MEANS FOR VISUALIZING FLUID FLOW PATTERNS

DOEpatents

Lynch, F.E.; Palmer, L.D.; Poppendick, H.F.; Winn, G.M.

1961-05-16

An apparatus is given for determining both the absolute and relative velocities of a phosphorescent fluid flowing through a transparent conduit. The apparatus includes a source for exciting a narrow trsnsverse band of the fluid to phosphorescence, detecting means such as a camera located downstream from the exciting source to record the shape of the phosphorescent band as it passes, and a timer to measure the time elapsed between operation of the exciting source and operation of the camera.

Laboratory Experiments Modelling Sediment Transport by River Plumes

NASA Astrophysics Data System (ADS)

Sutherland, Bruce; Gingras, Murray; Knudson, Calla; Steverango, Luke; Surma, Chris

2016-11-01

Through lock-release laboratory experiments, the transport of particles by hypopycnal (surface) currents is examined as they flow into a uniform-density and a two-layer ambient fluid. In most cases the tank is tilted so that the current flows over a slope representing an idealization of a sediment-bearing river flowing into the ocean and passing over the continental shelf. When passing into a uniform-density ambient, the hypopycnal current slows and stops as particles rain out, carrying some of the light interstitial fluid with them. Rather than settling on the bottom, in many cases the descending particles accumulate to form a hyperpycnal (turbidity) current that flows downslope. This current then slows and stops as particles both rain out to the bottom and also rise again to the surface, carried upward by the light interstitial fluid. For a hypopycnal current flowing into a two-layer fluid, the current slows as particles rain out and accumulate at the interface of the two-layer ambient. Eventually these particles penetrate through the interface and settle to the bottom with no apparent formation of a hyperpycnal current. Analyses are performed to characterize the speed of the currents and stopping distances as they depend upon experiment parameters. Natural Sciences and Engineering Research Council.

Multiple source/multiple target fluid transfer apparatus

DOEpatents

Turner, Terry D.

1997-01-01

A fluid transfer apparatus includes: a) a plurality of orifices for connection with fluid sources; b) a plurality of orifices for connection with fluid targets; c) a set of fluid source conduits and fluid target conduits associated with the orifices; d) a pump fluidically interposed between the source and target conduits to transfer fluid therebetween; e) a purge gas conduit in fluid communication with the fluid source conduits, fluid target conduits and pump to receive and pass a purge gas under pressure; f) a solvent conduit in fluid communication with the fluid source conduits, fluid target conduits and pump to receive and pass solvent, the solvent conduit including a solvent valve; g) pump control means for controlling operation of the pump; h) purge gas valve control means for controlling operation of the purge gas valve to selectively impart flow of purge gas to the fluid source conduits, fluid target conduits and pump; i) solvent valve control means for controlling operation of the solvent valve to selectively impart flow of solvent to the fluid source conduits, fluid target conduits and pump; and j) source and target valve control means for controlling operation of the fluid source conduit valves and the fluid target conduit valves to selectively impart passage of fluid between a selected one of the fluid source conduits and a selected one of the fluid target conduits through the pump and to enable passage of solvent or purge gas through selected fluid source conduits and selected fluid target conduits.

Multiple source/multiple target fluid transfer apparatus

DOEpatents

Turner, T.D.

1997-08-26

A fluid transfer apparatus includes: (a) a plurality of orifices for connection with fluid sources; (b) a plurality of orifices for connection with fluid targets; (c) a set of fluid source conduits and fluid target conduits associated with the orifices; (d) a pump fluidically interposed between the source and target conduits to transfer fluid there between; (e) a purge gas conduit in fluid communication with the fluid source conduits, fluid target conduits and pump to receive and pass a purge gas under pressure; (f) a solvent conduit in fluid communication with the fluid source conduits, fluid target conduits and pump to receive and pass solvent, the solvent conduit including a solvent valve; (g) pump control means for controlling operation of the pump; (h) purge gas valve control means for controlling operation of the purge gas valve to selectively impart flow of purge gas to the fluid source conduits, fluid target conduits and pump; (i) solvent valve control means for controlling operation of the solvent valve to selectively impart flow of solvent to the fluid source conduits, fluid target conduits and pump; and (j) source and target valve control means for controlling operation of the fluid source conduit valves and the fluid target conduit valves to selectively impart passage of fluid between a selected one of the fluid source conduits and a selected one of the fluid target conduits through the pump and to enable passage of solvent or purge gas through selected fluid source conduits and selected fluid target conduits. 6 figs.

Counter flow cooling drier with integrated heat recovery

DOEpatents

Shivvers, Steve D [Prole, IA

2009-08-18

A drier apparatus for removing water or other liquids from various materials includes a mixer, drying chamber, separator and regenerator and a method for use of the apparatus. The material to be dried is mixed with a heated media to form a mixture which then passes through the chamber. While passing through the chamber, a comparatively cool fluid is passed counter current through the mixture so that the mixture becomes cooler and drier and the fluid becomes hotter and more saturated with moisture. The mixture is then separated into drier material and media. The media is transferred to the regenerator and heated therein by the hot fluid from the chamber and supplemental heat is supplied to bring the media to a preselected temperature for mixing with the incoming material to be dried. In a closed loop embodiment of the apparatus, the fluid is also recycled from the regenerator to the chamber and a chiller is utilized to reduce the temperature of the fluid to a preselected temperature and dew point temperature.

Fiber optic liquid mass flow sensor and method

NASA Technical Reports Server (NTRS)

Korman, Valentin (Inventor); Gregory, Don Allen (Inventor); Wiley, John T. (Inventor); Pedersen, Kevin W. (Inventor)

2010-01-01

A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

Countercurrent direct contact heat exchange process and system

DOEpatents

Wahl, III, Edward F.; Boucher, Frederic B.

1979-01-01

Recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange with a working fluid, such as a hydrocarbon working fluid, e.g. isobutane. The process and system consists of a plurality of stages, each stage including mixing and settling units. In the first stage, hot brine and arm working fluid are intimately mixed and passed into a settler wherein the brine settles to the bottom of the settler and the hot working fluid rises to the top. The hot working fluid is passed to a heat engine or turbine to produce work and the working fluid is then recycled back into the system. The system is comprised of a series of stages each containing a settler and mixer, and wherein the working fluid and the brine flow in a countercurrent manner through the stages to recover the heat from the brine in increments and raise the temperature of the working fluid in increments.

COOLED NEUTRONIC REACTOR

DOEpatents

Binner, C.R.; Wilkie, C.B.

1958-03-18

This patent relates to a design for a reactor of the type in which a fluid coolant is flowed through the active portion of the reactor. This design provides for the cooling of the shielding material as well as the reactor core by the same fluid coolant. The core structure is a solid moderator having coolant channels in which are disposed the fuel elements in rod or slug form. The coolant fluid enters the chamber in the shield, in which the core is located, passes over the inner surface of said chamber, enters the core structure at the center, passes through the coolant channels over the fuel elements and out through exhaust ducts.

Flow monitoring and control system for injection wells

DOEpatents

Corey, John C.

1993-01-01

A system for monitoring and controlling the injection rate of fluid by an injection well of an in-situ remediation system for treating a contaminated groundwater plume. The well is fitted with a gated insert, substantially coaxial with the injection well. A plurality of openings, some or all of which are equipped with fluid flow sensors and gates, are spaced along the insert. The gates and sensors are connected to a surface controller. The insert may extend throughout part of, or substantially the entire length of the injection well. Alternatively, the insert may comprise one or more movable modules which can be positioned wherever desired along the well. The gates are opened part-way at the start of treatment. The sensors monitor and display the flow rate of fluid passing through each opening on a controller. As treatment continues, the gates are opened to increase flow in regions of lesser flow, and closed to decrease flow in regions of greater flow, thereby approximately equalizing the amount of fluid reaching each part of the plume.

Flow monitoring and control system for injection wells

DOEpatents

Corey, J.C.

1993-02-16

A system for monitoring and controlling the injection rate of fluid by an injection well of an in-situ remediation system for treating a contaminated groundwater plume. The well is fitted with a gated insert, substantially coaxial with the injection well. A plurality of openings, some or all of which are equipped with fluid flow sensors and gates, are spaced along the insert. The gates and sensors are connected to a surface controller. The insert may extend throughout part of, or substantially the entire length of the injection well. Alternatively, the insert may comprise one or more movable modules which can be positioned wherever desired along the well. The gates are opened part-way at the start of treatment. The sensors monitor and display the flow rate of fluid passing through each opening on a controller. As treatment continues, the gates are opened to increase flow in regions of lesser flow, and closed to decrease flow in regions of greater flow, thereby approximately equalizing the amount of fluid reaching each part of the plume.

Method and apparatus for a catalytic firebox reactor

DOEpatents

Smith, Lance L.; Etemad, Shahrokh; Ulkarim, Hasan; Castaldi, Marco J.; Pfefferle, William C.

2001-01-01

A catalytic firebox reactor employing an exothermic catalytic reaction channel and multiple cooling conduits for creating a partially reacted fuel/oxidant mixture. An oxidation catalyst is deposited on the walls forming the boundary between the multiple cooling conduits and the exothermic catalytic reaction channel, on the side of the walls facing the exothermic catalytic reaction channel. This configuration allows the oxidation catalyst to be backside cooled by any fluid passing through the cooling conduits. The heat of reaction is added to both the fluid in the exothermic catalytic reaction channel and the fluid passing through the cooling conduits. After discharge of the fluids from the exothermic catalytic reaction channel, the fluids mix to create a single combined flow. A further innovation in the reactor incorporates geometric changes in the exothermic catalytic reaction channel to provide streamwise variation of the velocity of the fluids in the reactor.

Medical and Scientific Evaluations aboard the KC-135. Microgravity-Compatible Flow Cytometer

NASA Technical Reports Server (NTRS)

Crucian, Brian; Nelman-Gonzalez, Mayra; Sams, Clarence

2005-01-01

A spaceflight-compatible flow cytometer would be useful for the diagnosis of astronaut illness during long duration spaceflight and for conducting in-flight research to evaluate the effects of microgravity on human physiology. Until recently, the primary limitations preventing the development of a spaceflight compatible flow cytometer have been largely mechanical. Standard commercially available flow cytometers are large, complex instruments that use high-energy lasers and require significant training to operate. Standard flow cytometers function by suspending the particles to be analyzed inside a sheath fluid for analysis. This requires the presence of several liters of sheath fluid for operation, and generates a corresponding amount of liquid hazardous waste. The particles are then passed through a flow cell which uses the fluid mechanical property of hydrodynamic focusing to place the cells in single-file (laminar flow) as they pass through a laser beam for scanning and evaluation. Many spaceflight experiments have demonstrated that fluid physics is dramatically altered in microgravity (MSF [Manned Space Flight] Fluid Physics Data Sheet-August 1997) and previous studies have shown that sheath-fluid based hydrodynamic focusing may also be altered during microgravity (Crucian et al, 2000). For these reasons it is likely that any spaceflight compatible design for a flow cytometer would abandon the sheath fluid requirement. The elimination of sheath fluid would remove both the problems of weight associated with large volumes of liquids as well as the large volume of liquid waste generated. It would also create the need for a method to create laminar particle flow distinct from the standard sheath-fluid based method. The spaceflight prototype instrument is based on a recently developed commercial flow cytometer possessing a novel flow cell design that creates single-particle laser scanning and evaluation without the need for sheath-fluid based hydrodynamic focusing. This instrument also possesses a number of design advances that make it conditionally microgravity compatible: it is highly miniaturized and lightweight, uses a low energy diode laser, has a small number of moving parts, does not use sheath fluid and does not generate significant liquid waste. Although possessing certain limitations, the commercial cytometer functions operationally like a standard bench top laboratory flow cytometer, aspirating liquid particle samples and generating histogram or dot-plot data in standard FCS file format. In its current configuration however, the cytometer is limited to three parameter/two-color capability (two color PMTs + forward scatter), does not allow compensation between colors, does not allow linear analysis and is operated by rather inflexible software with limited capabilities. This is due to the fact that the cytometer has been designed and marketed as an instrument specific to a few particular assays, not as a multipurpose cytometer.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-02-05

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Parallel Three-Dimensional Computation of Fluid Dynamics and Fluid-Structure Interactions of Ram-Air Parachutes

NASA Technical Reports Server (NTRS)

Tezduyar, Tayfun E.

1998-01-01

This is a final report as far as our work at University of Minnesota is concerned. The report describes our research progress and accomplishments in development of high performance computing methods and tools for 3D finite element computation of aerodynamic characteristics and fluid-structure interactions (FSI) arising in airdrop systems, namely ram-air parachutes and round parachutes. This class of simulations involves complex geometries, flexible structural components, deforming fluid domains, and unsteady flow patterns. The key components of our simulation toolkit are a stabilized finite element flow solver, a nonlinear structural dynamics solver, an automatic mesh moving scheme, and an interface between the fluid and structural solvers; all of these have been developed within a parallel message-passing paradigm.

Comparison of steady and unsteady secondary flows in a turbine stator cascade

NASA Technical Reports Server (NTRS)

Hebert, Gregory J.; Tiederman, William G.

1989-01-01

The effect of periodic rotor wakes on the secondary flow structure in a turbine stator cascade was investigated. A mechanism simulated the wakes shed from rotor blades by passing cylindrical rods across the inlet to a linear cascade installed in a recirculating water flow loop. Velocity measurements showed a passage vortex, similar to that seen in steady flow, during the time associated with undisturbed fluid. However, as the rotor wake passed through the blade row, a large crossflow toward the suction surface was observed in the midspan region. This caused the development of two large areas of circulation between the midspan and endwall regions, significantly distorting and weakening the passage vortices.

Cooling system with compressor bleed and ambient air for gas turbine engine

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

Marsh, Jan H.; Marra, John J.

A cooling system for a turbine engine for directing cooling fluids from a compressor to a turbine blade cooling fluid supply and from an ambient air source to the turbine blade cooling fluid supply to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The cooling system may include a compressor bleed conduit extending from a compressor to the turbine blade cooling fluid supply that provides cooling fluid to at least one turbine blade. The compressor bleed conduit may include an upstream section and a downstream section whereby the upstream section exhausts compressed bleed airmore » through an outlet into the downstream section through which ambient air passes. The outlet of the upstream section may be generally aligned with a flow of ambient air flowing in the downstream section. As such, the compressed air increases the flow of ambient air to the turbine blade cooling fluid supply.« less

Infusion volume control and calculation using metronome and drop counter based intravenous infusion therapy helper.

PubMed

Park, Kyungnam; Lee, Jangyoung; Kim, Soo-Young; Kim, Jinwoo; Kim, Insoo; Choi, Seung Pill; Jeong, Sikyung; Hong, Sungyoup

2013-06-01

This study assessed the method of fluid infusion control using an IntraVenous Infusion Controller (IVIC). Four methods of infusion control (dial flow controller, IV set without correction, IV set with correction and IVIC correction) were used to measure the volume of each technique at two infusion rates. The infused fluid volume with a dial flow controller was significantly larger than other methods. The infused fluid volume was significantly smaller with an IV set without correction over time. Regarding the concordance correlation coefficient (CCC) of infused fluid volume in relation to a target volume, IVIC correction was shown to have the highest level of agreement. The flow rate measured in check mode showed a good agreement with the volume of collected fluid after passing through the IV system. Thus, an IVIC could assist in providing an accurate infusion control. © 2013 Wiley Publishing Asia Pty Ltd.

Flow of a Casson fluid through a locally-constricted porous channel: a numerical study

NASA Astrophysics Data System (ADS)

Amlimohamadi, Haleh; Akram, Maryammosadat; Sadeghy, Kayvan

2016-05-01

Flow of a Casson fluid through a two-dimensional porous channel containing a local constriction is numerically investigated assuming that the resistance offered by the porous medium obeys the Darcy's law. Treating the constriction as another porous medium which obeys the Darcy-Forcheimer model, the equations governing fluid flow in the main channel and the constriction itself are numerically solved using the finite-volume method (FVM) based on the pseudo-transient SIMPLE algorithm. It is shown that an increase in the porosity of the channel decreases the shear stress exerted on the constriction. On the other hand, an increase in the fluid's yield stress is predicted to increase the maximum shear stress experienced by the constriction near its crest. The porosity of the constriction itself is predicted to have a negligible effect on the plaque's shear stress. But, the momentum of the weak flow passing through the constriction is argued to lower the bulk fluid from separating downstream of the constriction.

Flow plug with length-to-hole size uniformity for use in flow conditioning and flow metering

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

2012-01-01

A flow plug of varying thickness has a plurality of holes formed therethrough. The plug fits in a conduit such that a fluid flow in the conduit passes through the plug's holes. Each hole is defined by a parameter indicative of size in terms of the cross-sectional area thereof. A ratio of hole length-to-parameter is approximately the same for all of the holes.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

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

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channelmore » wherein the carrier fluid is not appreciably heated by the laser beam.« less

Hazardous fluid leak detector

DOEpatents

Gray, Harold E.; McLaurin, Felder M.; Ortiz, Monico; Huth, William A.

1996-01-01

A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.

Parametric study of fluid flow manipulation with piezoelectric macrofiber composite flaps

NASA Astrophysics Data System (ADS)

Sadeghi, O.; Tarazaga, P.; Stremler, M.; Shahab, S.

2017-04-01

Active Fluid Flow Control (AFFC) has received great research attention due to its significant potential in engineering applications. It is known that drag reduction, turbulence management, flow separation delay and noise suppression through active control can result in significantly increased efficiency of future commercial transport vehicles and gas turbine engines. In microfluidics systems, AFFC has mainly been used to manipulate fluid passing through the microfluidic device. We put forward a conceptual approach for fluid flow manipulation by coupling multiple vibrating structures through flow interactions in an otherwise quiescent fluid. Previous investigations of piezoelectric flaps interacting with a fluid have focused on a single flap. In this work, arrays of closely-spaced, free-standing piezoelectric flaps are attached perpendicular to the bottom surface of a tank. The coupling of vibrating flaps due to their interacting with the surrounding fluid is investigated in air (for calibration) and under water. Actuated flaps are driven with a harmonic input voltage, which results in bending vibration of the flaps that can work with or against the flow-induced bending. The size and spatial distribution of the attached flaps, and the phase and frequency of the input actuation voltage are the key parameters to be investigated in this work. Our analysis will characterize the electrohydroelastic dynamics of active, interacting flaps and the fluid motion induced by the system.

Phase change material storage heater

DOEpatents

Goswami, D. Yogi; Hsieh, Chung K.; Jotshi, Chand K.; Klausner, James F.

1997-01-01

A storage heater for storing heat and for heating a fluid, such as water, has an enclosure defining a chamber therein. The chamber has a lower portion and an upper portion with a heating element being disposed within the enclosure. A tube through which the fluid flows has an inlet and an outlet, both being disposed outside of the enclosure, and has a portion interconnecting the inlet and the outlet that passes through the enclosure. A densely packed bed of phase change material pellets is disposed within the enclosure and is surrounded by a viscous liquid, such as propylene glycol. The viscous liquid is in thermal communication with the heating element, the phase change material pellets, and the tube and transfers heat from the heating element to the pellets and from the pellets to the tube. The viscous fluid has a viscosity so that the frictional pressure drop of the fluid in contact with the phase change material pellets substantially reduces vertical thermal convection in the fluid. As the fluid flows through the tube heat is transferred from the viscous liquid to the fluid flowing through the tube, thereby heating the fluid.

Mass flow sensor utilizing a resistance bridge

NASA Technical Reports Server (NTRS)

Fralick, Gustave C. (Inventor); Hwang, Danny P. (Inventor); Wrbanek, John D. (Inventor)

2004-01-01

A mass flow sensor to be mounted within a duct and measures the mass flow of a fluid stream moving through the duct. The sensor is an elongated thin quartz substrate having a plurality of platinum strips extending in a parallel relationship on the strip, with certain of the strips being resistors connected to an excitation voltage. The resistors form the legs of a Wheatstone bridge. The resistors are spaced a sufficient distance inwardly from the leading and trailing edges of the substrate to lie within the velocity recovery region so that the measured flow is the same as the actual upstream flow. The resistor strips extend at least half-way through the fluid stream to include a substantial part of the velocity profile of the stream. Certain of the resistors detect a change in temperature as the fluid stream moves across the substrate to provide an output signal from the Wheatstone bridge which is representative of the fluid flow. A heater is located in the midst of the resistor array to heat the air as it passes over the array.

Links between fluid circulation, temperature, and metamorphism in subducting slabs

USGS Publications Warehouse

Spinelli, G.A.; Wang, K.

2009-01-01

The location and timing of metamorphic reactions in subducting lithosph??re are influenced by thermal effects of fluid circulation in the ocean crust aquifer. Fluid circulation in subducting crust extracts heat from the Nankai subduction zone, causing the crust to pass through cooler metamorphic faci??s than if no fluid circulation occurs. This fluid circulation shifts the basalt-to-eclogite transition and the associated slab dehydration 14 km deeper (35 km farther landward) than would be predicted with no fluid flow. For most subduction zones, hydrothermal cooling of the subducting slab will delay eclogitization relative to estimates made without considering fluid circulation. Copyright 2009 by the American Geophysical Union.

Monitoring probe for groundwater flow

DOEpatents

Looney, Brian B.; Ballard, Sanford

1994-01-01

A monitoring probe for detecting groundwater migration. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow.

Monitoring probe for groundwater flow

DOEpatents

Looney, B.B.; Ballard, S.

1994-08-23

A monitoring probe for detecting groundwater migration is disclosed. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow. 4 figs.

Cellular fluid mechanics.

PubMed

Kamm, Roger D

2002-01-01

The coupling of fluid dynamics and biology at the level of the cell is an intensive area of investigation because of its critical role in normal physiology and disease. Microcirculatory flow has been a focus for years, owing to the complexity of cell-cell or cell-glycocalyx interactions. Noncirculating cells, particularly those that comprise the walls of the circulatory system, experience and respond biologically to fluid dynamic stresses. In this article, we review the more recent studies of circulating cells, with an emphasis on the role of the glycocalyx on red-cell motion in small capillaries and on the deformation of leukocytes passing through the microcirculation. We also discuss flows in the vicinity of noncirculating cells, the influence of fluid dynamic shear stress on cell biology, and diffusion in the lipid bi-layer, all in the context of the important fluid-dynamic phenomena.

Characterization of Magma-Driven Hydrothermal Systems at Oceanic Spreading Centers

NASA Astrophysics Data System (ADS)

Farough, A.; Lowell, R. P.; Corrigan, R.

2012-12-01

Fluid circulation in high-temperature hydrothermal systems involves complex water-rock chemical reactions and phase separation. Numerical modeling of reactive transport in multi-component, multiphase systems is required to obtain a full understanding of the characteristics and evolution of hydrothermal vent systems. We use a single-pass parameterized model of high-temperature hydrothermal circulation at oceanic spreading centers constrained by observational parameters such as vent temperature, heat output, and vent field area, together with surface area and depth of the sub-axial magma chamber, to deduce fundamental hydrothermal parameters such as mass flow rate, bulk permeability, conductive boundary layer thickness at the base of the system, magma replenishment rate, and residence time in the discharge zone. All of these key subsurface characteristics are known for fewer than 10 sites out of 300 known hydrothermal systems. The principal limitations of this approach stem from the uncertainty in heat output and vent field area. For systems where data are available on partitioning of heat and chemical output between focused and diffuse flow, we determined the fraction of high-temperature vent fluid incorporated into diffuse flow using a two-limb single pass model. For EPR 9°50` N and ASHES, the diffuse flow temperatures calculated assuming conservative mixing are nearly equal to the observed temperatures indicating that approximately 80%-90% of the hydrothermal heat output occurs as high-temperature flow derived from magmatic heat even though most of the heat output appears as low-temperature diffuse discharge. For the Main Endeavour Field and Lucky Strike, diffuse flow fluids show significant conductive cooling and heating respectively. Finally, we calculate the transport of various geochemical constituents in focused and diffuse flow at the vent field scale and compare the results with estimates of geochemical transports from the Rainbow hydrothermal field where diffuse flow is absent.

Seeing Fluid Physics via Visual Expertise Training

NASA Astrophysics Data System (ADS)

Hertzberg, Jean; Goodman, Katherine; Curran, Tim

2016-11-01

In a course on Flow Visualization, students often expressed that their perception of fluid flows had increased, implying the acquisition of a type of visual expertise, akin to that of radiologists or dog show judges. In the first steps towards measuring this expertise, we emulated an experimental design from psychology. The study had two groups of participants: "novices" with no formal fluids education, and "experts" who had passed as least one fluid mechanics course. All participants were trained to place static images of fluid flows into two categories (laminar and turbulent). Half the participants were trained on flow images with a specific format (Von Kármán vortex streets), and the other half on a broader group. Novices' results were in line with past perceptual expertise studies, showing that it is easier to transfer learning from a broad category to a new specific format than vice versa. In contrast, experts did not have a significant difference between training conditions, suggesting the experts did not undergo the same learning process as the novices. We theorize that expert subjects were able to access their conceptual knowledge about fluids to perform this new, visual task. This finding supports new ways of understanding conceptual learning.

Flow visualization V; Proceedings of the 5th International Symposium, Prague, Czechoslovakia, Aug. 21-25, 1989

NASA Astrophysics Data System (ADS)

Reznicek, R.

The present conference on flow visualization encompasses methods exploiting tracing particles, surface tracing methods, methods exploiting the effects of streaming fluid on passing radiation/field, computer-aided flow visualization, and applications to fluid mechanics, aerodynamics, flow devices, shock tubes, and heat/mass transfer. Specific issues include visualizing velocity distribution by stereo photography, dark-field Fourier quasiinterferometry, speckle tomography of an open flame, a fast eye for real-time image analysis, and velocity-field determination based on flow-image analysis. Also addressed are flows around rectangular prisms with oscillating flaps at the leading edges, the tomography of aerodynamic objects, the vapor-screen technique applied to a delta-wing aircraft, flash-lamp planar imaging, IR-thermography applications in convective heat transfer, and the visualization of marangoni effects in evaporating sessile drops.

Radiative Effects on a Free Convective MHD Flow past a Vertically Inclined Plate with with Heat Source and Sink

NASA Astrophysics Data System (ADS)

Sambath, P.; Pullepu, Bapuji; Kannan, R. M.

2018-04-01

The impact of thermal radiation on unsteady laminar free convective MHD flow of a incompressible viscous fluid passes through a vertically inclined plate under the persuade of heat source and sink is presented here.Plate surface is considered to have variable wall temperature. The fluid regarded as gray absorbing / emitting, but non dispersing medium. The periphery layer dimensionless equations that administer the flow are evaluated by a finite difference implicit method called Crank Nicolson method. Numerical solutions are carried out for velocity, temperature, local shear stress, heat transfer rate for various values of the parameters (Pr, λ, Δ M, Rd ) are presented.

Research in Varying Burner Tilt Angle to Reduce Rear Pass Temperature in Coal Fired Boiler

NASA Astrophysics Data System (ADS)

Thrangaraju, Savithry K.; Munisamy, Kannan M.; Baskaran, Saravanan

2017-04-01

This research shows the investigation conducted on one of techniques that is used in Manjung 700 MW tangentially fired coal power plant. The investigation conducted in this research is finding out the right tilt angle for the burners in the boiler that causes an efficient temperature distribution and combustion gas flow pattern in the boiler especially at the rear pass section. The main outcome of the project is to determine the right tilt angle for the burner to create an efficient temperature distribution and combustion gas flow pattern that able to increase the efficiency of the boiler. The investigation is carried out by using Computational Fluid Dynamics method to obtain the results by varying the burner tilt angle. The boiler model is drawn by using designing software which is called Solid Works and Fluent from Computational Fluid Dynamics is used to conduct the analysis on the boiler model. The analysis is to imitate the real combustion process in the real Manjung 700 MW boiler. The expected results are to determine the right burner tilt angle with a computational fluid analysis by obtaining the temperature distribution and combustion gas flow pattern for each of the three angles set for the burner tilt angle in FLUENT software. Three burner tilt angles are selected which are burner tilt angle at (0°) as test case 1, burner tilt angle at (+10°) as test case 2 and burner tilt angle at (-10°) as test case 3. These entire three cases were run in CFD software and the results of temperature distribution and velocity vector were obtained to find out the changes on the three cases at the furnace and rear pass section of the boiler. The results are being compared in analysis part by plotting graphs to determine the right tilting angle that reduces the rear pass temperature.

Method for driving two-phase turbines with enhanced efficiency

NASA Technical Reports Server (NTRS)

Elliott, D. G. (Inventor)

1985-01-01

A method for driving a two phase turbine characterized by an output shaft having at least one stage including a bladed rotor connected in driving relation with the shaft is described. A two phase fluid is introduced into one stage at a known flow velocity and caused to pass through the rotor for imparing angular velocity thereto. The angular velocity of the rotor is maintained at a value such that the angular velocity of the tips of the blades of the rotor is a velocity equal to at least 50% of the velocity of the flow of the two phase fluid.

Fluid-Structure Interactions as Flow Propagates Tangentially Over a Flexible Plate with Application to Voiced Speech Production

NASA Astrophysics Data System (ADS)

Westervelt, Andrea; Erath, Byron

2013-11-01

Voiced speech is produced by fluid-structure interactions that drive vocal fold motion. Viscous flow features influence the pressure in the gap between the vocal folds (i.e. glottis), thereby altering vocal fold dynamics and the sound that is produced. During the closing phases of the phonatory cycle, vortices form as a result of flow separation as air passes through the divergent glottis. It is hypothesized that the reduced pressure within a vortex core will alter the pressure distribution along the vocal fold surface, thereby aiding in vocal fold closure. The objective of this study is to determine the impact of intraglottal vortices on the fluid-structure interactions of voiced speech by investigating how the dynamics of a flexible plate are influenced by a vortex ring passing tangentially over it. A flexible plate, which models the medial vocal fold surface, is placed in a water-filled tank and positioned parallel to the exit of a vortex generator. The physical parameters of plate stiffness and vortex circulation are scaled with physiological values. As vortices propagate over the plate, particle image velocimetry measurements are captured to analyze the energy exchange between the fluid and flexible plate. The investigations are performed over a range of vortex formation numbers, and lateral displacements of the plate from the centerline of the vortex trajectory. Observations show plate oscillations with displacements directly correlated with the vortex core location.

Pre-mixing apparatus for a turbine engine

DOEpatents

Lacy, Benjamin Paul [Greer, SC; Varatharajan, Balachandar [Cincinnati, OH; Ziminsky, Willy Steve [Simpsonville, SC; Kraemer, Gilbert Otto [Greer, SC; Yilmaz, Ertan [Albany, NY; Melton, Patrick Benedict [Horse Shoe, NC; Zuo, Baifang [Simpsonville, SC; Stevenson, Christian Xavier [Inman, SC; Felling, David Kenton [Greenville, SC; Uhm, Jong Ho [Simpsonville, SC

2012-04-03

A pre-mixing apparatus for a turbine engine includes a main body having an inlet portion, an outlet portion and an exterior wall that collectively establish at least one fluid delivery plenum, and a plurality of fluid delivery tubes extending through at least a portion of the at least one fluid delivery plenum. Each of the plurality of fluid delivery tubes includes at least one fluid delivery opening fluidly connected to the at least one fluid delivery plenum. With this arrangement, a first fluid is selectively delivered to the at least one fluid delivery plenum, passed through the at least one fluid delivery opening and mixed with a second fluid flowing through the plurality of fluid delivery tubes prior to being combusted in a combustion chamber of a turbine engine.

