability, and the ratio of electroviscous to electroosmotic velocities which governs the convective versus absolute nature of instability.

An electrical sensor for long-term monitoring of ultrafine particles in workplaces

NASA Astrophysics Data System (ADS)

Lanki, Timo; Tikkanen, Juha; Janka, Kauko; Taimisto, Pekka; Lehtimäki, Matti

2011-07-01

Pegasor Oy Ltd. (Finland) has developed a diffusion charging measurement device that enables continuous monitoring of fine particle concentration at a low initial and lifecycle cost. The innovation, for which an international process and apparatus patent has been applied for, opens doors for monitoring nanoparticle concentrations in workplaces. The Pegasor Particle Sensor (PPS) operates by electrostatically charging particles passing through the sensor and then measuring the current caused by the charged particles as they leave the sensor. The particles never touch the sensor and so never accumulate on its surfaces or need to be cleaned off. The sensor uses an ejector pump to draw a constant sample flow into the sensing area where it is mixed with the clean, charged pump flow air (provided by an external source). The sample flow containing charged particles passes through the sensor. The current generated by the charge leaving the detection volume is measured and related to the particle surface area. This system is extremely simple and reliable - no contact, no moving parts, and all critical parts of the sensor are constantly cleaned by a stream of fresh, filtered air. Due to the ejector pump, the sample flow, and respectively the sensor response is independent of the flow and pressure conditions around the sampling inlet. Tests with the Pegasor Particle Sensor have been conducted in a laboratory, and at a workplace producing nanoparticles for glass coatings. A new measurement protocol has been designed to ensure that process workers are not exposed to unusually high nanoparticle concentrations at any time during their working day. One sensor is placed inside the process line, and a light alarm system indicates the worker not to open any protective shielding or ventilation systems before concentration inside has reached background levels. The benefits of PPS in industrial hygiene are that the same monitoring technology can be used at the source as well as at the worker breathing zone. Up to eight sensors can be installed in series for centralized monitoring of the whole process in real time.

Development of a microimpedance pump for pulsatile flow transport - Part : Flow characteristics of the microimpedance pump. Part 2: A systematic study of steady and pulsatile transport in microscale cavities

NASA Astrophysics Data System (ADS)

Rinderknecht, Derek

Microfluidics offers an effective means to carry out a wide range of transport processes within a controlled microenvironment by drawing on the benefits imparted by increasing surface area to volume ratio at the microscale. Critical to the impact of microfluidics on integrated devices in the fields of bioengineering and biomedicine is the ability to transport fluids and biomolecules effectively particularly at the size scales involved. In this context a bio-inspired pumping mechanism, the valveless impedance pump, was explored for applications in microfluidics ranging from micro total analysis systems to microchannel cooling. Adhering to the basic principles of the impedance pump mechanism, pumps have been constructed at a variety of size scales from a few centimeters to a few hundred microns. The micro impedance pump is valveless, bidirectional, and can be constructed simply from a wide range of materials. Depending on the size of the pump flow rates range from nL/min to mL/min and pressures can be generated that exceed 20 kPa. Another benefit of the impedance pump is the pulsatile flow output which can be used in the context of microfluidic applications to enhance transport at low Reynolds numbers as well as metering in drug delivery. Pulsatile flow was therefore investigated as a method of augmenting transport in microfluidic systems. Micro PIV was used to study the affect of both steady and pulsatile flows on transport at low Reynolds number was examined in microscale rectangular cavities. Ventilation of the cavity contents was examined in terms of the residence time or average time a particle remains in the cavity region. Lagrangian coherent structures (LCS) were applied to empirical velocity fields to determine the impact of unsteadiness on time dependent boundaries to fluid transport present in the flow. Experimental results show that there are both frequencies which are beneficial and detrimental to cavity ventilation as well as certain frequencies which more evenly distribute particles originating in the cavity throughout the freestream.

Does an Open Recirculation Line Affect the Flow Rate and Pressure in a Neonatal Extracorporeal Life Support Circuit With a Centrifugal or Roller Pump?

PubMed

Wang, Shigang; Spencer, Shannon B; Woitas, Karl; Glass, Kristen; Kunselman, Allen R; Ündar, Akif

2017-01-01

The objective of this study is to evaluate the impact of an open or closed recirculation line on flow rate, circuit pressure, and hemodynamic energy transmission in simulated neonatal extracorporeal life support (ECLS) systems. The two neonatal ECLS circuits consisted of a Maquet HL20 roller pump (RP group) or a RotaFlow centrifugal pump (CP group), Quadrox-iD Pediatric oxygenator, and Biomedicus arterial and venous cannulae (8 Fr and 10 Fr) primed with lactated Ringer's solution and packed red blood cells (hematocrit 35%). Trials were conducted at flow rates ranging from 200 to 600 mL/min (200 mL/min increments) with a closed or open recirculation line at 36°C. Real-time pressure and flow data were recorded using a custom-based data acquisition system. In the RP group, the preoxygenator flow did not change when the recirculation line was open while the prearterial cannula flow decreased by 15.7-20.0% (P < 0.01). Circuit pressure, total circuit pressure drop, and hemodynamic energy delivered to patients also decreased (P < 0.01). In the CP group, the prearterial cannula flow did not change while preoxygenator flow increased by 13.6-18.8% (P < 0.01). Circuit pressure drop and hemodynamic energy transmission remained the same. The results showed that the shunt of an open recirculation line could decrease perfusion flow in patients in the ECLS circuit using a roller pump, but did not change perfusion flow in the circuit using a centrifugal pump. An additional flow sensor is needed to monitor perfusion flow in patients if any shunts exist in the ECLS circuit. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

PUMPS FOR LIQUID CURRENT-CONDUCTING MATERIAL

DOEpatents

Watt, D.A.

1958-12-23

An induction-type liquid conductor pump is described wherein the induced current flow is substantially tnansverse to the flow of the liquid in the duct, thus eliminating parallel current flow that tends to cause unwanted pressures resulting in turbulence, eddy-flow, heating losses, and reduced pumping efficiency. This improvement is achieved by offering the parallel current a path of lower impedance along the duct than that offered by the liquid so that the induced currents remaining in the liquid flow in a substantially transverse directlon. Thick copper bars are brazed to the liquid duct parallel to the flow, and additional induced currents are created in the copper bars of appropriate magnitude to balance the ohmic drop ln the current paths outside of the liquid metal.

Conference on Fluid Machinery, 8th, Budapest, Hungary, Sept. 1987, Proceedings. Volumes 1 & 2

NASA Astrophysics Data System (ADS)

Szabo, A.; Kisbocskoi, L.

The present conference on turbomachine fluid mechanics gives attention to the analysis of labyrinth seals, irrigation turbomachinery, axial-flow fans, poppet valves, the generation of Karman vortices, self-rectifying Wells-type air turbines, computer simulations for water-supply systems, the computation of meridional flow in turbomachines, entrained air effects on vortex pump performance, the three-dimensional potential flow in a draft tube, and hydro powerplant diagnostic methods. Also discussed are a mathematical model for the initiation of cavitation wear, cryogenic flow in ejectors, flow downstream of guide vanes in a Kaplan turbine, unsteady flow in rotating cascades, novel methods for turbomachine vibration monitoring, cavitation breakdown in centrifugal pumps, test results for Banki turbines, centrifugal compressor return-channel flow, performance predictions for regenerative turbomachines, and secondary flows in a centrifugal pump.

Body position and activity, but not heart rate, affect pump flows in patients with continuous-flow left ventricular assist devices.

PubMed

Muthiah, Kavitha; Gupta, Sunil; Otton, James; Robson, Desiree; Walker, Robyn; Tay, Andre; Macdonald, Peter; Keogh, Anne; Kotlyar, Eugene; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

2014-08-01

The aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). Although it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. Two studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. Heart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. Centrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Flow tube used to cool solar-pumped laser

NASA Technical Reports Server (NTRS)

1968-01-01

A flow tube has been designed and constructed to provide two major functions in the application of a laser beam for transmission of both sound and video. It maintains the YAG laser at the proper operating temperature of 300 degrees K under solar pumping conditions, and it serves as a pump cavity for the laser crystal.

Effects of irrigation water supply variations on limited resource farming in Conejos County, Colorado

NASA Astrophysics Data System (ADS)

Eckert, Jerry B.; Wang, Erda

1993-02-01

Farms in NE Conejos County, Colorado, are characterized by limited resources, uncertain surface flow irrigation systems, and mixed crop-livestock enterprise combinations which are dependent on public grazing resources. To model decision making on these farms, a linear program is developed stressing enterprise choices under conditions of multiple resource constraints. Differential access to grazing resources and irrigation water is emphasized in this research. Regarding the water resource, the model reflects farms situated alternatively on high-, medium-, and low-priority irrigation ditches within the Alamosa-La Jara river system, each with and without supplemental pumping. Differences are found in optimum enterprise mixes, net returns, choice of cropping technology, level of marketings, and other characteristics in response to variations in the availability of irrigation water. Implications are presented for alternative improvement strategies.

Best practices for concrete pumping.

DOT National Transportation Integrated Search

2016-12-01

Pumping is one of the major placement techniques used in the concrete industry to deliver concrete : from the mixing truck to the formwork. Although concrete pumping has been used to place concrete since : the 1960s, there is still a lack of exact kn...

Improving the Efficiency of 3-D Hydrogeological Mixers: Dilution Enhancement Via Coupled Engineering-Induced Transient Flows and Spatial Heterogeneity

NASA Astrophysics Data System (ADS)

Di Dato, Mariaines; de Barros, Felipe P. J.; Fiori, Aldo; Bellin, Alberto

2018-03-01

Natural attenuation and in situ oxidation are commonly considered as low-cost alternatives to ex situ remediation. The efficiency of such remediation techniques is hindered by difficulties in obtaining good dilution and mixing of the contaminant, in particular if the plume deformation is physically constrained by an array of wells, which serves as a containment system. In that case, dilution may be enhanced by inducing an engineered sequence of injections and extractions from such pumping system, which also works as a hydraulic barrier. This way, the aquifer acts as a natural mixer, in a manner similar to the industrialized engineered mixers. Improving the efficiency of hydrogeological mixers is a challenging task, owing to the need to use a 3-D setup while relieving the computational burden. Analytical solutions, though approximated, are a suitable and efficient tool to seek the optimum solution among all possible flow configurations. Here we develop a novel physically based model to demonstrate how the combined spatiotemporal fluctuations of the water fluxes control solute trajectories and residence time distributions and therefore, the effectiveness of contaminant plume dilution and mixing. Our results show how external forcing configurations are capable of inducing distinct time-varying groundwater flow patterns which will yield different solute dilution rates.

Supercritical fuel injection system

NASA Technical Reports Server (NTRS)

Marek, C. J.; Cooper, L. P. (Inventor)

1980-01-01

a fuel injection system for gas turbines is described including a pair of high pressure pumps. The pumps provide fuel and a carrier fluid such as air at pressures above the critical pressure of the fuel. A supercritical mixing chamber mixes the fuel and carrier fluid and the mixture is sprayed into a combustion chamber. The use of fuel and a carrier fluid at supercritical pressures promotes rapid mixing of the fuel in the combustion chamber so as to reduce the formation of pollutants and promote cleaner burning.

Self-actuated nuclear reactor shutdown system using induction pump to facilitate sensing of core coolant temperature

DOEpatents

Sievers, Robert K.; Cooper, Martin H.; Tupper, Robert B.

1987-01-01

A self-actuated shutdown system incorporated into a reactivity control assembly in a nuclear reactor includes pumping means for creating an auxiliary downward flow of a portion of the heated coolant exiting from the fuel assemblies disposed adjacent to the control assembly. The shutdown system includes a hollow tubular member which extends through the outlet of the control assembly top nozzle so as to define an outer annular flow channel through the top nozzle outlet separate from an inner flow channel for primary coolant flow through the control assembly. Also, a latching mechanism is disposed in an inner duct of the control assembly and is operable for holding absorber bundles in a raised position in the control assembly and for releasing them to drop them into the core of the reactor for shutdown purposes. The latching mechanism has an inner flow passage extending between and in flow communication with the absorber bundles and the inner flow channel of the top nozzle for accommodating primary coolant flow upwardly through the control assembly. Also, an outer flow passage separate from the inner flow passage extends through the latching mechanism between and in flow communication with the inner duct and the outer flow channel of the top nozzle for accommodating inflow of a portion of the heated coolant from the adjacent fuel assemblies. The latching mechanism contains a magnetic material sensitive to temperature and operable to cause mating or latching together of the components of the latching mechanism when the temperature sensed is below a known temperature and unmating or unlatching thereof when the temperature sensed is above a given temperature. The temperature sensitive magnetic material is positioned in communication with the heated coolant flow through the outer flow passage for directly sensing the temperature thereof. Finally, the pumping means includes a jet induction pump nozzle and diffuser disposed adjacent the bottom nozzle of the control assembly and in flow communication with the inlet thereof. The pump nozzle is operable to create an upward driving flow of primary coolant through the pump diffuser and then to the absorber bundles. The upward driving flow of primary coolant, in turn, creates a suction head within the outer flow channel of the top nozzle and thereby an auxiliary downward flow of the heated coolant portion exiting from the upper end of the adjacent fuel assemblies through the outer flow channel to the pump nozzle via the outer flow passage of the latching mechanism and an annular space between the outer and inner spaced ducts of the control assembly housing. The temperature of the heated coolant exiting from the adjacent fuel assemblies can thereby be sensed directly by the temperature sensitive magnetic material in the latching mechanism.

Fluid dynamic characteristics of the VentrAssist rotary blood pump.

PubMed

Tansley, G; Vidakovic, S; Reizes, J

2000-06-01

The VentrAssist pump has no shaft or seal, and the device is unique in design because the rotor is suspended passively by hydrodynamic forces, and urging is accomplished by an integrated direct current motor rotor that also acts as the pump impeller. This device has led to many challenges in its fluidic design, namely large flow-blockage from impeller blades, low stiffness of bearings with concomitant impeller displacement under pulsatile load conditions, and very small running clearances. Low specific speed and radial blade off-flow were selected in order to minimize the hemolysis. Pulsatile and steady-flow tests show the impeller is stable under normal operating conditions. Computational fluid dynamics (CFD) has been used to optimize flow paths and reduce net axial force imbalance to acceptably small values. The latest design of the pump achieved a system efficiency of 18% (in 30% hematocrit of red blood cells suspended in phosphate-buffered saline), and efficiency was optimized over the range of operating conditions. Parameters critical to improving pump efficiency were investigated.

Experimental Determination of Cavitation Characteristics of Low Specific Speed Pump using Noise and Vibration

NASA Astrophysics Data System (ADS)

Stephen, Christopher; Kumaraswamy, S.

2018-01-01

An experimental investigation of the cavitation behaviour of a radial flow pump of metric specific speed 23.62 rpm having different leading edge profiles of the vane is presented. The pump was operated for flow rates from 80 to 120% of the best efficiency point. The measurement included noise and vibration signals apart from the hydraulic parameters. The results exhibited the trends of noise and vibration with respect to percentage of head drops for all operating conditions. It was concluded that the trends were totally different for various flow rates. Hence it is suggested that the criteria to be used for detecting the early cavitation in pump based on noise and vibration signals should be a function of the flow rate. Further, it was found that the range of frequency band for noise and vibration was within 5 kHz with reference to the magnitude of fluctuation. The repeatable predominant frequency of vibration for prediction of cavitation behaviour of this particular pump was established as 0.992 kHz.

The Sponge Pump: The Role of Current Induced Flow in the Design of the Sponge Body Plan

PubMed Central

Leys, Sally P.; Yahel, Gitai; Reidenbach, Matthew A.; Tunnicliffe, Verena; Shavit, Uri; Reiswig, Henry M.

2011-01-01

Sponges are suspension feeders that use flagellated collar-cells (choanocytes) to actively filter a volume of water equivalent to many times their body volume each hour. Flow through sponges is thought to be enhanced by ambient current, which induces a pressure gradient across the sponge wall, but the underlying mechanism is still unknown. Studies of sponge filtration have estimated the energetic cost of pumping to be <1% of its total metabolism implying there is little adaptive value to reducing the cost of pumping by using “passive” flow induced by the ambient current. We quantified the pumping activity and respiration of the glass sponge Aphrocallistes vastus at a 150 m deep reef in situ and in a flow flume; we also modeled the glass sponge filtration system from measurements of the aquiferous system. Excurrent flow from the sponge osculum measured in situ and in the flume were positively correlated (r>0.75) with the ambient current velocity. During short bursts of high ambient current the sponges filtered two-thirds of the total volume of water they processed daily. Our model indicates that the head loss across the sponge collar filter is 10 times higher than previously estimated. The difference is due to the resistance created by a fine protein mesh that lines the collar, which demosponges also have, but was so far overlooked. Applying our model to the in situ measurements indicates that even modest pumping rates require an energetic expenditure of at least 28% of the total in situ respiration. We suggest that due to the high cost of pumping, current-induced flow is highly beneficial but may occur only in thin walled sponges living in high flow environments. Our results call for a new look at the mechanisms underlying current-induced flow and for reevaluation of the cost of biological pumping and its evolutionary role, especially in sponges. PMID:22180779

Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

NASA Technical Reports Server (NTRS)

Schwarz, Jordan B.; Mulder, Andrew; Zoladz, Thomas

2011-01-01

The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and test scale. The amplitude and frequency of oscillations varied considerably over the pump s operating space, making it difficult to predict blade loads.