A numerical study of the supercritical CO2 plate heat exchanger subject to U-type, Z-type, and multi-pass arrangements

NASA Astrophysics Data System (ADS)

Zhu, Chen-Xi; Wang, Chi-Chuan

2018-01-01

This study proposes a numerical model for plate heat exchanger that is capable of handling supercritical CO2 fluid. The plate heat exchangers under investigation include Z-type (1-pass), U-type (1-pass), and 1-2 pass configurations. The plate spacing is 2.9 mm with a plate thickness of 0.8 mm, and the size of the plate is 600 mm wide and 218 mm in height with 60 degrees chevron angle. The proposed model takes into account the influence of gigantic change of CO2 properties. The simulation is first compared with some existing data for water-to-water plate heat exchangers with good agreements. The flow distribution, pressure drop, and heat transfer performance subject to the supercritical CO2 in plate heat exchangers are then investigated. It is found that the flow velocity increases consecutively from the entrance plate toward the last plate for the Z-type arrangement, and this is applicable for either water side or CO2 side. However, the flow distribution of the U-type arrangement in the water side shows opposite trend. Conversely, the flow distribution for U-type arrangement of CO2 depends on the specific flow ratio (C*). A lower C* like 0.1 may reverse the distribution, i.e. the flow velocity increases moderately alongside the plate channel like Z-type while a large C* of 1 would resemble the typical distribution in water channel. The flow distribution of CO2 side at the first and last plate shows a pronounced drop/surge phenomenon while the channels in water side does not reveal this kind of behavior. The performance of 2-pass plate heat exchanger, in terms of heat transfer rate, is better than that of 1-pass design only when C* is comparatively small (C* < 0.5). Multi-pass design is more effective when the dominant thermal resistance falls in the CO2 side.

Blood and interstitial flow in the hierarchical pore space architecture of bone tissue.

PubMed

Cowin, Stephen C; Cardoso, Luis

2015-03-18

There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Blood and Interstitial flow in the hierarchical pore space architecture of bone tissue

PubMed Central

Cowin, Stephen C.; Cardoso, Luis

2015-01-01

There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells. PMID:25666410

Near wall cooling for a highly tapered turbine blade

DOEpatents

Liang, George [Palm City, FL

2011-03-08

A turbine blade having a pressure sidewall and a suction sidewall connected at chordally spaced leading and trailing edges to define a cooling cavity. Pressure and suction side inner walls extend radially within the cooling cavity and define pressure and suction side near wall chambers. A plurality of mid-chord channels extend radially from a radially intermediate location on the blade to a tip passage at the blade tip for connecting the pressure side and suction side near wall chambers in fluid communication with the tip passage. In addition, radially extending leading edge and trailing edge flow channels are located adjacent to the leading and trailing edges, respectively, and cooling fluid flows in a triple-pass serpentine path as it flows through the leading edge flow channel, the near wall chambers and the trailing edge flow channel.

Method and apparatus for improving heat transfer in a fluidized bed

DOEpatents

Lessor, Delbert L.; Robertus, Robert J.

1990-01-01

An apparatus contains a fluidized bed that includes particles of different triboelectrical types, each particle type acquiring an opposite polarity upon contact. The contact may occur between particles of the two types or between particles of etiher type and structure or fluid present in the apparatus. A fluidizing gas flow is passed through the particles to produce the fluidized bed. Immersed within the bed are electrodes. An alternating EMF source connected to the electrodes applies an alternating electric field across the fluidized bed to cause particles of the first type to move relative to particles of the second type and relative to the gas flow. In a heat exchanger incorporating the apparatus, the electrodes are conduits conveying a fluid to be heated. The two particle types alternately contact each conduit to transfer heat from a hot gas flow to the second fluid within the conduit.

Evaluation of flow mixing in an ARID-HV algal raceway using statistics of temporal and spatial distribution of fluid particles

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

Xu, Ben; Li, Peiwen; Waller, Peter

2015-02-27

This paper analyzes and evaluates the flow mixing in an open channel algal raceway for biofuel production. The flow mixing governs the frequency of how algae cells are exposed to sunlight, due to the fluid movement between the surface and the bottom of the algal raceway, thereby affecting algal growth rate. In this work, we investigated the flow mixing performance in a table-sized model of the High Velocity Algae Raceway Integrated Design (ARID-HV). Various geometries of the raceway channels and dams were considered in both the CFD analysis and experimental flowvisualization. In the CFD simulation, the pathlines of fluid particlesweremore » analyzed to obtain the distribution of the number of times that particles passed across a critical water depth, Dc, defined as a cycle count. In addition, the distribution of the time period fraction that the fluid particles stayed in the zones above and below Dc was recorded. Such information was used to evaluate the flow mixing in the raceway. The CFD evaluation of the flow mixing was validated using experimental flow visualization, which showed a good qualitative agreement with the numerical results. In conclusion, this CFD-based evaluation methodology is recommended for flow field optimization for open channel algal raceways, as well as for other engineering applications in which flow mixing is an important concern.« less

Time-of-flight dependency on transducer separation distance in a reflective-path guided-wave ultrasonic flow meter at zero flow conditions.

PubMed

Aanes, Magne; Kippersund, Remi Andre; Lohne, Kjetil Daae; Frøysa, Kjell-Eivind; Lunde, Per

2017-08-01

Transit-time flow meters based on guided ultrasonic wave propagation in the pipe spool have several advantages compared to traditional inline ultrasonic flow metering. The extended interrogation field, obtained by continuous leakage from guided waves traveling in the pipe wall, increases robustness toward entrained particles or gas in the flow. In reflective-path guided-wave ultrasonic flow meters (GW-UFMs), the flow equations are derived from signals propagating solely in the pipe wall and from signals passing twice through the fluid. In addition to the time-of-flight (TOF) through the fluid, the fluid path experiences an additional time delay upon reflection at the opposite pipe wall due to specular and non-specular reflections. The present work investigates the influence of these reflections on the TOF in a reflective-path GW-UFM as a function of transducer separation distance at zero flow conditions. Two models are used to describe the signal propagation through the system: (i) a transient full-wave finite element model, and (ii) a combined plane-wave and ray-tracing model. The study shows that a range-dependent time delay is associated with the reflection of the fluid path, introducing transmitter-receiver distance dependence. Based on these results, the applicability of the flow equations derived using model (ii) is discussed.

MHD Flow of Sodium Alginate-Based Casson Type Nanofluid Passing Through A Porous Medium With Newtonian Heating.

PubMed

Khan, Arshad; Khan, Dolat; Khan, Ilyas; Ali, Farhad; Karim, Faizan Ul; Imran, Muhammad

2018-06-05

Casson nanofluid, unsteady flow over an isothermal vertical plate with Newtonian heating (NH) is investigated. Sodium alginate (base fluid)is taken as counter example of Casson fluid. MHD and porosity effects are considered. Effects of thermal radiation along with heat generation are examined. Sodium alginate with Silver, Titanium oxide, Copper and Aluminum oxide are added as nano particles. Initial value problem with physical boundary condition is solved by using Laplace transform method. Exact results are obtained for temperature and velocity fields. Skin-friction and Nusselt number are calculated. The obtained results are analyzed graphically for emerging flow parameters and discussed. It is bring into being that temperature and velocity profile are decreasing with increasing nano particles volume fraction.

Charon Message-Passing Toolkit for Scientific Computations

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob F.; Yan, Jerry (Technical Monitor)

2000-01-01

Charon is a library, callable from C and Fortran, that aids the conversion of structured-grid legacy codes-such as those used in the numerical computation of fluid flows-into parallel, high- performance codes. Key are functions that define distributed arrays, that map between distributed and non-distributed arrays, and that allow easy specification of common communications on structured grids. The library is based on the widely accepted MPI message passing standard. We present an overview of the functionality of Charon, and some representative results.

Dual laser optical system and method for studying fluid flow

NASA Technical Reports Server (NTRS)

Owen, R. B.; Witherow, W. K. (Inventor)

1983-01-01

A dual laser optical system and method is disclosed for visualization of phenomena in transport substances which induce refractive index gradients such as fluid flow and pressure and temperature gradients in fluids and gases. Two images representing mutually perpendicular components of refractive index gradients may be viewed simultaneously on screen. Two lasers having wave lengths in the visible range but separated by about 1000 angstroms are utilized to provide beams which are collimated into a beam containing components of the different wave lengths. The collimated beam is passed through a test volume of the transparent substance. The collimated beam is then separated into components of the different wave lengths and focused onto a pair of knife edges arranged mutually perpendicular to produce and project images onto the screen.

Application of computational fluid dynamics to closed-loop bioreactors: I. Characterization and simulation of fluid-flow pattern and oxygen transfer.

PubMed

Littleton, Helen X; Daigger, Glen T; Strom, Peter F

2007-06-01

A full-scale, closed-loop bioreactor (Orbal oxidation ditch, Envirex brand technologies, Siemens, Waukesha, Wisconsin), previously examined for simultaneous biological nutrient removal (SBNR), was further evaluated using computational fluid dynamics (CFD). A CFD model was developed first by imparting the known momentum (calculated by tank fluid velocity and mass flowrate) to the fluid at the aeration disc region. Oxygen source (aeration) and sink (consumption) terms were introduced, and statistical analysis was applied to the CFD simulation results. The CFD model was validated with field data obtained from a test tank and a full-scale tank. The results indicated that CFD could predict the mixing pattern in closed-loop bioreactors. This enables visualization of the flow pattern, both with regard to flow velocity and dissolved-oxygen-distribution profiles. The velocity and oxygen-distribution gradients suggested that the flow patterns produced by directional aeration in closed-loop bioreactors created a heterogeneous environment that can result in dissolved oxygen variations throughout the bioreactor. Distinct anaerobic zones on a macroenvironment scale were not observed, but it is clear that, when flow passed around curves, a secondary spiral flow was generated. This second current, along with the main recirculation flow, could create alternating anaerobic and aerobic conditions vertically and horizontally, which would allow SBNR to occur. Reliable SBNR performance in Orbal oxidation ditches may be a result, at least in part, of such a spatially varying environment.

Pressure measurements in a rapidly sheared turbulent wall layer

NASA Astrophysics Data System (ADS)

Diwan, Sourabh; Morrison, Jonathan

2014-11-01

The aim of the present work is to improve understanding of the role of pressure fluctuations in the generation of coherent structures in wall-bounded turbulent flows, with particular regard to the rapid and slow source terms. The work is in part motivated by the recent numerical simulations of Sharma et al. (Phy. Fluids, 23, 2011), which showed the importance of pressure fluctuations (and their spatial gradients) in the dynamics of large-scale turbulent motions. Our experimental design consists of first generating a shearless boundary layer in a wind tunnel by passing a grid-generated turbulent flow over a moving floor whose speed is matched to the freestream velocity, and then shearing it rapidly by passing it over a stationary floor further downstream. Close to the leading edge of the stationary floor, the resulting flow is expected to satisfy the approximations of the Rapid Distortion Theory and therefore would be an ideal candidate for studying linear processes in wall turbulence. We carry out pressure measurements on the wall as well as within the flow - the former using surface mounted pressure transducers and the latter using a static pressure probe similar in design to that used by Tsuji et al. (J. Fluid. Mech. 585, 2007). We also present a comparison between the rapidly sheared flow and a more conventional boundary layer subjected to a turbulent free stream. We acknowledge the financial support from EPSRC (Grant No. EP/I037938).

Investigation of Multiphase Flow in a Packed Bed Reactor Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Lian, Yongsheng; Motil, Brian; Rame, Enrique

2016-01-01

In this paper we study the two-phase flow phenomena in a packed bed reactor using an integrated experimental and numerical method. The cylindrical bed is filled with uniformly sized spheres. In the experiment water and air are injected into the bed simultaneously. The pressure distribution along the bed will be measured. The numerical simulation is based on a two-phase flow solver which solves the Navier-Stokes equations on Cartesian grids. A novel coupled level set and moment of fluid method is used to construct the interface. A sequential method is used to position spheres in the cylinder. Preliminary experimental results showed that the tested flow rates resulted in pulse flow. The numerical simulation revealed that air bubbles could merge into larger bubbles and also could break up into smaller bubbles to pass through the pores in the bed. Preliminary results showed that flow passed through regions where the porosity is high. Comparison between the experimental and numerical results in terms of pressure distributions at different flow injection rates will be conducted. Comparison of flow phenomena under terrestrial gravity and microgravity will be made.

The volumetric flux through Deception Pass, Washington and its effects on the circulation in the Whidbey Basin.

NASA Astrophysics Data System (ADS)

Heinze, K. R.

2002-05-01

The volumetric flux through Deception Pass, Washington will be determined by using tidal height differences between Bowman and Cornet Bays, which are located on the seaward and landward sides of Deception Pass respectively in Deception Pass State Park. Hydrolab sensors for measuring temperature, salinity and fluid depth will be attached to public boat docks in each of these bays. The numerical Puget Sound Regional Synthesis Model, PRISM, will be run with and without the flux through Deception Pass and compared to determine theoretically whether or not the flow through Deception Pass plays a significant role in the circulation of the Whidbey Basin, which could affect the circulation in the northern part of the Main Basin known as the Triple Junction. This could influence water movement near the new sewer outfall that King County is proposing to build in that area.

Coolant monitoring apparatus for nuclear reactors

DOEpatents

Tokarz, Richard D.

1983-01-01

A system for monitoring coolant conditions within a pressurized vessel. A length of tubing extends outward from the vessel from an open end containing a first line restriction at the location to be monitored. The flowing fluid is cooled and condensed before passing through a second line restriction. Measurement of pressure drop at the second line restriction gives an indication of fluid condition at the first line restriction. Multiple lengths of tubing with open ends at incremental elevations can measure coolant level within the vessel.

Energy transfer between a passing vortex ring and a flexible plate in an ideal quiescent fluid

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

Hu, JiaCheng; Peterson, Sean D., E-mail: peterson@mme.uwaterloo.ca; Porfiri, Maurizio

Recent advancements in highly deformable smart materials have lead to increasing interest in small-scale energy harvesting research for powering low consumption electronic devices. One such recent experimental study by Goushcha et al. explored energy harvesting from a passing vortex ring by a cantilevered smart material plate oriented parallel to and offset from the path of the ring in an otherwise quiescent fluid. The present study focuses on modeling this experimental study using potential flow to facilitate optimization of the energy extraction from the passing ring to raise the energy harvesting potential of the device. The problem is modeled in two-dimensionsmore » with the vortex ring represented as a pair of counter-rotating free vortices. Vortex pair parameters are determined to match the convection speed of the ring in the experiments, as well as the imposed pressure loading on the plate. The plate is approximated as a Kirchhoff-Love plate and represented as a finite length vortex sheet in the fluid domain. The analytical model matches experimental measurements, including the tip displacement, the integrated force along the entire plate length as a function of vortex ring position, and the pressure along the plate. The potential flow solution is employed in a parametric study of the governing dimensionless parameters in an effort to guide the selection of plate properties for optimal energy harvesting performance. Results of the study indicate an optimal set of plate properties for a given vortex ring configuration, in which the time-scale of vortex advection matches that of the plate vibration.« less

Mechanical membrane for the separation of a paramagnetic constituent from a fluid

DOEpatents

Maurice, David

2017-05-02

The disclosure provides an apparatus and method for the separation of a paramagnetic component from a mixture using a mechanical membrane apparatus. The mechanical membrane comprises a supporting material having a plurality of pores where each pore is surrounded by a plurality of magnetic regions. The magnetic regions augment a magnetic field on one side of the supporting material while mitigating the field to near zero on the opposite side. In operation, a flow of fluid such as air comprising a paramagnetic component such as O.sub.2 is directed toward the mechanical membrane, and the paramagnetic component is typically attracted toward a magnetic field surrounding a pore while dimagnetic components such as N.sub.2 are generally repelled. As some portion of the fluid passes through the plurality of magnetic apertures to the opposite side of the mechanical membrane, the mechanical membrane generates a fluid enriched in the paramagnetic component. Alternately, the magnetic field may act to repel the paramagnetic component while diamagnetic components such as N.sub.2 are generally unaffected and pass to the opposite side of the mechanical membrane.

Fluid mechanics relevant to flow through pretreatment of cellulosic biomass.

PubMed

Archambault-Léger, Véronique; Lynd, Lee R

2014-04-01

The present study investigates fluid mechanical properties of cellulosic feedstocks relevant to flow through (FT) pretreatment for biological conversion of cellulosic biomass. The results inform identifying conditions for which FT pretreatment can be implemented in a practical context. Measurements of pressure drop across packed beds, viscous compaction and water absorption are reported for milled and not milled sugarcane bagasse, switchgrass and poplar, and important factors impacting viscous flow are deduced. Using biomass knife-milled to pass through a 2mm sieve, the observed pressure drop was highest for bagasse, intermediate for switchgrass and lowest for poplar. The highest pressure drop was associated with the presence of more fine particles, greater viscous compaction and the degree of water absorption. Using bagasse without particle size reduction, the instability of the reactor during pretreatment above 140kg/m(3) sets an upper bound on the allowable concentration for continuous stable flow. Copyright © 2014. Published by Elsevier Ltd.

Ultrasound Thermal Field Imaging of Opaque Fluids

NASA Technical Reports Server (NTRS)

Andereck, C. David

1999-01-01

We have initiated an experimental program to develop an ultrasound system for non-intrusively imaging the thermal field in opaque fluids under an externally imposed temperature gradient. Many industrial processes involve opaque fluids, such as molten metals, semiconductors, and polymers, often in situations in which thermal gradients are important. For example, one may wish to understand semiconductor crystal growth dynamics in a Bridgman apparatus. Destructive testing of the crystal after the process is completed gives only indirect information about the fluid dynamics of the formation process. Knowledge of the coupled thermal and velocity fields during the growth process is then essential. Most techniques for non-intrusive velocity and temperature measurement in fluids are optical in nature, and hence the fluids studied must be transparent. In some cases (for example, LDV (laser Doppler velocimetry) and PIV (particle imaging velocimetry)) the velocities of small neutrally buoyant seed particles suspended in the fluid, are measured. Without particle seeding one can use the variation of the index of refraction of the fluid with temperature to visualize, through interferometric, Schlieren or shadowgraph techniques, the thermal field. The thermal field in turn gives a picture of the pattern existing in the fluid. If the object of study is opaque, non-optical techniques must be used. In this project we focus on the use of ultrasound, which propagates easily through opaque liquids and solids. To date ultrasound measurements have almost exclusively relied on the detection of sound scattered from density discontinuities inside the opaque material of interest. In most cases it has been used to visualize structural properties, but more recently the ultrasound Doppler velocimeter has become available. As in the optical case, it relies on seed particles that scatter Doppler shifted sound back to the detector. Doppler ultrasound techniques are, however, not useful for studying convective fluid flow in crystal growth, because particle seeding is unacceptable and flow velocities are typically too low to be resolved, and may be even lower in microgravity conditions where buoyancy forces are negligible. We will investigate a different use of ultrasound to probe the flows of opaque fluids non-intrusively and without the use of seed particles: our goal is to ultrasonically visualize the thermal field of opaque fluids with relatively high spatial resolution. The proposed technique relies upon the variation of sound speed with temperature of the fluid. A high frequency ultra-sound pulse passing through a fluid-filled chamber will traverse the chamber in a time determined by the relevant chamber dimension and the temperature of the fluid through which the pulse passes. With high time-resolution instrumentation that compares the excitation signal with the received pulse we can detect the influence of the fluid temperature on the pulse travel time. This is effectively an interferometric system, which in its optical form is an extremely sensitive approach to measuring thermal fields in fluids. Moreover, the temperature dependence of sound velocity in liquid metals is comparable to the temperature dependence of the speed of light required for accurate interferometric thermal images in transparent fluids. With an array of transducers scanned electronically a map of the thermal field over the chamber could be produced. An alternative approach would be to use the ultrasound analog of the shadowgraph technique. In the optical version, collimated light passes through the fluid, where it is focused or defocused locally by temperature field induced variations of the index of refraction. The resulting image reveals the thermal field through the spatial pattern of light intensity variations. By analogy, an ultrasound plane wave traversing an opaque fluid sample would be also locally focused or defocused depending on the speed of sound variations, giving rise to spatial variations in sound intensity that will reveal the thermal field pattern. These approaches could be applied to any situation in which temperature differences are expected to occur, and will rapidly provide information about the flow that simply cannot be obtained by any current intrusive or non-intrusive diagnostic technique. As materials processing in microgravity matures it will become increasingly important to have available simple and versatile diagnostic tools, such as we will develop, for studying the flows of opaque fluids under thermal forcing.

Calibration, Data Acquisition, and Post Analysis of Turbulent Fluid Flow in a Calibration Jet Using Hot-wire Anemometry

NASA Technical Reports Server (NTRS)

Moreno, Michelle

2004-01-01

The Turbine Branch concentrates on the following areas: Computational Fluid Dynamics (CFD), and implementing experimental procedures to obtain physical modeling data. Hot-wire Anemometry is a valuable tool for obtaining physical modeling data. Hot-wire Anemometry is likely to remain the principal research tool for most turbulent air/gas flow studies. The Hot-wire anemometer consists of a fine wire heated by electric current. When placed in a fluid stream, the hot-wire loses heat to the fluid by forced convection. In forced convection, energy transfer is due to molecular motion imposed by an extraneous force moving fluid parcels. When the hot-wire is in "equilibrium", the rate of heat input to the wire is equal to the rate of heat loss at the wire ends. The equality between heat input and heat loss is the basis for King s equation, which relates the electrical parameters of the hot-wire to the flow parameters of the fluid. Hot-wire anemometry is based on convective heat transfer from a heated wire element placed in a fluid flow. Any change in the fluid flow condition that affects the heat transfer from the heated element will be detected virtually instantaneously by a constant-temperature Hot-wire anemometry system. The system implemented for this research is the IFA 300. The system is a fully-integrated, thermal anemometer-based system that measures mean and fluctuating velocity components in air, water, and other fluids. It also measures turbulence and makes localized temperature measurements. A constant-temperature anemometer is a bridge and amplifier circuit that controls a tiny wire at constant temperature. As a fluid flow passes over the heated sensor, the amplifier senses the bridge off-balance and adjusts the voltage to the top of the bridge, keeping the bridge in balance. The voltage on top of the bridge can then be related to the velocity of the flow. The bridge voltage is sensitive to temperature as well as velocity and so the built-in thermocouple circuit can be attached to a thermocouple that can measure the fluid temperature. Additional information is included in the original extended abstract.

Play-fairway analysis for geothermal exploration: Examples from the Great Basin, western USA

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

Siler, Drew L; Faulds, James E

2013-10-27

Elevated permeability within fault systems provides pathways for circulation of geothermal fluids. Future geothermal development depends on precise and accurate location of such fluid flow pathways in order to both accurately assess geothermal resource potential and increase drilling success rates. The collocation of geologic characteristics that promote permeability in a given geothermal system define the geothermal ‘fairway’, the location(s) where upflow zones are probable and where exploration efforts including drilling should be focused. We define the geothermal fairway as the collocation of 1) fault zones that are ideally oriented for slip or dilation under ambient stress conditions, 2) areas withmore » a high spatial density of fault intersections, and 3) lithologies capable of supporting dense interconnected fracture networks. Areas in which these characteristics are concomitant with both elevated temperature and fluids are probable upflow zones where economic-scale, sustainable temperatures and flow rates are most likely to occur. Employing a variety of surface and subsurface data sets, we test this ‘play-fairway’ exploration methodology on two Great Basin geothermal systems, the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These analyses, based on 3D structural and stratigraphic framework models, reveal subsurface characteristics about each system, well beyond the scope of standard exploration methods. At Brady’s, the geothermal fairways we define correlate well with successful production wells and pinpoint several drilling targets for maintaining or expanding production in the field. In addition, hot-dry wells within the Brady’s geothermal field lie outside our defined geothermal fairways. At Astor Pass, our play-fairway analysis provides for a data-based conceptual model of fluid flow within the geothermal system and indicates several targets for exploration drilling.« less

Contributions Regarding the Aircraft Nuclear Propulsion

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

Mitrica, Bogdan; Petre, Marian; Dima, Mihai Octavian

2010-01-21

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor's core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle, where the energy transfer should be performed by a heat exchanger that must work at very high speed of the fluid. The heat exchanger will replace the classical burning room. We had performed a more precise theoretical study for themore » nuclear jet engine regarding the performances of the nuclear reactor, of the heat exchanger and of the jet engine. It was taken in to account that in the moment when the burning room is replaced by a heat exchanger, a new model for gasodynamic process from the engine must be performed. Studies regarding the high flow speed heat transfer were performed.« less

Investigation of wind behaviour around high-rise buildings

NASA Astrophysics Data System (ADS)

Mat Isa, Norasikin; Fitriah Nasir, Nurul; Sadikin, Azmahani; Ariff Hairul Bahara, Jamil

2017-09-01

A study on the investigation of wind behaviour around the high-rise buildings is done through an experiment using a wind tunnel and computational fluid dynamics. High-rise buildings refer to buildings or structures that have more than 12 floors. Wind is invisible to the naked eye; thus, it is hard to see and analyse its flow around and over buildings without the use of proper methods, such as the use of wind tunnel and computational fluid dynamics software.The study was conducted on buildings located in Presint 4, Putrajaya, Malaysia which is the Ministry of Rural and Regional Development, Ministry of Information Communications and Culture, Ministry of Urban Wellbeing, Housing and Local Government and the Ministry of Women, Family, and Community by making scaled models of the buildings. The parameters in which this study is conducted on are, four different wind velocities used based on the seasonal monsoons, and wind direction. ANSYS Fluent workbench software is used to compute the simulations in order to achieve the objectives of this study. The data from the computational fluid dynamics are validated with the experiment done through the wind tunnel. From the results obtained through the use of the computation fluid dynamics, this study can identify the characteristics of wind around buildings, including boundary layer of the buildings, separation flow, wake region and etc. Then analyses is conducted on the occurance resulting from the wind that passes the buildings based on the velocity difference between before and after the wind passes the buildings.

Cryogenic Flow Sensor

NASA Technical Reports Server (NTRS)

Justak, John

2010-01-01

An acousto-optic cryogenic flow sensor (CFS) determines mass flow of cryogens for spacecraft propellant management. The CFS operates unobtrusively in a high-pressure, high-flowrate cryogenic environment to provide measurements for fluid quality as well as mass flow rate. Experimental hardware uses an optical plane-of-light (POL) to detect the onset of two-phase flow, and the presence of particles in the flow of water. Acousto-optic devices are used in laser equipment for electronic control of the intensity and position of the laser beam. Acousto-optic interaction occurs in all optical media when an acoustic wave and a laser beam are present. When an acoustic wave is launched into the optical medium, it generates a refractive index wave that behaves like a sinusoidal grating. An incident laser beam passing through this grating will diffract the laser beam into several orders. Its angular position is linearly proportional to the acoustic frequency, so that the higher the frequency, the larger the diffracted angle. If the acoustic wave is traveling in a moving fluid, the fluid velocity will affect the frequency of the traveling wave, relative to a stationary sensor. This frequency shift changes the angle of diffraction, hence, fluid velocity can be determined from the diffraction angle. The CFS acoustic Bragg grating data test indicates that it is capable of accurately determining flow from 0 to 10 meters per second. The same sensor can be used in flow velocities exceeding 100 m/s. The POL module has successfully determined the onset of two-phase flow, and can distinguish vapor bubbles from debris.

Noise Production of an Idealized Two-Dimensional Fish School

NASA Astrophysics Data System (ADS)

Wagenhoffer, Nathan; Moored, Keith; Jaworski, Justin

2017-11-01

The analysis of quiet bio-inspired propulsive concepts requires a rapid, unified computational framework that integrates the coupled fluid-solid dynamics of swimmers and their wakes with the resulting noise generation. Such a framework is presented for two-dimensional flows, where the fluid motion is modeled by an unsteady boundary element method with a vortex-particle wake. The unsteady surface forces from the potential flow solver are then passed to an acoustic boundary element solver to predict the radiated sound in low-Mach-number flows. The coupled flow-acoustic solver is validated against canonical vortex-sound problems. A diamond arrangement of four airfoils are subjected to traveling wave kinematics representing a known idealized pattern for a school of fish, and the airfoil motion and inflow values are derived from the range of Strouhal values common to many natural swimmers. The coupled flow-acoustic solver estimates and analyzes the hydrodynamic performance and noise production of the idealized school of swimmers.

Structural cooling fluid tube for supporting a turbine component and supplying cooling fluid to transition section

DOEpatents

Charron, Richard; Pierce, Daniel

2015-08-11

A shaft cover support for a gas turbine engine is disclosed. The shaft cover support not only provides enhanced support to a shaft cover of the gas turbine engine, but also includes a cooling fluid chamber for passing fluids from a rotor air cooling supply conduit to an inner ring cooling manifold. Furthermore, the shaft cover support may include a cooling shield supply extending from the cooling fluid chamber between the radially outward inlet and the radially inward outlet on the radially extending region and in fluid communication with the cooling fluid chamber for providing cooling fluids to a transition section. The shaft cover support may also provide additional stiffness and reduce interference of the flow from the compressor. In addition, the shaft cover support accommodates a transition section extending between compressor and turbine sections of the gas turbine engine.

Systems and methods for separating particles and/or substances from a sample fluid

DOEpatents

Mariella, Jr., Raymond P.; Dougherty, George M.; Dzenitis, John M.; Miles, Robin R.; Clague, David S.

2016-11-01

Systems and methods for separating particles and/or toxins from a sample fluid. A method according to one embodiment comprises simultaneously passing a sample fluid and a buffer fluid through a chamber such that a fluidic interface is formed between the sample fluid and the buffer fluid as the fluids pass through the chamber, the sample fluid having particles of interest therein; applying a force to the fluids for urging the particles of interest to pass through the interface into the buffer fluid; and substantially separating the buffer fluid from the sample fluid.

3D printed modular centrifugal contactors and method for separating moieties using 3D printed optimized surfaces

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

Wardle, Kent E.

The present invention provides an annular centrifugal contactor, having a housing to receive a plurality of liquids; a rotor inside the housing; an annular mixing zone, with a plurality of fluid retention reservoirs; and an adjustable stem that can be raised to restrict the flow of a liquid into the rotor or lowered to increase the flow of liquid into the rotor. The invention also provides a method for transferring moieties from a first liquid to a second liquid, the method having the steps of combining the fluids in a housing whose interior has helically shaped first channels; subjecting themore » fluids to a spinning rotor to produce a mixture, whereby the channels simultaneously conduct the mixture downwardly and upwardly; and passing the mixture through the rotor to contact second channels, whereby the channels pump the second liquid through a first aperture while the first fluid exits a second aperture.« less

Noise optimization of a regenerative automotive fuel pump

NASA Astrophysics Data System (ADS)

Wang, J. F.; Feng, H. H.; Mou, X. L.; Huang, Y. X.

2017-03-01

The regenerative pump used in automotive is facing a noise problem. To understand the mechanism in detail, Computational Fluid Dynamics (CFD) and Computational Acoustic Analysis (CAA) together were used to understand the fluid and acoustic characteristics of the fuel pump using ANSYS-CFX 15.0 and LMS Virtual. Lab Rev12, respectively. The CFD model and acoustical model were validated by mass flow rate test and sound pressure test, respectively. Comparing the computational and experimental results shows that sound pressure levels at the observer position are consistent at high frequencies, especially at blade passing frequency. After validating the models, several numerical models were analyzed in the study for noise improvement. It is observed that for configuration having greater number of impeller blades, noise level was significantly improved at blade passing frequency, when compared to that of the original model.

Investigation of SSME alternate high pressure fuel turbopump lift-off seal fluid and structural dynamic interaction

NASA Technical Reports Server (NTRS)

Elrod, David A.

1989-01-01

The Space Shuttle main engine (SSME) alternate turbopump development program (ATD) high pressure fuel turbopump (HPFTP) design utilizes an innovative lift-off seal (LOS) design that is located in close proximity to the turbine end bearing. Cooling flow exiting the bearing passes through the lift-off seal during steady state operation. The potential for fluid excitation of lift-off seal structural resonances is investigated. No fluid excitation of LOS resonances is predicted. However, if predicted LOS natural frequencies are significantly lowered by the presence of the coolant, pressure oscillations caused by synchronous whirl of the HPFTP rotor may excite a resonance.

Deriving a blood-mimicking fluid for particle image velocimetry in Sylgard-184 vascular models.

PubMed

Yousif, Majid Y; Holdsworth, David W; Poepping, Tamie L

2009-01-01

A new blood-mimicking fluid (BMF) has been developed for particle image velocimetry (PIV), which enables flow studies in vascular models (phantoms). A major difficulty in PIV that affects measurement accuracy is the refraction and distortion of light passing through the interface between the model and the fluid, due to the difference in refractive index (n) between the two materials. The problem can be eliminated by using a fluid with a refractive index matching that of the model. Such fluids are not commonly available, especially for vascular research where the fluid should also have a viscosity similar to human blood. In this work, a blood-mimicking fluid, composed of water (47.38% by weight), glycerol (36.94% by weight) and sodium iodide salt (15.68% by weight), was developed for compatibility with our silicone (Sylgard 184; n = 1.414) phantoms. The fluid exhibits a dynamic viscosity of 4.31+/-0.03 cP which lies within the range of human blood viscosity (4.4+/-0.6 cP). Both refractive index and viscosity were attained at 22.2+/-0.2 degrees C, which is a feasible room temperature, thus eliminating the need for a temperature-control system. The fluid will be used to study hemodynamics in vascular flow models fabricated from Sylgard 184.

Porous plug for reducing orifice induced pressure error in airfoils

NASA Technical Reports Server (NTRS)

Plentovich, Elizabeth B. (Inventor); Gloss, Blair B. (Inventor); Eves, John W. (Inventor); Stack, John P. (Inventor)

1988-01-01

A porous plug is provided for the reduction or elimination of positive error caused by the orifice during static pressure measurements of airfoils. The porous plug is press fitted into the orifice, thereby preventing the error caused either by fluid flow turning into the exposed orifice or by the fluid flow stagnating at the downstream edge of the orifice. In addition, the porous plug is made flush with the outer surface of the airfoil, by filing and polishing, to provide a smooth surface which alleviates the error caused by imperfections in the orifice. The porous plug is preferably made of sintered metal, which allows air to pass through the pores, so that the static pressure measurements can be made by remote transducers.

Convective fluid flow through the paracellular system of Necturus gall-bladder epithelium as revealed by dextran probes.

PubMed Central

Shachar-Hill, B; Hill, A E

1993-01-01

1. Bidirectional paracellular fluxes using radioactive dextrans as inert molecular probes have been measured across Necturus gall-bladder epithelium during conditions of normal fluid absorption. There is a net flux at all radii analysed (0.4-2.2 nm) in the direction of fluid absorption. 2. The net flux is substantial at all radii within the range. The data extraplate to 2 x 10(-6) cm s-1 at zero probe radius, which is very close to the rate of epithelial fluid absorption. 3. The unstirred layers at the epithelial faces during transport have been determined; their contribution to the net fluxes is negligible. 4. Two possible mechanisms for the net flow of probes are considered: (i) that the probes diffuse across the junctions and are then entrained in a local osmotic flow along the interspaces and subepithelium; (ii) that the probes are entrained in volume flow across the junctions and the emergent solution subsequently passes through the interspaces and subepithelium. Model calculations clearly rule out mechanism (i) in which the maximum net flow obtainable is less than 10% of that observed. In addition the presence of leak paths shunting the junctions is not compatible with the observed fluxes. With mechanism (ii) the net flows are correctly predicted with all the fluid flow being transjunctional. The fluid absorption is therefore entirely paracellular. 5. The slope of the net flow curve shows no apparent change in magnitude over the range of the probe radii, indicating that effectively only one population of convective channels is present with parallel walls separated by about 7.7 nm. This agrees with the width previously determined by electron microscopy. 6. If the fluid absorption is junctional then the cellular route offers little if any relative contribution. The hydraulic conductivity of the junctions is not high enough, or the osmotic permeability of the membranes low enough, to accommodate this by osmosis and therefore the junctional fluid absorption must be non-osmotic. Images Fig. 1 Fig. 4 PMID:7504731

Convective heater

DOEpatents

Thorogood, Robert M.

1986-01-01

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

Convective heater

DOEpatents

Thorogood, Robert M.

1983-01-01

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation.

Convective heater

DOEpatents

Thorogood, R.M.

1983-12-27

A convective heater for heating fluids such as a coal slurry is constructed of a tube circuit arrangement which obtains an optimum temperature distribution to give a relatively constant slurry film temperature. The heater is constructed to divide the heating gas flow into two equal paths and the tube circuit for the slurry is arranged to provide a mixed flow configuration whereby the slurry passes through the two heating gas paths in successive co-current, counter-current and co-current flow relative to the heating gas flow. This arrangement permits the utilization of minimum surface area for a given maximum film temperature of the slurry consistent with the prevention of coke formation. 14 figs.

Electrochemical cell for rebalancing REDOX flow system

NASA Technical Reports Server (NTRS)

Thaller, L. H. (Inventor)

1979-01-01

An electrically rechargeable REDOX cell or battery system including one of more rebalancing cells is described. Each rebalancing cell is divided into two chambers by an ion permeable membrane. The first chamber is fed with gaseous hydrogen and a cathode fluid which is circulated through the cathode chamber of the REDOX cell is also passed through the second chamber of the rebalancing cell. Electrochemical reactions take place on the surface of insert electrodes in the first and second chambers to rebalance the electrochemical capacity of the anode and cathode fluids of the REDOX system.

Optical elements formed by compressed gases: Analysis and potential applications

NASA Technical Reports Server (NTRS)

Howes, W. L.

1986-01-01

Spherical, cylindrical, and conical shock waves are optically analogous to gas lenses. The geometrical optics of these shock configurations are analyzed as they pertain to flow visualization instruments, particularly the rainbow schlieren apparatus and single-pass interferometers. It is proposed that a lens or mirror formed by gas compressed between plastic sheets has potential as a fluid visualization test object; as the objective mirror in a very large space-based telescope, communication antenna, or energy collector; as the objective mirror in inexpensive commercial telescopes; and as a component in fluid visualization apparatuses.

Numerical investigations on the effect of slenderness ratio of matrix elements in cryogenic chill down process

NASA Astrophysics Data System (ADS)

Reby Roy, K. E.; Mohammed, Jesna; Abhiroop, V. M.; Thekkethil, S. R.

2017-02-01

Cryogenic fluids have many applications in space, medicine, preservation etc. The chill-down of cryogenic fluid transfer line is a complicated phenomenon occurring in most of the cryogenic systems. The cryogenic fluid transfer line, which is initially at room temperature, has to be cooled to the temperature of the cryogen as fast as possible. When the cryogenic fluid at liquid state passes along the line, transient heat transfer between the cryogen and the transfer line causes voracious evaporation of the liquid. This paper makes a contribution to the two-phase flow along a rectangular flow passage consisting of an array of elliptically shaped matrix elements. A simplified 2D model is considered and the problem is solved using ANSYS FLUENT. The present analysis aims to study the influence of the slenderness ratio of matrix elements on the heat transfer rate and chill down time. For a comparative study, matrix elements of slenderness ratios 5 and 10 are considered. Liquid nitrogen at 74K flows through the matrix. The material of the transfer line is assumed to be aluminium which is initially at room temperature. The influence of Reynolds numbers from 800 to 3000 on chill-down is also investigated.

Rotary adsorbers for continuous bulk separations

DOEpatents

Baker, Frederick S [Oak Ridge, TN

2011-11-08

A rotary adsorber for continuous bulk separations is disclosed. The rotary adsorber includes an adsorption zone in fluid communication with an influent adsorption fluid stream, and a desorption zone in fluid communication with a desorption fluid stream. The fluid streams may be gas streams or liquid streams. The rotary adsorber includes one or more adsorption blocks including adsorbent structure(s). The adsorbent structure adsorbs the target species that is to be separated from the influent fluid stream. The apparatus includes a rotary wheel for moving each adsorption block through the adsorption zone and the desorption zone. A desorption circuit passes an electrical current through the adsorbent structure in the desorption zone to desorb the species from the adsorbent structure. The adsorbent structure may include porous activated carbon fibers aligned with their longitudinal axis essentially parallel to the flow direction of the desorption fluid stream. The adsorbent structure may be an inherently electrically-conductive honeycomb structure.

Unified description of the slip phenomena in sheared polymer films: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Priezjev, Nikolai

2010-03-01

The dynamic behavior of the slip length in shear flow of polymer melts past atomically smooth surfaces is investigated using MD simulations. The polymer melt was modeled as a collection of FENE-LJ bead-spring chains. We consider shear flow conditions at low pressures and weak wall-fluid interaction energy so that fluid velocity profiles are linear throughout the channel at all shear rates examined. In agreement with earlier studies we confirm that for shear- thinning fluids the slip length passes through a local minimum at low shear rates and then increases rapidly at higher shear rates. We found that the rate dependence of the slip length depends on the lattice orientation at high shear rates. The MD results show that the ratio of slip length to viscosity follows a master curve when plotted as a function of a single variable that depends on the structure factor, contact density and temperature of the first fluid layer near the solid wall. The universal dependence of the slip length holds for a number of parameters of the interface: fluid density and structure (chain length), wall-fluid interaction energy, wall density, lattice orientation, thermal or solid walls.

Optimum periodicity of repeated contractile actions applied in mass transport

NASA Astrophysics Data System (ADS)

Ahn, Sungsook; Lee, Sang Joon

2015-01-01

Dynamically repeated periodic patterns are abundant in natural and artificial systems, such as tides, heart beats, stock prices, and the like. The characteristic repeatability and periodicity are expected to be optimized in effective system-specific functions. In this study, such optimum periodicity is experimentally evaluated in terms of effective mass transport using one-valve and multi-valve systems working in contractile fluid flows. A set of nanoscale gating functions is utilized, operating in nanocomposite networks through which permeates selectively pass under characteristic contractile actions. Optimized contractile periodicity exists for effective energy impartment to flow in a one-valve system. In the sequential contractile actions for a multi-valve system, synchronization with the fluid flow is critical for effective mass transport. This study provides fundamental understanding on the various repeated periodic patterns and dynamic repeatability occurring in nature and mechanical systems, which are useful for broad applications.

Adjustable Pitot Probe

NASA Technical Reports Server (NTRS)

Ashby, George C., Jr.; Robbins, W. Eugene; Horsley, Lewis A.

1991-01-01

Probe readily positionable in core of uniform flow in hypersonic wind tunnel. Formed of pair of mating cylindrical housings: transducer housing and pitot-tube housing. Pitot tube supported by adjustable wedge fairing attached to top of pitot-tube housing with semicircular foot. Probe adjusted both radially and circumferentially. In addition, pressure-sensing transducer cooled internally by water or other cooling fluid passing through annulus of cooling system.

Basic fluid system trainer

DOEpatents

Semans, Joseph P.; Johnson, Peter G.; LeBoeuf, Jr., Robert F.; Kromka, Joseph A.; Goron, Ronald H.; Hay, George D.

1993-01-01

A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.

Combuster. [low nitrogen oxide formation

NASA Technical Reports Server (NTRS)

Mckay, R. A. (Inventor)

1978-01-01

A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

Connection between encounter volume and diffusivity in geophysical flows

NASA Astrophysics Data System (ADS)

Rypina, Irina I.; Smith, Stefan G. Llewellyn; Pratt, Larry J.

2018-04-01

Trajectory encounter volume - the volume of fluid that passes close to a reference fluid parcel over some time interval - has been recently introduced as a measure of mixing potential of a flow. Diffusivity is the most commonly used characteristic of turbulent diffusion. We derive the analytical relationship between the encounter volume and diffusivity under the assumption of an isotropic random walk, i.e., diffusive motion, in one and two dimensions. We apply the derived formulas to produce maps of encounter volume and the corresponding diffusivity in the Gulf Stream region of the North Atlantic based on satellite altimetry, and discuss the mixing properties of Gulf Stream rings. Advantages offered by the derived formula for estimating diffusivity from oceanographic data are discussed, as well as applications to other disciplines.

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.

Fast fluidized bed steam generator

DOEpatents

Bryers, Richard W.; Taylor, Thomas E.

1980-01-01

A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

Corrosion test cell for bipolar plates

DOEpatents

Weisbrod, Kirk R.

2002-01-01

A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

Laser beam micro-milling of nickel alloy: dimensional variations and RSM optimization of laser parameters

NASA Astrophysics Data System (ADS)

Ahmed, Naveed; Alahmari, Abdulrahman M.; Darwish, Saied; Naveed, Madiha

2016-12-01

Micro-channels are considered as the integral part of several engineering devices such as micro-channel heat exchangers, micro-coolers, micro-pulsating heat pipes and micro-channels used in gas turbine blades for aerospace applications. In such applications, a fluid flow is required to pass through certain micro-passages such as micro-grooves and micro-channels. The fluid flow characteristics (flow rate, turbulence, pressure drop and fluid dynamics) are mainly established based on the size and accuracy of micro-passages. Variations (oversizing and undersizing) in micro-passage's geometry directly affect the fluid flow characteristics. In this study, the micro-channels of several sizes are fabricated in well-known aerospace nickel alloy (Inconel 718) through laser beam micro-milling. The variations in geometrical characteristics of different-sized micro-channels are studied under the influences of different parameters of Nd:YAG laser. In order to have a minimum variation in the machined geometries of each size of micro-channel, the multi-objective optimization of laser parameters has been carried out utilizing the response surface methodology approach. The objective was set to achieve the targeted top widths and depths of micro-channels with minimum degree of taperness associated with the micro-channel's sidewalls. The optimized sets of laser parameters proposed for each size of micro-channel can be used to fabricate the micro-channels in Inconel 718 with minimum amount of geometrical variations.

Advanced ballistic range technology

NASA Technical Reports Server (NTRS)

Yates, Leslie A.

1993-01-01

Experimental interferograms, schlieren, and shadowgraphs are used for quantitative and qualitative flow-field studies. These images are created by passing light through a flow field, and the recorded intensity patterns are functions of the phase shift and angular deflection of the light. As part of the grant NCC2-583, techniques and software have been developed for obtaining phase shifts from finite-fringe interferograms and for constructing optical images from Computational Fluid Dynamics (CFD) solutions. During the period from 1 Nov. 1992 - 30 Jun. 1993, research efforts have been concentrated in improving these techniques.

Thermal-hydraulic behavior of Sc-C02 in a horizontal circular straight tube

NASA Astrophysics Data System (ADS)

Tanimizu, Katsuyoshi; Sadr, Reza; Ranjan, Davesh

2011-11-01

Fluids above critical pressure have been practically utilized for 60 years in many applications and their use and interest is still increasing in many areas, especially power generation industries and chemical industries. Above critical pressure, very rapid changes in thermophysical properties take place near the pseudocritical temperature. In this region, the fluid transforms from liquid-like to gas-like behavior when the fluid temperature rises up and passes through the pseudocritical temperature. This allows enormous potential for energy transfer, but also alters the turbulent flow due to changes in the turbulent shear stress brought about by acceleration and buoyancy effects. However, we have not fully understood their dynamic behaviors such as turbulence yet. A supercritical CO2 testing loop has been built at Texas A&M University at Qatar to perform heat transfer and pressure drop measurements and investigate the thermo-physical and dynamic characteristics of supercritical carbon dioxide flow. The results of heat transfer measurements in a super critical fluid conducted in a horizontal pipe are reported and discussed here. Supported by QNRF.

Magnus Effect: An Overview of Its Past and Future Practical Applications. Volumes 1 and 2

DTIC Science & Technology

1986-01-01

bearings to which he could impart a high speed of rotation by means of a string, in the fashion of a boy spinning a top Lo _ (Figure 1). He mounted the...34. the fluid flow. As the shafts pass this transverse porn . 290/55 tion, a torque is developed by the rotating cylinder that (56] eeea ie rotates the

Control of Flowing Liquid Films by Electrostatic Fields in Space

NASA Technical Reports Server (NTRS)

Griffing, E. M.; Bankoff, S. G.; Schluter, R. A.; Miksis, M. J.

1999-01-01

The interaction of a spacially varying electric field and a flowing thin liquid film is investigated experimentally for the design of a proposed light weight space radiator. Electrodes are utilized to create a negative pressure at the bottom of a fluid film and suppress leaks if a micrometeorite punctures the radiator surface. Experimental pressure profiles under a vertical falling film, which passes under a finite electrode, show that fields of sufficient strength can be used safely in such a device. Leak stopping experiments demonstrate that leaks can be stopped with an electric field in earth gravity. A new type of electrohydrodynamic instability causes waves in the fluid film to develop into 3D cones and touch the electrode at a critical voltage. Methods previously used to calculate critical voltages for non moving films are shown to be inappropriate for this situation. The instability determines a maximum field which may be utilized in design, so the possible dependence of critical voltage on electrode length, height above the film, and fluid Reynolds number is discussed.

A 3D, fully Eulerian, VOF-based solver to study the interaction between two fluids and moving rigid bodies using the fictitious domain method

NASA Astrophysics Data System (ADS)

Pathak, Ashish; Raessi, Mehdi

2016-04-01

We present a three-dimensional (3D) and fully Eulerian approach to capturing the interaction between two fluids and moving rigid structures by using the fictitious domain and volume-of-fluid (VOF) methods. The solid bodies can have arbitrarily complex geometry and can pierce the fluid-fluid interface, forming contact lines. The three-phase interfaces are resolved and reconstructed by using a VOF-based methodology. Then, a consistent scheme is employed for transporting mass and momentum, allowing for simulations of three-phase flows of large density ratios. The Eulerian approach significantly simplifies numerical resolution of the kinematics of rigid bodies of complex geometry and with six degrees of freedom. The fluid-structure interaction (FSI) is computed using the fictitious domain method. The methodology was developed in a message passing interface (MPI) parallel framework accelerated with graphics processing units (GPUs). The computationally intensive solution of the pressure Poisson equation is ported to GPUs, while the remaining calculations are performed on CPUs. The performance and accuracy of the methodology are assessed using an array of test cases, focusing individually on the flow solver and the FSI in surface-piercing configurations. Finally, an application of the proposed methodology in simulations of the ocean wave energy converters is presented.

High temperature helical tubular receiver for concentrating solar power system

NASA Astrophysics Data System (ADS)

Hossain, Nazmul

In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional receivers. The helical tubular solar receiver placed at the focused sunlight region meets the higher outlet temperature and efficiency. A vertical tubular receiver is modeled and analyzed for single phase flow with molten salt as heat transfer fluid and alloy625 as heat transfer material. The result is compared to a journal paper of similar numerical and experimental setup for validating our modeling. New types of helical tubular solar receivers are modeled and analyzed with heat transfer fluid turbulent flow in single phase, and granular particle and air plug flow in multiphase to observe the temperature rise in one cyclic operation. The Discrete Ordinate radiation model is used for numerical analysis with simulation software Ansys Fluent 15.0. The Eulerian granular multiphase model is used for multiphase flow. Applying the same modeling parameters and boundary conditions, the results of vertical and helical receivers are compared. With a helical receiver, higher temperature gain of heat transfer fluid is achieved in one cycle for both single phase and multiphase flow compared to the vertical receiver. Performance is also observed by varying dimension of helical receiver.

Concurrent studies of the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves. 3. Further studies on the addition of fat to skim milk and the use of non-milk proteins in milk-substitute diets.

PubMed

Ternouth, J H; Roy, J H; Thompson, S Y; Toothill, J; Gillies, C M; Edward-Webb, J D

1975-03-01

1. The flow of digesta through the duodenum and the concurrent secretion of the pancreas were studied in four Friesian calves given four milk-substitute diets. The diets were: reconstituted, "mildly" pre-heated, spray-dried skim-milk powder with (SKF) or without (SK) margarine fat or with 5o percent of the skim-milk powder in diet SKF replaced by soya-bean flour (ASKF) or fish-protein concentrate (BSKF), together with dried whey. The diets were given ad lib. twice daily from 13 to 37 d of age, each diet being given for 6 consecutive days. Collections of duodenal digesta and pancreatic secretions, from cannulas, were made for 12 h after feeding the 6th and 12th meals ("experimental" meals) for each diet. 2. The diets fed as "experimental" meals contained polyethylene glycol (PEG) as a fluid (whey) marker and goat's milk containing (3H)lysine as a marker for total protein; beta-carotene was added as a lipid marker to the three diets containing margarine fat. 3. Over the 12 h postprandial period, the patterns of duodenal digesta flow and secretion of pancreatic fluid did not differ markedly between the four diets. The abomasal outflow of both nitrogen and lipid in a 12 h postprandial period was related to their intakes from the "penultimate" (5th and 11th) meals for diets SKF and SK BUT TO THEIR INTAKES AT THE "EXPERIMENTAL MEALS" FOR DIETS ASKF and BSKF. Secretion of pancreatic enzyme activity was highest during the 1st hour after feeding but the main outflow from the abomasum of total N and lipid occurred 5-10 h after feeding. 4. The time required for all the whey marker (PEG) to pass through the duodenum was similar for diets SKF and SK, but only 53 and 42 percent respectively of the ingested protein marker passed through the duodenum in the 12 h after feeding. More acid appeared to be secreted by the abomasum when diet SK was given; also less undigested protein passed out of the abomasum after giving this diet. It is concluded that the physical absence of fat globules in the abomasal clot increases the degree of proteolysis. 5. The secretions of pancreatic fluid and pancreatic enzyme activity were all markedly lower for diet SK than for diet SKF. 6. With diets containing non-milk proteins (ASKF and BSKF), abomasal proteolysis was less efficient and the ingested protein passed out of the abomasum more rapidly than for diet SKF. There was no difference in the rate of abomasal outflow of the whey fluids between diets SKF, ASKF and BSKF. 7. In comparison with diet SKF, diets ASKF and BSKF tended to induce less pancreatic enzyme secretion over a 12 h postprandial period, with the exception of lipase. 8. There appeared to be no direct relationship between the quantities of any of the pancreatic enzymes secreted during a postprandial period and either the concurrent flow of duodenal digesta or the total quantities of dietary constituents passing through the duodenum.

Rotational microfluidic motor for on-chip microcentrifugation

NASA Astrophysics Data System (ADS)

Shilton, Richie J.; Glass, Nick R.; Chan, Peggy; Yeo, Leslie Y.; Friend, James R.

2011-06-01

We report on the design of a surface acoustic wave (SAW) driven fluid-coupled micromotor which runs at high rotational velocities. A pair of opposing SAWs generated on a lithium niobate substrate are each obliquely passed into either side of a fluid drop to drive rotation of the fluid, and the thin circular disk set on the drop. Using water for the drop, a 5 mm diameter disk was driven with rotation speeds and start-up torques up to 2250 rpm and 60 nN m, respectively. Most importantly for lab-on-a-chip applications, radial accelerations of 172 m/s2 was obtained, presenting possibilities for microcentrifugation, flow sequencing, assays, and cell culturing in truly microscale lab-on-a-chip devices.

A pumped, two-phase flow heat transport system for orbiting instrument payloads

NASA Technical Reports Server (NTRS)

Fowle, A. A.

1981-01-01

A pumped two-phase (heat absorption/heat rejection) thermal transport system for orbiting instrument payloads is investigated. The thermofluid characteristics necessary for the system design are discussed. A preliminary design with a series arrangement of four instrument heat stations and six radiators in a single loop is described in detail, and the total mass is estimated to be 134 kg, with the radiators, instrument heat stations, and fluid reservoir accounting for approximately 86, 24, and 12 kg, respectively. The evaluation of preliminary test results shows that the system has potential advantages; however, further research is necessary in the areas of one-g and zero-g heat transfer coefficients/fluid regimes, fluid by-pass temperature control, and reliability of small pumps.

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.

Fluid flow monitoring device

DOEpatents

McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

1993-11-30

A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

Effects of stiffness and volume on the transit time of an erythrocyte through a slit.

PubMed

Salehyar, Sara; Zhu, Qiang

2017-06-01

By using a fully coupled fluid-cell interaction model, we numerically simulate the dynamic process of a red blood cell passing through a slit driven by an incoming flow. The model is achieved by combining a multiscale model of the composite cell membrane with a boundary element fluid dynamics model based on the Stokes flow assumption. Our concentration is on the correlation between the transit time (the time it takes to finish the whole translocation process) and different conditions (flow speed, cell orientation, cell stiffness, cell volume, etc.) that are involved. According to the numerical prediction (with some exceptions), the transit time rises as the cell is stiffened. It is also highly sensitive to volume increase inside the cell. In general, even slightly swollen cells (i.e., the internal volume is increased while the surface area of the cell kept unchanged) travel dramatically slower through the slit. For these cells, there is also an increased chance of blockage.

The fluid dynamics of Balanus glandula barnacles: Adaptations to sheltered and exposed habitats.

PubMed

Vo, Maureen; Mehrabian, Sasan; Villalpando, Fernando; Etienne, Stephane; Pelletier, Dominique; Cameron, Christopher B

2018-04-11

Suspension feeders use a wide range of appendages to capture particles from the surrounding fluid. Their functioning, either as a paddle or a sieve, depends on the leakiness, or amount of fluid that passes through the gaps between the appendages. Balanus glandula is the most common species of barnacle distributed along the Pacific coast of North America. It shows a strong phenotypic response to water flow velocity. Individuals from exposed, high flow sites have short and robust cirral filters, whereas those from sheltered, low velocity sites have long, spindly appendages. Computational fluid dynamics (CFD) simulations of these two ecophenotypes were done using a finite volume method. Leakiness was determined by simulating flow velocity fields at increasing Reynolds numbers, results that have been unattainable at higher velocities by observation. CFD also allowed us to characterize flow in hard to see regions of the feeding legs (rami). Laser-illumination experiments were performed at low to medium flow velocities in a flume tank and corroborated results from CFD. Barnacle filters from a sheltered site become completely leaky at Re=2.24(0.16m/s), well above the maximum habitat velocity, suggesting that this ecophenotype is not mechanically optimized for feeding. Barnacles from exposed environments become fully leaky within the range of habitat velocities Re=3.50(0.18m/s). Our CFD results revealed that the drag force on exposed barnacles feeding appendages are the same as the sheltered barnacles feeding appendages despite their shape difference and spacing ratio. Copyright © 2018 Elsevier Ltd. All rights reserved.

Soap-film flow induced by electric fields in asymmetric frames

NASA Astrophysics Data System (ADS)

Mollaei, S.; Nasiri, M.; Soltanmohammadi, N.; Shirsavar, R.; Ramos, A.; Amjadi, A.

2018-04-01

Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.

Soap-film flow induced by electric fields in asymmetric frames.

PubMed

Mollaei, S; Nasiri, M; Soltanmohammadi, N; Shirsavar, R; Ramos, A; Amjadi, A

2018-04-01

Net fluid flow of soap films induced by (ac or dc) electric fields in asymmetric frames is presented. Previous experiments of controllable soap film flow required the simultaneous use of an electrical current passing through the film and an external electric field or the use of nonuniform ac electric fields. Here a single voltage difference generates both the electrical current going through the film and the electric field that actuates on the charge induced on the film. The film is set into global motion due to the broken symmetry that appears by the use of asymmetric frames. If symmetric frames are used, the film flow is not steady but time dependent and irregular. Finally, we study numerically these film flows by employing the model of charge induction in ohmic liquids.

Extensional flow of hyaluronic acid solutions in an optimized microfluidic cross-slot device.

PubMed

Haward, S J; Jaishankar, A; Oliveira, M S N; Alves, M A; McKinley, G H

2013-07-01

We utilize a recently developed microfluidic device, the Optimized Shape Cross-slot Extensional Rheometer (OSCER), to study the elongational flow behavior and rheological properties of hyaluronic acid (HA) solutions representative of the synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation point device that imposes a planar extensional flow with a homogenous extension rate over a significant length of the inlet and outlet channel axes. Due to the compressive nature of the flow generated along the inlet channels, and the planar elongational flow along the outlet channels, the flow field in the OSCER device can also be considered as representative of the flow field that arises between compressing articular cartilage layers of the knee joints during running or jumping movements. Full-field birefringence microscopy measurements demonstrate a high degree of localized macromolecular orientation along streamlines passing close to the stagnation point of the OSCER device, while micro-particle image velocimetry is used to quantify the flow kinematics. The stress-optical rule is used to assess the local extensional viscosity in the elongating fluid elements as a function of the measured deformation rate. The large limiting values of the dimensionless Trouton ratio, Tr ∼ O(50), demonstrate that these fluids are highly extensional-thickening, providing a clear mechanism for the load-dampening properties of SF. The results also indicate the potential for utilizing the OSCER in screening of physiological SF samples, which will lead to improved understanding of, and therapies for, disease progression in arthritis sufferers.

Extensional flow of hyaluronic acid solutions in an optimized microfluidic cross-slot devicea

PubMed Central

Haward, S. J.; Jaishankar, A.; Oliveira, M. S. N.; Alves, M. A.; McKinley, G. H.

2013-01-01

We utilize a recently developed microfluidic device, the Optimized Shape Cross-slot Extensional Rheometer (OSCER), to study the elongational flow behavior and rheological properties of hyaluronic acid (HA) solutions representative of the synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation point device that imposes a planar extensional flow with a homogenous extension rate over a significant length of the inlet and outlet channel axes. Due to the compressive nature of the flow generated along the inlet channels, and the planar elongational flow along the outlet channels, the flow field in the OSCER device can also be considered as representative of the flow field that arises between compressing articular cartilage layers of the knee joints during running or jumping movements. Full-field birefringence microscopy measurements demonstrate a high degree of localized macromolecular orientation along streamlines passing close to the stagnation point of the OSCER device, while micro-particle image velocimetry is used to quantify the flow kinematics. The stress-optical rule is used to assess the local extensional viscosity in the elongating fluid elements as a function of the measured deformation rate. The large limiting values of the dimensionless Trouton ratio, Tr ∼ O(50), demonstrate that these fluids are highly extensional-thickening, providing a clear mechanism for the load-dampening properties of SF. The results also indicate the potential for utilizing the OSCER in screening of physiological SF samples, which will lead to improved understanding of, and therapies for, disease progression in arthritis sufferers. PMID:24738010

Fluid sampling system

DOEpatents

Houck, Edward D.

1994-01-01

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank.

Fluid sampling system

DOEpatents

Houck, E.D.

1994-10-11

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Migration of magnetotactic bacteria in porous media.

PubMed

Rismani Yazi, Saeed; Nosrati, Reza; Stevens, Corey A; Vogel, David; Escobedo, Carlos

2018-01-01

Magnetotactic bacteria (MTB) migrate in complex porous sediments where fluid flow is ubiquitous. Here, we demonstrate that magnetotaxis enables MTB to migrate effectively through porous micromodels. Directed MTB can circumvent curved obstacles by traveling along the boundaries and pass flat obstacles by repeatedly switching between forward and backward runs. Magnetotaxis enables directed motion of MTB through heterogeneous porous media, overcoming tortuous flow fields with local velocities as high as 250  μ m s -1 . Our findings bring new insights into the migration behaviour of MTB in their natural habitats and their potential in vivo applications as microbiorobots.

Fluid dynamics in suspension-feeding blackfish.

PubMed

Sanderson, S L; Cech, J J; Patterson, M R

1991-03-15

Measurements of flow patterns and water velocities inside the oral cavity of blackfish (Orthodon microlepidotus), made with a fiberoptic endoscope and thermistor flow probe, revealed that gill-arch structures act in blackfish as barriers that direct particle-laden water to the mucus-covered roof of the oral cavity, where particles are retained. Gill-arch structures have previously been assumed to be the site of particle retention in suspension-feeding fishes. Water does not pass between these structures in blackfish, and they do not serve as filters that separate particles from the water. These results emphasize the importance of directly assessing flow velocity and direction inside the oral cavity of vertebrate suspension feeders, particularly at the level of the filtering elements.

Reciprocating free-flow isoelectric focusing device for preparative separation of proteins.