Hydraulic refinement of an intraarterial microaxial blood pump.

PubMed

Siess, T; Reul, H; Rau, G

1995-05-01

Intravascularly operating microaxial pumps have been introduced clinically proving to be useful tools for cardiac assist. However, a number of complications have been reported in literature associated with the extra-corporeal motor and the flexible drive shaft cable. In this paper, a new pump concept is presented which has been mechanically and hydraulically refined during the developing process. The drive shaft cable has been replaced by a proximally integrated micro electric motor and an extra-corporeal power supply. The conduit between pump and power supply consists of only an electrical power cable within the catheter resulting in a device which is indifferent to kinking and small curvature radii. Anticipated insertion difficulties, as a result of a large outer pump diameter, led to a two-step approach with an initial 6,4mm pump version and a secondary 5,4mm version. Both pumps meet the hydraulic requirement of at least 2.5l/min at a differential pressure of 80-100 mmHg. The hydraulic refinements necessary to achieve the anticipated goal are based on ongoing hydrodynamic studies of the flow inside the pumps. Flow visualization on a 10:1 scale model as well as on 1:1 scale pumps have yielded significant improvements in the overall hydraulic performance of the pumps. One example of this iterative developing process by means of geometrical changes on the basis of flow visualization is illustrated for the 6.4mm pump.

An electrochemical pumping system for on-chip gradient generation.

PubMed

Xie, Jun; Miao, Yunan; Shih, Jason; He, Qing; Liu, Jun; Tai, Yu-Chong; Lee, Terry D

2004-07-01

Within the context of microfluidic systems, it has been difficult to devise pumping systems that can deliver adequate flow rates at high pressure for applications such as HPLC. An on-chip electrochemical pumping system based on electrolysis that offers certain advantages over designs that utilize electroosmotic driven flow has been fabricated and tested. The pump was fabricated on both silicon and glass substrates using photolithography. The electrolysis electrodes were formed from either platinum or gold, and SU8, an epoxy-based photoresist, was used to form the pump chambers. A glass cover plate and a poly(dimethylsiloxane) (PDMS) gasket were used to seal the chambers. Filling of the chambers was accomplished by using a syringe to inject liquid via filling ports, which were later sealed using a glass cover plate. The current supplied to the electrodes controlled the rate of gas formation and, thus, the resulting fluid flow rate. At low backpressures, flow rates >1 microL/min have been demonstrated using <1 mW of power. Pumping at backpressures as high as 200 psi have been demonstrated, with 20 nL/min having been observed using <4 mW. By integrating two electrochemical pumps with a polymer electrospray nozzle, we have confirmed the successful generation of a solvent gradient via a mass spectrometer.

Slush hydrogen quantity gaging and mixing for the National Aerospace Plane

NASA Astrophysics Data System (ADS)

Rudland, R. S.; Kroenke, I. M.; Urbach, A. R.

The National Aerospace Plane (NASP) design team has selected slush hydrogen as the fuel needed to power the high-speed ramjet-scramjet engines. Use of slush hydrogen rather than normal hydrogen provides significant improvements in density and cooling capacity for the aircraft. The loading of slush hydrogen in the NASP tank must be determined accurately to allow the vehicle size and weight to be kept to a minimum. A unique sensor developed at Ball to measure the slush density will be used in each region of the hydrogen tank to accurately determine the total mass of fuel loaded in the vehicle. The design, analysis, and test configuration for the mixing system is described in this paper. The mixing system is used to eliminate large-scale disturbances in the fluid produced by the large heat flux through the wall. The mixer also provides off-bottom suspension of the solids to create a more uniform slush mixture. The mixer design uses a pump to supply flow to an array of jets that produce mixing throughout the tank. Density sensors will be used in the test configuration to evaluate the mixing effectiveness.

Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

NASA Astrophysics Data System (ADS)

Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

2006-12-01

The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or calculated deliveries. IWFM utilizes a very straight-forward input file structure, allowing rapid development of complex simulations. A key feature of IWFM is a new algorithm for computation of groundwater flow across element faces. Enhancements to version 3.0 include automatic time-tracking of input and output data sets, linkage with the HEC-DSS database, and dynamic crop allocation using logit functions. Utilities linking IWFM to the PEST automated calibration suite are also available. All source code, executables and documentation are available for download from the DWR web site. IWFM is currently being used to develop hydrologic simulations of California's Central Valley (C2VSIM); the west side of California's San Joaquin Valley (WESTSIM); Butte County, CA; Solano County, CA; Merced County, CA; and the Oregon side of the Walla Walla River Basin.

Comprehensive experimental and numerical analysis of instability phenomena in pump turbines

NASA Astrophysics Data System (ADS)

Gentner, Ch; Sallaberger, M.; Widmer, Ch; Bobach, B.-J.; Jaberg, H.; Schiffer, J.; Senn, F.; Guggenberger, M.

2014-03-01

The changes in the electricity market have led to changed requirements for the operation of pump turbines. Utilities need to change fast and frequently between pumping and generating modes and increasingly want to operate at off-design conditions for extended periods. Operation of the units in instable areas of the machine characteristic is not acceptable and may lead to self-excited vibration of the hydraulic system. In turbine operation of pump turbines unstable behaviour can occur at low load off-design operation close to runaway conditions (S-shape of the turbine characteristic). This type of instability may impede the synchronization of the machine in turbine mode and thus increase start-up and switch over times. A pronounced S-shaped instability can also lead to significant drop of discharge in the event of load rejection. Low pressure on the suction side and in the tail-race tunnel could cause dangerous separation of the water column. Understanding the flow features that lead to the instable behaviour of pump turbines is a prerequisite to the design of machines that can fulfil the growing requirements relating to operational flexibility. Flow simulation in these instability zones is demanding due to the complex and highly unsteady flow patterns. Only unsteady simulation methods are able to reproduce the governing physical effects in these operating regions. ANDRITZ HYDRO has been investigating the stability behaviour of pump turbines in turbine operation in cooperation with several universities using simulation and measurements. In order to validate the results of flow simulation of unstable operating points, the Graz University of Technology (Austria) performed detailed experimental investigations. Within the scope of a long term research project, the operating characteristics of several pump turbine runners have been measured and flow patterns in the pump turbine at speed no load and runaway have been examined by 2D Laser particle image velocimetry (PIV). For several wicket gate positions, the flow fields in the vane-less space at runner inlet observed in the experiment are compared with the results of unsteady CFD flow simulations. Physical phenomena are visualized and insight to flow phenomena is given. Analyses using both results of simulation and measurement allow deriving a consistent explanation of the fluid mechanical mechanisms leading to the S-shaped instability of pump turbines.

A compact centrifugal pump for cardiopulmonary bypass.

PubMed

Sasaki, T; Jikuya, T; Aizawa, T; Shiono, M; Sakuma, I; Takatani, S; Glueck, J; Noon, G P; Nosé, Y; DeBakey, M E

1992-12-01

A majority of the cardiopulmonary bypass (CPB) systems still utilize bulky roller pumps. A direct-drive small centrifugal pump intended for second-generation CPB pump has been developed. The pump has a 50 mm diameter impeller and provides a 6 L/min flow at 3,000 rpm against 300 mm Hg. A flexible drive shaft allows us to separate the pump head from the console resulting in easier manipulation. An in vitro study showed that the pump generated less hemolysis (index of hemolysis = 0.0011, comparable to the value for Bio-medicus BP-80). To improve blood flow around the shaft-seal region and to reduce thrombus formation around the shaft, six holes were drilled through the impeller. In biventricular bypass experiments using calves, our pump demonstrated excellent antithrombogenicity and durability for 48 h. And the compact and atraumatic centrifugal pump system showed excellent performance and easy manipulation under actual CPB conditions in animal.

Human Aorta Is a Passive Pump

NASA Astrophysics Data System (ADS)

Pahlevan, Niema; Gharib, Morteza

2012-11-01

Impedance pump is a simple valveless pumping mechanism that operates based on the principles of wave propagation and reflection. It has been shown in a zebrafish that a similar mechanism is responsible for the pumping action in the embryonic heart during early stages before valve formation. Recent studies suggest that the cardiovascular system is designed to take advantage of wave propagation and reflection phenomena in the arterial network. Our aim in this study was to examine if the human aorta is a passive pump working like an impedance pump. A hydraulic model with different compliant models of artificial aorta was used for series of in-vitro experiments. The hydraulic model includes a piston pump that generates the waves. Our result indicates that wave propagation and reflection can create pumping mechanism in a compliant aorta. Similar to an impedance pump, the net flow and the flow direction depends on the frequency of the waves, compliance of the aorta, and the piston stroke.

Conjunctive management of multi-reservoir network system and groundwater system

NASA Astrophysics Data System (ADS)

Mani, A.; Tsai, F. T. C.

2015-12-01

This study develops a successive mixed-integer linear fractional programming (successive MILFP) method to conjunctively manage water resources provided by a multi-reservoir network system and a groundwater system. The conjunctive management objectives are to maximize groundwater withdrawals and maximize reservoir storages while satisfying water demands and raising groundwater level to a target level. The decision variables in the management problem are reservoir releases and spills, network flows and groundwater pumping rates. Using the fractional programming approach, the objective function is defined as a ratio of total groundwater withdraws to total reservoir storage deficits from the maximum storages. Maximizing this ratio function tends to maximizing groundwater use and minimizing surface water use. This study introduces a conditional constraint on groundwater head in order to sustain aquifers from overpumping: if current groundwater level is less than a target level, groundwater head at the next time period has to be raised; otherwise, it is allowed to decrease up to a certain extent. This conditional constraint is formulated into a set of mixed binary nonlinear constraints and results in a mixed-integer nonlinear fractional programming (MINLFP) problem. To solve the MINLFP problem, we first use the response matrix approach to linearize groundwater head with respect to pumping rate and reduce the problem to an MILFP problem. Using the Charnes-Cooper transformation, the MILFP is transformed to an equivalent mixed-integer linear programming (MILP). The solution of the MILP is successively updated by updating the response matrix in every iteration. The study uses IBM CPLEX to solve the MILP problem. The methodology is applied to water resources management in northern Louisiana. This conjunctive management approach aims to recover the declining groundwater level of the stressed Sparta aquifer by using surface water from a network of four reservoirs as an alternative source of supply.

Fluid extraction across pumping and permeable walls in the viscous limit

NASA Astrophysics Data System (ADS)

Herschlag, G.; Liu, J.-G.; Layton, A. T.

2016-04-01

In biological transport mechanisms such as insect respiration and renal filtration, fluid travels along a leaky channel allowing material exchange with systems exterior to the channel. The channels in these systems may undergo peristaltic pumping which is thought to enhance the material exchange. To date, little analytic work has been done to study the effect of pumping on material extraction across the channel walls. In this paper, we examine a fluid extraction model in which fluid flowing through a leaky channel is exchanged with fluid in a reservoir. The channel walls are allowed to contract and expand uniformly, simulating a pumping mechanism. In order to efficiently determine solutions of the model, we derive a formal power series solution for the Stokes equations in a finite channel with uniformly contracting/expanding permeable walls. This flow has been well studied in the case in which the normal velocity at the channel walls is proportional to the wall velocity. In contrast we do not assume flow that is proportional to the wall velocity, but flow that is driven by hydrostatic pressure, and we use Darcy's law to close our system for normal wall velocity. We incorporate our flow solution into a model that tracks the material pressure exterior to the channel. We use this model to examine flux across the channel-reservoir barrier and demonstrate that pumping can either enhance or impede fluid extraction across channel walls. We find that associated with each set of physical flow and pumping parameters, there are optimal reservoir conditions that maximize the amount of material flowing from the channel into the reservoir.

14 CFR 29.955 - Fuel flow.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.955 Fuel flow. (a) General. The fuel system for each engine must provide the engine with at least 100 percent of the fuel required under all... flow transmitter, if installed, and the critical fuel pump (for pump-fed systems) must be installed to...

14 CFR 29.955 - Fuel flow.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.955 Fuel flow. (a) General. The fuel system for each engine must provide the engine with at least 100 percent of the fuel required under all... flow transmitter, if installed, and the critical fuel pump (for pump-fed systems) must be installed to...

14 CFR 29.955 - Fuel flow.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.955 Fuel flow. (a) General. The fuel system for each engine must provide the engine with at least 100 percent of the fuel required under all... flow transmitter, if installed, and the critical fuel pump (for pump-fed systems) must be installed to...

14 CFR 29.955 - Fuel flow.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.955 Fuel flow. (a) General. The fuel system for each engine must provide the engine with at least 100 percent of the fuel required under all... flow transmitter, if installed, and the critical fuel pump (for pump-fed systems) must be installed to...

14 CFR 29.955 - Fuel flow.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.955 Fuel flow. (a) General. The fuel system for each engine must provide the engine with at least 100 percent of the fuel required under all... flow transmitter, if installed, and the critical fuel pump (for pump-fed systems) must be installed to...

Ground Water Flow No Longer A Mystery

ERIC Educational Resources Information Center

Lehr, Jay H.; Pettyjohn, Wayne A.

1976-01-01

Examined are the physical characteristics of ground water movement. Some potential pollution problems are identified. Models are used to explain mathematical and hydraulic principles of flow toward a pumping well and an effluent stream, flow around and through lenticular beds, and effects of pumping on the water table. (Author/MR)

Best practices for concrete pumping : technical summary.

DOT National Transportation Integrated Search

2016-12-01

Pumping is one of the major placement techniques used in the concrete industry : to deliver concrete from the mixing truck to the formwork. Although concrete : pumping has been used to place concrete since the 1960s, there is still a lack : of exact ...

Ultra high vacuum pumping system and high sensitivity helium leak detector

DOEpatents

Myneni, G.R.

1997-12-30

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

Electrokinetic high pressure hydraulic system

DOEpatents

Paul, Phillip H.; Rakestraw, David J.

2000-01-01

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

Numerical investigation of the entrainment and mixing processes in neutral and stably-stratified mixing layers

NASA Astrophysics Data System (ADS)

Cortesi, A. B.; Smith, B. L.; Yadigaroglu, G.; Banerjee, S.

1999-01-01

The direct numerical simulation (DNS) of a temporally-growing mixing layer has been carried out, for a variety of initial conditions at various Richardson and Prandtl numbers, by means of a pseudo-spectral technique; the main objective being to elucidate how the entrainment and mixing processes in mixing-layer turbulence are altered under the combined influence of stable stratification and thermal conductivity. Stratification is seen to significantly modify the way by which entrainment and mixing occur by introducing highly-localized, convective instabilities, which in turn cause a substantially different three-dimensionalization of the flow compared to the unstratified situation. Fluid which was able to cross the braid region mainly undisturbed (unmixed) in the unstratified case, pumped by the action of rib pairs and giving rise to well-formed mushroom structures, is not available with stratified flow. This is because of the large number of ribs which efficiently mix the fluid crossing the braid region. More efficient entrainment and mixing has been noticed for high Prandtl number computations, where vorticity is significantly reinforced by the baroclinic torque. In liquid sodium, however, for which the Prandtl number is very low, the generation of vorticity is very effectively suppressed by the large thermal conduction, since only small temperature gradients, and thus negligible baroclinic vorticity reinforcement, are then available to counterbalance the effects of buoyancy. This is then reflected in less efficient entrainment and mixing. The influence of the stratification and the thermal conductivity can also be clearly identified from the calculated entrainment coefficients and turbulent Prandtl numbers, which were seen to accurately match experimental data. The turbulent Prandtl number increases rapidly with increasing stratification in liquid sodium, whereas for air and water the stratification effect is less significant. A general law for the entrainment coefficient as a function of the Richardson and Prandtl numbers is proposed, and critically assessed against experimental data.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1999-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1998-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galambos, Paul C.