PubMed

Kong, Fan-Zhi; Yang, Ying; Wang, Yi; Li, Guo-Qing; Li, Shan; Xiao, Hua; Fan, Liu-Yin; Liu, Shao-Rong; Cao, Cheng-Xi

2015-11-27

The traditional recycling free-flow isoelectric focusing (RFFIEF) suffered from complex structure, tedious operations and poor extensibility as well as high cost. To address these issues, a novel reciprocating free-flow isoelectric focusing device (ReFFIEF) was developed for proteins or peptides pre-fractionation. In the new device, a reciprocating background flow was for the first time introduced into free flow electrophoresis (FFE) system. The gas cushion injector (GCI) used in the previous continuous free-flow electrophoresis (CFFE) was redesigned for the reciprocating background flow. With the GCI, the reciprocating background flow could be achieved between the GCI, separation chamber and transient self-balance collector (tSBC). In a run, process fluid flowed to and from, forming a stable reciprocating fluid flow in the separation chamber. A pH gradient was created within the separation chamber, and at the same time proteins were focused repeatedly when passing through the chamber under perpendicular electric field. The ReFFIEF procedure was optimized for fractionations of three model proteins, and the optimized method was further used for pre-fractionation of model human serum samples. As compared with the traditional RFFIEF devices developed about 25 years ago, the new ReFFIEF system showed several merits, such as simple design and structure, user-friendly operation and easy to extend as well as low cost. Copyright © 2015 Elsevier B.V. All rights reserved.

Radial cold trap

DOEpatents

Grundy, Brian R.

1981-01-01

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

Radial cold trap

DOEpatents

Grundy, B.R.

1981-09-29

The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

[Concepts of basic physics that every cardiovascular surgeon should know: part I - mechanics of fluids].

PubMed

Oliveira, Marcos Aurélio Barboza de; Alves, Fernanda Tomé; Silva, Marcos Vinícius Pinto e; Croti, Ulisses Alexandre; Godoy, Moacir Fernandes de; Braile, Domingo Marcolino

2010-01-01

The professional activity that the cardiovascular surgeon performs is much more than a simple gesture to mechanically operate the patient's heart. There is in every act of intraoperative most notions of physiology and physics than we generally realize. This paper discusses, in the light of mathematics, on the dynamics of fluids, ie blood, focused on invasive measurements of blood pressure, the effect of vessel size on its internal resistance and the flow passing through it in conversion of various units of measurements of pressure and resistance, blood viscosity and its relationship to the vessel, hemodilution, differences in laminar and turbulent flow, velocity and blood pressure and wall tension after a stenosis and the origin of poststenotic aneurysm. This study is not to enable the reader to the knowledge of all physics, but to show it as a useful tool in explaining phenomena known in the routine of cardiovascular surgery.

Structural cooling fluid tube for supporting a turbine component and supplying cooling fluid

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

Charron, Richard; Pierce, Daniel

2015-02-24

A shaft cover support for a gas turbine engine is disclosed. The shaft cover support not only provides enhanced support to a shaft cover of the gas turbine engine, but also includes a cooling fluid chamber for passing fluids from a rotor air cooling supply conduit to an inner ring cooling manifold. As such, the shaft cover support accomplishes in a single component what was only partially accomplished in two components in conventional configurations. The shaft cover support may also provide additional stiffness and reduce interference of the flow from the compressor. In addition, the shaft cover support accommodates amore » transition section extending between compressor and turbine sections of the engine. The shaft cover support has a radially extending region that is offset from the inlet and outlet that enables the shaft cover support to surround the transition, thereby reducing the overall length of this section of the engine.« less

Microfluidic device, and related methods

NASA Technical Reports Server (NTRS)

Wong, Eric W. (Inventor)

2010-01-01

A method of making a microfluidic device is provided. The method features patterning a permeable wall on a substrate, and surrounding the permeable wall with a solid, non-permeable boundary structure to establish a microfluidic channel having a cross-sectional dimension less than 5,000 microns and a cross-sectional area at least partially filled with the permeable wall so that fluid flowing through the microfluidic channel at least partially passes through the permeable wall.

Enhanced heat transfer characteristics of viscous liquid flows in a chevron plate heat exchanger

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

Muley, A.; Manglik, R.M.; Metwally, H.M.

1999-11-01

Thermal processing and manufacturing in the chemical, foods, pharmaceutical, hygiene products, and biochemical industries invariably involve heating and cooling of highly viscous fluid media. These fluids tend to flow in the low Reynolds number regime, inherently have relatively low heat transfer coefficients, and are often temperature sensitive and prone to thermal degradation in the presence of large temperature differences. In recent times, plate heat exchangers (PHEs) have found increasing usage in such applications, primarily due to their features that promote enhanced heat transfer, and provide for the flexibility in altering their unit thermal size with ease, close approach temperature operation,more » and mitigation of thermal degradation of the process fluid. Here, steady-state heat transfer and pressure drop data for single-phase viscous fluid flows (2 {le} Re {le} 400) in a single-pass U-type counterflow plate heat exchanger (PHE) with chevron plates are presented. With vegetable oil as test fluid (130 {lt} Pr {lt} 290), three different plate arrangements are employed: two symmetric ({beta} = 30 deg/30 deg and 60 deg/60 deg) and one mixed ({beta} = 30 deg/60 deg). The effects of chevron angle {beta}, corrugation aspect ratio {gamma}, and flow conditions (Re, Pr, {mu}/{mu}{sub w}) on Nu and f characteristics of the PHE are delineated. The results show a rather complex influence of plate surface corrugations on the enhanced thermal-hydraulic behavior. Relative to the performance of equivalent flat-plate packs, chevron plates sustain up to 2.9 times higher heat transfer rates on a fixed geometry and constant pumping power basis, and require up to 48% less surface area for the fixed heat load and pressure drop constraint.« less

A survey of oscillating flow in Stirling engine heat exchangers

NASA Technical Reports Server (NTRS)

Simon, Terrence W.; Seume, Jorge R.

1988-01-01

Similarity parameters for characterizing the effect of flow oscillation on wall shear stress, viscous dissipation, pressure drop and heat transfer rates are proposed. They are based on physical agruments and are derived by normalizing the governing equations. The literature on oscillating duct flows, regenerator and porous media flows is surveyed. The operating characteristics of the heat exchanger of eleven Stirling engines are discribed in terms of the similarity parameters. Previous experimental and analytical results are discussed in terms of these parameters and used to estimate the nature of the oscillating flow under engine operating conditions. The operating points for many of the modern Stirling engines are in or near the laminar to turbulent transition region. In several engines, working fluid does not pass entirely through heat exchangers during a cycle. Questions that need to be addressed by further research are identified.

Shaft seal system

DOEpatents

Kapich, Davorin D.

1985-01-01

A shaft seal system is disclosed for isolating two regions of different fluid mediums through which a rotatable shaft extends. The seal system includes a seal housing through which the shaft extends and which defines an annular land and an annular labyrinth both of which face on the shaft so that each establishes a corresponding fluid sealing annulus. A collection cavity is formed in communication with the annular sealing spaces, and fluids compatible with the fluids in each of the two regions to be isolated are introduced, respectively, into the annular sealing spaces and collected in the collection cavity from which the fluid mixture is removed and passed to a separator which separates the fluids and returns them to their respective annular sealing spaces in a recycling manner. In the illustrated embodiment, the isolated fluid mediums comprise a liquid region and a gas region. Gas is removed from the gas region and passed through a purifier and a gas pump operative to introduce the purified gas through the labyrinth sealing annulus to the collection cavity. After passing to the separator, the separated gas is passed through a dryer from which the dried gas is caused to pass through the labyrinth sealing annulus into the collection cavity independently of the purified gas so as to insure isolation of the gas region in the event of sealing gas pump malfunction.

The Transformative Experience in Engineering Education

NASA Astrophysics Data System (ADS)

Goodman, Katherine Ann

This research evaluates the usefulness of transformative experience (TE) in engineering education. With TE, students 1) apply ideas from coursework to everyday experiences without prompting (motivated use); 2) see everyday situations through the lens of course content (expanded perception); and 3) value course content in new ways because it enriches everyday affective experience (affective value). In a three-part study, we examine how engineering educators can promote student progress toward TE and reliably measure that progress. For the first study, we select a mechanical engineering technical elective, Flow Visualization, that had evidence of promoting expanded perception of fluid physics. Through student surveys and interviews, we compare this elective to the required Fluid Mechanics course. We found student interest in fluids fell into four categories: complexity, application, ubiquity, and aesthetics. Fluid Mechanics promotes interest from application, while Flow Visualization promotes interest based in ubiquity and aesthetics. Coding for expanded perception, we found it associated with students' engineering identity, rather than a specific course. In our second study, we replicate atypical teaching methods from Flow Visualization in a new design course: Aesthetics of Design. Coding of surveys and interviews reveals that open-ended assignments and supportive teams lead to increased ownership of projects, which fuels risk-taking, and produces increased confidence as an engineer. The third study seeks to establish parallels between expanded perception and measurable perceptual expertise. Our visual expertise experiment uses fluid flow images with both novices and experts (students who had passed fluid mechanics). After training, subjects sort images into laminar and turbulent categories. The results demonstrate that novices learned to sort the flow stimuli in ways similar to subjects in prior perceptual expertise studies. In contrast, the experts' significantly better results suggest they are accessing conceptual fluids knowledge to perform this new, visual task. The ability to map concepts onto visual information is likely a necessary step toward expanded perception. Our findings suggest that open-ended aesthetic experiences with engineering content unexpectedly support engineering identity development, and that visual tasks could be developed to measure conceptual understanding, promoting expanded perception. Overall, we find TE a productive theoretical framework for engineering education research.

Systems and methods for analyzing liquids under vacuum

DOEpatents

Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

2013-10-15

Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

Study of the effects of Shockwaves on Nano fluids

NASA Astrophysics Data System (ADS)

Shreekhar; Akhil, Mohan; Ram, Sai; Gopaiah, Venkata; Koundinya, Sandeep; Nagaraja, S. R.

2018-02-01

Nanofluids are fluids with nanoparticles dispersed in them. Due to the presence of Nano particles, these fluids exhibit unique properties that can used in various applications such as heat exchangers and in medical fields. However, due to agglomeration, the size of these particle increases, reducing their efficiency. In order to break the agglomeration, we are passing shockwaves in the fluid. Shockwaves theoretically carry energy which can be used to break the agglomerating particles. In this paper, silver nanoparticles were synthesized using silver nitrate. Tri sodium citrate was used as the reducing agent. Shock waves were passed to the fluid containing silver Nano particles. The changes in the Nano fluid was measured by a UV-Vis Spectrophotometer. With each shock passed, the fluid’s absorbance and wavelength peak was measured and compared with Nano fluid without shock.

Method of and apparatus for preheating pressurized fluidized bed combustor and clean-up subsystem of a gas turbine power plant

DOEpatents

Cole, Rossa W.; Zoll, August H.

1982-01-01

In a gas turbine power plant having a pressurized fluidized bed combustor, gas turbine-air compressor subsystem and a gas clean-up subsystem interconnected for fluid flow therethrough, a pipe communicating the outlet of the compressor of the gas turbine-air compressor subsystem with the interior of the pressurized fluidized bed combustor and the gas clean-up subsystem to provide for flow of compressed air, heated by the heat of compression, therethrough. The pressurized fluidized bed combustor and gas clean-up subsystem are vented to atmosphere so that the heated compressed air flows therethrough and loses heat to the interior of those components before passing to the atmosphere.

Analysis of heat transfer for unsteady MHD free convection flow of rotating Jeffrey nanofluid saturated in a porous medium

NASA Astrophysics Data System (ADS)

Mohd Zin, Nor Athirah; Khan, Ilyas; Shafie, Sharidan; Alshomrani, Ali Saleh

In this article, the influence of thermal radiation on unsteady magnetohydrodynamics (MHD) free convection flow of rotating Jeffrey nanofluid passing through a porous medium is studied. The silver nanoparticles (AgNPs) are dispersed in the Kerosene Oil (KO) which is chosen as conventional base fluid. Appropriate dimensionless variables are used and the system of equations is transformed into dimensionless form. The resulting problem is solved using the Laplace transform technique. The impact of pertinent parameters including volume fraction φ , material parameters of Jeffrey fluid λ1 , λ , rotation parameter r , Hartmann number Ha , permeability parameter K , Grashof number Gr , Prandtl number Pr , radiation parameter Rd and dimensionless time t on velocity and temperature profiles are presented graphically with comprehensive discussions. It is observed that, the rotation parameter, due to the Coriolis force, tends to decrease the primary velocity but reverse effect is observed in the secondary velocity. It is also observed that, the Lorentz force retards the fluid flow for both primary and secondary velocities. The expressions for skin friction and Nusselt number are also evaluated for different values of emerging parameters. A comparative study with the existing published work is provided in order to verify the present results. An excellent agreement is found.

Fuel injection of coal slurry using vortex nozzles and valves

DOEpatents

Holmes, Allen B.

1989-01-01

Injection of atomized coal slurry fuel into an engine combustion chamber is achieved at relatively low pressures by means of a vortex swirl nozzle. The outlet opening of the vortex nozzle is considerably larger than conventional nozzle outlets, thereby eliminating major sources of failure due to clogging by contaminants in the fuel. Control fluid, such as air, may be used to impart vorticity to the slurry and/or purge the nozzle of contaminants during the times between measured slurry charges. The measured slurry charges may be produced by a diaphragm pump or by vortex valves controlled by a separate control fluid. Fluidic circuitry, employing vortex valves to alternatively block and pass cool slurry fuel flow, is disclosed.

Theory for nanoparticle retention time in the helical channel of quadrupole magnetic field-flow fractionation

NASA Astrophysics Data System (ADS)

Williams, P. Stephen; Carpino, Francesca; Zborowski, Maciej

2009-05-01

Quadrupole magnetic field-flow fractionation (QMgFFF) is a separation and characterization technique for magnetic nanoparticles such as those used for cell labeling and for targeted drug therapy. A helical separation channel is used to efficiently exploit the quadrupole magnetic field. The fluid and sample components therefore have angular and longitudinal components to their motion in the thin annular space occupied by the helical channel. The retention ratio is defined as the ratio of the times for non-retained and a retained material to pass through the channel. Equations are derived for the respective angular and longitudinal components to retention ratio.

Active learning of constitutive relation from mesoscopic dynamics for macroscopic modeling of non-Newtonian flows

NASA Astrophysics Data System (ADS)

Zhao, Lifei; Li, Zhen; Caswell, Bruce; Ouyang, Jie; Karniadakis, George Em

2018-06-01

We simulate complex fluids by means of an on-the-fly coupling of the bulk rheology to the underlying microstructure dynamics. In particular, a continuum model of polymeric fluids is constructed without a pre-specified constitutive relation, but instead it is actively learned from mesoscopic simulations where the dynamics of polymer chains is explicitly computed. To couple the bulk rheology of polymeric fluids and the microscale dynamics of polymer chains, the continuum approach (based on the finite volume method) provides the transient flow field as inputs for the (mesoscopic) dissipative particle dynamics (DPD), and in turn DPD returns an effective constitutive relation to close the continuum equations. In this multiscale modeling procedure, we employ an active learning strategy based on Gaussian process regression (GPR) to minimize the number of expensive DPD simulations, where adaptively selected DPD simulations are performed only as necessary. Numerical experiments are carried out for flow past a circular cylinder of a non-Newtonian fluid, modeled at the mesoscopic level by bead-spring chains. The results show that only five DPD simulations are required to achieve an effective closure of the continuum equations at Reynolds number Re = 10. Furthermore, when Re is increased to 100, only one additional DPD simulation is required for constructing an extended GPR-informed model closure. Compared to traditional message-passing multiscale approaches, applying an active learning scheme to multiscale modeling of non-Newtonian fluids can significantly increase the computational efficiency. Although the method demonstrated here obtains only a local viscosity from the polymer dynamics, it can be extended to other multiscale models of complex fluids whose macro-rheology is unknown.

Loss of efficiency of polymeric drag reducers induced by high Reynolds number flows in tubes with imposed pressure

NASA Astrophysics Data System (ADS)

Soares, Edson J.; Sandoval, Gustavo A. B.; Silveira, Lucas; Pereira, Anselmo S.; Trevelin, Renata; Thomaz, Fabricio

2015-12-01

This paper studies the loss of efficiency of polymeric drag reducers induced by high Reynolds number flows in tubes. The overall pressure was fixed and the apparatus was built so as to minimize the polymer degradation. We used three kinds of polymers: two flexible and one rigid. We conducted our tests to take into account the drag reduction (DR) for a wide range of concentrations of each polymer. The main results are displayed for the DR as a function of the number of passes through the apparatus. The mechanism of the loss of efficiency for the Xanthan Gum (XG) solutions (the rigid one) seems to be completely different from that observed for Poly (ethylene oxide) (PEO) and Polyacrylamide (PAM) (the flexible materials). While the PEO and PAM mechanically degrade by the action of the turbulent flow, the XG seems to remain intact, even after many passes through the pipe flow apparatus. From the practical point of view, it is worth noting that the PAM solutions are clearly more efficient than the PEO and XG. Another practical point that deserves attention is concerned with the asymptotic drag reduction found for XG. Although its maximum DR was significantly smaller than that found for PEO, the final value for both polymers were quite the same, which is obviously related to the intensified mechanical molecule scission in the PEO solutions. Our results for the relative drag reduction (the current value of DR divided by its maximum obtained at the first pass) was quite well fitted by the decay function proposed in our previous paper [A. S. Pereira and E. J. Soares, "Polymer degradation of dilute solutions in turbulent drag reducing flows in a cylindrical double gap rheometer device," J. Non-Newtonian Fluid Mech. 179, 9-22 (2012)], in which a rotating apparatus was used. This strongly suggests that the physical mechanism that governs the degradation phenomenon is independent of the geometry. We also used a degradation model for PEO proposed by Vonlanthen and Monkewitz ["Grid turbulence in dilute polymer solution: Peo in water," J. Fluid Mech. 730, 76-98 (2013)] to fit our data of relative drag reduction for PEO and PAM.

Ion processing element with composite media

DOEpatents

Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

2003-02-04

An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

Ion processing element with composite media

DOEpatents

Mann, Nick R [Blackfoot, ID; Tranter, Troy J [Idaho Falls, ID; Todd, Terry A [Aberdeen, ID; Sebesta, Ferdinand [Prague, CZ

2009-03-24

An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

Towards a Coupled Vortex Particle and Acoustic Boundary Element Solver to Predict the Noise Production of Bio-Inspired Propulsion

NASA Astrophysics Data System (ADS)

Wagenhoffer, Nathan; Moored, Keith; Jaworski, Justin

2016-11-01

The design of quiet and efficient bio-inspired propulsive concepts requires a rapid, unified computational framework that integrates the coupled fluid dynamics with the noise generation. Such a framework is developed where the fluid motion is modeled with a two-dimensional unsteady boundary element method that includes a vortex-particle wake. The unsteady surface forces from the potential flow solver are then passed to an acoustic boundary element solver to predict the radiated sound in low-Mach-number flows. The use of the boundary element method for both the hydrodynamic and acoustic solvers permits dramatic computational acceleration by application of the fast multiple method. The reduced order of calculations due to the fast multipole method allows for greater spatial resolution of the vortical wake per unit of computational time. The coupled flow-acoustic solver is validated against canonical vortex-sound problems. The capability of the coupled solver is demonstrated by analyzing the performance and noise production of an isolated bio-inspired swimmer and of tandem swimmers.

Investigation of the Profile Control Mechanisms of Dispersed Particle Gel

PubMed Central

Zhao, Guang; Dai, Caili; Zhao, Mingwei

2014-01-01

Dispersed particle gel (DPG) particles of nano- to micron- to mm-size have been prepared successfully and will be used for profile control treatment in mature oilfields. The profile control and enhanced oil recovery mechanisms of DPG particles have been investigated using core flow tests and visual simulation experiments. Core flow test results show that DPG particles can easily be injected into deep formations and can effectively plug the high permeability zones. The high profile improvement rate improves reservoir heterogeneity and diverts fluid into the low permeability zone. Both water and oil permeability were reduced when DPG particles were injected, but the disproportionate permeability reduction effect was significant. Water permeability decreases more than the oil permeability to ensure that oil flows in its own pathways and can easily be driven out. Visual simulation experiments demonstrate that DPG particles can pass directly or by deformation through porous media and enter deep formations. By retention, adsorption, trapping and bridging, DPG particles can effectively reduce the permeability of porous media in high permeability zones and divert fluid into a low permeability zone, thus improving formation profiles and enhancing oil recovery. PMID:24950174

Supersonic flows past an obstacle in Yukawa liquids

NASA Astrophysics Data System (ADS)

Charan, Harish; Ganesh, Rajaraman

2018-04-01

Shock formation, when a supersonic flow passes a stationary obstacle, is ubiquitous in nature. Considering particles mediating via a Yukawa-type interaction as a prototype for a strongly coupled complex plasma, characterized by coupling strength (Γ, ratio of the average potential to kinetic energy per particle) and screening parameter (κ, ratio of the mean inter-particle distance to the shielding length), we address the fundamental problem of supersonic fluid flow U0, past a stationary obstacle immersed in this strongly coupled system. We here report the results on the bow shocks formed in Yukawa liquids when the liquid flows at speeds larger than the speed of sound in the system. Depending on the values of Mach number MC L=U/0 CL , where CL is the longitudinal speed of sound in the system, the bow shocks are found to be either traveling or localized. We find that for the transonic flows (0.8 ≲ MC L≲ 1.2), the bow shocks travel in the upstream direction opposite to the incoming fluid. The phase velocity of the traveling bow shocks is found to be a non-monotonous function of κ, varying as ∝1 /k1.11 at a fixed value of Γ, and is found to be independent of Γ at a fixed value of κ. It is observed that for the flow values with MC L>1.5 , the shock waves do not travel in the upstream direction but instead form a stationary arc like structure around the obstacle. For the fluid flows with 1 ≲ MC L≲ 2.6 , secondary bow shocks are seen to emerge behind the stationary obstacle which travel in the downstream direction, and the phase velocity of these secondary bow shocks is found to be equal to that of the primary bow shocks.

Efforts to reduce mortality to hydroelectric turbine-passed fish: locating and quantifying damaging shear stresses.

PubMed

Cada, Glenn; Loar, James; Garrison, Laura; Fisher, Richard; Neitzel, Duane

2006-06-01

Severe fluid forces are believed to be a source of injury and mortality to fish that pass through hydroelectric turbines. A process is described by which laboratory bioassays, computational fluid dynamics models, and field studies can be integrated to evaluate the significance of fluid shear stresses that occur in a turbine. Areas containing potentially lethal shear stresses were identified near the stay vanes and wicket gates, runner, and in the draft tube of a large Kaplan turbine. However, under typical operating conditions, computational models estimated that these dangerous areas comprise less than 2% of the flow path through the modeled turbine. The predicted volumes of the damaging shear stress zones did not correlate well with observed fish mortality at a field installation of this turbine, which ranged from less than 1% to nearly 12%. Possible reasons for the poor correlation are discussed. Computational modeling is necessary to develop an understanding of the role of particular fish injury mechanisms, to compare their effects with those of other sources of injury, and to minimize the trial and error previously needed to mitigate those effects. The process we describe is being used to modify the design of hydroelectric turbines to improve fish passage survival.

Disposable and removable nucleic acid extraction and purification cartridges for automated flow-through systems

DOEpatents

Regan, John Frederick

2014-09-09

Removable cartridges are used on automated flow-through systems for the purpose of extracting and purifying genetic material from complex matrices. Different types of cartridges are paired with specific automated protocols to concentrate, extract, and purifying pathogenic or human genetic material. Their flow-through nature allows large quantities sample to be processed. Matrices may be filtered using size exclusion and/or affinity filters to concentrate the pathogen of interest. Lysed material is ultimately passed through a filter to remove the insoluble material before the soluble genetic material is delivered past a silica-like membrane that binds the genetic material, where it is washed, dried, and eluted. Cartridges are inserted into the housing areas of flow-through automated instruments, which are equipped with sensors to ensure proper placement and usage of the cartridges. Properly inserted cartridges create fluid- and air-tight seals with the flow lines of an automated instrument.

Spray Formation from a Charged Liquid Jet of a Dielectric Fluid

NASA Astrophysics Data System (ADS)

Doak, William; de Bellis, Victor; Chiarot, Paul; Microfluidics; Multiphase Flow Laboratory Team

2017-11-01

Atomization of a dielectric micro-jet is achieved via an electrohydrodynamic charge injection process. The atomizer is comprised of a grounded nozzle housing (ground electrode) and an internal probe (high voltage electrode) that is concentric with the emitting orifice. The internal probe is held at electric potentials ranging from 1-10 kV. A pressurized reservoir drives a dielectric fluid at a desired flow rate through the 100-micrometer diameter orifice. The fluid fills the cavity between the electrodes as it passes through the atomizer, impeding the transport of electrons. This process injects charge into the flowing fluid. Upon exiting the orifice, the emitted jet is highly charged and it deforms via a bending instability that is qualitatively similar to the behavior observed in the electrospinning of fibers. We observed bulging regions, or nodes, of highly charged fluid forming along the bent, rotating jet. These nodes separate into highly charged droplets that emit satellite droplets. The remaining ligaments break up due to capillarity in a process that produces additional satellites. All of the droplets possess a normal (inertial) and radial (electrically-driven) momentum component. The radial component is responsible for the formation of a conical spray envelope. Our research focuses on the jet, its break up, and the droplet dynamics of this system. This research supported by the American Chemical Society.

Rotating flow of carbon nanotube over a stretching surface in the presence of magnetic field: a comparative study

NASA Astrophysics Data System (ADS)

Acharya, Nilankush; Das, Kalidas; Kundu, Prabir Kumar

2018-04-01

In this piece of writing, we have demonstrated the rotating flow of carbon nanotube passing over a stretching sheet. Two types of carbon nanotube, i.e. single-wall carbon nanotube (SWCNT) and multi-wall carbon nanotube, (MWCNT) have been employed to illustrate the fine points of the flow. Suitable transformations have been consumed to construct its non-dimensional appearance from the partial ones. Transformed forms of equations have been sketched out by RK-4 procedure. Outcomes of the key flow factors on velocity along with temperature outline have been exemplified through tables and graphs, and scrutinized from the sensible judgement. Our investigation authenticates that the temperature of the fluid enhances owing to the improvisation of rotation parameter. Nusselt number goes down with the authority of magnetic parameter.

Impact on Water Heater Performance of Heating Methods that Promote Tank Temperature Stratification

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

Gluesenkamp, Kyle R; BushPE, John D

2016-01-01

During heating of a water heater tank, the vertical temperature stratification of the water can be increased or decreased, depending on the method of heating. Methods that increase stratification during heating include (1) removing cold water from the tank bottom, heating it, and re-introducing it to the tank top at relatively low flow rate, (2) using a heat exchanger wrapped around the tank, through which heating fluid (with finite specific heat) flows from top to bottom, and (3) using an immersed heat element that is relatively high in the tank. Using such methods allows for improved heat pump water heatermore » (HPWH) cycle efficiencies when the heat pump can take advantage of the lower temperatures that exist lower in the tank, and accommodate the resulting glide. Transcritical cycles are especially well-suited to capitalize on this opportunity, and other HPWH configurations (that have been proposed elsewhere) may benefit as well. This work provides several stratification categories of heat pump water heater tank configurations relevant to their stratification potential. To illustrate key differences among categories, it also compiles available experimental data for (a) single pass pumped flow, (b) multi-pass pumped flow, and (c) top-down wrapped tank with transcritical refrigerant.« less

Randomized Dynamic Mode Decomposition

NASA Astrophysics Data System (ADS)

Erichson, N. Benjamin; Brunton, Steven L.; Kutz, J. Nathan

2017-11-01

The dynamic mode decomposition (DMD) is an equation-free, data-driven matrix decomposition that is capable of providing accurate reconstructions of spatio-temporal coherent structures arising in dynamical systems. We present randomized algorithms to compute the near-optimal low-rank dynamic mode decomposition for massive datasets. Randomized algorithms are simple, accurate and able to ease the computational challenges arising with `big data'. Moreover, randomized algorithms are amenable to modern parallel and distributed computing. The idea is to derive a smaller matrix from the high-dimensional input data matrix using randomness as a computational strategy. Then, the dynamic modes and eigenvalues are accurately learned from this smaller representation of the data, whereby the approximation quality can be controlled via oversampling and power iterations. Here, we present randomized DMD algorithms that are categorized by how many passes the algorithm takes through the data. Specifically, the single-pass randomized DMD does not require data to be stored for subsequent passes. Thus, it is possible to approximately decompose massive fluid flows (stored out of core memory, or not stored at all) using single-pass algorithms, which is infeasible with traditional DMD algorithms.

Experimental Observations of Vortex Ring Interaction with the Fluid Adjacent to a Surface.

DTIC Science & Technology

1983-10-01

minute. The water enters the inlet tank from a distribution manifold pipe and rises vertically through a 15 cm. thick plastic sponge. The flow then passes...parts exposed to water are made from PVC plastic to resist corrosion. The generator was designed to have interchangeable parts which allow the generation...of vortex rings over a range of caracteristics . The motor speed is continuously variable up to a speed of 7400 rpm. Cams with stroke lengths of 0.64

A fluid-structure interaction (FSI)-based numerical investigation of peristalsis in an obstructed human ureter.

PubMed

Takaddus, Ahmed Tasnub; Gautam, Prashanta; Chandy, Abhilash J

2018-05-08

Urine moves from the kidney to the bladder through the ureter. A series of compression waves facilitates this transport. Due to the highly concentrated mineral deposits in urine, stones are formed in the kidney and travel down through the urinary tract. While passing, a larger stone can get stuck and cause severe damage to ureter wall. Also, stones in the ureter obstructing the urine flow can cause pain and backflow of urine which in turn might require surgical intervention. The current study develops a 2D axisymmetric numerical model to gain an understanding of the ureter obstruction and its effects on the flow, which are critical in assessing the different treatment options. Transient computational analysis involving a two-way fully coupled fluid-structure interaction with the arbitrary Lagrangian-Eulerian method between the ureteral wall and urine flow is conducted with an obstruction in the ureter. The ureter wall is modeled as an anisotropic hyperelastic material, data of which, is based on biaxial tests on human ureter from previous literature, while the incompressible Navier-Stokes equations are solved to calculate urine flow. A finite element-based monolithic solver is used for the simulations here. The obstruction is placed in the fluid domain as a circular stone at the proximal part of the ureter. One of the objectives of this study is to quantify the effect of the ureteral obstruction. A sharp jump in pressure gradient and wall shear stress, as well as retrograde urine flow, is observed as a result of the obstruction. Copyright © 2018 John Wiley & Sons, Ltd.

Heat exchanger

DOEpatents

Daman, Ernest L.; McCallister, Robert A.

1979-01-01

A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

Turbulent entrainment across turbulent-nonturbulent interfaces in stably stratified mixing layers

NASA Astrophysics Data System (ADS)

Watanabe, T.; Riley, J. J.; Nagata, K.

2017-10-01

The entrainment process in stably stratified mixing layers is studied in relation to the turbulent-nonturbulent interface (TNTI) using direct numerical simulations. The statistics are calculated with the interface coordinate in an Eulerian frame as well as with the Lagrangian fluid particles entrained from the nonturbulent to the turbulent regions. The characteristics of entrainment change as the buoyancy Reynolds number Reb decreases and the flow begins to layer. The baroclinic torque delays the enstrophy growth of the entrained fluids at small Reb, while this effect is less efficient for large Reb. The entrained particle movement within the TNTI layer is dominated by the small dissipative scales, and the rapid decay of the kinetic energy dissipation rate due to buoyancy causes the entrained particle movement relative to the interface location to become slower. Although the Eulerian statistics confirm that there exists turbulent fluid with strong vorticity or with large buoyancy frequency near the TNTI, the entrained fluid particles circumvent these regions by passing through the TNTI in strain-dominant regions or in regions with small buoyancy frequency. The multiparticle statistics show that once the nonturbulent fluid volumes are entrained, they are deformed into flattened shapes in the vertical direction and diffuse in the horizontal direction. When Reb is large enough for small-scale turbulence to exist, the entrained fluid is able to penetrate into the turbulent core region. Once the flow begins to layer with decreasing Reb, however, the entrained fluid volume remains near the outer edge of the turbulent region and forms a stably stratified layer without vertical overturning.

Highly Permeable Silicon Membranes for Shear Free Chemotaxis and Rapid Cell Labeling

PubMed Central

Chung, Henry H.; Chan, Charles K.; Khire, Tejas S.; Marsh, Graham A.; Clark, Alfred; Waugh, Richard E.; McGrath, James L.