This is the latest in a series of LDRD's that we have been conducting with Florida State University/Florida A&M University (FSU/FAMU) under the campus executive program. This research builds on the earlier projects; ''Development of Highly Integrated Magnetically and Electrostatically Actuated Micropumps'' (SAND2003-4674) and ''Development of Magnetically and Electrostatically Driven Surface Micromachined Pumps'' (SAND2002-0704P). In this year's LDRD we designed 2nd generation of surface micromachined (SMM) gear and viscous pumps. Two SUMMiT{trademark} modules full of design variations of these pumps were fabricated and one SwIFT{trademark} module is still in fabrication. The SwIFT{trademark} fabrication process results in a transparent pump housingmore » cover that will enable visualization inside the pumps. Since the SwIFT{trademark} pumps have not been tested as they are still in fabrication, this report will focus on the 2nd generation SUMMiT{trademark} designs. Pump testing (pressure vs. flow) was conducted on several of the SUMMiT{trademark} designs resulting in the first pump curve for this class of SMM pumps. A pump curve was generated for the higher torque 2nd generation gear pump designed by Jason Hendrix of FSU. The pump maximum flow rate at zero head was 6.5 nl/s for a 30V, 30 Hz square wave signal. This level of flow rate would be more than adequate for our typical SMM SUMMiT{trademark} or SwIFT{trademark} channels which have typical volumes on the order of 50 pl.« less

An extended CFD model to predict the pumping curve in low pressure plasma etch chamber

NASA Astrophysics Data System (ADS)

Zhou, Ning; Wu, Yuanhao; Han, Wenbin; Pan, Shaowu

2014-12-01

Continuum based CFD model is extended with slip wall approximation and rarefaction effect on viscosity, in an attempt to predict the pumping flow characteristics in low pressure plasma etch chambers. The flow regime inside the chamber ranges from slip wall (Kn ˜ 0.01), and up to free molecular (Kn = 10). Momentum accommodation coefficient and parameters for Kn-modified viscosity are first calibrated against one set of measured pumping curve. Then the validity of this calibrated CFD models are demonstrated in comparison with additional pumping curves measured in chambers of different geometry configurations. More detailed comparison against DSMC model for flow conductance over slits with contraction and expansion sections is also discussed.

System and method for continuous solids slurry depressurization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leininger, Thomas Frederick; Steele, Raymond Douglas; Cordes, Stephen Michael

A system includes a first pump having a first outlet and a first inlet, and a controller. The first pump is configured to continuously receive a flow of a slurry into the first outlet at a first pressure and to continuously discharge the flow of the slurry from the first inlet at a second pressure less than the first pressure. The controller is configured to control a first speed of the first pump against the flow of the slurry based at least in part on the first pressure, wherein the first speed of the first pump is configured to resistmore » a backflow of the slurry from the first outlet to the first inlet.« less

Thermal transpiration in zeolites: A mechanism for motionless gas pumps

NASA Astrophysics Data System (ADS)

Gupta, Naveen K.; Gianchandani, Yogesh B.

2008-11-01

We explore the use of a naturally occurring zeolite, clinoptilolite, for a chip-scale, thermal transpiration-based gas pump. The nanopores in clinoptilolite enable the required free-molecular flow, even at atmospheric pressure. The pump utilizes a foil heater located between zeolite disks in a plastic package. A 2.3mm thick zeolite disk generates a typical gas flow rate of 6.6×10-3 cc/min-cm2 with an input power of <300mW/cm2. The performance is constrained by imperfections in clinoptilolite, which provide estimated leakage apertures of 10.2-13.5μm/cm2 of flow cross section. The transient response of the pump is studied to quantify nonidealities.

Ozone profile measurements at McMurdo Station Antarctica during the spring of 1987

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Harder, J. W.; Rosen, J. M.; Hereford, J.; Carpenter, J. R.

1988-01-01

During the Antarctic spring of 1986, 33 ozone soundings were conducted from McMurdo Station. These data indicated that the springtime decrease in ozone occurred rapidly between the altitudes of 12 and 20 km. During 1987, these measurements were repeated with 50 soundings between 29 August and 9 November. Digital conversions of standard electrochemical cell ozonesondes were again employed. The ozonesonde pumps were individually calibrated for flow rate as the high altitude performance of these pumps have been in question. While these uncertainties are not large in the region of the ozone hole, they are significant at high altitude and apparently resulted in an underestimate of total ozone of about 7 percent (average) as compared to the Total Ozone Mapping Spectrometer (TOMS) in 1986, when the flow rate recommended by the manufacturer was used. At the upper altitudes (approx. 30 km) the flow rate may be overestimated by as much as 15 percent using recommended values (see Harder et al., The UW Digital Ozonesonde: Characteristics and Flow Rate Calibration, poster paper, this workshop). These upper level values are used in the extrapolation, at constant mixing ratio, required to complete the sounding for total ozone. The first sounding was on 29 August, prior to major ozone depletion, when 274 DU total ozone (25 DU extrapolated) was observed. By early October total ozone had decreased to the 150 DU range; it then increased during mid-October owing to motion of the vortex and returned to a value of 148 DU (29 DU extrapolated) on 27 October.

A Selected Operational History of the Internal Thermal Control System (ITCS) for International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Patel, Vipul P.; Winton, Dale; Ibarra, Thomas H.

2004-01-01

The Internal Thermal Control System (ITCS) has been developed jointly by Boeing Corporation, Huntsville, Alabama and Honeywell Engines & Systems, Torrance, California to meet the internal thermal control needs for the International Space Station (ISS). The ITCS provides heat removal for the critical life support systems and thermal conditioning for numerous experiment racks. The ITCS will be fitted on a number of modules on the ISS. The first US Element containing the ITCS, Node 1, was launched in December 1998. Since Node 1 does not contain a pump to circulate the fluid it was not filled with ITCS fluid until after the US Laboratory Module was installed. The second US Element module, US Laboratory Module, which contains the pumps and all the major ITCS control hardware, was launched in February 2001. The third US Element containing the ITCS, the US Airlock, was launched in July 2001. The dual loop system of the ITCS is comprised of a lowtemperature loop (LTL) and a moderate-temperature loop (MTL). Each loop has a pump package assembly (PPA), a system flow control assembly (SFCA), a threeway mixing valve (TWMV), several rack flow control assemblies (RFCA), cold plates, pressure sensors, temperature sensors, pump bypass assembly (PBA) and a heat exchanger. In addition, the MTL has an additional TWMV, a payload regeneration heat exchanger (P/RHE) and a manual flow control valve (MFCV). The LTL has a service performance and checkout unit (SPCU) heat exchanger. The two loops are linked via one loop crossover assembly (LCA) providing cross loop capabilities and a single PPA, two-loop functionality. One important parameter monitored by the ground stations and on-orbit is the amount of fluid leakage from the ITCS. ISS fluid leakage is of importance since ITCS fluid is costly to re-supply, may be difficult to clean up in zero-g, and if uncontained could lead to equipment failures and potential hazards. This paper examines the nominal leakage observed over period of a year of on-orbit operation and compares this with analysis predictions. This paper also addresses the off-nominal leakage and a fluid transfer event causing significant changes in accumulator quantity.

Application of a compressible flow solver and barotropic cavitation model for the evaluation of the suction head in a low specific speed centrifugal pump impeller channel

NASA Astrophysics Data System (ADS)

Limbach, P.; Müller, T.; Skoda, R.

2015-12-01

Commonly, for the simulation of cavitation in centrifugal pumps incompressible flow solvers with VOF kind cavitation models are applied. Since the source/sink terms of the void fraction transport equation are based on simplified bubble dynamics, empirical parameters may need to be adjusted to the particular pump operating point. In the present study a barotropic cavitation model, which is based solely on thermodynamic fluid properties and does not include any empirical parameters, is applied on a single flow channel of a pump impeller in combination with a time-explicit viscous compressible flow solver. The suction head curves (head drop) are compared to the results of an incompressible implicit standard industrial CFD tool and are predicted qualitatively correct by the barotropic model.

Advanced porous electrodes with flow channels for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Bhattarai, Arjun; Wai, Nyunt; Schweiss, Ruediger; Whitehead, Adam; Lim, Tuti M.; Hng, Huey Hoon

2017-02-01

Improving the overall energy efficiency by reducing pumping power and improving flow distribution of electrolyte, is a major challenge for developers of flow batteries. The use of suitable channels can improve flow distribution through the electrodes and reduce flow resistance, hence reducing the energy consumption of the pumps. Although several studies of vanadium redox flow battery have proposed the use of bipolar plates with flow channels, similar to fuel cell designs, this paper presents the use of flow channels in the porous electrode as an alternative approach. Four types of electrodes with channels: rectangular open channel, interdigitated open cut channel, interdigitated circular poked channel and cross poked circular channels, are studied and compared with a conventional electrode without channels. Our study shows that interdigitated open channels can improve the overall energy efficiency up to 2.7% due to improvement in flow distribution and pump power reduction while interdigitated poked channel can improve up to 2.5% due to improvement in flow distribution.

Effects of aquifer heterogeneity on ground-water flow and chloride concentrations in the Upper Floridan aquifer near and within an active pumping well field, west-central Florida

USGS Publications Warehouse

Tihansky, A.B.

2005-01-01

Chloride concentrations have been increasing over time in water from wells within and near the Eldridge-Wilde well field, near the coast in west-central Florida. Variable increases in chloride concentrations from well to well over time are the combined result of aquifer heterogeneity and ground-water pumping within the Upper Floridan aquifer. Deep mineralized water and saline water associated with the saltwater interface appear to move preferentially along flow zones of high transmissivity in response to ground-water withdrawals. The calcium-bicarbonate-type freshwater of the Upper Floridan aquifer within the study area is variably enriched with ions by mixing with introduced deep and saline ground water. The amount and variability of increases in chloride and sulfate concentrations at each well are related to well location, depth interval, and permeable intervals intercepted by the borehole. Zones of high transmissivity characterize the multilayered carbonate rocks of the Upper Floridan aquifer. Well-developed secondary porosity within the Tampa/Suwannee Limestones and the Avon Park Formation has created producing zones within the Upper Floridan aquifer. The highly transmissive sections of the Avon Park Formation generally are several orders of magnitude more permeable than the Tampa/Suwannee Limestones, but both are associated with increased ground-water flow. The Ocala Limestone is less permeable and is dominated by primary, intergranular porosity. Acoustic televiewer logging, caliper logs, and borehole flow logs (both electromagnetic and heat pulse) indicate that the Tampa/Suwannee Limestone units are dominated by porosity owing to dissolution between 200 and 300 feet below land surface, whereas the porosity of the Avon Park Formation is dominated by fractures that occur primarily from 600 to 750 feet below land surface and range in angle from horizontal to near vertical. Although the Ocala Limestone can act as a semiconfining unit between the Avon Park Formation and the Tampa/Suwannee Limestones, seismic-reflection data and photolinear analyses indicate that fractures and discontinuities in the Ocala Limestone are present within the southwestern part of the well field. It is possible that some fracture zones extend upward from the Avon Park Formation through the Ocala, Suwannee, and Tampa Limestones to land surface. These fractures may provide a more direct hydrologic connection between transmissive zones that are vertically separated by less permeable stratigraphic units. Ground water moves along permeable zones within the Upper Floridan aquifer in response to changes in head gradients as a result of pumping. Borehole geophysical measurements, including flow logs, specific conductance logs, and continuous monitoring of specific conductance at selected fixed depths, indicate that borehole specific conductance varies substantially with time and in response to pumping stresses. Ground-water mixing between hydrogeologic units likely occurs along highly transmissive zones and within boreholes of active production wells. Ground-water movement and water-quality changes were greatest along the most transmissive zones. Variable mixing of three water-type end members (freshwater, deepwater, and saltwater) occurs throughout the study area. Both deepwater and saltwater are likely sources for elevated chloride and sulfate concentrations in ground water. Mass-balance calculations of mixtures of the three end members indicate that deepwater is found throughout the aquifer units. Samples from wells within the southwestern part of the well field indicate that deepwater migrates into the shallow permeable units in the southwestern part of the well field. Deepwater contributes to elevated sulfate and chloride concentrations, which increase with depth and are elevated in wells less than 400 feet deep. The greatest increases in chloride concentrations over time are found in water from wells closest to the saltwater interface. Gro

Four wave mixing oscillation in a semiconductor microcavity: generation of two correlated polariton populations.

PubMed

Romanelli, M; Leyder, C; Karr, J Ph; Giacobino, E; Bramati, A

2007-03-09

We demonstrate a novel kind of polariton four wave mixing oscillation. Two pump polaritons scatter towards final states that emit two beams of equal intensity, separated both spatially and in polarization with respect to the pumps. The measurement of the intensity fluctuations of the emitted light demonstrates that the final states are strongly correlated.

Liquid rocket engine axial-flow turbopumps

NASA Technical Reports Server (NTRS)

Scheer, D. D.; Huppert, M. C.; Viteri, F.; Farquhar, J.; Keller, R. B., Jr. (Editor)

1978-01-01

The axial pump is considered in terms of the total turbopump assembly. Stage hydrodynamic design, pump rotor assembly, pump materials for liquid hydrogen applications, and safety factors as utilized in state of the art pumps are among the topics discussed. Axial pump applications are included.

Packaged peristaltic micropump for controlled drug delivery application

NASA Astrophysics Data System (ADS)

Vinayakumar, K. B.; Nadiger, Girish; R. Shetty, Vikas; Dinesh, N. S.; Nayak, M. M.; Rajanna, K.

2017-01-01

Micropump technology has evolved significantly in the last two decades and is finding a variety of applications ranging from μTAS (micro Total Analysis System) to drug delivery. However, the application area of the micropump is limited owing to: simple pumping mechanism, ease of handling, controlled (microliter to milliliter) delivery, continuous delivery, and accuracy in flow rate. Here, the author presents the design, development, characterization, and precision flow controlling of a DC-motor driven peristaltic pump for controlled drug delivery application. All the micropump components were fabricated using the conventional fabrication technique. The volume flow variation of the pump has been characterized for different viscous fluids. The change in volume flow due to change in back pressure has been presented in detail. The fail-safe mode operation of the pump has been tested and leak rate was measured (˜0.14% leak for an inlet pressure of 140 kPa) for different inlet pressures. The precision volume flow of the pump has been achieved by measuring the pinch cam position and load current. The accuracy in the volume flow has been measured after 300 rotations. Finally, the complete system has been integrated with the necessary electronics and an android application has been developed for the self-administration of bolus and basal delivery of insulin.

Experimental Determination of the Dynamic Hydraulic Transfer Function for the J-2X Oxidizer Turbopump. Part One; Methodology

NASA Technical Reports Server (NTRS)

Zoladz, Tom; Patel, Sandeep; Lee, Erik; Karon, Dave

2011-01-01

An advanced methodology for extracting the hydraulic dynamic pump transfer matrix (Yp) for a cavitating liquid rocket engine turbopump inducer+impeller has been developed. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Laboratory pulsed subscale waterflow test of the J-2X oxygen turbo pump is introduced and our new extraction method applied to the data collected. From accurate measures of pump inlet and discharge perturbational mass flows and pressures, and one-dimensional flow models that represents complete waterflow loop physics, we are able to derive Yp and hence extract the characteristic pump parameters: compliance, pump gain, impedance, mass flow gain. Detailed modeling is necessary to accurately translate instrument plane measurements to the pump inlet and discharge and extract Yp. We present the MSFC Dynamic Lump Parameter Fluid Model Framework and describe critical dynamic component details. We report on fit minimization techniques, cost (fitness) function derivation, and resulting model fits to our experimental data are presented. Comparisons are made to alternate techniques for spatially translating measurement stations to actual pump inlet and discharge.

Effect of the collector tube profile on Pitot pump performances

NASA Astrophysics Data System (ADS)

Komaki, K.; Kanemoto, T.; Sagara, K.; Umekage, T.

2013-12-01

The pitot pump is composed of the rotating casing with the impeller channel and the pitot tube type collector as the discharge line. The radial impeller feeds water to the rotating casing. The water rotating together with the casing is caught by the stationary pitot tube type collector, and then discharges to the outside. This type pump, as the extra high head pump, is provided mainly for boiler feed systems, and has been designed by trial and error. To optimize the pump profiles, it is desirable to investigate not only performances but also internal flow conditions. This paper discusses experimentally and numerically the relation between the pump performances and the flow conditions in the rotating casing. The moderately larger dimensions of the collector make the pump head and the discharge high with the higher hydraulic efficiency. The flow in the casing is almost the forced vortex type whose velocity is in proportion to the radius but the core velocity is affected with the drag force of the stationary collector. Based upon the above results, the profile of the pitot tube type collector was optimized with the numerical simulation.

Fluid dynamics of heart assist device

NASA Technical Reports Server (NTRS)

Jones, R. T.

1976-01-01

Certain hemodynamic phenomena that arise in connection with the use of artificial blood pumping devices are reviewed. Among these are: (1) Flows produced by collapsing bulbs; (2) the impedance presented by the aorta; (3) limiting velocities and instability of flow in elastic vessels; (4) effectiveness of valveless arterio-arterial pumps, and (5) wave reflection phenomena and instabilities associated with the intra-aortic balloon pump.

[Research on the feasibility of a magnetic-coupling-driven axial flow blood pump].

PubMed

Yu, Xiaoqing; Ding, Wenxiang; Wang, Wei; Chen, En; Jiang, Zuming; Zou, Wenyan

2004-02-01

A new-designed axial flow blood pump, dived by magnetic coupling and using internal hollow brushless DC motor and inlet and outlet in line with impeller, was tested in mimic circuit. The results showed good performance of the new pump and indicated that its hydrodynamic characteristic can meet the demands of clinical extracorporeal circulation and auxiliary circulation.

Grout Isolation and Stabilization of Structures and Materials within Nuclear Facilities at the U.S. Department of Energy, Hanford Site, Summary - 12309

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, S.J.; Phillips, M.; Etheridge, D.

2012-07-01

Per regulatory agreement and facility closure design, U.S. Department of Energy Hanford Site nuclear fuel cycle structures and materials require in situ isolation in perpetuity and/or interim physicochemical stabilization as a part of final disposal or interim waste removal, respectively. To this end, grout materials are being used to encase facilities structures or are being incorporated within structures containing hazardous and radioactive contaminants. Facilities where grout materials have been recently used for isolation and stabilization include: (1) spent fuel separations, (2) uranium trioxide calcining, (3) reactor fuel storage basin, (4) reactor fuel cooling basin transport rail tanker cars and casks,more » (5) cold vacuum drying and reactor fuel load-out, and (6) plutonium fuel metal finishing. Grout components primarily include: (1) portland cement, (2) fly ash, (3) aggregate, and (4) chemical admixtures. Mix designs for these typically include aggregate and non aggregate slurries and bulk powders. Placement equipment includes: (1) concrete piston line pump or boom pump truck for grout slurry, (2) progressive cavity and shearing vortex pump systems, and (3) extendable boom fork lift for bulk powder dry grout mix. Grout slurries placed within the interior of facilities were typically conveyed utilizing large diameter slick line and the equivalent diameter flexible high pressure concrete conveyance hose. Other facilities requirements dictated use of much smaller diameter flexible grout conveyance hose. Placement required direct operator location within facilities structures in most cases, whereas due to radiological dose concerns, placement has also been completed remotely with significant standoff distances. Grout performance during placement and subsequent to placement often required unique design. For example, grout placed in fuel basin structures to serve as interim stabilization materials required sufficient bearing i.e., unconfined compressive strength, to sustain heavy equipment yet, low breakout force to permit efficient removal by track hoe bucket or equivalent construction equipment. Further, flow of slurries through small orifice geometries of moderate head pressures was another typical design requirement. Phase separation of less than 1 percent was a typical design requirement for slurries. On the order of 30,000 cubic meters of cementitious grout have recently been placed in the above noted U.S. Department of Energy Hanford Site facilities or structures. Each has presented a unique challenge in mix design, equipment, grout injection or placement, and ultimate facility or structure performance. Unconfined compressive and shear strength, flow, density, mass attenuation coefficient, phase separation, air content, wash-out, parameters and others, unique to each facility or structure, dictate the grout mix design for each. Each mix design was tested under laboratory and scaled field conditions as a precursor to field deployment. Further, after injection or placement of each grout formulation, the material was field inspected either by standard laboratory testing protocols, direct physical evaluation, or both. (authors)« less

Development Specification for the Portable Life Support System (PLSS) Thermal Loop Pump

NASA Technical Reports Server (NTRS)

Anchondo, Ian; Campbell, Colin

2017-01-01

The AEMU Thermal Loop Pump Development Specification establishes the requirements for design, performance, and testing of the Water Pump as part of the Thermal System of the Advanced Portable Life Support System (PLSS). It is envisioned that the Thermal Loop Pump is a positive displacement pump that provides a repeatable volume of flow against a given range of back-pressures provided by the various applications. The intention is to operate the pump at a fixed speed for the given application. The primary system is made up of two identical and redundant pumps of which only one is in operation at given time. The Auxiliary Loop Pump is an identical pump design to the primary pumps but is operated at half the flow rate. Inlet positive pressure to the pumps is provided by the upstream Flexible Supply Assembly (FSA-431 and FSA-531) which are physically located inside the suit volume and pressurized by suit pressure. An integrated relief valve, placed in parallel to the pump's inlet and outlet protects the pump and loop from over-pressurization. An integrated course filter is placed upstream of the pump's inlet to provide filtration and prevent potential debris from damaging the pump.

What Can We Learn About Karst Aquifer Heterogeneity From Pumping Tests

NASA Astrophysics Data System (ADS)

Marechal, J. C.; Dewandel, B.; Ladouche, B.; Fleury, P.

2016-12-01

Due to the complexity and duality of flows, well-test interpretation into karst systems constitutes a challenging task for hydrogeologists. This is especially true when the pumping well intersects karst heterogeneities such as the conduit network. The method of diagnostic plots, widely used in oil industry, can be applied to karst hydrogeology. In this paper, the classical response of a well-test into a karst conduit is described on a log-log drawdown derivative curve. It allows identifying successive flow regimes corresponding to the contribution of various karst aquifer subsystems (fractured matrix, karst conduit, main karst drainage network) to the pumped well. In heterogeneous karst systems, the log-log diagnostic plot of drawdown and its derivative in the pumping well can help identifying departures in flow-geometry from the classical homogeneous radial case. Classically, the diagnostic plot can be divided into several portions with: (a) early data used for identifying the karst conduit storage; (b) intermediate data for identifying the type of aquifer model that should be used (e.g. double porosity, anisotropy...); and (c) late data for identifying the possible boundaries. This is illustrated on three examples from Mediterranean karsts in southern France. A one-month duratio pumping test on a well intersecting the main karst drainage network of the Cent-Fonts karst system shows (i) a preliminary contribution of the karst conduit storage capacity followed by (ii) linear flows into the fractured matrix. A pumping test on a well intersecting a small karst conduit of the Corbières karst system shows the existence of (i) bi-linear flow within both the karst conduit and the fractured matrix at early times, followed by (ii) radial flows within the fractured matrix and (iii) finally the contribution of a major karst cavity. A two-months duration pumping test on a deep confined karst aquifer under low permeability rocks into the Gardanne basin shows the existence of no-flow boundary conditions due to the basin extension. The use of diagnostic plots allows identifying the various flow regimes during pumping tests, corresponding to the response of the individual karst aquifer subsystems. This is helpful for improving the understanding of the structure of the karst aquifer and flow exchanges between subsystems.

Engineering quadrupole magnetic flow sorting for the isolation of pancreatic islets

NASA Astrophysics Data System (ADS)

Kennedy, David J.; Todd, Paul; Logan, Sam; Becker, Matthew; Papas, Klearchos K.; Moore, Lee R.

2007-04-01

Quadrupole magnetic flow sorting (QMS) is being adapted from the separation of suspensions of single cells (<15 μm) to the isolation of pancreatic islets (150-350 μm) for transplant. To achieve this goal, the critical QMS components have been modeled and engineered to optimize the separation process. A flow channel has been designed, manufactured, and tested. The quadrupole magnet assembly has been designed and verified by finite element analysis. Pumps have been selected and verified by test. Test data generated from the pumps and flow channel demonstrate that the fabricated channel and peristaltic pumps fulfill the requirements of successful QMS separation.

Computational Fluid Dynamics and Experimental Characterization of the Pediatric Pump-Lung.

PubMed

Wu, Zhongjun J; Gellman, Barry; Zhang, Tao; Taskin, M Ertan; Dasse, Kurt A; Griffith, Bartley P

2011-12-01

The pediatric pump-lung (PediPL) is a miniaturized integrated pediatric pump-oxygenator specifically designed for cardiac or cardiopulmonary support for patients weighing 5-20 kg to allow mobility and extended use for 30 days. The PediPL incorporates a magnetically levitated impeller with uniquely configured hollow fiber membranes into a single unit capable of performing both pumping and gas exchange. A combined computational and experimental study was conducted to characterize the functional and hemocompatibility performances of this newly developed device. The three-dimensional flow features of the PediPL and its hemolytic characteristics were analyzed using computational fluid dynamics based modeling. The oxygen exchange was modeled based on a convection-diffusion-reaction process. The hollow fiber membranes were modeled as a porous medium which incorporates the flow resistance in the bundle by an added momentum sink term. The pumping function was evaluated for the required range of operating conditions (0.5-2.5 L/min and 1000-3000 rpm). The blood damage potentials were further analyzed in terms of flow and shear stress fields, and the calculations of hemolysis index. In parallel, the hydraulic pump performance, oxygen transfer and hemolysis level were quantified experimentally. Based on the computational and experimental results, the PediPL device is found to be functional to provide necessary oxygen transfer and blood pumping requirements for the pediatric patients. Smooth blood flow characteristics and low blood damage potential were observed in the entire device. The in-vitro tests further confirmed that the PediPL can provide adequate blood pumping and oxygen transfer over the range of intended operating conditions with acceptable hemolytic performance. The rated flow rate for oxygenation is 2.5 L/min. The normalized index of hemolysis is 0.065 g/100L at 1.0 L/min and 3000 rpm.

Simulated effects of Lower Floridan aquifer pumping on the Upper Floridan aquifer at Rincon, Effingham County, Georgia

USGS Publications Warehouse

Cherry, Gregory S.; Clarke, John S.

2015-01-01

A steady-state simulation representing implementation of drawdown-offset-pumping reductions totaling 292 gal/min at Rincon UFA production wells 36S034 and 36S035 and pumping from the new LFA well 36S048 at 1,000 gal/min (scenario C) resulted in decreased magnitude and areal extent of drawdown in the UFA compared with scenario A. In the latter scenario, the LFA well was pumped without UFA drawdown-offset-pumping reductions. Water budgets for scenario C yielded percentage contributions from flow components that were consistent with those from scenario B. Specifically, 69 percent of the increased pumping in scenario C originated from general-head boundaries from overlying units of the surficial and Brunswick aquifer systems and the balance of flow was derived from general- and specified-head boundaries in the UFA. In all scenarios, the placement of model boundaries and type of boundary exerted the greatest control on overall groundwater flow and interaquifer leakage in the system.

High efficiency pump for space helium transfer

NASA Technical Reports Server (NTRS)

Hasenbein, Robert; Izenson, Michael G.; Swift, Walter L.; Sixsmith, Herbert

1991-01-01

A centrifugal pump was developed for the efficient and reliable transfer of liquid helium in space. The pump can be used to refill cryostats on orbiting satellites which use liquid helium for refrigeration at extremely low temperatures. The pump meets the head and flow requirements of on-orbit helium transfer: a flow rate of 800 L/hr at a head of 128 J/kg. The overall pump efficiency at the design point is 0.45. The design head and flow requirements are met with zero net positive suction head, which is the condition in an orbiting helium supply Dewar. The mass transfer efficiency calculated for a space transfer operation is 0.99. Steel ball bearings are used with gas fiber-reinforced teflon retainers to provide solid lubrication. These bearings have demonstrated the longest life in liquid helium endurance tests under simulated pumping conditions. Technology developed in the project also has application for liquid helium circulation in terrestrial facilities and for transfer of cryogenic rocket propellants in space.

Machine learning to construct reduced-order models and scaling laws for reactive-transport applications

NASA Astrophysics Data System (ADS)

Mudunuru, M. K.; Karra, S.; Vesselinov, V. V.

2017-12-01

The efficiency of many hydrogeological applications such as reactive-transport and contaminant remediation vastly depends on the macroscopic mixing occurring in the aquifer. In the case of remediation activities, it is fundamental to enhancement and control of the mixing through impact of the structure of flow field which is impacted by groundwater pumping/extraction, heterogeneity, and anisotropy of the flow medium. However, the relative importance of these hydrogeological parameters to understand mixing process is not well studied. This is partially because to understand and quantify mixing, one needs to perform multiple runs of high-fidelity numerical simulations for various subsurface model inputs. Typically, high-fidelity simulations of existing subsurface models take hours to complete on several thousands of processors. As a result, they may not be feasible to study the importance and impact of model inputs on mixing. Hence, there is a pressing need to develop computationally efficient models to accurately predict the desired QoIs for remediation and reactive-transport applications. An attractive way to construct computationally efficient models is through reduced-order modeling using machine learning. These approaches can substantially improve our capabilities to model and predict remediation process. Reduced-Order Models (ROMs) are similar to analytical solutions or lookup tables. However, the method in which ROMs are constructed is different. Here, we present a physics-informed ML framework to construct ROMs based on high-fidelity numerical simulations. First, random forests, F-test, and mutual information are used to evaluate the importance of model inputs. Second, SVMs are used to construct ROMs based on these inputs. These ROMs are then used to understand mixing under perturbed vortex flows. Finally, we construct scaling laws for certain important QoIs such as degree of mixing and product yield. Scaling law parameters dependence on model inputs are evaluated using cluster analysis. We demonstrate application of the developed method for model analyses of reactive-transport and contaminant remediation at the Los Alamos National Laboratory (LANL) chromium contamination sites. The developed method is directly applicable for analyses of alternative site remediation scenarios.

The influence of velocity-changing collisions on resonant degenerate four-wave mixing

NASA Technical Reports Server (NTRS)

Richardson, W. H.; Maleki, L.; Garmire, Elsa

1989-01-01

The phase-conjugate signal observed in resonant degenerate four-wave mixing on the 6 3P2 to 7 3S1 transition of atomic Hg in an Hg-Ar discharge is investigated. At a fixed Ar pressure the variation of the signal with pump powers is explained by a model that includes the effects of velocity-changing collisions (VCCs). As the Ar pressure was varied from 0 to 1 torr, an increase in the phase-conjugate signal was observed and is ascribed to a change in the discharge dynamics with Ar pressure and to the influence of VCCs. To further clarify the role of collisions and optical pumping, degenerate four-wave mixing spectra are examined as a function of pump power. Line shapes are briefly discussed.

A hydrodynamically suspended, magnetically sealed mechanically noncontact axial flow blood pump: design of a hydrodynamic bearing.

PubMed

Mitamura, Yoshinori; Kido, Kazuyuki; Yano, Tetsuya; Sakota, Daisuke; Yambe, Tomoyuki; Sekine, Kazumitsu; OKamoto, Eiji

2007-03-01

To overcome the drive shaft seal and bearing problem in rotary blood pumps, a hydrodynamic bearing, a magnetic fluid seal, and a brushless direct current (DC) motor were employed in an axial flow pump. This enabled contact-free rotation of the impeller without material wear. The axial flow pump consisted of a brushless DC motor, an impeller, and a guide vane. The motor rotor was directly connected to the impeller by a motor shaft. A hydrodynamic bearing was installed on the motor shaft. The motor and the hydrodynamic bearing were housed in a cylindrical casing and were waterproofed by a magnetic fluid seal, a mechanically noncontact seal. Impeller shaft displacement was measured using a laser sensor. Axial and radial displacements of the shaft were only a few micrometers for motor speed up to 8500 rpm. The shaft did not make contact with the bearing housing. A flow of 5 L/min was obtained at 8000 rpm at a pressure difference of 100 mm Hg. In conclusion, the axial flow blood pump consisting of a hydrodynamic bearing, a magnetic fluid seal, and a brushless DC motor provided contact-free rotation of the impeller without material wear.

Groundwater-flow model of the Ozark Plateaus aquifer system, northwestern Arkansas, southeastern Kansas, southwestern Missouri, and northeastern Oklahoma

USGS Publications Warehouse

Czarnecki, John B.; Gillip, Jonathan A.; Jones, Perry M.; Yeatts, Daniel S.

2009-01-01

To assess the effect that increased water use is having on the long-term availability of groundwater within the Ozark Plateaus aquifer system, a groundwater-flow model was developed using MODFLOW 2000 for a model area covering 7,340 square miles for parts of Arkansas, Kansas, Missouri, and Oklahoma. Vertically the model is divided into five units. From top to bottom these units of variable thickness are: the Western Interior Plains confining unit, the Springfield Plateau aquifer, the Ozark confining unit, the Ozark aquifer, and the St. Francois confining unit. Large mined zones contained within the Springfield Plateau aquifer are represented in the model as extensive voids with orders-of-magnitude larger hydraulic conductivity than the adjacent nonmined zones. Water-use data were compiled for the period 1960 to 2006, with the most complete data sets available for the period 1985 to 2006. In 2006, total water use from the Ozark aquifer for Missouri was 87 percent (8,531,520 cubic feet per day) of the total pumped from the Ozark aquifer, with Kansas at 7 percent (727,452 cubic feet per day), and Oklahoma at 6 percent (551,408 cubic feet per day); water use for Arkansas within the model area was minor. Water use in the model from the Springfield Plateau aquifer in 2005 was specified from reported and estimated values as 569,047 cubic feet per day. Calibration of the model was made against average water-level altitudes in the Ozark aquifer for the period 1980 to 1989 and against waterlevel altitudes obtained in 2006 for the Springfield Plateau and Ozark aquifers. Error in simulating water-level altitudes was largest where water-level altitude gradients were largest, particularly near large cones of depression. Groundwater flow within the model area occurs generally from the highlands of the Springfield Plateau in southwestern Missouri toward the west, with localized flow occurring towards rivers and pumping centers including the five largest pumping centers near Joplin, Missouri; Carthage, Missouri; Noel, Missouri; Pittsburg, Kansas; and Miami, Oklahoma.Hypothetical scenarios involving various increases in groundwater-pumping rates were analyzed with the calibrated groundwater-flow model to assess changes in the flow system from 2007 to the year 2057. Pumping rates were increased between 0 and 4 percent per year starting with the 2006 rates for all wells in the model. Sustained pumping at 2006 rates was feasible at the five pumping centers until 2057; however, increases in pumping resulted in dewatering the aquifer and thus pumpage increases were not sustainable in Carthage and Noel for the 1 percent per year pumpage increase and greater hypothetical scenarios, and in Joplin and Miami for the 4 percent per year pumpage increase hypothetical scenarios.Zone-budget analyses were performed to assess the groundwater flow into and out of three zones specified within the Ozark-aquifer layer of the model. The three zones represented the model part of the Ozark aquifer in Kansas (zone 1), Oklahoma (zone 2), and Missouri and Arkansas (zone 3). Groundwater pumping causes substantial reductions in water in storage and induces flow through the Ozark confining unit for all hypothetical scenarios evaluated. Net simulated flow in 2057 from Kansas (zone 1) to Missouri (zone 3) ranges from 74,044 cubic feet per day for 2006 pumping rates (hypothetical scenario 1) to 625,319 cubic feet per day for a 4 percent increase in pumping per year (hypothetical scenario 5). Pumping from wells completed in the Ozark aquifer is the largest component of flow out of zone 3 in Missouri and Arkansas, and varies between 88 to 91 percent of the total flow out of zone 3 for all of the hypothetical scenarios. The largest component of flow into Oklahoma (zone 2) comes from the overlying Ozark confining unit, which is consistently about 45 percent of the total. Flow from the release of water in storage, from general-head boundaries, and from zones 1 and 3 is considerably smaller values that range from 3 to 22 percent of the total flow into zone 2. The largest flow out of the Oklahoma part of the model occurs from pumping from wells and ranges from 52 to 69 percent of the total.