2015-01-01

Microfluidic systems are powerful tools for cell biology studies because they enable the precise addition and removal of solutes in small volumes. However, the fluid forces inherent in the use of microfluidics for cell cultures are sometimes undesirable. An important example is chemotaxis systems where fluid flow creates well-defined and steady chemotactic gradients but also pushes cells downstream. Here we demonstrate a chemotaxis system in which two chambers are separated by a molecularly thin (15 nm), transparent, and nanoporous silicon membrane. One chamber is a microfluidic channel that carries a flow-generated gradient while the other chamber is a shear-free environment for cell observation. The molecularly thin membranes provide effectively no resistance to molecular diffusion between the two chambers, making them ideal elements for creating flow-free chambers in microfluidic systems. Analytical and computational flow models that account for membrane and chamber geometry, predict shear reduction of more than five orders of magnitude. This prediction is confirmed by observing the pure diffusion of nanoparticles in the cell-hosting chamber despite high input flow (Q = 10 µL min−1; vavg ~45 mm min−1) in the flow chamber only 15 nm away. Using total internal reflection fluorescence (TIRF) microscopy, we show that a flow-generated molecular gradient will pass through the membrane into the quiescent cell chamber. Finally we demonstrate that our device allows us to expose migrating neutrophils to a chemotactic gradient or fluorescent label without any influence from flow. PMID:24850320

Electric field effects on a near-critical fluid in microgravity

NASA Technical Reports Server (NTRS)

Zimmerli, G.; Wilkinson, R. A.; Ferrell, R. A.; Hao, H.; Moldover, M. R.

1994-01-01

The effects of an electric field on a sample of SF6 fluid in the vicinity of the liquid-vapor critical point is studied. The isothermal increase of the density of a near-critical sample as a function of the applied electric field was measured. In agreement with theory, this electrostriction effect diverges near the critical point as the isothermal compressibility diverges. Also as expected, turning on the electric field in the presence of density gradients can induce flow within the fluid, in a way analogous to turning on gravity. These effects were observed in a microgravity environment by using the Critical Point Facility which flew onboard the Space Shuttle Columbia in July 1994 as part of the Second International Microgravity Laboratory Mission. Both visual and interferometric images of two separate sample cells were obtained by means of video downlink. The interferometric images provided quantitative information about the density distribution throughout the sample. The electric field was generated by applying 500 Volts to a fine wire passing through the critical fluid.

Air conditioning system

DOEpatents

Lowenstein, Andrew; Miller, Jeffrey; Gruendeman, Peter; DaSilva, Michael

2005-02-01

An air conditioner comprises a plurality of plates arranged in a successively stacked configuration with portions thereof having a spaced apart arrangement, and defining between successive adjacent pairs of plates at the spaced apart portions a first and second series of discrete alternating passages wherein a first air stream is passed through the first series of passages and a second air stream is passed through the second series of passages; and said stacked configuration of plates forming integrally therewith a liquid delivery means for delivering from a source a sufficient quantity of a liquid to the inside surfaces of the first series of fluid passages in a manner which provides a continuous flow of the liquid from a first end to a second end of the plurality of plates while in contact with the first air stream.

Multi-partitioning for ADI-schemes on message passing architectures

NASA Technical Reports Server (NTRS)

Vanderwijngaart, Rob F.

1994-01-01

A kind of discrete-operator splitting called Alternating Direction Implicit (ADI) has been found to be useful in simulating fluid flow problems. In particular, it is being used to study the effects of hot exhaust jets from high performance aircraft on landing surfaces. Decomposition techniques that minimize load imbalance and message-passing frequency are described. Three strategies that are investigated for implementing the NAS Scalar Penta-diagonal Parallel Benchmark (SP) are transposition, pipelined Gaussian elimination, and multipartitioning. The multipartitioning strategy, which was used on Ethernet, was found to be the most efficient, although it was considered only a moderate success because of Ethernet's limited communication properties. The efficiency derived largely from the coarse granularity of the strategy, which reduced latencies and allowed overlap of communication and computation.

Directly connected heat exchanger tube section and coolant-cooled structure

DOEpatents

Chainer, Timothy J.; Coico, Patrick A.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

2015-09-15

A method is provided for fabricating a cooling apparatus for cooling an electronics rack, which includes an air-to-liquid heat exchanger, one or more coolant-cooled structures, and a tube. The heat exchanger is associated with the electronics rack and disposed to cool air passing through the rack, includes a plurality of coolant-carrying tube sections, each tube section having a coolant inlet and outlet, one of which is coupled in fluid communication with a coolant loop to facilitate flow of coolant through the tube section. The coolant-cooled structure(s) is in thermal contact with an electronic component(s) of the rack, and facilitates transfer of heat from the component(s) to the coolant. The tube connects in fluid communication one coolant-cooled structure and the other of the coolant inlet or outlet of the one tube section, and facilitates flow of coolant directly between that coolant-carrying tube section of the heat exchanger and the coolant-cooled structure.

Directly connected heat exchanger tube section and coolant-cooled structure

DOEpatents

Chainer, Timothy J; Coico, Patrick A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Steinke, Mark E

2014-04-01

A cooling apparatus for an electronics rack is provided which includes an air-to-liquid heat exchanger, one or more coolant-cooled structures and a tube. The heat exchanger, which is associated with the electronics rack and disposed to cool air passing through the rack, includes a plurality of distinct, coolant-carrying tube sections, each tube section having a coolant inlet and a coolant outlet, one of which is coupled in fluid communication with a coolant loop to facilitate flow of coolant through the tube section. The coolant-cooled structure(s) is in thermal contact with an electronic component(s) of the rack, and facilitates transfer of heat from the component(s) to the coolant. The tube connects in fluid communication one coolant-cooled structure and the other of the coolant inlet or outlet of the one tube section, and facilitates flow of coolant directly between that coolant-carrying tube section of the heat exchanger and the coolant-cooled structure.

Entropy Generation Analysis through Helical Coil Heat Exchanger in an Agitated Vessel

NASA Astrophysics Data System (ADS)

Ashok Reddy, K.

2018-03-01

Entropy Generation have been obtained while conducting the experiments for different sodium carboxymethyl cellulose concentrations 0.05%,0.1%,0.15% and 0.2% of Newtonian and non Newtonian fluids and the data made available by passing the test fluid at different flow rates through a helical coil in a mixing coil using paddle impeller. Heating of fluids depend on operational parameters, geometry of the mixing vessel and the type of impeller used. A new design of heating element was design and fabricated by providing kanthal wire inserted into a glove knitted with fiber glass yarn as glass fabric is flexible, heat resistant and can accommodate to adopt small difference in size of the vessel, perfectly. The knitted fabric is made to the shape of vessel used in the experiment and the heating elements are inserted so that it gets embedded and forms part of the glove knitted with yarn of fiber glass.

Cooled airfoil in a turbine engine

DOEpatents

Vitt, Paul H; Kemp, David A; Lee, Ching-Pang; Marra, John J

2015-04-21

An airfoil in a gas turbine engine includes an outer wall and an inner wall. The outer wall includes a leading edge, a trailing edge opposed from the leading edge in a chordal direction, a pressure side, and a suction side. The inner wall is coupled to the outer wall at a single chordal location and includes portions spaced from the pressure and suction sides of the outer wall so as to form first and second gaps between the inner wall and the respective pressure and suction sides. The inner wall defines a chamber therein and includes openings that provide fluid communication between the respective gaps and the chamber. The gaps receive cooling fluid that provides cooling to the outer wall as it flows through the gaps. The cooling fluid, after traversing at least substantial portions of the gaps, passes into the chamber through the openings in the inner wall.

Apparatus for unloading pressurized fluid

DOEpatents

Rehberger, Kevin M.

1994-01-01

An apparatus for unloading fluid, preferably pressurized gas, from containers in a controlled manner that protects the immediate area from exposure to the container contents. The device consists of an unloading housing, which is enclosed within at least one protective structure, for receiving the dispensed contents of the steel container, and a laser light source, located external to the protective structure, for opening the steel container instantaneously. The neck or stem of the fluid container is placed within the sealed interior environment of the unloading housing. The laser light passes through both the protective structure and the unloading housing to instantaneously pierce a small hole within the stem of the container. Both the protective structure and the unloading housing are specially designed to allow laser light passage without compromising the light's energy level. Also, the unloading housing allows controlled flow of the gas once it has been dispensed from the container. The external light source permits remote operation of the unloading device.

Thermal Analysis of the PediaFlow pediatric ventricular assist device.

PubMed

Gardiner, Jeffrey M; Wu, Jingchun; Noh, Myounggyu D; Antaki, James F; Snyder, Trevor A; Paden, David B; Paden, Brad E

2007-01-01

Accurate modeling of heat dissipation in pediatric intracorporeal devices is crucial in avoiding tissue and blood thermotrauma. Thermal models of new Maglev ventricular assist device (VAD) concepts for the PediaFlow VAD are developed by incorporating empirical heat transfer equations with thermal finite element analysis (FEA). The models assume three main sources of waste heat generation: copper motor windings, active magnetic thrust bearing windings, and eddy currents generated within the titanium housing due to the two-pole motor. Waste heat leaves the pump by convection into blood passing through the pump and conduction through surrounding tissue. Coefficients of convection are calculated and assigned locally along fluid path surfaces of the three-dimensional pump housing model. FEA thermal analysis yields a three-dimensional temperature distribution for each of the three candidate pump models. Thermal impedances from the motor and thrust bearing windings to tissue and blood contacting surfaces are estimated based on maximum temperature rise at respective surfaces. A new updated model for the chosen pump topology is created incorporating computational fluid dynamics with empirical fluid and heat transfer equations. This model represents the final geometry of the first generation prototype, incorporates eddy current heating, and has 60 discrete convection regions. Thermal analysis is performed at nominal and maximum flow rates, and temperature distributions are plotted. Results suggest that the pump will not exceed a temperature rise of 2 degrees C during normal operation.

Flow interaction in the combustor-diffusor system of industrial gas turbines

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

Agrawal, A.K.; Kapat, J.S.; Yang, T.

1996-05-01

This paper presents an experimental/computational study of cold flow in the combustor-diffuser system of industrial gas turbines to address issues relating to flow interactions and pressure losses in the pre- and dump diffusers. The present configuration with can annular combustors differs substantially from the aircraft engines which typically use a 360 degree annular combustor. Experiments were conducted in a one-third scale, annular 360-degree model using several can combustors equispaced around the turbine axis. A 3-D computational fluid dynamics analysis employing the multidomain procedure was performed to supplement the flow measurements. The measured data correlated well with the computations. The airflowmore » in the dump diffuser adversely affected the prediffuser flow by causing it to accelerate in the outer region at the prediffuser exit. This phenomenon referred to as the sink-effect also caused a large fraction of the flow to bypass much of the dump diffuser and go directly from the prediffuser exit to the bypass air holes on the combustor casing, thereby, rendering the dump diffuser ineffective in diffusing the flow. The dump diffuser was occupied by a large recirculation region which dissipated the flow kinetic energy. Approximately 1.2 dynamic head at the prediffuser inlet was lost in the combustor-diffuser system; much of it in the dump diffuser where the fluid passed through the narrow gaps and pathways. Strong flow interactions in the combustor-diffuser system indicate the need for design modifications which could not be addressed by empirical correlations based on simple flow configurations.« less

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater

PubMed Central

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2013-01-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s−1. Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s−1 with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency. PMID:25685486

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater.

PubMed

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2014-03-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s(-1). Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s(-1) with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency.

Local probing by use of transparent model materials

NASA Astrophysics Data System (ADS)

Philippe, P.

2017-12-01

The present contribution emphasizes on two distinct examples the benefit with using transparent materials that enable direct visualization within different types of model systems. Our first use of transparent materials investigates the elementary mechanisms involved in soil erosion based on three key ingredients: a) cohesive model materials (i.e. glass beads bonded by solid bridges); b) optical techniques (Refractive Index Matching and Planar Laser Induced Fluorescence [1,2]) ; c) specific mechanical tests to estimate the mechanical strength of the solid bonds. Then, critical shear-stress at erosion onset can be related to tensile strength considering an extension of the classical Shields' number [3,4].Our second example uses a transparent elasto-visco-plastic fluid (Carbopol) as a model of debris flows. Different geometrical configurations allow for an accurate investigation of the flow over an obstacle [5] or a cavity [6], inducing the existence of a dead-zone and consequently of a frontier between solid-like and fluid-like regions that is of particular relevance for debris flows mobilization and deposition. Practically, the hydrodynamics of the flow is investigated by means of high-resolution optical velocimetry (PIV) and underlines a non-monotonous evolution of the shear rate, which increases from zero at the solid-liquid interface, passes through a peak (sometimes leveling off at its maximum value), and returns to zero in a plug zone sufficiently far above the cavity or the obstacle. [1] Philippe P., and Badiane M. Phys. Rev. E 87, 042206 (2013). [2] Dijksman J.A., Rietz F., Lorincz K.A., van Hecke M., and Losert W. Review of Scientific Instruments 83(1), 011301 (2012). [3] Badr S., Gauthier G., and Gondret P. Phys. Fluids 26:023302 (2014). [4] Brunier-Coulin F., Cuéllar P., and Philippe P. Phys. Rev. Fluids 87, 2: 034302 (2017). [5] Luu L.-H., Philippe P., and Chambon G. Phys. Rev. E 91, 013013 (2015). [6] Luu L.-H., Philippe P.; and Chambon G. Journal of Non-Newtonian Fluid Mechanics 245, 25-37 (2017).

Design, Operation, and Modeling of a Vertical APCVD Reactor for Silicon Carbide Film Growth

NASA Technical Reports Server (NTRS)

DeAnna, Russell G.; Fleischman, Aaron J.; Zorman, Christian A.; Mehregany, Mehran

1998-01-01

An atmospheric pressure chemical vapor deposition (APCVD) reactor utilizing a unique vertical geometry which enables 3C-SiC films to be grown on two, 4-inch diameter Si wafers has been constructed. Contrary to expectations, 3C-SiC films grown in this reactor are thickest at the downstream end of the substrates. To better understand the reason for the thickness distribution on the wafers, an axisymmetric finite-element model of the gas flow in the reactor was constructed. The model uses the ANSYS53 Flowtran package and includes compressible and temperature-dependent fluid properties in laminar or turbulent flow. It does not include reaction chemistry or unsteady flow. The ANSYS53 results predict that the cool, inlet fluid falls through the inlet pipe and the warm, diffuser region like a jet. This jet impinges on top of the susceptor and gets diverted to the reactor side walls, where it flows to the bottom of the reactor, turns, and slowly rises along the face of the susceptor. This may explain why the SiC films are thickest at the downstream side of the wafers, as gas containing fresh reactants first passes over this region. Modeling results are presented for both one atmosphere and one half atmosphere reactor pressure.

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.

An inkjet-printed electrowetting valve for paper-fluidic sensors.

PubMed

Koo, Charmaine K W; He, Fei; Nugen, Sam R

2013-09-07

Paper-fluidic devices have become an emerging trend for micro total analysis systems (microTAS) in the bioengineering field due to their ability to maintain the rapid, sensitive and specific attributes of microfluidic devices. Subsequently, paper-fluidic devices are also more portable, have a lower production cost and are easier to use. However, one of the obstacles in developing paper fluidic devices is the limited ability to control the rate of fluid flow during an assay. In our project, we use electrowetting on dielectrics where a dielectric, which is normally hydrophobic, is polarized and becomes hydrophilic. We have fabricated paper-fluidic devices by inkjet printing and spraying conductive hydrophobic electrodes/valves in conjunction with conductive hydrophilic electrodes which are able to stop the fluid front of phosphate buffered saline (PBS). The hydrophobic valves were then actuated by an applied potential which altered the fluorinated monolayer on the electrode. As the applied potential between the electrodes was increased, the amount of time for the fluid front to pass the valve decreased because the monolayer was altered faster. However, we did not observe significant differences in time as we increased the distance between the electrodes. The valves were also incorporated in a lateral flow assay where the device was used to detect Saccharomyces cerevisiae rRNA sequences. With the ability to control the fluid flow in a paper-fluidic device, more complex and intricate assays can be developed, which not only can be applied in the biomedical, food and environmental fields, but also can be used in low resource settings for the detection of diseases.

Fluid-solid interaction: benchmarking of an external coupling of ANSYS with CFX for cardiovascular applications.

PubMed

Hose, D R; Lawford, P V; Narracott, A J; Penrose, J M T; Jones, I P

2003-01-01

Fluid-solid interaction is a primary feature of cardiovascular flows. There is increasing interest in the numerical solution of these systems as the extensive computational resource required for such studies becomes available. One form of coupling is an external weak coupling of separate solid and fluid mechanics codes. Information about the stress tensor and displacement vector at the wetted boundary is passed between the codes, and an iterative scheme is employed to move towards convergence of these parameters at each time step. This approach has the attraction that separate codes with the most extensive functionality for each of the separate phases can be selected, which might be important in the context of the complex rheology and contact mechanics that often feature in cardiovascular systems. Penrose and Staples describe a weak coupling of CFX for computational fluid mechanics to ANSYS for solid mechanics, based on a simple Jacobi iteration scheme. It is important to validate the coupled numerical solutions. An extensive analytical study of flow in elastic-walled tubes was carried out by Womersley in the late 1950s. This paper describes the performance of the coupling software for the straight elastic-walled tube, and compares the results with Womersley's analytical solutions. It also presents preliminary results demonstrating the application of the coupled software in the context of a stented vessel.

Short-lived Radium Isotopes in the Hawaiian Margin: Evidence for Large Fluid Fluxes Through the Puna Ridge

NASA Astrophysics Data System (ADS)

Moore, W. S.; Paull, C. K.; Ussler, W.

2001-12-01

Techniques to sample and measure short-lived radium isotopes have significantly advanced understanding of groundwater-seawater exchange in coastal areas. The established sampling protocol utilizes traditional wire-line samplers from surface vessels to recover large (200 L) seawater samples. These samples are subsequently passed through Mn-fiber columns at a slow rate (100 L per hour) to assure high radium stripping efficiency. But, sampling near-bottom waters in areas of complicated bathymetry represents a technical challenge for traditional wire-line water sampling equipment. For MBARI's 2001 Hawaii expedition, we built a simple sampler to extract Ra from seawater surrounding the ROV Tiburon. The system uses a variable-flow electric pump to provide 1-2 L/min flow through one of 12 Mn-fiber-filled Ra-stripping canisters mounted on the ROV Tiburon. Values allow the flow to be directed to specific canisters. A flow meter allows the operator to control the flow and compute the volume sampled. The fibers are counted shipboard shortly after vehicle recovery. The ROV proved to be an ideal platform for Ra-sampling because it is able to slowly pump considerable volumes of seawater through the Ra-stripping columns while maintaining close contact with the bottom. Because the manifold was mounted on the ROV's side arm, its interference with other research objectives was minimal. Most of our sampling in Hawaii was conducted as a piggyback effort. We were able to collect 167 radium samples on 37 ROV dives with an average of 206 liters of seawater passing through the stripping canisters. Moreover, we are confident that the sampled waters come from 1-3 above the bottom. We measured significant activities of short-lived radium isotopes, 223Ra (half-life = 11 days) and 224Ra (half-life = 3.7 days), around the margins of the Hawaiian Islands to depths of 3100 m. These measurements suggest numerous groundwater or pore fluid inputs to the surrounding ocean. In general 223Ra activities were considerably greater than 224Ra in spite of the expected higher production rate of 224Ra from basalt. 223Ra was not supported by dissolved 227Ac. The highest enrichments of 223Ra were measured over the Puna Ridge (2100 m depth) east of Hawaii. Here 223Ra activities reached 2 dpm/100L, similar to activities measured near sites of active submarine groundwater discharge in the South Atlantic Bight. The high 223Ra values were not associated with significant thermal anomalies. To explain the high activities of 223Ra unaccompanied by 224Ra, we postulate that thermally-driven circulation of sea water through the Puna Ridge deposits 231Pa on basalt surfaces. With time the 231Pa produces 227Ac and 223Ra, which desorbs into circulating fluids. These fluids then transport 223Ra into the overlying ocean. Based on the inventory of 223Ra above the Puna Ridge, we estimate the flow of fluids through the ridge to be on the order of 40cm3cm-2day-1. In less than 100 years the incoming seawater could provide enough 231Pa to basalt surfaces to balance the inventory of 223Ra above the ridge if all of the 223Ra was transported to the overlying water. These observations have significant implications for quantifying fluid fluxes from the flanks of the mid ocean ridge. By mapping 223Ra inventories in the ocean above ridge flanks and the activity of 223Ra in the emerging fluids, the fluid flux can be obtained. These measurements could help resolve the debate of the relative importance of high and low temperature venting from the ridge.

Resistance formulas in hydraulics-based models for routing debris flows

USGS Publications Warehouse

Chen, Cheng-lung; Ling, Chi-Hai

1997-01-01

The one-dimensional, cross-section-averaged flow equations formulated for routing debris flows down a narrow valley are identical to those for clear-water flow, except for the differences in the values of the flow parameters, such as the momentum (or energy) correction factor, resistance coefficient, and friction slope. Though these flow parameters for debris flow in channels with cross-sections of arbitrary geometric shape can only be determined empirically, the theoretical values of such parameters for debris flow in wide channels exist. This paper aims to derive the theoretical resistance coefficient and friction slope for debris flow in wide channels using a rheological model for highly-concentrated, rapidly-sheared granular flows, such as the generalized viscoplastic fluid (GVF) model. Formulating such resistance coefficient or friction slope is equivalent to developing a generally applicable resistance formula for routing debris flows. Inclusion of a nonuniform term in the expression of the resistance formula proves useful in removing the customary assumption that the spatially varied resistance at any section is equal to what would take place with the same rate of flow passing the same section under conditions of uniformity. This in effect implies an improvement in the accuracy of unsteady debris-flow computation.

Computer Simulation To Assess The Feasibility Of Coring Magma

NASA Astrophysics Data System (ADS)

Su, J.; Eichelberger, J. C.

2017-12-01

Lava lakes on Kilauea Volcano, Hawaii have been successfully cored many times, often with nearly complete recovery and at temperatures exceeding 1100oC. Water exiting nozzles on the diamond core bit face quenches melt to glass just ahead of the advancing bit. The bit readily cuts a clean annulus and the core, fully quenched lava, passes smoothly into the core barrel. The core remains intact after recovery, even when there are comparable amounts of glass and crystals with different coefficients of thermal expansion. The unique resulting data reveal the rate and sequence of crystal growth in cooling basaltic lava and the continuous liquid line of descent as a function of temperature from basalt to rhyolite. Now that magma bodies, rather than lava pooled at the surface, have been penetrated by geothermal drilling, the question arises as to whether similar coring could be conducted at depth, providing fundamentally new insights into behavior of magma. This situation is considerably more complex because the coring would be conducted at depths exceeding 2 km and drilling fluid pressures of 20 MPa or more. Criteria that must be satisfied include: 1) melt is quenched ahead of the bit and the core itself must be quenched before it enters the barrel; 2) circulating drilling fluid must keep the temperature of the coring assembling cooled to within operational limits; 3) the drilling fluid column must nowhere exceed the local boiling point. A fluid flow simulation was conducted to estimate the process parameters necessary to maintain workable temperatures during the coring operation. SolidWorks Flow Simulation was used to estimate the effect of process parameters on the temperature distribution of the magma immediately surrounding the borehole and of drilling fluid within the bottom-hole assembly (BHA). A solid model of the BHA was created in SolidWorks to capture the flow behavior around the BHA components. Process parameters used in the model include the fluid properties and temperature of magma, coolant flow rate, rotation speed, and rate of penetration (ROP). The modeling results indicate that there are combinations of process parameters that will provide sufficient cooling to enable the desired coring process in magma.

Electrospun polyurethane as an alternative ventricular catheter and in vitro model of shunt obstruction

PubMed Central

Suresh, Supraja

2015-01-01

Intracranial pressure and volume vary considerably between hydrocephalic patients, and with age, health and haemodynamic status; if left untreated, intracranial pressure rises and the ventricular system expands to accommodate the excess cerebrospinal fluid, with significant morbidity and mortality. Cerebrospinal fluid shunts in use today have a high incidence of failure with shunt obstruction being the most serious. Conventional proximal shunt catheters are made from poly(dimethyl)siloxane, the walls of which are perforated with holes for the cerebrospinal fluid to pass through. The limited range of catheters, in terms of material selection and flow distribution, is responsible in large part for their poor performance. In this study, we present an alternative design of proximal catheter made of electrospun polyether urethane, and evaluate its performance in the presence of glial cells, which are responsible for shunt blockage. The viability and growth of cells on catheter materials such as poly(dimethyl)siloxane and polyurethane in the form of cast films, microfibrous mats and porous sponges were studied in the presence of proteins present in cerebrospinal fluid after 48 h and 96 h in culture. The numbers of viable cells on each substrate were comparable to untreated poly(dimethyl)siloxane, both in the presence and absence of serum proteins found in cerebrospinal fluid. A cell culture model of shunt obstruction was developed in which cells on electrospun polyether urethane catheters were subjected to flow during culture in vitro, and the degree of obstruction quantified in terms of hydraulic permeability after static and perfusion culture. The results indicate that a catheter made of electrospun polyether urethane would be able to maintain cerebrospinal fluid flow even with the presence of cells for the time period chosen for this study. These findings have implications for the design and deployment of microporous shunt catheter systems for the treatment of hydrocephalus. PMID:25245779

Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions

PubMed Central

Herbst, Daniel P.

2017-01-01

Abstract: Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30–70% glycerol–saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another. PMID:28298665

Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions.

PubMed

Herbst, Daniel P

2017-03-01

Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30-70% glycerol-saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another.

Application of a Modular Particle-Continuum Method to Partially Rarefied, Hypersonic Flow

NASA Astrophysics Data System (ADS)

Deschenes, Timothy R.; Boyd, Iain D.

2011-05-01

The Modular Particle-Continuum (MPC) method is used to simulate partially-rarefied, hypersonic flow over a sting-mounted planetary probe configuration. This hybrid method uses computational fluid dynamics (CFD) to solve the Navier-Stokes equations in regions that are continuum, while using direct simulation Monte Carlo (DSMC) in portions of the flow that are rarefied. The MPC method uses state-based coupling to pass information between the two flow solvers and decouples both time-step and mesh densities required by each solver. It is parallelized for distributed memory systems using dynamic domain decomposition and internal energy modes can be consistently modeled to be out of equilibrium with the translational mode in both solvers. The MPC results are compared to both full DSMC and CFD predictions and available experimental measurements. By using DSMC in only regions where the flow is nonequilibrium, the MPC method is able to reproduce full DSMC results down to the level of velocity and rotational energy probability density functions while requiring a fraction of the computational time.

Microfluidic rectifier based on poly(dimethylsiloxane) membrane and its application to a micropump

PubMed Central

Wang, Yao-Nan; Tsai, Chien-Hsiung; Fu, Lung-Ming; Lin Liou, Lung-Kai

2013-01-01

A microfluidic rectifier incorporating an obstructed microchannel and a PDMS membrane is proposed. During forward flow, the membrane deflects in the upward direction; thereby allowing the fluid to pass over the obstacle. Conversely, during reverse flow, the membrane seals against the obstacle, thereby closing the channel and preventing flow. It is shown that the proposed device can operate over a wide pressure range by increasing or decreasing the membrane thickness as required. A microfluidic pump is realized by integrating the rectifier with a simple stepper motor mechanism. The experimental results show that the pump can achieve a vertical left height of more than 2 m. Moreover, it is shown that a maximum flow rate of 6.3 ml/min can be obtained given a membrane thickness of 200 μm and a motor velocity of 80 rpm. In other words, the proposed microfluidic rectifier not only provides an effective means of preventing reverse flow but also permits the realization of a highly efficient microfluidic pump. PMID:24404051

Microfluidic rectifier based on poly(dimethylsiloxane) membrane and its application to a micropump.

PubMed

Wang, Yao-Nan; Tsai, Chien-Hsiung; Fu, Lung-Ming; Lin Liou, Lung-Kai

2013-01-01

A microfluidic rectifier incorporating an obstructed microchannel and a PDMS membrane is proposed. During forward flow, the membrane deflects in the upward direction; thereby allowing the fluid to pass over the obstacle. Conversely, during reverse flow, the membrane seals against the obstacle, thereby closing the channel and preventing flow. It is shown that the proposed device can operate over a wide pressure range by increasing or decreasing the membrane thickness as required. A microfluidic pump is realized by integrating the rectifier with a simple stepper motor mechanism. The experimental results show that the pump can achieve a vertical left height of more than 2 m. Moreover, it is shown that a maximum flow rate of 6.3 ml/min can be obtained given a membrane thickness of 200 μm and a motor velocity of 80 rpm. In other words, the proposed microfluidic rectifier not only provides an effective means of preventing reverse flow but also permits the realization of a highly efficient microfluidic pump.

Solid oxide fuel cell power plant with an anode recycle loop turbocharger

DOEpatents

Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.

2015-07-14

An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).

Solid oxide fuel cell power plant with an anode recycle loop turbocharger

DOEpatents

Saito, Kazuo; Skiba, Tommy; Patel, Kirtikumar H.

2016-09-27

An anode exhaust recycle turbocharger (100) has a turbocharger turbine (102) secured in fluid communication with a compressed oxidant stream within an oxidant inlet line (218) downstream from a compressed oxidant supply (104), and the anode exhaust recycle turbocharger (100) also includes a turbocharger compressor (106) mechanically linked to the turbocharger turbine (102) and secured in fluid communication with a flow of anode exhaust passing through an anode exhaust recycle loop (238) of the solid oxide fuel cell power plant (200). All or a portion of compressed oxidant within an oxidant inlet line (218) drives the turbocharger turbine (102) to thereby compress the anode exhaust stream in the recycle loop (238). A high-temperature, automotive-type turbocharger (100) replaces a recycle loop blower-compressor (52).

Experimental and Computational Study of Trapped Vortex Combustor Sector Rig With Tri-Pass Diffuser

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Shouse, D. T.; Roquernore, W. M.; Burrus, D. L.; Duncan, B. S.; Ryder, R. C.; Brankovic, A.; Liu, N.-S.; Gallagher, J. R.; Hendricks, J. A.

2004-01-01

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

Fracture distribution and porosity in a fault-bound hydrothermal system (Grimsel Pass, Swiss Alps)

NASA Astrophysics Data System (ADS)

Egli, Daniel; Küng, Sulamith; Baumann, Rahel; Berger, Alfons; Baron, Ludovic; Herwegh, Marco

2017-04-01

The spatial distribution, orientation and continuity of brittle and ductile structures strongly control fluid pathways in a rock mass by joining existing pores and creating new pore space (fractures, joints) but can also act as seals to fluid flow (e.g. ductile shear zones, clay-rich fault gouges). In long-lived hydrothermal systems, permeability and the related fluid flow paths are therefore dynamic in space and time. Understanding the evolution and behaviour of naturally porous and permeable rock masses is critical for the successful exploration and sustainable exploitation of hydrothermal systems and can advance methods for planning and implementation of enhanced geothermal systems. This study focuses on an active fault-bound hydrothermal system in the crystalline basement of the Aar Massif (hydrothermal field Grimsel Pass, Swiss Alps) that has been exhumed from few kilometres depth and which documents at least 3 Ma of hydrothermal activity. The explored rock unit of the Aar massif is part of the External Crystalline Massifs that hosts a multitude of thermal springs on its southern border in the Swiss Rhône valley and furthermore represents the exhumed equivalent of potentially exploitable geothermal reservoirs in the deep crystalline subsurface of the northern Alpine foreland basin. This study combines structural data collected from a 125 m long drillhole across the hydrothermal zone, the corresponding drill core and surface mapping. Different methods are applied to estimate the porosity and the structural evolution with regard to porosity, permeability and fracture distribution. Analyses are carried out from the micrometre to decametre scale with main focus on the flow path evolution with time. This includes a large variety of porosity-types including fracture-porosity with up to cm-sized aperture down to grain-scale porosity. Main rock types are granitoid host rocks, mylonites, paleo-breccia and recent breccias. The porosity of the host rock as well as the cemented paleo-hydrothermal breccia is typically very low with values <1%. The high volume of mineralized fractures in the paleo-breccia indicates high porosity in former times, which is today closed by newly developed cements. The preservation of such paleo-breccias allow the investigation of contrasts between the fossil porosity/permeability and the present day active flow path, which is defined by fracture porosity that generally follows the regional deformation pattern and forms a wide network of interconnected fractures of variable orientation.