Stationary Engineers Apprenticeship. Related Training Modules. 13.1-13.7 Pumps.

ERIC Educational Resources Information Center

Lane Community Coll., Eugene, OR.

This learning module, one in a series of 20 related training modules for apprentice stationary engineers, deals with pumps. Addressed in the individual instructional packages included in the module are the following topics: types, classifications, and applications of pumps; pump construction; procedures for calculating pump heat and pump flow;…

Impact of typical steady-state conditions and transient conditions on flow ripple and its test accuracy for axial piston pump

NASA Astrophysics Data System (ADS)

Xu, Bing; Hu, Min; Zhang, Junhui

2015-09-01

The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ±6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test accuracy of flow ripple is above 93.07%. The model constructed in this research proposes a method to determine the flow ripple characteristics of pump and its attainable test accuracy under the large-scale and time-variant working conditions. Meanwhile, a discussion about the variation of flow ripple and its obtainable test accuracy with the conditions of the pump working in wide operating ranges is given as well.

Blood Pump Development Using Rocket Engine Flow Simulation Technology

NASA Technical Reports Server (NTRS)

Kwak, Dochan; Kiris, Cetin

2001-01-01

This paper reports the progress made towards developing complete blood flow simulation capability in humans, especially in the presence of artificial devices such as valves and ventricular assist devices. Devices modeling poses unique challenges different from computing the blood flow in natural hearts and arteries. There are many elements needed to quantify the flow in these devices such as flow solvers, geometry modeling including flexible walls, moving boundary procedures and physiological characterization of blood. As a first step, computational technology developed for aerospace applications was extended to the analysis and development of a ventricular assist device (VAD), i.e., a blood pump. The blood flow in a VAD is practically incompressible and Newtonian, and thus an incompressible Navier-Stokes solution procedure can be applied. A primitive variable formulation is used in conjunction with the overset grid approach to handle complex moving geometry. The primary purpose of developing the incompressible flow analysis capability was to quantify the flow in advanced turbopump for space propulsion system. The same procedure has been extended to the development of NASA-DeBakey VAD that is based on an axial blood pump. Due to massive computing requirements, high-end computing is necessary for simulating three-dimensional flow in these pumps. Computational, experimental, and clinical results are presented.

Experimental visualization of solutes transport in two-dimensional saturated permeable media

NASA Astrophysics Data System (ADS)

Muñoz, Edinsson; Herrera, Paulo

2017-04-01

Mass transport processes in groundwater flows control transport of contaminants or other dissolved substances. A good characterization of transport processes should allow, for example, the optimization of remediation systems or the prediction of natural attenuation or dilution of pollutants in aquifers. Several previous studies have highlighted the role of heterogeneity in transverse mixing processes, which may be enhanced by the convergence of streamlines due to the presence of high permeability materials. The convergence of streamlines increases the concentration gradients in the direction transverse to the flow, which results in greater transverse mixing and natural dilution. This mixing makes possible the occurrence of chemical reactions between species dissolved in groundwater of different origin. We used image analysis techniques to characterize experiments that replicate the transport of a conservative tracer in two types of quasi 2-D homogeneous and heterogeneous saturated permeable media. The experiments were carried out in an acrylic glass tank, 85 cm long, 16 cm wide and 1 cm thick. We simulated flow conditions found in confined aquifers by imposing a vertical flow fed by a peristaltic pump that injected water at eight points at the bottom of the tank, while we controlled the outflow through the top boundary by using a constant head reservoir. We filled the tank with glass beads with mean diameter 0.05 cm to model the matrix material of the porous media and we used glass beads of 0.2 cm to create a high permeability inclusion to study the effect of heterogeneity on transverse mixing. After steady-state of flux was reached, we injected a conservative tracer (Blue Brilliant) only at the two central ports, while clean water continued flowing through the other six ports. We took digital pictures of the steady-state plume and analyzed the concentration of the tracer along perpendicular to the mean flow fringes, using a piecewise linear model to convert light intensity to concentrations in every pixel. We compared the concentrations calculated with image analysis to theoretical and numerical solutions. We also compared the estimated concentration distributions for a homogeneous and a heterogeneous experiments using as quantitative index the flow-related dilution index (Rolle et al., 2009). We conclude that in the heterogeneous case the dilution index was 1.5 times greater than in the homogeneous case, which confirms that heterogeneity due to inclusions of permeable materials can increase the transverse mixing or dilution of a conservative tracer.

Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

PubMed

Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

2016-09-01

Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

NASA Astrophysics Data System (ADS)

Benghanem, M.; Daffallah, K. O.; Almohammedi, A.

2018-03-01

This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV) water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m) and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia). The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan) in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed.

MIXING STUDY FOR JT-71/72 TANKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2013-11-26

All modeling calculations for the mixing operations of miscible fluids contained in HBLine tanks, JT-71/72, were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed by using the validated model to quantify the mixing time for the HB-Line tanks. The mixing study results for the JT-71/72 tanks show that, for the cases modeled, the mixing time required for blending of the tank contents is no more than 35 minutes, which is well below 2.5more » hours of recirculation pump operation. Therefore, the results demonstrate the adequacy of 2.5 hours’ mixing time of the tank contents by one recirculation pump to get well mixed.« less

Ultralow-power four-wave mixing with Rb in a hollow-core photonic band-gap fiber.

PubMed

Londero, Pablo; Venkataraman, Vivek; Bhagwat, Amar R; Slepkov, Aaron D; Gaeta, Alexander L

2009-07-24

We demonstrate extremely efficient four-wave mixing with gains greater than 100 at microwatt pump powers and signal-to-idler conversion of 50% in Rb vapor confined to a hollow-core photonic band-gap fiber. We present a theoretical model that demonstrates such efficiency is consistent with the dimensions of the fiber and the optical depths attained. This is, to our knowledge, the largest four-wave mixing gain observed at such low total pump powers and the first demonstrated example of four-wave mixing in an alkali-metal vapor system with a large (approximately 30 MHz) ground state decoherence rate.

Impact of mixing chemically heterogeneous groundwaters on the sustainability of an open-loop groundwater heat pump

NASA Astrophysics Data System (ADS)

Burté, L.; Farasin, J.; Cravotta, C., III; Gerard, M. F.; Cotiche Baranger, C.; Aquilina, L.; Le Borgne, T.

2017-12-01

Geothermal systems using shallow aquifers are commonly used for heating and cooling. The sustainability of these systems can be severely impacted by the occurrence of clogging process. The geothermal loop operation (including pumping of groundwater, filtering and heat extraction through exchangers and cooled water injection) can lead to an unexpected biogeochemical reactivity and scaling formation that can ultimately lead to the shutdown of the geothermal doublet. Here, we report the results of investigations carried out on a shallow geothermal doublet (< 40 m depth) affected by rapid clogging processes linked to iron and manganese oxidation. Using a reactive transport model, we determine the parameters controlling clogging. To characterize the biogeochemical processes induced by the operation of the production well, we combined hydrodynamic measurements by flowmeter and in-situ chemical depth profiles. We thus investigated the chemical heterogeneity into the pumping well as a function of the operating conditions (static or dynamic). Hydrochemical data collected at the pumping well showed that groundwater was chemically heterogeneous long the 11 meters well screen. While the aquifer was dominantly oxic, a localized inflow of anoxic water was detected and evaluated to produce about 40% of the total flow . The mixture of chemically heterogeneous water induced by pumping lead to the oxidation of reductive species and thus to the formation of biogenic precipitates responsible for clogging. The impact of pumping waters of different redox potential and chemical characteristics was quantified by numerical modeling using PHREEQC. These results shows that natural chemical heterogeneity can occur at a small scale in heterogeneous aquifers and highlight the importance of their characterization during the production well testing and the geothermal loop operation in order to take preventive measures to avoid clogging.

Achieving high time-resolution with a new flow-through type analyzer for total inorganic carbon in seawater.

PubMed

Kimoto, Hideshi; Nozaki, Ken; Kudo, Setsuko; Kato, Ken; Negishi, Akira; Kayanne, Hajime

2002-03-01

A fully automated, continuous-flow-through type analyzer was developed to observe rapid changes in the concentration of total inorganic carbon (CT) in coastal zones. Seawater and an H3PO4 solution were fed into the analyzer's mixing coil by two high-precision valveless piston pumps. The CO2 was stripped from the seawater and moved into a carrier gas, using a newly developed continuous-flow-through CO2 extractor. A mass flow controller was used to assure a precise flow rate of the carrier gas. The CO2 concentration was then determined with a nondispersive infrared gas analyzer. This analyzer achieved a time-resolution of as good as 1 min. In field experiments on a shallow reef flat of Shiraho (Ishigaki Island, Southwest Japan), the analyzer detected short-term, yet extreme, variations in CT which manual sampling missed. Analytical values obtained by the analyzer on the boat were compared with those determined by potentiometric titration with a closed cell in a laboratory: CT(flow-through) = 0.980 x CT(titration) + 38.8 with r2 = 0.995 (n = 34; September 1998).

Effects of groundwater pumping in the lower Apalachicola-Chattahoochee-Flint River basin

USGS Publications Warehouse

Jones, L. Elliott

2012-01-01

USGS developed a groundwater-flow model of the Upper Floridan aquifer in lower Apalachicola-Chattahoochee-Flint River basin in southwest Georgia and adjacent parts of Alabama and Florida to determine the effect of agricultural groundwater pumping on aquifer/stream flow within the basin. Aquifer/stream flow is the sum of groundwater outflow to and inflow from streams, and is an important consideration for water managers in the development of water-allocation and operating plans. Specifically, the model was used to evaluate how agricultural pumping relates to 7Q10 low streamflow, a statistical low flow indicative of drought conditions that would occur during seven consecutive days, on average, once every 10 years. Argus ONETM, a software package that combines a geographic information system (GIS) and numerical modeling in an Open Numerical Environment, facilitated the design of a detailed finite-element mesh to represent the complex geometry of the stream system in the lower basin as a groundwater-model boundary. To determine the effects on aquifer/stream flow of pumping at different locations within the model area, a pumping rate equivalent to a typical center-pivot irrigation system (50,000 ft3/d) was applied individually at each of the 18,951 model nodes in repeated steady-state simulations that were compared to a base case representing drought conditions during October 1999. Effects of nodal pumping on aquifer/stream flow and other boundary flows, as compared with the base-case simulation, were computed and stored in a response matrix. Queries to the response matrix were designed to determine the sensitivity of targeted stream reaches to agricultural pumping. Argus ONE enabled creation of contour plots of query results to illustrate the spatial variation across the model area of simulated aquifer/streamflow reductions, expressed as a percentage of the long-term 7Q10 low streamflow at key USGS gaging stations in the basin. These results would enable water managers to assess the relative impact of agricultural pumping and drought conditions on streamflow throughout the basin, and to develop mitigation strategies to conserve water resources and preserve aquatic habitat.

Sealing performance of a magnetic fluid seal for rotary blood pumps.

PubMed

Mitamura, Yoshinori; Takahashi, Sayaka; Kano, Kentaro; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya; Higuchi, Taka-Aki

2009-09-01

A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Under the condition of continuous flow, the MF seal remained in perfect condition against a pressure of 298 mm Hg (pump flow rate: 3.96 L/min). The seal was also perfect against a pressure of 170 mm Hg in a continuous flow of 3.9 L/min for 275 days. We have developed a MF seal that works in liquid against clinically used pressures. The MF seal is promising as a shaft seal for rotary blood pumps.

Screw-actuated displacement micropumps for thermoplastic microfluidics.

PubMed

Han, J Y; Rahmanian, O D; Kendall, E L; Fleming, N; DeVoe, D L

2016-10-05

The fabrication of on-chip displacement pumps integrated into thermoplastic chips is explored as a simple and low cost method for achieving precise and programmable flow control for disposable microfluidic systems. The displacement pumps consist of stainless steel screws inserted into threaded ports machined into a thermoplastic substrate which also serve as on-chip reagent storage reservoirs. Three different methods for pump sealing are investigated to enable high pressure flows without leakage, and software-defined control of multiple pumps is demonstrated in a self-contained platform using a compact and self-contained microcontroller for operation. Using this system, flow rates ranging from 0.5-40 μl min -1 are demonstrated. The pumps are combined with on-chip burst valves to fully seal multiple reagents into fabricated chips while providing on-demand fluid distribution in a downstream microfluidic network, and demonstrated for the generation of size-tunable water-in-oil emulsions.

Design and cost analysis of rapid aquifer restoration systems using flow simulation and quadratic programming.

USGS Publications Warehouse

Lefkoff, L.J.; Gorelick, S.M.

1986-01-01

Detailed two-dimensional flow simulation of a complex ground-water system is combined with quadratic and linear programming to evaluate design alternatives for rapid aquifer restoration. Results show how treatment and pumping costs depend dynamically on the type of treatment process, and capacity of pumping and injection wells, and the number of wells. The design for an inexpensive treatment process minimizes pumping costs, while an expensive process results in the minimization of treatment costs. Substantial reductions in pumping costs occur with increases in injection capacity or in the number of wells. Treatment costs are reduced by expansions in pumping capacity or injecion capacity. The analysis identifies maximum pumping and injection capacities.-from Authors

Maximum Oxygen Content of Flowing Eutectic NaK in a Stainless Steel System.

DTIC Science & Technology

EUTECTICS, ALKALI METAL ALLOYS), (*LIQUID METALS, OXYGEN), (*POTASSIUM ALLOYS, SODIUM ALLOYS), LIQUID METAL PUMPS , FLUID FLOW, CONCENTRATION...CHEMISTRY), HIGH TEMPERATURE, FLOWMETERS, STAINLESS STEEL, ELECTROMAGNETIC PUMPS , TEMPERATURE, SAMPLING, LIQUID METAL COOLANTS, OXIDES, CRYSTALLIZATION.

Evaluation of the impeller shroud performance of an axial flow ventricular assist device using computational fluid dynamics.

PubMed

Su, Boyang; Chua, Leok P; Lim, Tau M; Zhou, Tongming

2010-09-01

Generally, there are two types of impeller design used in the axial flow blood pumps. For the first type, which can be found in most of the axial flow blood pumps, the magnet is embedded inside the impeller hub or blades. For the second type, the magnet is embedded inside the cylindrical impeller shroud, and this design has not only increased the rotating stability of the impeller but has also avoided the flow interaction between the impeller blade tip and the pump casing. Although the axial flow blood pumps with either impeller design have been studied individually, the comparisons between these two designs have not been conducted in the literature. Therefore, in this study, two axial flow blood pumps with and without impeller shrouds were numerically simulated with computational fluid dynamics and compared with each other in terms of hydraulic and hematologic performances. For the ease of comparison, these two models have the same inner components, which include a three-blade straightener, a two-blade impeller, and a three-blade diffuser. The simulation results showed that the model with impeller shroud had a lower static pressure head with a lower hydraulic efficiency than its counterpart. It was also found that the blood had a high possibility to deposit on the impeller shroud inner surface, which greatly enhanced the possibility of thrombus formation. The blood damage indices in both models were around 1%, which was much lower than the 13.1% of the axial flow blood pump of Yano et al. with the corresponding experimental hemolysis of 0.033 g/100 L. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Model calculations of kinetic and fluid dynamic processes in diode pumped alkali lasers

NASA Astrophysics Data System (ADS)

Barmashenko, Boris D.; Rosenwaks, Salman; Waichman, Karol

2013-10-01

Kinetic and fluid dynamic processes in diode pumped alkali lasers (DPALs) are analyzed in detail using a semianalytical model, applicable to both static and flowing-gas devices. The model takes into account effects of temperature rise, excitation of neutral alkali atoms to high lying electronic states and their losses due to ionization and chemical reactions, resulting in a decrease of the pump absorption, slope efficiency and lasing power. Effects of natural convection in static DPALs are also taken into account. The model is applied to Cs DPALs and the results are in good agreement with measurements in a static [B.V. Zhdanov, J. Sell and R.J. Knize, Electron. Lett. 44, 582 (2008)] and 1-kW flowing-gas [A.V. Bogachev et al., Quantum Electron. 42, 95 (2012)] DPALs. It predicts the dependence of power on the flow velocity in flowing-gas DPALs and on the buffer gas composition. The maximum values of the laser power can be substantially increased by optimization of the flowing-gas DPAL parameters. In particular for the aforementioned 1 kW DPAL, 6 kW maximum power is achievable just by increasing the pump power and the temperature of the wall and the gas at the flow inlet (resulting in increase of the alkali saturated vapor density). Dependence of the lasing power on the pump power is non-monotonic: the power first increases, achieves its maximum and then decreases. The decrease of the lasing power with increasing pump power at large values of the latter is due to the rise of the aforementioned losses of the alkali atoms as a result of ionization. Work in progress applying two-dimensional computational fluid dynamics modeling of flowing-gas DPALs is also reported.

Initial in vitro testing of a paediatric continuous-flow total artificial heart.

PubMed

Fukamachi, Kiyotaka; Karimov, Jamshid H; Horvath, David J; Sunagawa, Gengo; Byram, Nicole A; Kuban, Barry D; Moazami, Nader

2018-06-01

Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations. We aimed to evaluate the in vitro performance of the initial prototype of our paediatric continuous-flow total artificial heart. The paediatric continuous-flow total artificial heart pump was downsized from the adult continuous-flow total artificial heart configuration by a scale factor of 0.70 (1/3 of total volume) to enable implantation in infants. System performance of this prototype was evaluated using the continuous-flow total artificial heart mock loop set to mimic paediatric circulation. We generated maps of pump performance and atrial pressure differences over a wide range of systemic vascular resistance/pulmonary vascular resistance and pump speeds. Performance data indicated left pump flow range of 0.4-4.7 l/min at 100 mmHg delta pressure. The left/right atrial pressure difference was maintained within ±5 mmHg with systemic vascular resistance/pulmonary vascular resistance ratios between 1.4 and 35, with/without pump speed modulation, verifying expected passive self-regulation of atrial pressure balance. The paediatric continuous-flow total artificial heart prototype met design requirements for self-regulation and performance; in vivo pump performance studies are ongoing.

Hydrogen production from high moisture content biomass in supercritical water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antal, M.J. Jr.; Xu, X.

1998-08-01

By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22more » MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.« less

Application of a magnetic fluid seal to rotary blood pumps

NASA Astrophysics Data System (ADS)

Mitamura, Y.; Arioka, S.; Sakota, D.; Sekine, K.; Azegami, M.

2008-05-01

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps.

Application of a magnetic fluid seal to rotary blood pumps.

PubMed

Mitamura, Y; Arioka, S; Sakota, D; Sekine, K; Azegami, M

2008-05-21

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps.

Direct-injection chemiluminescence detector. Properties and potential applications in flow analysis.

PubMed

Koronkiewicz, Stanislawa; Kalinowski, Slawomir

2015-02-01

We present a novel chemiluminescence detector, with a cone-shaped detection chamber where the analytical reaction takes place. The sample and appropriate reagents are injected directly into the chamber in countercurrent using solenoid-operated pulse micro-pumps. The proposed detector allows for fast measurement of the chemiluminescence signal in stop-flow conditions from the moment of reagents mixing. To evaluate potential applications of the detector the Fenton-like reaction with a luminol-H2O2 system and several transition metal ions (Co(2+), Cu(2+), Cr(3+), Fe(3+)) as a catalyst were investigated. The results demonstrate suitability of the proposed detector for quantitative analysis and for investigations of reaction kinetics, particularly rapid reactions. A multi-pumping flow system was designed and optimized. The developed methodology demonstrated that the shape of the analytical signals strongly depends on the type and concentration of the metal ions. The application of the detector in quantitative analysis was assessed for determination of Fe(III). The direct-injection chemiluminescence detector allows for a sensitive and repeatable (R.S.D. 2%) determination. The intensity of chemiluminescence increased linearly in the range from about 0.5 to 10 mg L(-1) Fe(III) with the detection limit of 0.025 mg L(-1). The time of analysis depended mainly on reaction kinetics. It is possible to achieve the high sampling rate of 144 samples per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative assessment of haemolysis secondary to modern infusion pumps.

PubMed

Poder, T G; Boileau, J-C; Lafrenière, R; Thibault, L; Carrier, N; de Grandmont, M-J; Beauregard, P

2017-04-01

Although most studies have shown that little haemolysis is induced by infusion pumps, there are some notable exceptions. Only limited data are available on the actual infusion pumps that are most used in hospitals in Quebec and elsewhere, namely, the Infusomat ® Space (peristaltic), Plum A+™ (piston) and Colleague ® CXE (shuttle) pumps. Haemolysis and potassium levels were compared before and after the use of the three different infusion pumps. Using 135 units of packed red blood cells (RBCs) aged from 10 to 28 days, 27 measurements were taken for each pump at various flow rates (30, 60, 150, 300 and 450 ml/h) and were compared with measurements taken before using the pumps. The range of flow rates was chosen to cover those of paediatric and adult transfusions. The shuttle- and piston-type pumps resulted in low haemolysis levels. The peristaltic-type pump produced significantly more haemolysis, which worsened at low flow rates, but the absolute value of haemolysis remained within the range recommended by the regulatory agencies in North America and Europe. Approximately two-thirds of the haemolysis produced by the peristaltic-type pump seemed to be secondary to the use of an antisiphon valve (ASV) on the transfusion line recommended by the manufacturer. Potassium levels did not increase with the use of the pumps. Modern infusion pumps widely used in hospitals in Quebec and elsewhere produce non-threatening levels of haemolysis during the transfusion of packed RBCs aged from 10 to 28 days. ASVs appear to induce additional haemolysis, and we do not recommend using them for blood transfusion. © 2017 International Society of Blood Transfusion.

Thermal Analysis of Magnetically-Coupled Pump for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Senocak, Inanc; Udaykumar, H. S.; Ndri, Narcisse; Francois, Marianne; Shyy, Wei

1999-01-01

Magnetically-coupled pump is under evaluation at Kennedy Space Center for possible cryogenic applications. A major concern is the impact of low temperature fluid flows on the pump performance. As a first step toward addressing this and related issues, a computational fluid dynamics and heat transfer tool has been adopted in a pump geometry. The computational tool includes (i) a commercial grid generator to handle multiple grid blocks and complicated geometric definitions, and (ii) an in-house computational fluid dynamics and heat transfer software developed in the Principal Investigator's group at the University of Florida. Both pure-conduction and combined convection-conduction computations have been conducted. A pure-conduction analysis gives insufficient information about the overall thermal distribution. Combined convection-conduction analysis indicates the significant influence of the coolant over the entire flow path. Since 2-D simulation is of limited help, future work on full 3-D modeling of the pump using multi-materials is needed. A comprehensive and accurate model can be developed to take into account the effect of multi-phase flow in the cooling flow loop, and the magnetic interactions.

Space Station Environmental Control and Life Support System Purge Control Pump Assembly Modeling and Analysis

NASA Technical Reports Server (NTRS)

Schunk, R. Gregory; Hunt, Patrick L. (Technical Monitor)

2001-01-01

Preliminary results from a thermal/flow analysis of the Purge Control Pump Assembly (PCPA) indicate that pump performance (mass flow rate) is enhanced via cooling of the housing and lowering of the inlet vapor quality. Under a nominal operational profile (25% duty cycle or less), at the maximum motor dissipation, it appears that the peristaltic tubing temperature will still remain significantly below the expected UPA condenser temperature (78 F max versus approximately 105 F in the condenser) permitting condensation in the pump head.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1998-03-31

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1999-03-30

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Custom Unit Pump Development for the EVA PLSS

NASA Technical Reports Server (NTRS)

Schuller, Michael; Kurwitz, Cable; Little, Frank; Oinuma, Ryoji; Larsen, Ben; Goldman, Jeff; Reinis, Filip; Trevino, Luis

2010-01-01

This paper describes the effort by the Texas Engineering Experiment Station (TEES) and Honeywell for NASA to design and test a pre-flight prototype pump for use in the Extra-vehicular activity (EVA) portable life support subsystem (PLSS). Major design decisions were driven by the need to reduce the pump s mass, power, and volume compared to the existing PLSS pump. In addition, the pump must accommodate a much wider range of abnormal conditions than the existing pump, including vapor/gas bubbles and increased pressure drop when employed to cool two suits simultaneously. A positive displacement, external gear type pump was selected because it offers the most compact and highest efficiency solution over the required range of flow rates and pressure drops. An additional benefit of selecting a gear pump design is that it is self priming and capable of ingesting non-condensable gas without becoming air locked. The chosen pump design consists of a 28 V DC, brushless, seal-less, permanent magnet motor driven, external gear pump that utilizes a Honeywell development that eliminates the need for magnetic coupling. The pump design was based on existing Honeywell designs, but incorporated features specifically for the PLSS application, including all of the key features of the flight pump. Testing at TEES verified that the pump meets the design requirements for range of flow rates, pressure drop, power consumption, working fluid temperature, operating time, gas ingestion, and restart capability under both ambient and vacuum conditions. The pump operated at 40 to 240 lbm/hr flow rate, 35 to 100 oF pump temperature, and 5 to 10 psid pressure rise. Power consumption of the pump controller at the nominal operating point in both ambient and vacuum conditions was 9.5 W, which was less than the 12 W predicted. Gas ingestion capabilities were tested by injecting 100 cc of air into the fluid line; the pump operated normally throughout this test.

33 CFR 157.126 - Pumps.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.126 Pumps. (a) Crude oil must be supplied to the COW machines by COW system pumps or cargo pumps. (b) The pumps under paragraph...) A sufficient pressure and flow is supplied to allow the simultaneous operation of those COW machines...

Rotary blood pump

NASA Astrophysics Data System (ADS)

Bozeman, Richard J.; Akkerman, James W.; Aber, Greg S.; Vandamm, George A.; Bacak, James W.; Svejkovsky, Paul A.; Benkowski, Robert J.

1993-11-01

A rotary blood pump is presented. The pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial, and radial clearances of the blades associated with the flow straightener, inducer portion, impeller portion, and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with crosslinked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Rotary blood pump

NASA Technical Reports Server (NTRS)

Bozeman, Richard J. (Inventor); Akkerman, James W. (Inventor); Aber, Greg S. (Inventor); Vandamm, George A. (Inventor); Bacak, James W. (Inventor); Svejkovsky, Paul A. (Inventor); Benkowski, Robert J. (Inventor)

1993-01-01

A rotary blood pump is presented. The pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial, and radial clearances of the blades associated with the flow straightener, inducer portion, impeller portion, and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with crosslinked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Design, construction and evaluation of a system of forced solar water heating.

NASA Astrophysics Data System (ADS)

Hernández, E.; Bautista, G. A.; Ortiz, I. L.

2016-07-01

The main purpose of this project was to design, construct and evaluate a system of forced solar water heating for domestic consumption, at the Universidad Pontificia Bolivariana-Bucaramanga, Colombia; using solar energy. This is a totally system independent of the electrical grid and an important characteristic is the heating water doesn't mix with the consumption water. The system receives the solar radiation through a flat-plate collector, which it transmits the heat to the water that it flow with impulse from the centrifugal pump of 12VDC, the water circulates toward helical serpentine it is inside of the tank of the storage whose capacity is 100 liters of water. The temperature of the tank is regulated with a controller in such a way that de-energized the pump when it gets the temperature required. The performance thermal or efficiency of the system was evaluated like a relationship between the delivered energy to the water in storage tank and the incident energy in the flat-plate collector.

Using Hybrid Magnetic Bearings to Completely Suspend the Impeller of a Ventricular Assist Device.

PubMed

Khanwilkar, Pratap; Olsen, Don; Bearnson, Gill; Allaire, Paul; Maslen, Eric; Flack, Ron; Long, James

1996-05-01

Clinically available blood pumps and those under development suffer from poor mechanical reliability and poor biocompatibility related to anatomic fit, hemolysis, and thrombosis. To alleviate these problems concurrently in a long-term device is a substantial challenge. Based on testing the performance of a prototype, and on our judgment of desired characteristics, we have configured an innovative ventricular assist device, the CF-VAD4, for long-term use. The design process and its outcome, the CFVAD4 system configuration, is described. To provide unprecedented reliability and biocompatibility, magnetic bearings completely suspend the rotating pump impeller. The CFVAD4 uses a combination of passive (permanent) and active (electric) magnetic bearings, a mixed flow impeller, and a slotless 3-phase brushless DC motor. These components are shaped, oriented, and integrated to provide a compact, implantable, pancake-shaped unit for placement in the left upper abdominal quadrant of adult humans. © 1996 International Society for Artificial Organs.

Three-dimensional kinetic and fluid dynamic modeling and three iterative algorithms for side-pumped alkali vapor lasers

NASA Astrophysics Data System (ADS)

Shen, Binglin; Xu, Xingqi; Xia, Chunsheng; Pan, Bailiang

2017-11-01

Combining the kinetic and fluid dynamic processes in static and flowing-gas diode-pumped alkali vapor lasers, a comprehensive physical model with three cyclically iterative algorithms for simulating the three-dimensional pump and laser intensities as well as temperature distribution in the vapor cell of side-pumped alkali vapor lasers is established. Comparison with measurement of a static side-pumped cesium vapor laser with a diffuse type hollow cylinder cavity, and with classical and modified models is made. Influences of flowed velocity and pump power on laser power are calculated and analyzed. The results have demonstrated that for high-power side-pumped alkali vapor lasers, it is necessary to take into account the three-dimensional distributions of pump energy, laser energy and temperature in the cell to simultaneously obtain the thermal features and output characteristics. Therefore, the model can deepen the understanding of the complete kinetic and fluid dynamic mechanisms of a side-pumped alkali vapor laser, and help with its further experimental design.

Field Effect Flow Control in a Polymer T-Intersection Microfluidic Network

NASA Technical Reports Server (NTRS)

Sniadecki, Nathan J.; Chang, Richard; Beamesderfer, Mike; Lee, Cheng S.; DeVoe, Don L.

2003-01-01

We present a study of induced pressure pumping in a polymer microchannel due to differential electroosmotic flow @OF) rates via field-effect flow control (FEFC). The experimental results demonstrate that the induced pressure pumping is dependent on the distance of the FEFC gate from the cathodic gate. A proposed flow model based on a linearly-decaying zeta potential profile is found to successfully predict experimental trends.

Numerical study at moderate Reynolds number of peristaltic flow of micropolar fluid through a porous-saturated channel in magnetic field

NASA Astrophysics Data System (ADS)

Ahmed, Bilal; Javed, Tariq; Ali, N.

2018-01-01

This paper analyzes the MHD flow of micropolar fluid induced by peristaltic waves passing through the porous saturated channel at large Reynolds number. The flow model is formulated in the absence of assumptions of lubrication theory which yields the governing equations into a non-linear set of coupled partial differential equations which allows studying the peristaltic mechanism at non-zero Reynolds and wave numbers. The influence of other involved parameters on velocity, stream function and microrotation are discussed through graphs plotted by using Galerkin's finite element method. Besides that, the phenomena of pumping and trapping are also analyzed in the later part of the paper. To ensure the accuracy of the developed code, obtained results are compared with the results available in the literature and found in excellent agreement. It is found that the peristalsis mixing can be enhanced by increasing Hartmann number while it reduces by increasing permeability of the porous medium.

Observations from borehole dilution logging experiments in fractured crystalline rock under variable hydraulic conditions

USGS Publications Warehouse

Harte, Philip T.; Anderson, Alton; Williams, John H.

2014-01-01

Identifying hydraulically active fractures in low permeability, crystalline-bedrock aquifers requires a variety of geophysical and hydrogeophysical borehole tools and approaches. One such approach is Single Borehole Dilution Tests (SBDT), which in some low flow cases have been shown to provide greater resolution of borehole flow than other logging procedures, such as vertical differential Heat Pulse Flowmeter (HPFM) logging. Because the tools used in SBDT collect continuous profiles of water quality or dye changes, they can identify horizontal flow zones and vertical flow. We used SBDT with a food grade blue dye as a tracer and dual photometer-nephelometer measurements to identify low flow zones.SBDT were conducted at seven wells with open boreholes (exceeding 300 ft). At most of the wells HPFM logs were also collected. The seven wells are set in low-permeability, fractured granite and gneiss rocks underlying a former tetrachloroeythylene (PCE) source area at the Savage Municipal Well Superfund site in Milford, NH. Time series SBDT logs were collected at each of the seven wells under three distinct hydraulic conditions: (1) ambient conditions prior to a pump test at an adjacent well, (2) mid test, after 2-3 days of the start of the pump test, and (3) at the end of the test, after 8-9 days of the pump test. None of the SBDT were conducted under pumping conditions in the logged well. For each condition, wells were initially passively spiked with blue dye once and subsequent time series measurements were made.Measurement accuracy and precision of the photometer tool is important in SBDT when attempting to detect low rates of borehole flow. Tests indicate that under ambient conditions, none of the wells had detectable flow as measured with HPFM logging. With SBDT, 4 of the 7 showed the presence of some very low flow. None of 5 (2 of the 7 wells initially logged with HPFM under ambient conditions were not re-logged) wells logged with the HPFM during the pump test had detectable flow. However, 3 of the 5 wells showed the patterns of very low flow with SBDT during the pump test including pumping induced changes of inflow and outflow patterns at one well.