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.

Microfluidic ultralow interfacial tensiometry with magnetic particles.

PubMed

Tsai, Scott S H; Wexler, Jason S; Wan, Jiandi; Stone, Howard A

2013-01-07

We describe a technique that measures ultralow interfacial tensions using paramagnetic spheres in a co-flow microfluidic device designed with a magnetic section. Our method involves tuning the distance between the co-flowing interface and the magnet's center, and observing the behavior of the spheres as they approach the liquid-liquid interface-the particles either pass through or are trapped by the interface. Using threshold values of the magnet-to-interface distance, we make estimates of the two-fluid interfacial tension. We demonstrate the effectiveness of this technique for measuring very low interfacial tensions, O(10(-6)-10(-5)) N m(-1), by testing solutions of different surfactant concentrations, and we show that our results are comparable with measurements made using a spinning drop tensiometer.

Gap flow in an Alpine valley during a shallow south fo¨hn event: Observations, numerical simulations and hydraulic analogue

NASA Astrophysics Data System (ADS)

Flamant, C.; Drobinski, P.; Nance, L.; Banta, R.; Darby, L.; Dusek, J.; Hardesty, M.; Pelon, J.; Richard, E.

2002-04-01

This paper examines the three-dimensional structure and dynamics of southerly hybrid gap/mountain flow through the Wipp valley (Wipptal), Austria, observed on 30 October 1999 using high-resolution observations and model simulations. The observations were obtained during a shallow south föhn event documented in the framework of the Mesoscale Alpine Programme (MAP). Three important data sources were used: the airborne differential-absorption lidar LEANDRE 2, the ground-based Doppler lidar TEACO2 and in situ measurements from the National Oceanic and Atmospheric Administration P-3 aircraft. This event was simulated down to 2 km horizontal resolution using the non-hydrostatic mesoscale model Meso-NH. The structure and dynamics of the flow were realistically simulated. The combination of high-resolution observations and numerical simulations provided a comprehensive three-dimensional picture of the flow through the Wipptal: in the gap entrance region (Brenner Pass, Austria), the low-level jet was not solely due to the channelling of the southerly synoptic flow through the elevated gap. Part of the Wipptal flow originated as a mountain wave at the valley head wall of the Brenner Pass. Downstream of the pass, the shallow föhn flow had the characteristics of a downslope windstorm as it rushed down towards the Inn valley (Inntal) and the City of Innsbruck, Austria. Downhill of the Brenner Pass, the strongest flow was observed over a small obstacle along the western side wall (the Nösslachjoch), rather than channelled in the deeper part of the valley just to the east. Further north, the low-level jet was observed in the centre of the valley. Approximately halfway between Brenner Pass and Innsbruck, where the along-axis direction of the valley changes from north to north-north-west, the low-level jet was observed to be deflected to the eastern side wall of the Wipptal. Interaction between the Stubaier Alpen (the largest and highest topographic feature to the west of the Wipptal) and the south-westerly synoptic flow was found to be the primary mechanism responsible for the deflection. The along- and cross-valley structure and dynamics of the flow were observed to be highly variable due to the influence of surrounding mountains, localized steep slopes within the valley and outflows from tributaries (the Gschnitztal and the Stubaital) to the west of the Wipptal. For that shallow föhn case, observations and simulations provided a large body of evidence that downslope flow created thinning/thickening fluid and accelerations/decelerations reminiscent of mountain wave/hydraulic theory. Along the Wipptal, two hydraulic-jump-like transitions were observed and simulated, (i) on the lee slope of the Nösslachjoch and (ii) in the Gschnitztal exit region. A hydraulic solution of the flow was calculated in the framework of reduced-gravity shallow-water theory. The down-valley evolution of the Froude number computed using LEANDRE 2, P-3 flight level and TEACO2 measurements confirmed that these transitions were associated with super- to subcritical transitions.

Experimental and Computational Study of Trapped Vortex Combustor Sector Rig with Tri-pass Diffuser

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Shouse, D. T.; Roquemore, W. M.; Burrus, D. L.; Duncan, B. S.; Ryder, R. C.; Brankovic, A.; Liu, N.-S.; Gallagher, J. R.; Hendricks, J. A.

2001-01-01

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL (Rich burn/Quick mix/Lean burn) modes of combustion. The present work describes the operational principles of the TVC, and provides detailed performance data on a configuration featuring a tri-pass diffusion system. Performance data include EINOx (NO(sub x) emission index) results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable in comparison to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

Modular assembly for supporting, straining, and directing flow to a core in a nuclear reactor

DOEpatents

Pennell, William E.

1977-01-01

A reactor core support arrangement for supporting, straining, and providing fluid flow to the core and periphery of a nuclear reactor during normal operation. A plurality of removable inlet modular units are contained within permanent liners in the lower supporting plate of the reactor vessel lower internals. During normal operation (1) each inlet modular unit directs main coolant flow to a plurality of core assemblies, the latter being removably supported in receptacles in the upper portion of the modular unit and (2) each inlet modular unit may direct bypass flow to a low pressure annular region of the reactor vessel. Each inlet modular unit may include special fluid seals interposed between mating surfaces of the inlet modular units and the core assemblies and between the inlet modular units and the liners, to minimize leakage and achieve an hydraulic balance. Utilizing the hydraulic balance, the modular units are held in the liners and the assemblies are held in the modular unit receptacles by their own respective weight. Included as part of the permanent liners below the horizontal support plate are generally hexagonal axial debris barriers. The axial debris barriers collectively form a bottom boundary of a secondary high pressure plenum, the upper boundary of which is the bottom surface of the horizontal support plate. Peripheral liners include radial debris barriers which collectively form a barrier against debris entry radially. During normal operation primary coolant inlet openings in the liner, below the axial debris barriers, pass a large amount of coolant into the inlet modular units, and secondary coolant inlet openings in the portion of the liners within the secondary plenum pass a small amount of coolant into the inlet modular units. The secondary coolant inlet openings also provide alternative coolant inlet flow paths in the unlikely event of blockage of the primary inlet openings. The primary inlet openings have characteristics which limit the entry of debris and minimize the potential for debris entering the primary inlets blocking the secondary inlets from inside the modular unit.

Apparatus for removing a contaminant from a fluid stream

DOEpatents

Brewster, M.D.; Posa, R.P.

1998-12-22

A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall. 4 figs.

Apparatus for removing a contaminant from a fluid stream

DOEpatents

Brewster, Michael D.; Posa, Richard P.

1998-01-01

A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall.

Optical chromatographic sample separation of hydrodynamically focused mixtures

PubMed Central

Terray, A.; Hebert, C. G.; Hart, S. J.

2014-01-01

Optical chromatography relies on the balance between the opposing optical and fluid drag forces acting on a particle. A typical configuration involves a loosely focused laser directly counter to the flow of particle-laden fluid passing through a microfluidic device. This equilibrium depends on the intrinsic properties of the particle, including size, shape, and refractive index. As such, uniquely fine separations are possible using this technique. Here, we demonstrate how matching the diameter of a microfluidic flow channel to that of the focusing laser in concert with a unique microfluidic platform can be used as a method to fractionate closely related particles in a mixed sample. This microfluidic network allows for a monodisperse sample of both polystyrene and poly(methyl methacrylate) spheres to be injected, hydrodynamically focused, and completely separated. To test the limit of separation, a mixed polystyrene sample containing two particles varying in diameter by less than 0.5 μm was run in the system. The analysis of the resulting separation sets the framework for continued work to perform ultra-fine separations. PMID:25553179

Development of a microfluidics model for studying migration of sperm in the female reproductive tract

NASA Astrophysics Data System (ADS)

Tung, Chih-Kuan; Ardón, Florencia; Wu, Mingming; Suárez, Susan

2013-03-01

Infertility is a significant issue, both for humans and dairy cattle. In order for fertilization to happen, sperm must migrate through the female reproductive tract to reach the egg in the oviduct (fallopian tube). There is strong evidence that sperm interact with the female tract via both chemical and physical mechanisms. In this work, we focus on how the physical environment of the female tract influences the migration of bull sperm, which also serve as models for human sperm. In order for bull and human sperm to pass from the vagina into the uterus, they must swim through the cervical canal, which is lined by microchannels. Then, sperm must swim through the uterotubal junction, which also contains microchannels, in order to reach the oviduct. In both passageways, sperm must swim against a fluid flow, which would be less in the microchannels than in the central passageways. We have developed a microfluidic model for studying the sperm migration effects of the geometry of the cervix and uterotubal junction and the fluid flow within. Supported by NIH grant 1R01HD070038.

Advanced computational techniques for incompressible/compressible fluid-structure interactions

NASA Astrophysics Data System (ADS)

Kumar, Vinod

2005-07-01

Fluid-Structure Interaction (FSI) problems are of great importance to many fields of engineering and pose tremendous challenges to numerical analyst. This thesis addresses some of the hurdles faced for both 2D and 3D real life time-dependent FSI problems with particular emphasis on parachute systems. The techniques developed here would help improve the design of parachutes and are of direct relevance to several other FSI problems. The fluid system is solved using the Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) finite element formulation for the Navier-Stokes equations of incompressible and compressible flows. The structural dynamics solver is based on a total Lagrangian finite element formulation. Newton-Raphson method is employed to linearize the otherwise nonlinear system resulting from the fluid and structure formulations. The fluid and structural systems are solved in decoupled fashion at each nonlinear iteration. While rigorous coupling methods are desirable for FSI simulations, the decoupled solution techniques provide sufficient convergence in the time-dependent problems considered here. In this thesis, common problems in the FSI simulations of parachutes are discussed and possible remedies for a few of them are presented. Further, the effects of the porosity model on the aerodynamic forces of round parachutes are analyzed. Techniques for solving compressible FSI problems are also discussed. Subsequently, a better stabilization technique is proposed to efficiently capture and accurately predict the shocks in supersonic flows. The numerical examples simulated here require high performance computing. Therefore, numerical tools using distributed memory supercomputers with message passing interface (MPI) libraries were developed.

Self-contained heat rejection module for future spacecraft

NASA Technical Reports Server (NTRS)

Fleming, M. L.; Williams, J. L.; Baskett, J. D.; Leach, J. W.

1975-01-01

This paper discusses development of a Self-Contained Heat Rejection Module (SHRM) which can be used on a wide variety of future spacecraft launched by the space shuttle orbiter. The SHRM contains radiators which are deployed by a scissor-mechanism and the flow equipment including pumps, accumulator, by-pass valves, and controllers necessary to reject heat from those radiators. Heat transfer between SHRM and the parent vehicle is effected by a contact heat exchanger. This device provides heat transfer between two separate flow loops through a mechanical connection. This approach reduces the time required to attach the SHRM to the payload, and increases the reliability of the SHRM flow loop since breaking into the fluid system in the field is not required. The SHRM concept also includes a refrigeration system to increase heat rejection capacity in adverse environments, or to provide for a lower return temperature, down to -23 C.

MPI implementation of PHOENICS: A general purpose computational fluid dynamics code

NASA Astrophysics Data System (ADS)

Simunovic, S.; Zacharia, T.; Baltas, N.; Spalding, D. B.

1995-03-01

PHOENICS is a suite of computational analysis programs that are used for simulation of fluid flow, heat transfer, and dynamical reaction processes. The parallel version of the solver EARTH for the Computational Fluid Dynamics (CFD) program PHOENICS has been implemented using Message Passing Interface (MPI) standard. Implementation of MPI version of PHOENICS makes this computational tool portable to a wide range of parallel machines and enables the use of high performance computing for large scale computational simulations. MPI libraries are available on several parallel architectures making the program usable across different architectures as well as on heterogeneous computer networks. The Intel Paragon NX and MPI versions of the program have been developed and tested on massively parallel supercomputers Intel Paragon XP/S 5, XP/S 35, and Kendall Square Research, and on the multiprocessor SGI Onyx computer at Oak Ridge National Laboratory. The preliminary testing results of the developed program have shown scalable performance for reasonably sized computational domains.

MPI implementation of PHOENICS: A general purpose computational fluid dynamics code

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

Simunovic, S.; Zacharia, T.; Baltas, N.

1995-04-01

PHOENICS is a suite of computational analysis programs that are used for simulation of fluid flow, heat transfer, and dynamical reaction processes. The parallel version of the solver EARTH for the Computational Fluid Dynamics (CFD) program PHOENICS has been implemented using Message Passing Interface (MPI) standard. Implementation of MPI version of PHOENICS makes this computational tool portable to a wide range of parallel machines and enables the use of high performance computing for large scale computational simulations. MPI libraries are available on several parallel architectures making the program usable across different architectures as well as on heterogeneous computer networks. Themore » Intel Paragon NX and MPI versions of the program have been developed and tested on massively parallel supercomputers Intel Paragon XP/S 5, XP/S 35, and Kendall Square Research, and on the multiprocessor SGI Onyx computer at Oak Ridge National Laboratory. The preliminary testing results of the developed program have shown scalable performance for reasonably sized computational domains.« less

Apparatus for unloading pressurized fluid

DOEpatents

Rehberger, K.M.

1994-01-04

An apparatus is described for unloading fluid, preferably pressurized gas, from containers in a controlled manner that protects the immediate area from exposure to the container contents. The device consists of an unloading housing, which is enclosed within at least one protective structure, for receiving the dispensed contents of the steel container, and a laser light source, located external to the protective structure, for opening the steel container instantaneously. The neck or stem of the fluid container is placed within the sealed interior environment of the unloading housing. The laser light passes through both the protective structure and the unloading housing to instantaneously pierce a small hole within the stem of the container. Both the protective structure and the unloading housing are specially designed to allow laser light passage without compromising the light's energy level. Also, the unloading housing allows controlled flow of the gas once it has been dispensed from the container. The external light source permits remote operation of the unloading device. 2 figures.

Vortex Ring Interaction with a Heated Screen

NASA Astrophysics Data System (ADS)

Smith, Jason; Krueger, Paul S.

2008-11-01

Previous examinations of vortex rings impinging on porous screens has shown the reformation of the vortex ring with a lower velocity after passing through the screen, the creation of secondary vortices, and mixing. A heated screen could, in principle, alter the vortex-screen interaction by changing the local liquid viscosity and density. In the present investigation, a mechanical piston-cylinder vortex ring generator was used to create vortex rings in an aqueous sucrose solution. The rings impinged on a screen of horizontal wires that were heated using electrical current. The flow was visualized with food color and video imaging. Tests with and without heat were conducted at a piston stroke-to-jet diameter ratio of 4 and a jet Reynolds number (Re) of 1000. The vortex rings slowed after passing through the screen, but in tests with heat, they maintained a higher fraction of their before-screen velocity due to reduction in fluid viscosity near the wires. In addition, small ``fingers'' that developed on the front of the vortex rings as they passed through the screen exhibited positive buoyancy effects in the heated case.

Continuous flow real-time PCR device using multi-channel fluorescence excitation and detection.

PubMed

Hatch, Andrew C; Ray, Tathagata; Lintecum, Kelly; Youngbull, Cody

2014-02-07

High throughput automation is greatly enhanced using techniques that employ conveyor belt strategies with un-interrupted streams of flow. We have developed a 'conveyor belt' analog for high throughput real-time quantitative Polymerase Chain Reaction (qPCR) using droplet emulsion technology. We developed a low power, portable device that employs LED and fiber optic fluorescence excitation in conjunction with a continuous flow thermal cycler to achieve multi-channel fluorescence detection for real-time fluorescence measurements. Continuously streaming fluid plugs or droplets pass through tubing wrapped around a two-temperature zone thermal block with each wrap of tubing fluorescently coupled to a 64-channel multi-anode PMT. This work demonstrates real-time qPCR of 0.1-10 μL droplets or fluid plugs over a range of 7 orders of magnitude concentration from 1 × 10(1) to 1 × 10(7). The real-time qPCR analysis allows dynamic range quantification as high as 1 × 10(7) copies per 10 μL reaction, with PCR efficiencies within the range of 90-110% based on serial dilution assays and a limit of detection of 10 copies per rxn. The combined functionality of continuous flow, low power thermal cycling, high throughput sample processing, and real-time qPCR improves the rates at which biological or environmental samples can be continuously sampled and analyzed.

Translocation pathways for inhaled asbestos fibers

PubMed Central

Miserocchi, G; Sancini, G; Mantegazza, F; Chiappino, Gerolamo

2008-01-01

We discuss the translocation of inhaled asbestos fibers based on pulmonary and pleuro-pulmonary interstitial fluid dynamics. Fibers can pass the alveolar barrier and reach the lung interstitium via the paracellular route down a mass water flow due to combined osmotic (active Na+ absorption) and hydraulic (interstitial pressure is subatmospheric) pressure gradient. Fibers can be dragged from the lung interstitium by pulmonary lymph flow (primary translocation) wherefrom they can reach the blood stream and subsequently distribute to the whole body (secondary translocation). Primary translocation across the visceral pleura and towards pulmonary capillaries may also occur if the asbestos-induced lung inflammation increases pulmonary interstitial pressure so as to reverse the trans-mesothelial and trans-endothelial pressure gradients. Secondary translocation to the pleural space may occur via the physiological route of pleural fluid formation across the parietal pleura; fibers accumulation in parietal pleura stomata (black spots) reflects the role of parietal lymphatics in draining pleural fluid. Asbestos fibers are found in all organs of subjects either occupationally exposed or not exposed to asbestos. Fibers concentration correlates with specific conditions of interstitial fluid dynamics, in line with the notion that in all organs microvascular filtration occurs from capillaries to the extravascular spaces. Concentration is high in the kidney (reflecting high perfusion pressure and flow) and in the liver (reflecting high microvascular permeability) while it is relatively low in the brain (due to low permeability of blood-brain barrier). Ultrafine fibers (length < 5 μm, diameter < 0.25 μm) can travel larger distances due to low steric hindrance (in mesothelioma about 90% of fibers are ultrafine). Fibers translocation is a slow process developing over decades of life: it is aided by high biopersistence, by inflammation-induced increase in permeability, by low steric hindrance and by fibers motion pattern at low Reynolds numbers; it is hindered by fibrosis that increases interstitial flow resistances. PMID:18218073

Insertable fluid flow passage bridgepiece and method

DOEpatents

Jones, Daniel O.

2000-01-01

A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.

Arthroscopic labral repair of the hip, using a through-labral double-stranded single-pass suture technique.

PubMed

Ye, Ken; Singh, Parminder J

2014-10-01

The normal labrum is crucial to the biomechanical function of the hip joint, not only increasing the surface area and depth of the acetabulum but also maintaining a suction seal to assist in normal synovial fluid flow from the peripheral to the central compartment. Simple loop suture repairs of the labrum may evert the labrum, thus losing the optimal seal, as well as causing abrasion of the articular cartilage. Vertical mattress suture and labral base fixation techniques aim to leave the free edge of the labrum intact and undisturbed, therefore improving the contact of the labrum to the femoral head and neck to improve the seal of the acetabulum. We aim to describe a double-stranded single-pass vertical mattress suture technique that may allow greater versatility to the surgeon in repairing thinner labrums while still achieving a free and continuous free edge.

Transient nature of Arctic spring systems driven by subglacial meltwater

NASA Astrophysics Data System (ADS)

Scheidegger, J. M.; Bense, V. F.; Grasby, S. E.

2012-06-01

In the High Arctic, supra- and proglacial springs occur at Borup Fiord Pass, Ellesmere Island. Spring waters are sulfur bearing and isotope analysis suggests springs are fed by deeply circulating glacial meltwater. However, the mechanism maintaining spring flow is unclear in these areas of thick permafrost which would hamper the discharge of deep groundwater to the surface. It has been hypothesized that fracture zones along faults focus groundwater which discharges initially underneath wet-based parts of the ice. With thinning ice, the spring head is exposed to surface temperatures, tens of degrees lower than temperatures of pressure melting, and permafrost starts to develop. Numerical modeling of coupled heat and fluid flow suggest that focused groundwater discharge should eventually be cut off by permafrost encroaching into the feeding channel of the spring. Nevertheless, our model simulations show that these springs can remain flowing for millennia depending on the initial flow rate and ambient surface temperature. These systems might provide a terrestrial analog for the possible occurrence of Martian springs recharged by polar ice caps.

High-performance parallel analysis of coupled problems for aircraft propulsion

NASA Technical Reports Server (NTRS)

Felippa, C. A.; Farhat, C.; Chen, P.-S.; Gumaste, U.; Leoinne, M.; Stern, P.

1995-01-01

This research program deals with the application of high-performance computing methods to the numerical simulation of complete jet engines. The program was initiated in 1993 by applying two-dimensional parallel aeroelastic codes to the interior gas flow problem of a by-pass jet engine. The fluid mesh generation, domain decomposition and solution capabilities were successfully tested. Attention was then focused on methodology for the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by these structural displacements. The latter is treated by an ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field fluid elements. New partitioned analysis procedures to treat this coupled 3-component problem were developed in 1994. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers. For the global steady-state axisymmetric analysis of a complete engine we have decided to use the NASA-sponsored ENG10 program, which uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 has been developed. It is planned to use the steady-state global solution provided by ENG10 as input to a localized three-dimensional FSI analysis for engine regions where aeroelastic effects may be important.

Automatic vision system for analysis of microscopic behavior of flow and transport in porous media

NASA Astrophysics Data System (ADS)

Rashidi, Mehdi; Dehmeshki, Jamshid; Dickenson, Eric; Daemi, M. Farhang

1997-10-01

This paper describes the development of a novel automated and efficient vision system to obtain velocity and concentration measurement within a porous medium. An aqueous fluid lace with a fluorescent dye to microspheres flows through a transparent, refractive-index-matched column packed with transparent crystals. For illumination purposes, a planar sheet of laser passes through the column as a CCD camera records all the laser illuminated planes. Detailed microscopic velocity and concentration fields have been computed within a 3D volume of the column. For measuring velocities, while the aqueous fluid, laced with fluorescent microspheres, flows through the transparent medium, a CCD camera records the motions of the fluorescing particles by a video cassette recorder. The recorded images are acquired automatically frame by frame and transferred to the computer for processing, by using a frame grabber an written relevant algorithms through an RS-232 interface. Since the grabbed image is poor in this stage, some preprocessings are used to enhance particles within images. Finally, these enhanced particles are monitored to calculate velocity vectors in the plane of the beam. For concentration measurements, while the aqueous fluid, laced with a fluorescent organic dye, flows through the transparent medium, a CCD camera sweeps back and forth across the column and records concentration slices on the planes illuminated by the laser beam traveling simultaneously with the camera. Subsequently, these recorded images are transferred to the computer for processing in similar fashion to the velocity measurement. In order to have a fully automatic vision system, several detailed image processing techniques are developed to match exact images that have different intensities values but the same topological characteristics. This results in normalized interstitial chemical concentrations as a function of time within the porous column.

Acoustic concentration of particles in fluid flow

DOEpatents

Ward, Michael D.; Kaduchak, Gregory

2010-11-23

An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.

Three-dimensional flow characteristics of aluminum alloy in multi-pass equal channel angular pressing

NASA Astrophysics Data System (ADS)

Jin, Young-Gwan; Son, Il-Heon; Im, Yong-Taek

2010-06-01

Experiments with a square specimen made of commercially pure aluminum alloy (AA1050) were conducted to investigate deformation behaviour during a multi-pass Equal Channel Angular Pressing (ECAP) for routes A, Bc, and C up to four passes. Three-dimensional finite element numerical simulations of the multi-pass ECAP were carried out in order to evaluate the influence of processing routes and number of passes on local flow behaviour by applying a simplified saturation model of flow stress under an isothermal condition. Simulation results were investigated by comparing them with the experimentally measured data in terms of load variations and microhardness distributions. Also, transmission electron microscopy analysis was employed to investigate the microstructural changes. The present work clearly shows that the three-dimensional flow characteristics of the deformed specimen were dependent on the strain path changes due to the processing routes and number of passes that occurred during the multi-pass ECAP.

Quasi-steady Bingham plastic analysis of an electrorheological flow mode bypass damper with piston bleed

NASA Astrophysics Data System (ADS)

Lindler, Jason; Wereley, Norman M.

2003-06-01

We present an improved experimental validation of our nonlinear quasi-steady electrorheological (ER) and magnetorheological damper analysis, using an idealized Bingham plastic shear flow mechanism, for the flow mode of damper operation with leakage effect. To validate the model, a double-acting ER valve or bypass damper was designed and fabricated. Both the hydraulic cylinder and the bypass duct have cylindrical geometry, and damping forces are developed in the annular bypass via Poiseuille flow. The ER fluid damper contains a controlled amount of leakage around the piston head. The leakage allows ER fluid to flow from one side of the piston head to the opposite side without passing through the ER bypass. For this flow mode damper, the damping coefficient, defined as the ratio of equivalent viscous damping of the Bingham plastic material, Ceq, to the Newtonian viscous damping, C, is a function of the non-dimensional plug thickness only. The damper was tested for varying conditions of applied electric field and frequency using a mechanical damper dynamometer. In this analysis, the leakage damping coefficient with incorporated leakage effects, predict the amount of energy dissipated for a complete cycle of the piston rod. Measured force verses displacement cycles for multiple frequencies and electric fields validate the ability of the non-dimensional groups and the leakage damping coefficient to predict the damping levels for an ER bypass damper with leakage. Based on the experimental validation of the model using these data, the Bingham plastic analysis is shown to be an effective tool for the analysis-based design of double-acting ER bypass dampers.

Particle-bearing currents in uniform density and two-layer fluids

NASA Astrophysics Data System (ADS)

Sutherland, Bruce R.; Gingras, Murray K.; Knudson, Calla; Steverango, Luke; Surma, Christopher

2018-02-01

Lock-release gravity current experiments are performed to examine the evolution of a particle bearing flow that propagates either in a uniform-density fluid or in a two-layer fluid. In all cases, the current is composed of fresh water plus micrometer-scale particles, the ambient fluid is saline, and the current advances initially either over the surface as a hypopycnal current or at the interface of the two-layer fluid as a mesopycnal current. In most cases the tank is tilted so that the ambient fluid becomes deeper with distance from the lock. For hypopycnal currents advancing in a uniform density fluid, the current typically slows as particles rain out of the current. While the loss of particles alone from the current should increase the current's buoyancy and speed, in practice the current's speed decreases because the particles carry with them interstitial fluid from the current. Meanwhile, rather than settling on the sloping bottom of the tank, the particles form a hyperpycnal (turbidity) current that advances until enough particles rain out that the relatively less dense interstitial fluid returns to the surface, carrying some particles back upward. When a hypopycnal current runs over the surface of a two-layer fluid, the particles that rain out temporarily halt their descent as they reach the interface, eventually passing through it and again forming a hyperpycnal current. Dramatically, a mesopycnal current in a two-layer fluid first advances along the interface and then reverses direction as particles rain out below and fresh interstitial fluid rises above.

Computational Fluid Dynamics Modeling of the John Day Dam Tailrace

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

Rakowski, Cynthia L.; Perkins, William A.; Richmond, Marshall C.

US Army Corps of Engineers - Portland District required that a two-dimensional (2D) depth-averaged and a three-dimensional (3D) free-surface numerical models to be developed and validated for the John Day tailrace. These models were used to assess potential impact of a select group of structural and operational alternatives to tailrace flows aimed at improving fish survival at John Day Dam. The 2D model was used for the initial assessment of the alternatives in conjunction with a reduced-scale physical model of the John Day Project. A finer resolution 3D model was used to more accurately model the details of flow inmore » the stilling basin and near-project tailrace hydraulics. Three-dimensional model results were used as input to the Pacific Northwest National Laboratory particle tracking software, and particle paths and times to pass a downstream cross section were used to assess the relative differences in travel times resulting from project operations and structural scenarios for multiple total river flows. Streamlines and neutrally-buoyant particles were seeded in all turbine and spill bays with flows. For a Total River of 250 kcfs running with the Fish Passage Plan spill pattern and a spillwall, the mean residence times for all particles were little changed; however the tails of the distribution were truncated for both spillway and powerhouse release points, and, for the powerhouse releases, reduced the residence time for 75% of the particles to pass a downstream cross section from 45.5 minutes to 41.3 minutes. For a total river of 125 kcfs configured with the operations from the Fish Passage Plan for the temporary spillway weirs and for a proposed spillwall, the neutrally-buoyant particle tracking data showed that the river with a spillwall in place had the overall mean residence time increase; however, the residence time for 75% of the powerhouse-released particles to pass a downstream cross section was reduced from 102.4 min to 89 minutes.« less

Acoustic concentration of particles in fluid flow

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

Ward, Michael W.; Kaduchak, Gregory

Disclosed herein is a acoustic concentration of particles in a fluid flow that includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluidmore » flow path to the at least one pressure minima.« less

Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation

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

Jayaweera, Indira; Krishnan, Gopala N.; Sanjurjo, Angel

2016-04-26

The invention provides methods for preparing an asymmetric hollow fiber, the asymmetric hollow fibers prepared by such methods, and uses of the asymmetric hollow fibers. One method involves passing a polymeric solution through an outer annular orifice of a tube-in-orifice spinneret, passing a bore fluid though an inner tube of the spinneret, dropping the polymeric solution and bore fluid through an atmosphere over a dropping distance, and quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber.

Compact, Two-Sided Structural Cold Plate Configuration

NASA Technical Reports Server (NTRS)

Zaffetti, Mark

2011-01-01

In two-sided structural cold plates, typically there is a structural member, such as a honeycomb panel, that provides the structural strength for the cold plates that cool equipment. The cold plates are located on either side of the structural member and thus need to have the cooling fluid supplied to them. One method of accomplishing this is to route the inlet and outlet tubing to both sides of the structural member. Another method might be to supply the inlet to one side and the outlet to the other. With the latter method, an external feature such as a hose, tube, or manifold must be incorporated to pass the fluid from one side of the structural member to the other. Although this is a more compact design than the first option, since it eliminates the need for a dedicated supply and return line to each side of the structural member, it still poses problems, as these external features can be easily damaged and are now new areas for potential fluid leakage. This invention eliminates the need for an external feature and instead incorporates the feature internally to the structural member. This is accomplished by utilizing a threaded insert that not only connects the cold plate to the structural member, but also allows the cooling fluid to flow through it into the structural member, and then to the cold plate on the opposite side. The insert also employs a cap that acts as a cover to seal the open area needed to install the insert. There are multiple options for location of o-ring style seals, as well as the option to use adhesive for redundant sealing. Another option is to weld the cap to the cold plate after its installation, thus making it an integral part of the structural member. This new configuration allows the fluid to pass from one cold plate to the other without any exposed external features.

PUMP CONSTRUCTION

DOEpatents

Strickland, G.; Horn, F.L.; White, H.T.

1960-09-27

A pump which utilizes the fluid being pumped through it as its lubricating fluid is described. This is achieved by means of an improved bearing construction in a pump of the enclosed or canned rotor type. At the outlet end of the pump, adjacent to an impeller mechanism, there is a bypass which conveys some of the pumped fluid to a chamber at the inlet end of the pump. After this chamber becomes full, the pumped fluid passes through fixed orifices in the top of the chamber and exerts a thrust on the inlet end of the pump rotor. Lubrication of the rotor shaft is accomplished by passing the pumped fluid through a bypass at the outlet end of the rotor shaft. This bypass conveys Pumped fluid to a cooling means and then to grooves on the surface of the rotor shait, thus lubricating the shaft.

D and 18O enrichment measurements in biological fluids in a continuous-flow elemental analyser with an isotope-ratio mass spectrometer using two configurations.