Low-speed performance of an axisymmetric, mixed-compression, supersonic inlet with auxiliary inlets

NASA Technical Reports Server (NTRS)

Trefny, C. J.; Wasserbauer, J. W.

1986-01-01

A test program was conducted to determine the aerodynamic performance and acoustic characteristics associated with the low-speed operation of a supersonic, axisymmetric, mixed-compression inlet with auxiliary inlets. Blow-in-auxiliary doors were installed on the NASA Ames P inlet. One door per quadrant was located on the cowl in the subsonic diffuser selection of the inlet. Auxiliary inlets with areas of 20 and 40 percent of the inlet capture area were tested statically and at free-stream Mach numbers of 0.1 and 0.2. The effects of boundary layer bleed inflow were investigated. A JT8D fan simulator driven by compressed air was used to pump inlet flow and to provide a characteristic noise signature. Baseline data were obtained at static free-stream conditions with the sharp P-inlet cowl lip replaced by a blunt lip. Auxiliary inlets increased overall total pressure recovery of the order of 10 percent.

Self-mixing instrument for simultaneous distance and speed measurement

NASA Astrophysics Data System (ADS)

Norgia, Michele; Melchionni, Dario; Pesatori, Alessandro

2017-12-01

A novel instrument based on Self-mixing interferometry is proposed to simultaneously measure absolute distance and velocity. The measurement method is designed for working directly on each kind of surface, in industrial environment, overcoming also problems due to speckle pattern effect. The laser pump current is modulated at quite high frequency (40 kHz) and the estimation of the induced fringes frequency allows an almost instantaneous measurement (measurement time equal to 25 μs). A real time digital elaboration processes the measurement data and discards unreliable measurements. The simultaneous measurement reaches a relative standard deviation of about 4·10-4 in absolute distance, and 5·10-3 in velocity measurement. Three different laser sources are tested and compared. The instrument shows good performances also in harsh environment, for example measuring the movement of an opaque iron tube rotating under a running water flow.

Simulation of the effects of ground-water withdrawals and recharge on ground-water flow in Cape Cod, Martha's Vineyard, and Nantucket Island basins, Massachusetts

USGS Publications Warehouse

Masterson, John P.; Barlow, Paul M.

1994-01-01

The effects of changing patterns of ground-water pumping and aquifer recharge on the surface-water and ground-water hydrologic systems were determined for the Cape Cod, Martha's Vineyard, and Nantucket Island Basins. Three-dimensional, transient, ground-water-flow modelS that simulate both freshwater and saltwater flow were developed for the f1ow cells of Cape Cod which currently have large-capacity public-supply wells. Only the freshwater-flow system was simulated for the Cape Cod flow cells where public-water supply demands are satisfied by small-capacity domestic wells. Two- dimensional, finite-difference, change models were developed for Martha's Vineyard and Nantucket Island to determine the projected drawdowns in response to projected in-season pumping rates for 180 days of no aquifer recharge. Results of the simulations indicate very little change in the position of the freshwater-saltwater interface from predevelopment flow conditions to projected ground-water pumping and recharge rates for Cape Cod in the year 2020. Results of change model simulations for Martha's Vineyard and Nantucket Island indicate that the greatest impact in response to projected in-season ground-water pumping occurs at the pumping centers and the magnitude of the drawdowns are minimal with respect to the total thickness of the aquifers.

Numerical Investigation of the Influence of Blade Radial Gap Flow on Axial Blood Pump Performance.

PubMed

Liu, Guang-Mao; Jin, Dong-Hai; Zhou, Jian-Ye; Zhang, Yan; Chen, Hai-Bo; Sun, Han-Song; Hu, Sheng-Shou; Gui, Xing-Min

2018-01-05

The gaps between the blades and the shroud (or hub) of an axial blood pump affect the hydraulics, efficiency, and hemolytic performance. These gaps are critical parameters when a blood pump is manufactured. To evaluate the influence of blade gaps on axial blood pump performance, the flow characteristics inside an axial blood pump with different radial blade gaps were numerically simulated and analyzed with special attention paid to the hydraulic characteristics, gap flow, hydraulic efficiency, and hemolysis index (HI). In vitro hydraulic testing and particle image velocimetry testing were conducted to verify the numerical results. The simulation results showed that the efficiency and pressure rise decreased when the gap increased. The efficiency of the axial blood pump at design point decreased from 37.1% to 27.1% and the pressure rise decreased from 127.4 to 71.2 mm Hg when the gap increased from 0.1 to 0.3 mm. Return and vortex flows were present in the outlet guide vane channels when the gap was larger than 0.2 mm. The HI of the blood pump with a 0.1 mm gap was 1.5-fold greater than that with a 0.3 mm gap. The results illustrated poor hydraulic characteristics when the gap was larger than 0.15 mm and rapidly deteriorated hemolysis when the gap was larger than 0.1 mm. The numerical and experimental results demonstrated that the pressure rise, pump efficiency, and scalar shear stress decreased when the gap increased. The HI did not strictly decrease with gap increases. The preliminary results encourage the improvement of axial blood pump designs.

Numerical and In Vitro Experimental Investigation of the Hemolytic Performance at the Off-Design Point of an Axial Ventricular Assist Pump.

PubMed

Liu, Guang-Mao; Jin, Dong-Hai; Jiang, Xi-Hang; Zhou, Jian-Ye; Zhang, Yan; Chen, Hai-Bo; Hu, Sheng-Shou; Gui, Xing-Min

The ventricular assist pumps do not always function at the design point; instead, these pumps may operate at unfavorable off-design points. For example, the axial ventricular assist pump FW-2, in which the design point is 5 L/min flow rate against 100 mm Hg pressure increase at 8,000 rpm, sometimes works at off-design flow rates of 1 to 4 L/min. The hemolytic performance of the FW-2 at both the design point and at off-design points was estimated numerically and tested in vitro. Flow characteristics in the pump were numerically simulated and analyzed with special attention paid to the scalar sheer stress and exposure time. An in vitro hemolysis test was conducted to verify the numerical results. The simulation results showed that the scalar shear stress in the rotor region at the 1 L/min off-design point was 70% greater than at the 5 L/min design point. The hemolysis index at the 1 L/min off-design point was 3.6 times greater than at the 5 L/min design point. The in vitro results showed that the normalized index of hemolysis increased from 0.017 g/100 L at the 5 L/min design point to 0.162 g/100 L at the 1 L/min off-design point. The hemolysis comparison between the different blood pump flow rates will be helpful for future pump design point selection and will guide the usage of ventricular assist pumps. The hemolytic performance of the blood pump at the working point in the clinic should receive more focus.

Output characteristics of a series three-port axial piston pump

NASA Astrophysics Data System (ADS)

Zhang, Xiaogang; Quan, Long; Yang, Yang; Wang, Chengbin; Yao, Liwei

2012-05-01

Driving a hydraulic cylinder directly by a closed-loop hydraulic pump is currently a key research area in the field of electro-hydraulic control technology, and it is the most direct means to improve the energy efficiency of an electro-hydraulic control system. So far, this technology has been well applied to the pump-controlled symmetric hydraulic cylinder. However, for the differential cylinder that is widely used in hydraulic technology, satisfactory results have not yet been achieved, due to the asymmetric flow constraint. Therefore, based on the principle of the asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology, an innovative idea for an asymmetric pump controlled asymmetric cylinder is put forward to address this problem. The scheme proposes to transform the oil suction window of the existing axial piston pump into two series windows. When in use, one window is connected to the rod chamber of the hydraulic cylinder and the other is linked with a low-pressure oil tank. This allows the differential cylinders to be directly controlled by changing the displacement or rotation speed of the pumps. Compared with the loop principle of offsetting the area difference of the differential cylinder through hydraulic valve using existing technology, this method may simplify the circuits and increase the energy efficiency of the system. With the software SimulationX, a hydraulic pump simulation model is set up, which examines the movement characteristics of an individual piston and the compressibility of oil, as well as the flow distribution area as it changes with the rotation angle. The pump structure parameters, especially the size of the unloading groove of the valve plate, are determined through digital simulation. All of the components of the series arranged three distribution-window axial piston pump are designed, based on the simulation analysis of the flow pulse characteristics of the pump, and then the prototype pump is made. The basic characteristics, such as the pressure, flow and noise of the pumps under different rotation speeds, are measured on the test bench. The test results verify the correctness of the principle. The proposed research lays a theoretical foundation for the further development of a new pump-controlled cylinder system.

Incorporating high-pressure electroosmotic pump and a nano-flow gradient generator into a miniaturized liquid chromatographic system for peptide analysis.

PubMed

Chen, Apeng; Lynch, Kyle B; Wang, Xiaochun; Lu, Joann J; Gu, Congying; Liu, Shaorong

2014-09-24

We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations. Copyright © 2014. Published by Elsevier B.V.

The effect of step height on the performance of three-dimensional ac electro-osmotic microfluidic pumps.

PubMed

Urbanski, John Paul; Levitan, Jeremy A; Burch, Damian N; Thorsen, Todd; Bazant, Martin Z

2007-05-15

Recent numerical and experimental studies have investigated the increase in efficiency of microfluidic ac electro-osmotic pumps by introducing nonplanar geometries with raised steps on the electrodes. In this study, we analyze the effect of the step height on ac electro-osmotic pump performance. AC electro-osmotic pumps with three-dimensional electroplated steps are fabricated on glass substrates and pumping velocities of low ionic strength electrolyte solutions are measured systematically using a custom microfluidic device. Numerical simulations predict an improvement in pump performance with increasing step height, at a given frequency and voltage, up to an optimal step height, which qualitatively matches the trend observed in experiment. For a broad range of step heights near the optimum, the observed flow is much faster than with existing planar pumps (at the same voltage and minimum feature size) and in the theoretically predicted direction of the "fluid conveyor belt" mechanism. For small step heights, the experiments also exhibit significant flow reversal at the optimal frequency, which cannot be explained by the theory, although the simulations predict weak flow reversal at higher frequencies due to incomplete charging. These results provide insight to an important parameter for the design of nonplanar electro-osmotic pumps and clues to improve the fundamental theory of ACEO.

A ternary age-mixing model to explain contaminant occurrence in a deep supply well

USGS Publications Warehouse

Jurgens, Bryant; Bexfield, Laura M.; Eberts, Sandra

2014-01-01

The age distribution of water from a public-supply well in a deep alluvial aquifer was estimated and used to help explain arsenic variability in the water. The age distribution was computed using a ternary mixing model that combines three lumped parameter models of advection-dispersion transport of environmental tracers, which represent relatively recent recharge (post- 1950s) containing volatile organic compounds (VOCs), old intermediate depth groundwater (about 6500 years) that was free of drinking-water contaminants, and very old, deep groundwater (more than 21,000 years) containing arsenic above the USEPA maximum contaminant level of 10 µg/L. The ternary mixing model was calibrated to tritium, chloroflorocarbon-113, and carbon-14 (14C) concentrations that were measured in water samples collected on multiple occasions. Variability in atmospheric 14C over the past 50,000 years was accounted for in the interpretation of 14C as a tracer. Calibrated ternary models indicate the fraction of deep, very old groundwater entering the well varies substantially throughout the year and was highest following long periods of nonoperation or infrequent operation, which occured during the winter season when water demand was low. The fraction of young water entering the well was about 11% during the summer when pumping peaked to meet water demand and about 3% to 6% during the winter months. This paper demonstrates how collection of multiple tracers can be used in combination with simplified models of fluid flow to estimate the age distribution and thus fraction of contaminated groundwater reaching a supply well under different pumping conditions.

A Ternary Age-Mixing Model to Explain Contaminant Occurrence in a Deep Supply Well

PubMed Central

Jurgens, Bryant C; Bexfield, Laura M; Eberts, Sandra M

2014-01-01

The age distribution of water from a public-supply well in a deep alluvial aquifer was estimated and used to help explain arsenic variability in the water. The age distribution was computed using a ternary mixing model that combines three lumped parameter models of advection-dispersion transport of environmental tracers, which represent relatively recent recharge (post-1950s) containing volatile organic compounds (VOCs), old intermediate depth groundwater (about 6500 years) that was free of drinking-water contaminants, and very old, deep groundwater (more than 21,000 years) containing arsenic above the USEPA maximum contaminant level of 10 µg/L. The ternary mixing model was calibrated to tritium, chloroflorocarbon-113, and carbon-14 (14C) concentrations that were measured in water samples collected on multiple occasions. Variability in atmospheric 14C over the past 50,000 years was accounted for in the interpretation of 14C as a tracer. Calibrated ternary models indicate the fraction of deep, very old groundwater entering the well varies substantially throughout the year and was highest following long periods of nonoperation or infrequent operation, which occured during the winter season when water demand was low. The fraction of young water entering the well was about 11% during the summer when pumping peaked to meet water demand and about 3% to 6% during the winter months. This paper demonstrates how collection of multiple tracers can be used in combination with simplified models of fluid flow to estimate the age distribution and thus fraction of contaminated groundwater reaching a supply well under different pumping conditions. PMID:24597520

Optimizing the longitudinal and transverse electroosmotic pumping in a rectangular channel with horizontal baffle plates

NASA Astrophysics Data System (ADS)

Lai, Anison K. R.; Chang, Chien-Cheng; Wang, Chang-Yi

2018-04-01

This paper presents a continued study to our previous work on electroosmotic (EO) flow in a channel with vertical baffle plates by further investigating EO flow through an array of baffle plates arranged in parallel to the channel walls. The flow may be driven either in the direction along or in the direction transverse to the plates, thus distinguishing the longitudinal EO pumping (LEOP) and the transverse EO pumping (TEOP). In both types of EO pumping, it is more interesting to examine the cases when the baffle plates develop a higher zeta potential (denoted by α) than that on the channel walls (β). This semi-analytical study enables us to compare between LEOP and TEOP in the pumping efficiency under similar conditions. The TEOP case is more difficult to solve due to the higher order governing partial differential equations caused by the induced non-uniform pressure gradient distribution. In particular, we examine how the EO pumping rates deviate from those predicted by the Helmholtz-Smoluchowski velocity and illustrate the general trend of optimizing the EO pumping rates with respect to the physical and geometric parameters involved.

Autotrophic denitrification supported by biotite dissolution in crystalline aquifers: (2) transient mixing and denitrification dynamic during long-term pumping.

PubMed

Roques, Clément; Aquilina, Luc; Boisson, Alexandre; Vergnaud-Ayraud, Virginie; Labasque, Thierry; Longuevergne, Laurent; Laurencelle, Marc; Dufresne, Alexis; de Dreuzy, Jean-Raynald; Pauwels, Hélène; Bour, Olivier

2018-04-01

We investigated the mixing and dynamic of denitrification processes induced by long-term pumping in the crystalline aquifer of Ploemeur (Brittany, France). Hydrological and geochemical parameters have been continuously recorded over 15 boreholes in 5km 2 on a 25-year period. This extensive spatial and temporal monitoring of conservative as well as reactive compounds is a key opportunity to identify aquifer-scale transport and reactive processes in crystalline aquifers. Time series analysis of the conservative elements recorded at the pumped well were used to determine mixing fractions from different compartments of the aquifer on the basis of a Principal Component Analysis approach coupled with an end-member mixing analysis. We could reveal that pumping thus induces a thorough reorganization of fluxes known as capture, favoring infiltration and vertical fluxes in the recharge zone, and upwelling of deep and distant water at long-term time scales. These mixing fractions were then used to quantify the extent of denitrification linked to pumping. Based on the results from batch experiments described in a companion paper, our computations revealed that i) autotrophic denitrification processes are dominant in this context where carbon sources are limited, that ii) nitrate reduction does not only come from the oxidation of pyrite as classically described in previous studies analyzing denitrification processes in similar contexts, and that iii) biotite plays a critical role in sustaining the nitrate reduction process. Both nitrate reduction, sulfate production as well as fluor release ratios support the hypothesis that biotite plays a key role of electron donor in this context. The batch-to-site similarities support biotite availability and the role by bacterial communities as key controls of nitrate removal in such crystalline aquifers. However, the long term data monitoring also indicates that mixing and reactive processes evolve extremely slowly at the scale of the decade. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of left ventricular assist device speed adjustment on exercise tolerance and markers of wall stress.