PubMed

Ripoche, N; Ferchaud-Roucher, V; Krempf, M; Ritz, P

2006-09-01

In doubly labelled water studies, biological sample enrichments are mainly measured using off-line techniques (equilibration followed by dual-inlet introduction) or high-temperature elemental analysis (HT-EA), coupled with an isotope-ratio mass spectrometer (IRMS). Here another continuous-flow method, (CF-EA/IRMS), initially dedicated to water, is tested for plasma and urine analyses. The elemental analyser configuration is adapted for each stable isotope: chromium tube for deuterium reduction and glassy carbon reactor for 18O pyrolysis. Before on-line conversion of water into gas, each matrix is submitted to a short and easy treatment, which is the same for the analysis of the two isotopes. Plasma is passed through centrifugal filters. Urine is cleaned with black carbon and filtered (0.45 microm diameter). Tested between 150 and 300 ppm in these fluids, the D/H ratio response is linear with good repeatability (SD<0.2 ppm) and reproducibility (SD<0.5 ppm). For 18O/16O ratios (from 2000 to 2200 ppm), the same repeatability is obtained with a between-day precision lower than 1.4 ppm. The accuracy on biological samples is validated by comparison to classical dual-inlet methods: 18O analyses give more accurate results. The data show that enriched physiological fluids can be successfully analysed in CF-EA/IRMS. Copyright (c) 2006 John Wiley & Sons, Ltd.

Suppression of tonal noise in a centrifugal fan using guide vanes

NASA Astrophysics Data System (ADS)

Paramasivam, Kishokanna; Rajoo, Srithar; Romagnoli, Alessandro

2015-11-01

This paper presents the work aiming for tonal noise reduction in a centrifugal fan. In previous studies, it is well documented that tonal noise is the dominant noise source generated in centrifugal fans. Tonal noise is generated due to the aerodynamic interaction between the rotating impeller and stationary diffuser vanes. The generation of tonal noise is related to the pressure fluctuation at the leading edge of the stationary vane. The tonal noise is periodic in time which occurs at the blade passing frequency (BPF) and its harmonics. Much of previous studies, have shown that the stationary vane causes the tonal noise and generation of non-rotational turbulent noise. However, omitting stationary vanes will lead to the increase of non-rotational turbulent noise resulted from the high velocity of the flow leaving the impeller. Hence in order to reduce the tonal noise and the non-rotational noise, guide vanes were designed as part of this study to replace the diffuser vanes, which were originally used in the chosen centrifugal fan. The leading edge of the guide vane is tapered. This modification reduces the strength of pressure fluctuation resulting from the interaction between the impeller outflow and stationary vane. The sound pressure level at blade passing frequency (BPF) is reduced by 6.8 dB, the 2nd BPF is reduced by 4.1 dB and the 3rd BPF reduced by about 17.5 dB. The overall reduction was 0.9 dB. The centrifugal fan with tapered guide vanes radiates lower tonal noise compared to the existing diffuser vanes. These reductions are achieved without compromising the performance of the centrifugal fan. The behavior of the fluid flow was studied using computational fluid dynamics (CFD) tools and the acoustics characteristics were determined through experiments in an anechoic chamber.

Magnetic Partitioning Nanofluid for Rare Earth Extraction from Geothermal Fluids

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

McGrail, Bernard P.; Thallapally, Praveen K.; Liu, Jian

Rare earth metals are critical materials in a wide variety of applications in generating and storing renewable energy and in designing more energy efficient devices. Extracting rare earth metals from geothermal brines is a very challenging problem due to the low concentrations of these elements and engineering challenges with traditional chemical separations methods involving packed sorbent beds or membranes that would impede large volumetric flow rates of geothermal fluids transitioning through the plant. We are demonstrating a simple and highly cost-effective nanofluid-based method for extracting rare earth metals from geothermal brines. Core-shell composite nanoparticles are produced that contain a magneticmore » iron oxide core surrounded by a shell made of silica or metal-organic framework (MOF) sorbent functionalized with chelating ligands selective for the rare earth elements. By introducing the nanoparticles at low concentration (≈0.05 wt%) into the geothermal brine after it passes through the plant heat exchanger, the brine is exposed to a very high concentration of chelating sites on the nanoparticles without need to pass through a large and costly traditional packed bed or membrane system where pressure drop and parasitic pumping power losses are significant issues. Instead, after a short residence time flowing with the brine, the particles are effectively separated out with an electromagnet and standard extraction methods are then applied to strip the rare earth metals from the nanoparticles, which are then recycled back to the geothermal plant. Recovery efficiency for the rare earths at ppm level has now been measured for both silica and MOF sorbents functionalized with a variety of chelating ligands. A detailed preliminary techno-economic performance analysis of extraction systems using both sorbents showed potential to generate a promising internal rate of return (IRR) up to 20%.« less

The Glymphatic System in Central Nervous System Health and Disease: Past, Present, and Future.

PubMed

Plog, Benjamin A; Nedergaard, Maiken

2018-01-24

The central nervous system (CNS) is unique in being the only organ system lacking lymphatic vessels to assist in the removal of interstitial metabolic waste products. Recent work has led to the discovery of the glymphatic system, a glial-dependent perivascular network that subserves a pseudolymphatic function in the brain. Within the glymphatic pathway, cerebrospinal fluid (CSF) enters the brain via periarterial spaces, passes into the interstitium via perivascular astrocytic aquaporin-4, and then drives the perivenous drainage of interstitial fluid (ISF) and its solute. Here, we review the role of the glymphatic pathway in CNS physiology, the factors known to regulate glymphatic flow, and the pathologic processes in which a breakdown of glymphatic CSF-ISF exchange has been implicated in disease initiation and progression. Important areas of future research, including manipulation of glymphatic activity aiming to improve waste clearance and therapeutic agent delivery, are also discussed.

The glymphatic system in CNS health and disease: past, present and future

PubMed Central

Plog, Benjamin A.; Nedergaard, Maiken

2018-01-01

The central nervous system (CNS) is unique in being the only organ system lacking lymphatic vessels to assist in the removal of interstitial metabolic waste products. Recent work has led to the discovery of the glymphatic system, a glial-dependent perivascular network that subserves a pseudo-lymphatic function in the brain. Within the glymphatic pathway, cerebrospinal fluid (CSF) enters brain via periarterial spaces, passes into the interstitium via perivascular astrocytic aquaporin-4, and then drives the perivenous drainage of interstitial fluid (ISF) and its solute. Here we review the role of the glymphatic pathway in CNS physiology, factors known to regulate glymphatic flow, and pathologic processes where a breakdown of glymphatic CSF-ISF exchange has been implicated in disease initiation and progression. Important areas of future research, including manipulation of glymphatic activity aiming to improve waste clearance and therapeutic agent delivery, will also be discussed. PMID:29195051

Dynamic bed reactor

DOEpatents

Stormo, Keith E.

1996-07-02

A dynamic bed reactor is disclosed in which a compressible open cell foam matrix is periodically compressed and expanded to move a liquid or fluid through the matrix. In preferred embodiments, the matrix contains an active material such as an enzyme, biological cell, chelating agent, oligonucleotide, adsorbent or other material that acts upon the liquid or fluid passing through the matrix. The active material may be physically immobilized in the matrix, or attached by covalent or ionic bonds. Microbeads, substantially all of which have diameters less than 50 microns, can be used to immobilize the active material in the matrix and further improve reactor efficiency. A particularly preferred matrix is made of open cell polyurethane foam, which adsorbs pollutants such as polychlorophenol or o-nitrophenol. The reactors of the present invention allow unidirectional non-laminar flow through the matrix, and promote intimate exposure of liquid reactants to active agents such as microorganisms immobilized in the matrix.

Flow Cage Assemblies

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bao, Xiaoqi (Inventor)

2017-01-01

Apparatus, systems and methods for implementing flow cages and flow cage assemblies in association with high pressure fluid flows and fluid valves are provided. Flow cages and flow assemblies are provided to dissipate the energy of a fluid flow, such as by reducing fluid flow pressure and/or fluid flow velocity. In some embodiments the dissipation of the fluid flow energy is adapted to reduce erosion, such as from high-pressure jet flows, to reduce cavitation, such as by controllably increasing the flow area, and/or to reduce valve noise associated with pressure surge.

Rotor cascade shape optimization with unsteady passing wakes using implicit dual time stepping method

NASA Astrophysics Data System (ADS)

Lee, Eun Seok

2000-10-01

An improved aerodynamics performance of a turbine cascade shape can be achieved by an understanding of the flow-field associated with the stator-rotor interaction. In this research, an axial gas turbine airfoil cascade shape is optimized for improved aerodynamic performance by using an unsteady Navier-Stokes solver and a parallel genetic algorithm. The objective of the research is twofold: (1) to develop a computational fluid dynamics code having faster convergence rate and unsteady flow simulation capabilities, and (2) to optimize a turbine airfoil cascade shape with unsteady passing wakes for improved aerodynamic performance. The computer code solves the Reynolds averaged Navier-Stokes equations. It is based on the explicit, finite difference, Runge-Kutta time marching scheme and the Diagonalized Alternating Direction Implicit (DADI) scheme, with the Baldwin-Lomax algebraic and k-epsilon turbulence modeling. Improvements in the code focused on the cascade shape design capability, convergence acceleration and unsteady formulation. First, the inverse shape design method was implemented in the code to provide the design capability, where a surface transpiration concept was employed as an inverse technique to modify the geometry satisfying the user specified pressure distribution on the airfoil surface. Second, an approximation storage multigrid method was implemented as an acceleration technique. Third, the preconditioning method was adopted to speed up the convergence rate in solving the low Mach number flows. Finally, the implicit dual time stepping method was incorporated in order to simulate the unsteady flow-fields. For the unsteady code validation, the Stokes's 2nd problem and the Poiseuille flow were chosen and compared with the computed results and analytic solutions. To test the code's ability to capture the natural unsteady flow phenomena, vortex shedding past a cylinder and the shock oscillation over a bicircular airfoil were simulated and compared with experiments and other research results. The rotor cascade shape optimization with unsteady passing wakes was performed to obtain an improved aerodynamic performance using the unsteady Navier-Stokes solver. Two objective functions were defined as minimization of total pressure loss and maximization of lift, while the mass flow rate was fixed. A parallel genetic algorithm was used as an optimizer and the penalty method was introduced. Each individual's objective function was computed simultaneously by using a 32 processor distributed memory computer. One optimization took about four days.

Evaluation and comparison of nasal airway flow patterns among three subjects from Caucasian, Chinese and Indian ethnic groups using computational fluid dynamics simulation.

PubMed

Zhu, Jian Hua; Lee, Heow Pueh; Lim, Kian Meng; Lee, Shu Jin; Wang, De Yun

2011-01-31

Nasal airflow is one of the most important determinants for nasal physiology. During the long evolution of human beings, different races have developed their own attributes of nasal morphologies which result in variations of nasal airflow patterns and nasal functions. This study evaluated and compared the effects of differences of nasal morphology among three healthy male subjects from Caucasian, Chinese and Indian ethnic groups on nasal airflow patterns using computational fluid dynamics simulation. By examining the anterior nasal airway, the nasal indices and the nostril shapes of the three subjects were found to be similar to nasal cavities of respective ethnic groups. Computed tomography images of these three subjects were obtained to reconstruct 3-dimensional models of nasal cavities. To retain the flow characteristics around the nasal vestibules, a 40 mm-radius semi sphere was assembled around the human face for the prescription of zero ambient gauge pressure. The results show that more airflow tends to pass through the middle passage of the nasal airway in the Caucasian model, and through the inferior portion in the Indian model. The Indian model was found with extremely low flow flux flowing through the olfactory region. The sizes of vortexes near the anterior cavity were found to be correlated with the angles between the upper nasal valve wall and the anterior head of the nasal cavity. Copyright © 2010 Elsevier B.V. All rights reserved.

Optical correlator method and apparatus for particle image velocimetry processing

NASA Technical Reports Server (NTRS)

Farrell, Patrick V. (Inventor)

1991-01-01

Young's fringes are produced from a double exposure image of particles in a flowing fluid by passing laser light through the film and projecting the light onto a screen. A video camera receives the image from the screen and controls a spatial light modulator. The spatial modulator has a two dimensional array of cells the transmissiveness of which are controlled in relation to the brightness of the corresponding pixel of the video camera image of the screen. A collimated beam of laser light is passed through the spatial light modulator to produce a diffraction pattern which is focused onto another video camera, with the output of the camera being digitized and provided to a microcomputer. The diffraction pattern formed when the laser light is passed through the spatial light modulator and is focused to a point corresponds to the two dimensional Fourier transform of the Young's fringe pattern projected onto the screen. The data obtained fro This invention was made with U.S. Government support awarded by the Department of the Army (DOD) and NASA grand number(s): DOD #DAAL03-86-K0174 and NASA #NAG3-718. The U.S. Government has certain rights in this invention.

Optical Correlation Techniques In Fluid Dynamics

NASA Astrophysics Data System (ADS)

Schatzel, K.; Schulz-DuBois, E. O.; Vehrenkamp, R.

1981-05-01

Three flow measurement techniques make use of fast digital correlators. (1) Most widely spread is photon correlation velocimetry using crossed laser beams and detecting Doppler shifted light scattered by small particles in the flow. Depending on the processing of the photon correlogram, this technique yields mean velocity, turbulence level, or even the detailed probability distribution of one velocity component. An improved data processing scheme is demonstrated on laminar vortex flow in a curved channel. (2) Rate correlation based upon threshold crossings of a high pass filtered laser Doppler signal can he used to obtain velocity correlation functions. The most powerful setup developed in our laboratory uses a phase locked loop type tracker and a multibit correlator to analyse time-dependent Taylor vortex flow. With two optical systems and trackers, crosscorrelation functions reveal phase relations between different vortices. (3) Making use of refractive index fluctuations (e. g. in two phase flows) instead of scattering particles, interferometry with bidirectional fringe counting and digital correlation and probability analysis constitute a new quantitative technique related to classical Schlieren methods. Measurements on a mixing flow of heated and cold air contribute new ideas to the theory of turbulent random phase screens.

Optical correlation techniques in fluid dynamics

NASA Astrophysics Data System (ADS)

Schätzel, K.; Schulz-Dubois, E. O.; Vehrenkamp, R.

1981-04-01

Three flow measurement techniques make use of fast digital correlators. The most widely spread is photon correlation velocimetry using crossed laser beams, and detecting Doppler shifted light scattered by small particles in the flow. Depending on the processing of the photon correlation output, this technique yields mean velocity, turbulence level, and even the detailed probability distribution of one velocity component. An improved data processing scheme is demonstrated on laminar vortex flow in a curved channel. In the second method, rate correlation based upon threshold crossings of a high pass filtered laser Doppler signal can be used to obtain velocity correlation functions. The most powerful set-up developed in our laboratory uses a phase locked loop type tracker and a multibit correlator to analyze time-dependent Taylor vortex flow. With two optical systems and trackers, cross-correlation functions reveal phase relations between different vortices. The last method makes use of refractive index fluctuations (eg in two phase flows) instead of scattering particles. Interferometry with bidirectional counting, and digital correlation and probability analysis, constitutes a new quantitative technique related to classical Schlieren methods. Measurements on a mixing flow of heated and cold air contribute new ideas to the theory of turbulent random phase screens.

Numerical analysis of mixing enhancement for micro-electroosmotic flow

NASA Astrophysics Data System (ADS)

Tang, G. H.; He, Y. L.; Tao, W. Q.

2010-05-01

Micro-electroosmotic flow is usually slow with negligible inertial effects and diffusion-based mixing can be problematic. To gain an improved understanding of electroosmotic mixing in microchannels, a numerical study has been carried out for channels patterned with wall blocks, and channels patterned with heterogeneous surfaces. The lattice Boltzmann method has been employed to obtain the external electric field, electric potential distribution in the electrolyte, the flow field, and the species concentration distribution within the same framework. The simulation results show that wall blocks and heterogeneous surfaces can significantly disturb the streamlines by fluid folding and stretching leading to apparently substantial improvements in mixing. However, the results show that the introduction of such features can substantially reduce the mass flow rate and thus effectively prolongs the available mixing time when the flow passes through the channel. This is a non-negligible factor on the effectiveness of the observed improvements in mixing efficiency. Compared with the heterogeneous surface distribution, the wall block cases can achieve more effective enhancement in the same mixing time. In addition, the field synergy theory is extended to analyze the mixing enhancement in electroosmotic flow. The distribution of the local synergy angle in the channel aids to evaluate the effectiveness of enhancement method.

Theoretical fluid dynamics

NASA Astrophysics Data System (ADS)

Shivamoggi, B. K.

This book is concerned with a discussion of the dynamical behavior of a fluid, and is addressed primarily to graduate students and researchers in theoretical physics and applied mathematics. A review of basic concepts and equations of fluid dynamics is presented, taking into account a fluid model of systems, the objective of fluid dynamics, the fluid state, description of the flow field, volume forces and surface forces, relative motion near a point, stress-strain relation, equations of fluid flows, surface tension, and a program for analysis of the governing equations. The dynamics of incompressible fluid flows is considered along with the dynamics of compressible fluid flows, the dynamics of viscous fluid flows, hydrodynamic stability, and dynamics of turbulence. Attention is given to the complex-variable method, three-dimensional irrotational flows, vortex flows, rotating flows, water waves, applications to aerodynamics, shock waves, potential flows, the hodograph method, flows at low and high Reynolds numbers, the Jeffrey-Hamel flow, and the capillary instability of a liquid jet.

Doppler radar flowmeter

DOEpatents

Petlevich, Walter J.; Sverdrup, Edward F.

1978-01-01

A Doppler radar flowmeter comprises a transceiver which produces an audio frequency output related to the Doppler shift in frequency between radio waves backscattered from particulate matter carried in a fluid and the radiated radio waves. A variable gain amplifier and low pass filter are provided for amplifying and filtering the transceiver output. A frequency counter having a variable triggering level is also provided to determine the magnitude of the Doppler shift. A calibration method is disclosed wherein the amplifier gain and frequency counter trigger level are adjusted to achieve plateaus in the output of the frequency counter and thereby allow calibration without the necessity of being able to visually observe the flow.

Hydrologic models of modern and fossil geothermal systems in the Great Basin: Genetic implications for epithermal Au-Ag and Carlin-type gold deposits

USGS Publications Warehouse

Person, M.; Banerjee, A.; Hofstra, A.; Sweetkind, D.; Gao, Y.

2008-01-01

The Great Basin region in the western United States contains active geothermal systems, large epithermal Au-Ag deposits, and world-class Carlin-type gold deposits. Temperature profiles, fluid inclusion studies, and isotopic evidence suggest that modern and fossil hydrothermal systems associated with gold mineralization share many common features, including the absence of a clear magmatic fluid source, discharge areas restricted to fault zones, and remarkably high temperatures (>200 ??C) at shallow depths (200-1500 m). While the plumbing of these systems varies, geochemical and isotopic data collected at the Dixie Valley and Beowawe geothermal systems suggest that fluid circulation along fault zones was relatively deep (>5 km) and comprised of relatively unexchanged Pleistocene meteoric water with small (<2.5%) shifts from the meteoric water line (MWL). Many fossil ore-forming systems were also dominated by meteoric water, but usually exhibit ??18O fluid-rock interactions with larger shifts of 5???-20??? from the MWL. Here we present a suite of two-dimensional regional (100 km) and local (40-50 km) scale hydrologic models that we have used to study the plumbing of modern and Tertiary hydrothermal systems of the Great Basin. Geologically and geophysically consistent cross sections were used to generate somewhat idealized hydrogeologic models for these systems that include the most important faults, aquifers, and confining units in their approximate configurations. Multiple constraints were used, including enthalpy, ??18O, silica compositions of fluids and/or rocks, groundwater residence times, fluid inclusion homogenization temperatures, and apatite fission track anomalies. Our results suggest that these hydrothermal systems were driven by natural thermal convection along anisotropic, subvertical faults connected in many cases at depth by permeable aquifers within favorable lithostratigraphic horizons. Those with minimal fluid ?? 18O shifts are restricted to high-permeability fault zones and relatively small-scale (???5 km), single-pass flow systems (e.g., Beowawe). Those with intermediate to large isotopic shifts (e.g., epithermal and Carlin-type Au) had larger-scale (???15 km) loop convection cells with a greater component of flow through marine sedimentary rocks at lower water/rock ratios and greater endowments of gold. Enthalpy calculations constrain the duration of Carlin-type gold systems to probably <200 k.y. Shallow heat flow gradients and fluid silica concentrations suggest that the duration of the modern Beowawe system is <5 k.y. However, fluid flow at Beowawe during the Quaternary must have been episodic with a net duration of ???200 k.y. to account for the amount of silica in the sinter deposits. In the Carlin trend, fluid circulation extended down into Paleozoic siliciclastic rocks, which afforded more mixing with isotopically enriched higher enthalpy fluids. Computed fission track ages along the Carlin trend included the convective effects, and ranged between 91.6 and 35.3 Ma. Older fission track ages occurred in zones of groundwater recharge, and the younger ages occurred in discharge areas. This is largely consistent with fission track ages reported in recent studies. We found that either an amagmatic system with more permeable faults (10-11 m2) or a magmatic system with less permeable faults (10-13 m2) could account for the published isotopic and thermal data along the Carlin trend systems. Localized high heat flow beneath the Muleshoe fault was needed to match fl uid inclusion temperatures at Mule Canyon. However, both magmatic and amagmatic scenarios require the existence of deep, permeable faults to bring hot fluids to the near surface. ?? 2008 Geological Society of America.

Parallelization of TWOPORFLOW, a Cartesian Grid based Two-phase Porous Media Code for Transient Thermo-hydraulic Simulations

NASA Astrophysics Data System (ADS)

Trost, Nico; Jiménez, Javier; Imke, Uwe; Sanchez, Victor

2014-06-01

TWOPORFLOW is a thermo-hydraulic code based on a porous media approach to simulate single- and two-phase flow including boiling. It is under development at the Institute for Neutron Physics and Reactor Technology (INR) at KIT. The code features a 3D transient solution of the mass, momentum and energy conservation equations for two inter-penetrating fluids with a semi-implicit continuous Eulerian type solver. The application domain of TWOPORFLOW includes the flow in standard porous media and in structured porous media such as micro-channels and cores of nuclear power plants. In the latter case, the fluid domain is coupled to a fuel rod model, describing the heat flow inside the solid structure. In this work, detailed profiling tools have been utilized to determine the optimization potential of TWOPORFLOW. As a result, bottle-necks were identified and reduced in the most feasible way, leading for instance to an optimization of the water-steam property computation. Furthermore, an OpenMP implementation addressing the routines in charge of inter-phase momentum-, energy- and mass-coupling delivered good performance together with a high scalability on shared memory architectures. In contrast to that, the approach for distributed memory systems was to solve sub-problems resulting by the decomposition of the initial Cartesian geometry. Thread communication for the sub-problem boundary updates was accomplished by the Message Passing Interface (MPI) standard.

Electrochemical treatment of tannery effluent using a battery integrated DC-DC converter and solar PV power supply--an approach towards environment and energy management.

PubMed

Iyappan, K; Basha, C Ahmed; Saravanathamizhan, R; Vedaraman, N; Tahiyah Nou Shene, C A; Begum, S Nathira

2014-01-01

Electrochemical oxidation of tannery effluent was carried out in batch, batch recirculation and continuous reactor configurations under different conditions using a battery-integrated DC-DC converter and solar PV power supply. The effect of current density, electrolysis time and fluid flow rate on chemical oxygen demand (COD) removal and energy consumption has been evaluated. The results of batch reactor show that a COD reduction of 80.85% to 96.67% could be obtained. The results showed that after 7 h of operation at a current density of 2.5 A dm(-2) and flow rate of 100 L h(-1) in batch recirculation reactor, the removal of COD is 82.14% and the specific energy consumption was found to be 5.871 kWh (kg COD)(-1) for tannery effluent. In addition, the performance of single pass flow reactors (single and multiple reactors) system of various configurations are analyzed.

Preconditioned implicit solvers for the Navier-Stokes equations on distributed-memory machines

NASA Technical Reports Server (NTRS)

Ajmani, Kumud; Liou, Meng-Sing; Dyson, Rodger W.

1994-01-01

The GMRES method is parallelized, and combined with local preconditioning to construct an implicit parallel solver to obtain steady-state solutions for the Navier-Stokes equations of fluid flow on distributed-memory machines. The new implicit parallel solver is designed to preserve the convergence rate of the equivalent 'serial' solver. A static domain-decomposition is used to partition the computational domain amongst the available processing nodes of the parallel machine. The SPMD (Single-Program Multiple-Data) programming model is combined with message-passing tools to develop the parallel code on a 32-node Intel Hypercube and a 512-node Intel Delta machine. The implicit parallel solver is validated for internal and external flow problems, and is found to compare identically with flow solutions obtained on a Cray Y-MP/8. A peak computational speed of 2300 MFlops/sec has been achieved on 512 nodes of the Intel Delta machine,k for a problem size of 1024 K equations (256 K grid points).

Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures.

PubMed

Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R; Crowhurst, Jonathan C; Weisz, David G; Zaug, Joseph M; Dai, Zurong; Radousky, Harry B; Chernov, Alex; Ramon, Erick; Stavrou, Elissaios; Knight, Kim; Fabris, Andrea L; Cappelli, Mark A; Rose, Timothy P

2017-09-01

We present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 < T < 5000 K) and atmospheric pressure. The reactor consists of a glass tube that is attached to an inductively coupled argon plasma generator via an adaptor (ring flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after they pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.

Flow Diode and Method for Controlling Fluid Flow Origin of the Invention

NASA Technical Reports Server (NTRS)

Dyson, Rodger W (Inventor)

2015-01-01

A flow diode configured to permit fluid flow in a first direction while preventing fluid flow in a second direction opposite the first direction is disclosed. The flow diode prevents fluid flow without use of mechanical closures or moving parts. The flow diode utilizes a bypass flowline whereby all fluid flow in the second direction moves into the bypass flowline having a plurality of tortuous portions providing high fluidic resistance. The portions decrease in diameter such that debris in the fluid is trapped. As fluid only travels in one direction through the portions, the debris remains trapped in the portions.

Fluids of the ocular surface: concepts, functions and physics.

PubMed

Cher, Ivan

2012-08-01

General adoption of the ocular surface (OS) concept has advanced the therapy of the external eye. Fresh physical findings have prompted new concepts; examples taken from each section of the text are: (i) ever-present lipid sealant bridges the palpebral fissure capping the three-dimensional 'OS' sac. The muco-aqueous pool (MAP) is thus enclosed, secluded from atmosphere, evaporation mitigated. Hence, the OS is conceptually, a compartment. The term 'dacruon' (otherwise 'tear film') has been coined for the combined fluids of the OS, viz. lipid film and MAP. (ii) Investigative techniques of physics yield data on (say) surface tension and viscosity, and on functions such as anchorage of dacruon base to the varied mucosae of the OS, lubrication, renovation of intermarginal fluid layers as the eye opens after each blink, and refinement of optics and vision by the fluids attached to the cornea. (iii) Physical events in the opening eye produce the unique 'black line' phenomenon in which capillary force induces subsurface flows into thirsty menisci, bringing about parameniscal dark grooves, pupil-ward of each meniscus. Attenuation of fluorescein in the shallowed fluid gaps behind each groove makes the dye appear unilluminated ('black lines') relative to adjacent full-thickness MAP fluid glowing under cobalt-blue illumination. Isolated from cornea by grooves and gaps, the meniscal fluid cannot pass freely over the cornea. It therefore streams through the menisci to nasolacrimal outflow. © 2012 The Author. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

PREFACE: Special section on Computational Fluid Dynamics—in memory of Professor Kunio Kuwahara Special section on Computational Fluid Dynamics—in memory of Professor Kunio Kuwahara

NASA Astrophysics Data System (ADS)

Ishii, Katsuya

2011-08-01

This issue includes a special section on computational fluid dynamics (CFD) in memory of the late Professor Kunio Kuwahara, who passed away on 15 September 2008, at the age of 66. In this special section, five articles are included that are based on the lectures and discussions at `The 7th International Nobeyama Workshop on CFD: To the Memory of Professor Kuwahara' held in Tokyo on 23 and 24 September 2009. Professor Kuwahara started his research in fluid dynamics under Professor Imai at the University of Tokyo. His first paper was published in 1969 with the title 'Steady Viscous Flow within Circular Boundary', with Professor Imai. In this paper, he combined theoretical and numerical methods in fluid dynamics. Since that time, he made significant and seminal contributions to computational fluid dynamics. He undertook pioneering numerical studies on the vortex method in 1970s. From then to the early nineties, he developed numerical analyses on a variety of three-dimensional unsteady phenomena of incompressible and compressible fluid flows and/or complex fluid flows using his own supercomputers with academic and industrial co-workers and members of his private research institute, ICFD in Tokyo. In addition, a number of senior and young researchers of fluid mechanics around the world were invited to ICFD and the Nobeyama workshops, which were held near his villa, and they intensively discussed new frontier problems of fluid physics and fluid engineering at Professor Kuwahara's kind hospitality. At the memorial Nobeyama workshop held in 2009, 24 overseas speakers presented their papers, including the talks of Dr J P Boris (Naval Research Laboratory), Dr E S Oran (Naval Research Laboratory), Professor Z J Wang (Iowa State University), Dr M Meinke (RWTH Aachen), Professor K Ghia (University of Cincinnati), Professor U Ghia (University of Cincinnati), Professor F Hussain (University of Houston), Professor M Farge (École Normale Superieure), Professor J Y Yong (National Taiwan University), and Professor H S Kwak (Kumoh National Institute of Technology). For his contributions to CFD, Professor Kuwahara received Awards from the Japan Society of Automobile Engineers and the Japan Society of Mechanical Engineers in 1992, the Computational Mechanics Achievement Award from the Japan Society of Mechanical Engineers in 1993, and the Max Planck Research Award in 1993. He received the Computational Mechanics Award from the Japan Society of Mechanical Engineers again in 2008. Professor Kuwahara also supported the development of the Japan Society of Fluid Mechanics, whose office is located in the same building as ICFD. In the proceedings of the 6th International Nobeyama Workshop on CFD to commemorate the 60th birthday of Professor Kuwahara, Professor Jae Min Hyun of KAIST wrote 'The major professional achievement of Professor Kuwahara may be compressed into two main categories. First and foremost, Professor Kuwahara will long be recorded as the front-line pioneer in using numerical computations to tackle complex problems in fluid mechanics. ...Another important contribution of Professor Kuwahara was in the training and fostering of talented manpower of computational mechanics research.'[1] Among the various topics of the five papers in this special section are examples of Professor Kuwahara's works mentioned by Professor Hyun. The main authors of all papers have grown up in the research circle of Professor Kuwahara. All the papers demostrate the challenge of new aspects of computational fluid dynamics; a new numerical method for compressible flows, thermo-acoustic flows of helium gas in a small tube, electro-osmic flows in a micro/nano channel, MHD flows over a wavy disk, and a new extraction method of multi-object aircraft design rules. Last but not least, this special section is cordially dedicated to the late Professor Kuwahara and his family. Reference [1] Hyun J M 2005 Preface of New Developments in Computational Fluid Dynamics vol 90 Notes on Numerical Fluid Mechanics and Multidisciplinary Design ed K Fujii et al (Berlin: Springer)

A numerical performance assessment of a commercial cardiopulmonary by-pass blood heat exchanger.