PubMed

Hayward, Christopher S; Salamonsen, Robert; Keogh, Anne M; Woodard, John; Ayre, Peter; Prichard, Roslyn; Kotlyar, Eugene; Macdonald, Peter S; Jansz, Paul; Spratt, Phillip

2015-09-01

Left ventricular assist devices are crucial in rehabilitation of patients with end-stage heart failure. Whether cardiopulmonary function is enhanced with higher pump output is unknown. 10 patients (aged 39±16 years, mean±SD) underwent monitored adjustment of pump speed to determine minimum safe low speed and maximum safe high speed at rest. Patients were then randomized to these speed settings and underwent three 6-minute walk tests (6MWT) and symptom-limited cardiopulmonary stress tests (CPX) on separate days. Pump speed settings (low, normal and high) resulted in significantly different resting pump flows of 4.43±0.6, 5.03±0.94, and 5.72±1.2 l/min (P<.001). There was a significant enhancement of pump flows (greater at higher speed settings) with exercise (P<0.05). Increased pump speed was associated with a trend to increased 6MWT distance (P=.10); and CPX exercise time (p=.27). Maximum workload achieved and peak oxygen consumption were significantly different comparing low to high pump speed settings only (P<.05). N-terminal-pro-B-type natriuretic peptide release was significantly reduced at higher pump speed with exercise (P<.01). We have found that alteration of pump speed setting resulted in significant variation in estimated pump flow. The high-speed setting was associated with lower natriuretic hormone release consistent with lower myocardial wall stress. This did not, however, improve exercise tolerance.

Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

PubMed

Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

2016-03-01

Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

Fluid delivery control system

DOEpatents

Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad

2006-06-06

A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.

Investigation of Turbulent Tip Leakage Vortex in an Axial Water Jet Pump with Large Eddy Simulation

NASA Technical Reports Server (NTRS)

Hah, Chunill; Katz, Joseph

2012-01-01

Detailed steady and unsteady numerical studies were performed to investigate tip clearance flow in an axial water jet pump. The primary objective is to understand physics of unsteady tip clearance flow, unsteady tip leakage vortex, and cavitation inception in an axial water jet pump. Steady pressure field and resulting steady tip leakage vortex from a steady flow analysis do not seem to explain measured cavitation inception correctly. The measured flow field near the tip is unsteady and measured cavitation inception is highly transient. Flow visualization with cavitation bubbles shows that the leakage vortex is oscillating significantly and many intermittent vortex ropes are present between the suction side of the blade and the tip leakage core vortex. Although the flow field is highly transient, the overall flow structure is stable and a characteristic frequency seems to exist. To capture relevant flow physics as much as possible, a Reynolds-averaged Navier-Stokes (RANS) calculation and a Large Eddy Simulation (LES) were applied for the current investigation. The present study reveals that several vortices from the tip leakage vortex system cross the tip gap of the adjacent blade periodically. Sudden changes in local pressure field inside tip gap due to these vortices create vortex ropes. The instantaneous pressure filed inside the tip gap is drastically different from that of the steady flow simulation. Unsteady flow simulation which can calculate unsteady vortex motion is necessary to calculate cavitation inception accurately even at design flow condition in such a water jet pump.

Axial Pump

NASA Technical Reports Server (NTRS)

Bozeman, Richard J., Jr. (Inventor); Akkerman, James W. (Inventor); Aber, Gregory S. (Inventor); VanDamm, George Arthur (Inventor); Bacak, James W. (Inventor); Svejkovsky, Paul A. (Inventor); Benkowski, Robert J. (Inventor)

1997-01-01

A rotary blood pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial and radial clearances of blades associated with the flow straightener, inducer portion, impeller portion and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with cross-linked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Geothermal down well pumping system

NASA Technical Reports Server (NTRS)

Matthews, H. B.; Mcbee, W. D.

1974-01-01

A key technical problem in the exploitation of hot water geothermal energy resources is down-well pumping to inhibit mineral precipitation, improve thermal efficiency, and enhance flow. A novel approach to this problem involves the use of a small fraction of the thermal energy of the well water to boil and super-heat a clean feedwater flow in a down-hole exchanger adjacent to the pump. This steam powers a high-speed turbine-driven pump. The exhaust steam is brought to the surface through an exhaust pipe, condensed, and recirculated. A small fraction of the high-pressure clean feedwater is diverted to lubricate the turbine pump bearings and prevent leakage of brine into the turbine-pump unit. A project demonstrating the feasibility of this approach by means of both laboratory and down-well tests is discussed.

Simulated flow of groundwater and brine from a flooded salt mine in Livingston County, New York, and effects of remedial pumping on an overlying aquifer

USGS Publications Warehouse

Yager, Richard M.; Miller, Todd S.; Kappel, William M.; Misut, Paul E.; Langevin, Christian D.; Parkhurst, David L.; deVries, M. Peter

2012-01-01

Two ceiling collapses in the Retsof salt mine near Geneseo in upstate New York in spring 1994 resulted in the upward propagation of two columns of rubble through 600 feet of overlying shale and carbonate bedrock. This upward propagation formed a hydraulic connection between the lower confined aquifer (LCA) and the mine and allowed water from the aquifer and bedrock fracture zones that intersected the rubble columns to flow into the mine at a rate of 18,000 gallons per minute (gal/min) . All salt mining ceased in September 1995, and the mine was completely flooded by January 1996. The flow of water from the lower confined aquifer into the mine caused widespread drawdowns, and water levels in the aquifer declined by as much as 400 feet near the collapse area and by more than 50 feet at wells 7 miles to the north and south. Within 3 to 4 weeks of the collapses, water levels in about a dozen domestic and industrial wells had declined severely, and some wells went dry. Water levels in at least 58 wells in the lower and middle confined aquifers were affected by mine flooding. Groundwater in the upper unconfined aquifer and surface water in streams were unaffected by water-level drawdown, but channels of the Genesee River and Beards Creek were altered by land subsidence related to the mine collapse. Water levels recovered from 1996 through 2006, but the mine is now filled with about 15 billion gallons of saturated halite brine. The weight of the overlying rock and sediment is expected to cause the salt beds to deform and fill the mine cavity during the next several hundred years; this in turn could displace as much as 80 percent of the brine and cause it to move upward through the rubble chimneys, rendering the LCA unusable as a source of water supply. Saline water was detected in the LCA in 2002 but was found to be derived primarily from fractures in the limestone and shale units between the mine and the LCA, rather than from the mine. In September 2006, the mine company began a brine-mitigation project that entailed pumping five wells finished in limestone and shale units within the collapse areas to alter the flow gradient and thereby prevent further movement of brine and saline water into the LCA. The pumped brine was routed to an onsite desalination plant. At the same time, the U.S. Geological Survey (USGS) began a study in cooperation with the New York State Office of the Attorney General to construct numerical models to analyze the groundwater chemistry and delineate the directions of flow. Specific objectives of the study were to: * Assess the sources of salinity within the collapse area and identify the factors that control the movement and mixing of freshwater, saline waters from fracture zones, and brine; * Evaluate the likelihood that the pumping will induce anhydrite dissolution and lead to continued land subsidence; * Construct variable-density groundwater flow models to predict the effect of remedial pumping on salinity within the LCA; * Evaluate the effectiveness of remedial pumping in preventing the movement of saline water into the LCA; and * Predict the extent of brine migration 8 years after a hypothetical shutdown of all pumping in 2008. This report (1) summarizes the hydrogeologic setting and effects of mine flooding, (2) describes the geochemical and variable-density model simulations and their principal results, (3) discusses the implications of (a) continued pumping and desalination to protect the LCA and (b) a full shutdown of pumping after 2008, and (4) suggests further research that could lead to refinement of model predictions. Additional information may be found in Yager and others (2001 and 2009). These reports can be accessed at http://pubs.usgs.gov/pp/pp1611/ and http://pubs.usgs.gov/pp/pp1767/, respectively. A summary of simulation results can be accessed at http://ny.water.usgs.gov/projects/Coram/seawat/seawat.html.

Computational Fluid Dynamics (CFD) study of the 4th generation prototype of a continuous flow Ventricular Assist Device (VAD).

PubMed

Song, Xinwei; Wood, Houston G; Olsen, Don

2004-04-01

The continuous flow ventricular assist device (VAD) is a miniature centrifugal pump, fully suspended by magnetic bearings, which is being developed for implantation in humans. The CF4 model is the first actual prototype of the final design product. The overall performances of blood flow in CF4 have been simulated using computational fluid dynamics (CFD) software: CFX, which is commercially available from ANSYS Inc. The flow regions modeled in CF4 include the inlet elbow, the five-blade impeller, the clearance gap below the impeller, and the exit volute. According to different needs from patients, a wide range of flow rates and revolutions per minute (RPM) have been studied. The flow rate-pressure curves are given. The streamlines in the flow field are drawn to detect stagnation points and vortices that could lead to thrombosis. The stress is calculated in the fluid field to estimate potential hemolysis. The stress is elevated to the decreased size of the blood flow paths through the smaller pump, but is still within the safe range. The thermal study on the pump, the blood and the surrounding tissue shows the temperature rise due to magnetoelectric heat sources and thermal dissipation is insignificant. CFD simulation proved valuable to demonstrate and to improve the performance of fluid flow in the design of a small size pump.

Modeling of static and flowing-gas diode pumped alkali lasers

NASA Astrophysics Data System (ADS)

Barmashenko, Boris D.; Auslender, Ilya; Yacoby, Eyal; Waichman, Karol; Sadot, Oren; Rosenwaks, Salman

2016-03-01

Modeling of static and flowing-gas subsonic, transonic and supersonic Cs and K Ti:Sapphire and diode pumped alkali lasers (DPALs) is reported. A simple optical model applied to the static K and Cs lasers shows good agreement between the calculated and measured dependence of the laser power on the incident pump power. The model reproduces the observed threshold pump power in K DPAL which is much higher than that predicted by standard models of the DPAL. Scaling up flowing-gas DPALs to megawatt class power is studied using accurate three-dimensional computational fluid dynamics model, taking into account the effects of temperature rise and losses of alkali atoms due to ionization. Both the maximum achievable power and laser beam quality are estimated for Cs and K lasers. The performance of subsonic and, in particular, supersonic DPALs is compared with that of transonic, where supersonic nozzle and diffuser are spared and high power mechanical pump (needed for recovery of the gas total pressure which strongly drops in the diffuser), is not required for continuous closed cycle operation. For pumping by beams of the same rectangular cross section, comparison between end-pumping and transverse-pumping shows that the output power is not affected by the pump geometry, however, the intensity of the output laser beam in the case of transverse-pumped DPALs is strongly non-uniform in the laser beam cross section resulting in higher brightness and better beam quality in the far field for the end-pumping geometry where the intensity of the output beam is uniform.

Generating pulsatility by pump speed modulation with continuous-flow total artificial heart in awake calves.

PubMed

Fukamachi, Kiyotaka; Karimov, Jamshid H; Sunagawa, Gengo; Horvath, David J; Byram, Nicole; Kuban, Barry D; Dessoffy, Raymond; Sale, Shiva; Golding, Leonard A R; Moazami, Nader

2017-12-01

The purpose of this study was to evaluate the effects of sinusoidal pump speed modulation of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) on hemodynamics and pump flow in an awake chronic calf model. The sinusoidal pump speed modulations, performed on the day of elective sacrifice, were set at ±15 and ± 25% of mean pump speed at 80 bpm in four awake calves with a CFTAH. The systemic and pulmonary arterial pulse pressures increased to 12.0 and 12.3 mmHg (±15% modulation) and to 15.9 and 15.7 mmHg (±25% modulation), respectively. The pulsatility index and surplus hemodynamic energy significantly increased, respectively, to 1.05 and 1346 ergs/cm at ±15% speed modulation and to 1.51 and 3381 ergs/cm at ±25% speed modulation. This study showed that it is feasible to generate pressure pulsatility with pump speed modulation; the platform is suitable for evaluating the physiologic impact of pulsatility and allows determination of the best speed modulations in terms of magnitude, frequency, and profiles.

Two-phase flow in the cooling circuit of a cryogenic rocket engine

NASA Astrophysics Data System (ADS)

Preclik, D.

1992-07-01

Transient two-phase flow was investigated for the hydrogen cooling circuit of the HM7 rocket engine. The nuclear reactor code ATHLET/THESEUS was adapted to cryogenics and applied to both principal and prototype experiments for validation and simulation purposes. The cooling circuit two-phase flow simulation focused on the hydrogen prechilling and pump transient phase prior to ignition. Both a single- and a multichannel model were designed and employed for a valve leakage flow, a nominal prechilling flow, and a prechilling with a subsequent pump-transient flow. The latter case was performed in order to evaluate the difference between a nominal and a delayed turbo-pump start-up. It was found that an extension of the nominal prechilling sequence in the order of 1 second is sufficient to finally provide for liquid injection conditions of hydrogen which, as commonly known, is undesirable for smooth ignition and engine starting transients.

Flow through electrode with automated calibration

DOEpatents

Szecsody, James E [Richland, WA; Williams, Mark D [Richland, WA; Vermeul, Vince R [Richland, WA

2002-08-20

The present invention is an improved automated flow through electrode liquid monitoring system. The automated system has a sample inlet to a sample pump, a sample outlet from the sample pump to at least one flow through electrode with a waste port. At least one computer controls the sample pump and records data from the at least one flow through electrode for a liquid sample. The improvement relies upon (a) at least one source of a calibration sample connected to (b) an injection valve connected to said sample outlet and connected to said source, said injection valve further connected to said at least one flow through electrode, wherein said injection valve is controlled by said computer to select between said liquid sample or said calibration sample. Advantages include improved accuracy because of more frequent calibrations, no additional labor for calibration, no need to remove the flow through electrode(s), and minimal interruption of sampling.

Building a Better Neonatal Extracorporeal Life Support Circuit: Comparison of Hemodynamic Performance and Gaseous Microemboli Handling in Different Pump and Oxygenator Technologies.

PubMed

Glass, Kristen; Trivedi, Payal; Wang, Shigang; Woitas, Karl; Kunselman, Allen R; Ündar, Akif

2017-04-01

Neurologic complications during neonatal extracorporeal life support (ECLS) are associated with significant morbidity and mortality. Gaseous microemboli (GME) in the ECLS circuit may be a possible cause. Advances in neonatal circuitry may improve hemodynamic performance and GME handling leading to reduction in patient complications. This study compared hemodynamic performance and GME handling using two centrifugal pumps (Maquet RotaFlow and Medos Deltastream DP3) and polymethylpentene oxygenators (Maquet Quadrox-iD and Medos Hilite 800LT) in a neonatal ECLS circuit model. The experimental circuit was primed with Lactated Ringer's solution and packed human red blood cells (hematocrit 40%) and arranged in parallel with the RotaFlow and DP3 pump, Quadrox-iD and Hilite oxygenator, and Better-Bladder. Hemodynamic trials evaluating pressure drops and total hemodynamic energy (THE) were conducted at 300 and 500 mL/min at 36°C. GME handling was measured after 0.5 mL of air was injected into the venous line using the Emboli Detection and Classification Quantifier System with unique pump, oxygenator, and Better-Bladder combinations. The RotaFlow pump and Quadrox oxygenator arrangement had lower pressure drops and THE loss at both flow rates compared to the DP3 pump and Hilite oxygenator (P < 0.01). Total GME volume and counts decreased with Better-Bladder at both flow rates with all combinations (P < 0.01). Hemodynamic performance and energy loss were similar in all of the circuit combinations. The Better-Bladder significantly decreased GME. All four combinations of pumps and oxygenators also performed similarly in terms of GME handling. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Functional and biocompatibility performances of an integrated Maglev pump-oxygenator.

PubMed

Zhang, Tao; Cheng, Guangming; Koert, Andrew; Zhang, Juntao; Gellman, Barry; Yankey, G Kwame; Satpute, Aditee; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

2009-01-01

To provide respiratory support for patients with lung failure, a novel compact integrated pump-oxygenator is being developed. The functional and biocompatibility performances of this device are presented. The pump-oxygenator is designed by combining a magnetically levitated pump/rotor with a uniquely configured hollow fiber membrane bundle to create an assembly free, ultracompact, all-in-one system. The hemodynamics, gas transfer and biocompatibility performances of this novel device were investigated both in vitro in a circulatory flow loop and in vivo in an ovine animal model. The in vitro results showed that the device was able to pump blood flow from 2 to 8 L/min against a wide range of pressures and to deliver an oxygen transfer rate more than 300 mL/min at a blood flow of 6 L/min. Blood damage tests demonstrated low hemolysis (normalized index of hemolysis [NIH] approximately 0.04) at a flow rate of 5 L/min against a 100-mm Hg afterload. The data from five animal experiments (4 h to 7 days) demonstrated that the device could bring the venous blood to near fully oxygen-saturated condition (98.6% +/- 1.3%). The highest oxygen transfer rate reached 386 mL/min. The gas transfer performance was stable over the study duration for three 7-day animals. There was no indication of blood damage. The plasma free hemoglobin and platelet count were within the normal ranges. No gross thrombus is found on the explanted pump components and fiber surfaces. Both in vitro and in vivo results demonstrated that the newly developed pump-oxygenator can achieve sufficient blood flow and oxygen transfer with excellent biocompatibility.