PubMed

Consolo, Filippo; Fiore, Gianfranco B; Pelosi, Alessandra; Reggiani, Stefano; Redaelli, Alberto

2015-06-01

We developed a numerical model, based on multi-physics computational fluid dynamics (CFD) simulations, to assist the design process of a plastic hollow-fiber bundle blood heat exchanger (BHE) integrated within the INSPIRE(TM), a blood oxygenator (OXY) for cardiopulmonary by-pass procedures, recently released by Sorin Group Italia. In a comparative study, we analyzed five different geometrical design solutions of the BHE module. Quantitative geometrical-dependent parameters providing a comprehensive evaluation of both the hemo- and thermo-dynamics performance of the device were extracted to identify the best-performing prototypical solution. A convenient design configuration was identified, characterized by (i) a uniform blood flow pattern within the fiber bundle, preventing blood flow shunting and the onset of stagnation/recirculation areas and/or high velocity pathways, (ii) an enhanced blood heating efficiency, and (iii) a reduced blood pressure drop. The selected design configuration was then prototyped and tested to experimentally characterize the device performance. Experimental results confirmed numerical predictions, proving the effectiveness of CFD modeling as a reliable tool for in silico identification of suitable working conditions of blood handling medical devices. Notably, the numerical approach limited the need for extensive prototyping, thus reducing the corresponding machinery costs and time-to-market. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Microscopic motion of particles flowing through a porous medium

NASA Astrophysics Data System (ADS)

Lee, Jysoo; Koplik, Joel

1999-01-01

Stokesian dynamics simulations are used to study the microscopic motion of particles suspended in fluids passing through porous media. Model porous media with fixed spherical particles are constructed, and mobile ones move through this fixed bed under the action of an ambient velocity field. The pore scale motion of individual suspended particles at pore junctions are first considered. The relative particle flux into different possible directions exiting from a single pore, for two- and three-dimensional model porous media is found to approximately equal the corresponding fractional channel width or area. Next the waiting time distribution for particles which are delayed in a junction due to a stagnation point caused by a flow bifurcation is considered. The waiting times are found to be controlled by two-particle interactions, and the distributions take the same form in model porous media as in two-particle systems. A simple theoretical estimate of the waiting time is consistent with the simulations. It is found that perturbing such a slow-moving particle by another nearby one leads to rather complicated behavior. Finally, the stability of geometrically trapped particles is studied. For simple model traps, it is found that particles passing nearby can "relaunch" the trapped particle through its hydrodynamic interaction, although the conditions for relaunching depend sensitively on the details of the trap and its surroundings.

Development of a dynamic coupled hydro-geomechanical code and its application to induced seismicity

NASA Astrophysics Data System (ADS)

Miah, Md Mamun

This research describes the importance of a hydro-geomechanical coupling in the geologic sub-surface environment from fluid injection at geothermal plants, large-scale geological CO2 sequestration for climate mitigation, enhanced oil recovery, and hydraulic fracturing during wells construction in the oil and gas industries. A sequential computational code is developed to capture the multiphysics interaction behavior by linking a flow simulation code TOUGH2 and a geomechanics modeling code PyLith. Numerical formulation of each code is discussed to demonstrate their modeling capabilities. The computational framework involves sequential coupling, and solution of two sub-problems- fluid flow through fractured and porous media and reservoir geomechanics. For each time step of flow calculation, pressure field is passed to the geomechanics code to compute effective stress field and fault slips. A simplified permeability model is implemented in the code that accounts for the permeability of porous and saturated rocks subject to confining stresses. The accuracy of the TOUGH-PyLith coupled simulator is tested by simulating Terzaghi's 1D consolidation problem. The modeling capability of coupled poroelasticity is validated by benchmarking it against Mandel's problem. The code is used to simulate both quasi-static and dynamic earthquake nucleation and slip distribution on a fault from the combined effect of far field tectonic loading and fluid injection by using an appropriate fault constitutive friction model. Results from the quasi-static induced earthquake simulations show a delayed response in earthquake nucleation. This is attributed to the increased total stress in the domain and not accounting for pressure on the fault. However, this issue is resolved in the final chapter in simulating a single event earthquake dynamic rupture. Simulation results show that fluid pressure has a positive effect on slip nucleation and subsequent crack propagation. This is confirmed by running a sensitivity analysis that shows an increase in injection well distance results in delayed slip nucleation and rupture propagation on the fault.

On N. Park's Analytical solution for steady state density- and mixing regime—dependent solute transport in a vertical soil column

NASA Astrophysics Data System (ADS)

Thiele, Michael

1998-04-01

Recently, Park [1996] presented an analytical solution for stationary one-dimensional solute transport in a variable-density fluid flow through a vertical soil column. He used the widespread Bear-Scheidegger dispersion model describing solute mixing as a sum of molecular diffusion and velocity-proportional mechanical dispersion effects. His closed-form implicit concentration and pressure distributions thus allow for a discussion of the combined impact of molecular diffusion and mechanical dispersion in a variable-density environment. Whereas Park only considered the example of vanishing molecular diffusion in detail, both phenomena are taken into account simultaneously in the present study in order to elucidate their different influences on concentration distribution characteristics. The boundary value problem dealt with herein is based on an upward inflow of high-density fluid of constant solute concentration and corresponding outflow of a lower constant concentration fluid at the upper end of the column when dispersivity does not change along the flow path. The thickness of the transition zone between the two fluids appeared to strongly depend on the prevailing share of the molecular diffusion and mechanical dispersion mechanisms. The latter can be characterized by a molecular Peclet number Pe, which here is defined as the ratio of the column outflow velocity multiplied by a characteristic pore size and the molecular diffusion coefficient. For very small values of Pe, when molecular diffusion represents the exclusive mixing process, density differences have no impact on transition zone thicknesses. A relative density-;dependent thickness increases with flow velocities (increasing Pe values) very rapidly compared to the density-independent case, and after having passed a maximum decreases asymptotically to a constant value for the large Peclet number limit when mechanical dispersion is the only mixing mechanism. Hence the special transport problem analyzed gives further evidence for the importance of simultaneously considering molecular diffusion and mechanical dispersion in gravity-affected solute transport in porous media.

Determining the inertial states of low Prandtl number fluids using electrochemical cells

NASA Astrophysics Data System (ADS)

Crunkleton, Daniel Wray

The quality of crystals grown from the melt is often deteriorated by the presence of buoyancy-induced convection, produced by temperature or concentration inhomogenities. It is, therefore, important to develop techniques to visualize such flows. In this study, a novel technique is developed that uses solid-state electrochemical cells to establish and measure dissolved oxygen boundary conditions. To visualize convection, a packet of oxygen is electrochemically introduced at a specific location in the melt. As the fluid convects, this oxygen packet follows the flow, acting as a tracer. Electrochemical sensors located along the enclosure then detect the oxygen as it passes. Over sufficiently long times, oxygen diffusion is important; consequently, the oxygen diffusivity in the fluid is measured. This diffusivity is determined using both transient and steady state experiments with tin and tin-lead alloys as model fluids. It is concluded that the presence of convection due to solutal gradients and/or tilt increases the measured diffusivity by one-half to one order of magnitude. The oxygen diffusivity in tin-lead alloys is measured and the results show that the alloy diffusivities are lower than those of the corresponding pure metals. This concentration functionality is explained with a multicomponent diffusion model and shows good agreement. Rayleigh-Benard convection was used to validate the electrochemical approach to flow visualization. Thus, a numerical characterization of the second critical Rayleigh numbers in liquid tin was conducted for a variety of Cartesian aspect ratios. The extremely low Prandtl number of tin represents the lowest value studied numerically. Additionally, flow field oscillations are visualized and the effect of tilt on convecting systems is quantified. Finally, experimental studies of the effect of convection in liquid tin are presented. Three geometries are studied: (1) double cell with vertical concentration gradients; (2) double cell with horizontal concentration gradients; and (3) multiple cell with vertical temperature gradients. The first critical Rayleigh number transition is detected with geometry (1) and it is concluded that current measurements are not as affected by convection as EMF measurements. The system is compared with numerical simulations in geometry (2), and oscillating convection is detected with geometry (3).

Enhanced Microfluidic Electromagnetic Measurements

NASA Technical Reports Server (NTRS)

Ricco, Antonio J. (Inventor); Kovacs, Gregory (Inventor); Giovangrandi, Laurent (Inventor)

2015-01-01

Techniques for enhanced microfluidic impedance spectroscopy include causing a core fluid to flow into a channel between two sheath flows of one or more sheath fluids different from the core fluid. Flow in the channel is laminar. A dielectric constant of a fluid constituting either sheath flow is much less than a dielectric constant of the core fluid. Electrical impedance is measured in the channel between at least a first pair of electrodes. In some embodiments, enhanced optical measurements include causing a core fluid to flow into a channel between two sheath flows of one or more sheath fluids different from the core fluid. An optical index of refraction of a fluid constituting either sheath flow is much less than an optical index of refraction of the core fluid. An optical property is measured in the channel.

Electrothermal flow effects in insulating (electrodeless) dielectrophoresis systems.

PubMed

Hawkins, Benjamin G; Kirby, Brian J

2010-11-01

We simulate electrothermally induced flow in polymeric, insulator-based dielectrophoresis (iDEP) systems with DC-offset, AC electric fields at finite thermal Péclet number, and we identify key regimes where electrothermal (ET) effects enhance particle deflection and trapping. We study a single, two-dimensional constriction in channel depth with parametric variations in electric field, channel geometry, fluid conductivity, particle electrophoretic (EP) mobility, and channel electroosmotic (EO) mobility. We report the effects of increasing particle EP mobility, channel EO mobility, and AC and DC field magnitudes on the mean constriction temperature and particle behavior. Specifically, we quantify particle deflection and trapping, referring to the deviation of particles from their pathlines due to dielectrophoresis as they pass a constriction and the stagnation of particles due to negative dielectrophoresis near a constriction, respectively. This work includes the coupling between fluid, heat, and electromagnetic phenomena via temperature-dependent physical parameters. Results indicate that the temperature distribution depends strongly on the fluid conductivity and electric field magnitude, and particle deflection and trapping depend strongly on the channel geometry. Electrothermal (ET) effects perturb the EO flow field, creating vorticity near the channel constriction and enhancing the deflection and trapping effects. ET effects alter particle deflection and trapping responses in insulator-based dielectrophoresis devices, especially at intermediate device aspect ratios (2 ≤ r ≤ 7) in solutions of higher conductivity (σ m ≥ 1 × 10(-3)S/m). The impact of ET effects on particle deflection and trapping are diminished when particle EP mobility or channel EO mobility is high. In almost all cases, ET effects enhance negative dielectrophoretic particle deflection and trapping phenomena. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zika - Sexual Transmission and Prevention

MedlinePlus

... Español (Spanish) Recommend on Facebook Tweet Share Compartir Zika Can Be Passed Through Sex Zika can be ... in other body fluids. Infected People Can Pass Zika Through Sex Even When They Don’t Have ...

Pulsatile Flow and Gas Transport of Blood over an Array of Cylinders

NASA Astrophysics Data System (ADS)

Chan, Kit Yan

2005-11-01

In the artificial lung, blood passes through an array of micro-fibers and the gas transfer is strongly dependent on the flow field. The blood flow is unsteady and pulsatile. We have numerically simulated pulsatile flow and gas transfer of blood (modeled as a Casson fluid) over arrays of cylindrical micro-fibers. Oxygen and carbon dioxide are assumed to be in local equilibrium with hemoglobin in blood; and the carbon dioxide facilitated oxygen transport is incorporated into the model by allowing the coupling of carbon dioxide partial pressure and oxygen saturation. The pulsatile flow inputs considered are the sinusoidal and the cardiac waveforms. The squared and staggered arrays of arrangement of the cylinders are considered in this study. Gas transport can be enhanced by: increasing the oscillation frequency; increasing the Reynolds number; increasing the oscillation amplitude; decreasing the void fraction; the use of the cardiac pulsatile input. The overall gas transport is greatly enhanced by the presence of hemoglobin in blood even though the non-Newtonian effect of blood tends to decrease the size and strength of vortices. The pressure drop is also presented as it is an important design parameter confronting the heart.

Near Wall measurement in Turbulent Flow over Rough Wall using microscopic HPIV

NASA Astrophysics Data System (ADS)

Talapatra, Siddharth; Hong, Jiarong; Katz, Joseph

2009-11-01

Using holographic PIV, 3D velocity measurements are being performed in a turbulent rough wall channel flow. Our objective is to examine the contribution of coherent structures to the flow dynamics, momentum and energy fluxes in the roughness sublayer. The 0.45mm high, pyramid-shaped roughness is uniformly distributed on the top and bottom surfaces of a 5X20cm rectangular channel flow, where the Reτ is 3400. To facilitate recording of holograms through a rough plate, the working fluid is a concentrated solution of NaI in water, whose optical refractive index is matched with that of the acrylic rough plates. The test section is illuminated by a collimated laser beam from the top, and the sample volume extends from the bottom wall up to 7 roughness heights. After passing through the sample volume, the in-line hologram is magnified and recorded on a 4864X3248 pixels camera at a resolution of 0.74μm/pixel. The flow is locally seeded with 2μm particles. Reconstruction, spatial filtering and particle tracking provide the 3D velocity field. This approach has been successfully implemented recently, as preliminary data demonstrate.

Monodisperse microdroplet generation and stopping without coalescence

DOEpatents

Beer, Neil Reginald

2015-04-21

A system for monodispersed microdroplet generation and trapping including providing a flow channel in a microchip; producing microdroplets in the flow channel, the microdroplets movable in the flow channel; providing carrier fluid in the flow channel using a pump or pressure source; controlling movement of the microdroplets in the flow channel and trapping the microdroplets in a desired location in the flow channel. The system includes a microchip; a flow channel in the microchip; a droplet maker that generates microdroplets, the droplet maker connected to the flow channel; a carrier fluid in the flow channel, the carrier fluid introduced to the flow channel by a source of carrier fluid, the source of carrier fluid including a pump or pressure source; a valve connected to the carrier fluid that controls flow of the carrier fluid and enables trapping of the microdroplets.

Monodisperse microdroplet generation and stopping without coalescence

DOEpatents

Beer, Neil Reginald

2016-02-23

A system for monodispersed microdroplet generation and trapping including providing a flow channel in a microchip; producing microdroplets in the flow channel, the microdroplets movable in the flow channel; providing carrier fluid in the flow channel using a pump or pressure source; controlling movement of the microdroplets in the flow channel and trapping the microdroplets in a desired location in the flow channel. The system includes a microchip; a flow channel in the microchip; a droplet maker that generates microdroplets, the droplet maker connected to the flow channel; a carrier fluid in the flow channel, the carrier fluid introduced to the flow channel by a source of carrier fluid, the source of carrier fluid including a pump or pressure source; a valve connected to the carrier fluid that controls flow of the carrier fluid and enables trapping of the microdroplets.

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

N, Gwilliam M; J, Collins D; O, Leach M

Purpose: To assess the feasibility of accurately quantifying the concentration of MRI contrast agent (CA) in pulsatile flowing blood by measuring its T{sub 1}, as is common for the purposes of obtaining a patientspecific arterial input function (AIF). Dynamic contrast enhanced (DCE) - MRI and pharmacokinetic (PK) modelling is widely used to produce measures of vascular function but accurate measurement of the AIF undermines their accuracy. A proposed solution is to measure the T{sub 1} of blood in a large vessel using the Fram double flip angle method during the passage of a bolus of CA. This work expands onmore » previous work by assessing pulsatile flow and the changes in T{sub 1} seen with a CA bolus. Methods: A phantom was developed which used a physiological pump to pass fluid of a known T{sub 1} (812ms) through the centre of a head coil of a clinical 1.5T MRI scanner. Measurements were made using high temporal resolution sequences suitable for DCE-MRI and were used to validate a virtual phantom that simulated the expected errors due to pulsatile flow and bolus of CA concentration changes typically found in patients. Results: : Measured and virtual results showed similar trends, although there were differences that may be attributed to the virtual phantom not accurately simulating the spin history of the fluid before entering the imaging volume. The relationship between T{sub 1} measurement and flow speed was non-linear. T{sub 1} measurement is compromised by new spins flowing into the imaging volume, not being subject to enough excitations to have reached steady-state. The virtual phantom demonstrated a range of recorded T{sub 1} for various simulated T{sub 1} / flow rates. Conclusion: T{sub 1} measurement of flowing blood using standard DCE-MRI sequences is very challenging. Measurement error is non-linear with relation to instantaneous flow speed. Optimising sequence parameters and lowering baseline T{sub 1} of blood should be considered.« less

Fabrication and flow characterization of vertically aligned carbon-nanotube/polymer membranes

NASA Astrophysics Data System (ADS)

Castellano, Richard; Meshot, Eric; Fornasiero, Francesco; Shan, Jerry

2017-11-01

Membranes with well-controlled nanopores are of interest for applications as diverse as chemical separations, water purification, and ``green'' power generation. In particular, membranes incorporating carbon nanotubes (CNTs) as through-pores have been shown to pass fluids at rates orders-of-magnitude faster than predicted by continuum theory. However, cost-effective and scalable solutions for fabricating such membranes are still an area of research. We describe a solution-based fabrication technique for creating polymer composite membranes from bulk nanotubes using electric-field alignment and electrophoretic concentration. We then focus on flow characterization of membranes with single-wall nanotube (SWNT) pores. We demonstrate membrane quality by size-exclusion testing and showing that the flowrate of different gasses scales as the square root of molecular weight. The gas flowrates and moisture-vapor-transmission rates are compared with theoretical predictions and with composite membranes -fabricated from CVD-grown SWNT arrays. Funded by DTRA Grant BA12PHM123.

Prospects of application of additive technologies for increasing the efficiency of impeller machines

NASA Astrophysics Data System (ADS)

Belova, O. V.; Borisov, Yu. A.

2017-08-01

Impeller machine is a device in which the flow path carries out the supply (or retraction) of mechanical energy to the flow of a working fluid passing through the machine. To increase the efficiency of impeller machines, it is necessary to use design modern technologies, namely the use of numerical methods for conducting research in the field of gas dynamics, as well as additive manufacturing (AM) for the of both prototypes and production model. AM technologies are deservedly rightly called revolutionary because they give unique possibility for manufacturing products, creating perfect forms, both light and durable. The designers face the challenge of developing a new design methodology, since AM allows the use of the concept of "Complexity For Free". The "Complexity For Free" conception is based on: complexity of the form; hierarchical complexity; complexity of the material; functional complexity. The new technical items design method according to a functional principle is also investigated.

Aeroacoustic Analysis of a Simplified Landing Gear

NASA Technical Reports Server (NTRS)

Lockard, David P.; Khorrami, Mehdi, R.; Li, Fei

2004-01-01

A hybrid approach is used to investigate the noise generated by a simplified landing gear without small scale parts such as hydraulic lines and fasteners. The Ffowcs Williams and Hawkings equation is used to predict the noise at far-field observer locations from flow data provided by an unsteady computational fluid dynamics calculation. A simulation with 13 million grid points has been completed, and comparisons are made between calculations with different turbulence models. Results indicate that the turbulence model has a profound effect on the levels and character of the unsteadiness. Flow data on solid surfaces and a set of permeable surfaces surrounding the gear have been collected. Noise predictions using the porous surfaces appear to be contaminated by errors caused by large wake fluctuations passing through the surfaces. However, comparisons between predictions using the solid surfaces with the near-field CFD solution are in good agreement giving confidence in the far-field results.

Numerical Analysis of the Interaction between Thermo-Fluid Dynamics and Auto-Ignition Reaction in Spark Ignition Engines

NASA Astrophysics Data System (ADS)

Saijyo, Katsuya; Nishiwaki, Kazuie; Yoshihara, Yoshinobu

The CFD simulations were performed integrating the low-temperature oxidation reaction. Analyses were made with respect to the first auto-ignition location in the case of a premixed-charge compression auto-ignition in a laminar flow field and in the case of the auto-ignition in an end gas during an S. I. Engine combustion process. In the latter simulation, the spatially-filtered transport equations were solved to express fluctuating temperatures in a turbulent flow in consideration of strong non-linearity to temperature in the reaction equations. It is suggested that the first auto-ignition location does not always occur at higher-temperature locations and that the difference in the locations of the first auto-ignition depends on the time period during which the local end gas temperature passes through the region of shorter ignition delay, including the NTC region.

A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute

PubMed Central

Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

2000-01-01

A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio of the solute (influx/outflux) is small (2–4) in agreement with experiments. The virtual solute concentration of fluid emerging from lis is then significantly larger than the concentration in lis. Thus, in absence of external driving forces the model generates isotonic transport provided a component of the solute flux emerging downstream lis is taken up by cells through the serosal membrane and pumped back into lis, i.e., the solute would have to be recirculated. With input variables from toad intestine (Nedergaard, S., E.H. Larsen, and H.H. Ussing, J. Membr. Biol. 168:241–251), computations predict that 60–80% of the pumped flux stems from serosal bath in agreement with the experimental estimate of the recirculation flux. Robust solutions are obtained with realistic concentrations and pressures of lis, and with the following features. Rate of fluid absorption is governed by the solute permeability of mucosal membrane. Maximum fluid flow is governed by density of pumps on lis-membranes. Energetic efficiency increases with hydraulic conductance of the pathway carrying water from mucosal solution into lis. Uphill water transport is accomplished, but with high hydraulic conductance of cell membranes strength of transport is obscured by water flow through cells. Anomalous solvent drag occurs when back flux of water through cells exceeds inward water flux between cells. Molecules moving along the paracellular pathway are driven by a translateral flow of water, i.e., the model generates pseudo-solvent drag. The associated flux-ratio equation is derived. PMID:10919860

On the Induced Flow of an Electrically Conducting Liquid in a Rectangular Duct by Electric and Magnetic Fields of Finite Extent

NASA Technical Reports Server (NTRS)

Rossow, Vernon J.; Jones, William Prichard; Huerta, Robert H.

1961-01-01

Reported here are the results of a systematic study of a model of the direct-current electromagnetic pump. Of particular interest is the motion imparted to the electrically conducting fluid in the rectangular duct by the body forces that result from applied electric and magnetic fields. The purpose of the investigation is to associate the observed fluid motion with the characteristics of the electric and magnetic fields which cause them. The experiments were carried out with electromagnetic fields that moved a stream of copper sulphate solution through a clear plastic channel. Ink filaments injected into the stream ahead of the region where the fields were applied identify the motion of the fluid elements as they passed through the test channel. Several magnetic field configurations were employed with a two-dimensional electric current distribution in order to study and identify the magnitude of some of the effects on the fluid motion brought about by nonuniformities in the electromagnetic fields. A theoretical analysis was used to guide and evaluate the identification of the several fluid motions observed. The agreement of the experimental data with the theoretical predictions is satisfactory. It is found that sizable variations in the velocity profile and pressure head of the output stream are produced by the shape of the electric and magnetic fields.

Seismic texture and amplitude analysis of large scale fluid escape pipes using time lapses seismic surveys: examples from the Loyal Field (Scotland, UK)

NASA Astrophysics Data System (ADS)

Maestrelli, Daniele; Jihad, Ali; Iacopini, David; Bond, Clare

2016-04-01

Fluid escape pipes are key features of primary interest for the analysis of vertical fluid flow and secondary hydrocarbon migration in sedimentary basin. Identified worldwide (Løset et al., 2009), they acquired more and more importance as they represent critical pathways for supply of methane and potential structure for leakage into the storage reservoir (Cartwright & Santamarina, 2015). Therefore, understanding their genesis, internal characteristics and seismic expression, is of great significance for the exploration industry. Here we propose a detailed characterization of the internal seismic texture of some seal bypass system (e.g fluid escape pipes) from a 4D seismic survey (released by the BP) recently acquired in the Loyal Field. The seal by pass structure are characterized by big-scale fluid escape pipes affecting the Upper Paleogene/Neogene stratigraphic succession in the Loyal Field, Scotland (UK). The Loyal field, is located on the edge of the Faroe-Shetland Channel slope, about 130 km west of Shetland (Quadrants 204/205 of the UKCS) and has been recently re-appraised and re developed by a consortium led by BP. The 3D detailed mapping analysis of the full and partial stack survey (processed using amplitude preservation workflows) shows a complex system of fluid pipe structure rooted in the pre Lista formation and developed across the paleogene and Neogene Units. Geometrical analysis show that pipes got diameter varying between 100-300 m and a length of 500 m to 2 km. Most pipes seem to terminate abruptly at discrete subsurface horizons or in diffuse termination suggesting multiple overpressured events and lateral fluid migration (through Darcy flows) across the overburden units. The internal texture analysis of the large pipes, (across both the root and main conduit zones), using near, medium and far offset stack dataset (processed through an amplitude preserved PSTM workflow) shows a tendency of up-bending of reflection (rather than pulls up artefacts) affected by large scale fracture (semblance image) and seem consistent with a suspended mud/sand mixture non-fluidized fluid flow. Near-Middle-Far offsets amplitude analysis confirms that most of the amplitude anomalies within the pipes conduit and terminus are only partly related to gas. An interpretation of the possible texture observed is proposed with a discussion of the noise and artefact induced by resolution and migration problems. Possible hypothetical formation mechanisms for those Pipes are discussed.

Computational fluid dynamics-habitat suitability index (CFD-HSI) modelling as an exploratory tool for assessing passability of riverine migratory challenge zones for fish

USGS Publications Warehouse

Haro, Alexander J.; Chelminski, Michael; Dudley, Robert W.

2015-01-01

We developed two-dimensional computational fluid hydraulics-habitat suitability index (CFD-HSI) models to identify and qualitatively assess potential zones of shallow water depth and high water velocity that may present passage challenges for five major anadromous fish species in a 2.63-km reach of the main stem Penobscot River, Maine, as a result of a dam removal downstream of the reach. Suitability parameters were based on distribution of fish lengths and body depths and transformed to cruising, maximum sustained and sprint swimming speeds. Zones of potential depth and velocity challenges were calculated based on the hydraulic models; ability of fish to pass a challenge zone was based on the percent of river channel that the contiguous zone spanned and its maximum along-current length. Three river flows (low: 99.1 m3 sec-1; normal: 344.9 m3 sec-1; and high: 792.9 m3 sec-1) were modelled to simulate existing hydraulic conditions and hydraulic conditions simulating removal of a dam at the downstream boundary of the reach. Potential depth challenge zones were nonexistent for all low-flow simulations of existing conditions for deeper-bodied fishes. Increasing flows for existing conditions and removal of the dam under all flow conditions increased the number and size of potential velocity challenge zones, with the effects of zones being more pronounced for smaller species. The two-dimensional CFD-HSI model has utility in demonstrating gross effects of flow and hydraulic alteration, but may not be as precise a predictive tool as a three-dimensional model. Passability of the potential challenge zones cannot be precisely quantified for two-dimensional or three-dimensional models due to untested assumptions and incomplete data on fish swimming performance and behaviours.

Influence of ammonia flow rate for improving properties of polycrystalline GaN

NASA Astrophysics Data System (ADS)

Ariff, A.; Ahmad, M. A.; Hassan, Z.; Zainal, N.

2018-06-01

Post-annealing treatment in ammonia ambient is widely accepted for GaN material, but less works have been done to investigate the influence of the ammonia (NH3) flow rate for reducing the N-deficiency as well as improving the quality of the material. In this work, we investigated the influence of NH3 flow rate at 1, 2, 3, and 4 slm in improving properties of a ∼1 μm thick polycrystalline GaN layer. Our simulation work suggested that the uniformity of temperature and pressure gradient of the NH3 gas did not lead to the reduction of N-deficiency of the polycrystalline GaN layer. Instead, it was found that the mitigation of the N-deficiency was strongly influenced by the fluid velocity of the NH3 gas, which had passed over the layer. Either at lower or higher fluid velocity, the chance for the active N atoms to incorporate into the GaN lattice structure was low. Therefore, the N-deficiency on the polycrystalline GaN layer could not be minimized under these conditions. As measured by EDX, the N atoms incorporation was the most effective when the NH3 flow rate at 3 slm, suggesting the flow rate significantly improved the N-deficiency of the polycrystalline GaN layer. Furthermore, it favored the formation of larger hexagonal faceted grains, with the smallest FWHM of XRD peaks from the GaN diffractions in (10 1 bar 0), (0002) and (10 1 bar 1) orientations, while allowing the polycrystalline GaN layer to show sharp and intense emissions peak of NBE in a PL spectrum.

Power tong torque control

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

Buck, D.A.; James, R.N.

1987-10-20

Torque controlled powered pipe tongs, are described the apparatus comprises: (a) a power tong powered by a fluid motor; (b) a fluid power source connected to the motor; (c) a force conducting element attached to the power tong, situated to oppose reaction torque from the tongs when torque is applied to pipe; (d) force sensing means operatively associated with the force conducting element situated to sense at least part of the force experienced by the force conducting element, arranged to produce a pressure signal proportional to force sensed; and (e) a fluid by-pass valve, adjustably biased toward a closed position,more » responsive to the signal to tend to move toward an open position, the by-pass valve connected between the fluid power source and the motor.« less

Physical aspects of computing the flow of a viscous fluid

NASA Technical Reports Server (NTRS)

Mehta, U. B.

1984-01-01

One of the main themes in fluid dynamics at present and in the future is going to be computational fluid dynamics with the primary focus on the determination of drag, flow separation, vortex flows, and unsteady flows. A computation of the flow of a viscous fluid requires an understanding and consideration of the physical aspects of the flow. This is done by identifying the flow regimes and the scales of fluid motion, and the sources of vorticity. Discussions of flow regimes deal with conditions of incompressibility, transitional and turbulent flows, Navier-Stokes and non-Navier-Stokes regimes, shock waves, and strain fields. Discussions of the scales of fluid motion consider transitional and turbulent flows, thin- and slender-shear layers, triple- and four-deck regions, viscous-inviscid interactions, shock waves, strain rates, and temporal scales. In addition, the significance and generation of vorticity are discussed. These physical aspects mainly guide computations of the flow of a viscous fluid.

Determination of methylglyoxal-bis(guanylhydrazone) in body fluids by ion-pair chromatography.

PubMed

Roboz, J; Wu, K T; Hart, R D

1980-01-01

Methylglyoxal-bis(guanylhydrazone), Methyl-G, is a potent antineoplastic agent currently undergoing Phase l clinical trials. Serum, ascitic and pleural fluids, and urine are deproteinized with methanol, supernatant is evaporated, residue is redissolved in the eluent, lipids are removed with carbon tetrachloride, and an aliquot of the aqueous layer injected into the chromatograph. Ethylglyoxal-bis(guanylhydrazone) (Ethyl-G) is the internal standard. The mobile phase is a mixture of an aqueous buffer (containing 0.004 M heptane and pentane sulfonic acid, 90%:10%, buffered to pH 3.5) and methanol (68%:32%). The ion-pair complex is retained on a micro Bondapak C18 column, eluted with a flow of 2.0 mL/min. Absorbance is measured at 280 nm. Detectability: 30 ng/mL (0.11 micro M) in serum, ascitic and pleural fluids, 300 ng/mL (1.1 micro M) in urine. Calibration curves (peak height ratios of Methyl-G/Ethyl-G plotted against known drug concentrations) were linear in the 0.1-30 microg/mL range. Correlation coefficinets were 0.999; coefficients of variation for reproducibility were less than 5%. Residual blood levels of Methyl-G persist for several days. Methyl-G was found to pass into ascitic fluid.

Use of hollow fiber membrane filtration for the removal of DMSO from platelet concentrates.

PubMed

Arnaud, F; Kapnik, E; Meryman, H T

2003-05-01

It has been hypothesized that, in addition to freezing injury, some damage to platelets may result from the cell packing that occurs during removal of the cryoprotectant. This study examined DMSO removal by fluid exchange across hollow-fiber (HF) filters as an alternative to centrifugation. The DMSO solution with or without cell suspension was passed once through the filter. The optimum exchange during unloading of DMSO was determined by varying the flow rates in the external and internal compartments of the HF filter. Initially, buffered solutions of a 5% DMSO solution in the absence of platelets were pumped into the fibers and exchanged against PBS. The residual DMSO was determined by osmometry. The exchange of DMSO across the membrane was flow dependent and also influenced by the chemical nature of the HF fibers. No protocol using a reasonable rate flow through the fibers removed more than 95% of the DMSO in a single pass. The optimum protocol was achieved with polysynthane fibers with an internal flow rate of approximately 20 mi/min and an external flow rate of 100 ml/min. Subsequently, frozen/thawed platelet concentrates in DMSO were washed using centrifugation and compared to the HF filtration method. Platelet quality was assayed by flow cytometry, cell count, morphology and osmotic stress test. Both filtration and centrifugal washing techniques resulted in comparable morphological scores and numbers of discoid cells. When agents reducing platelet activation were added, platelet quality was improved after washing by either technique. The lower platelet osmotic response with HF filtration than with centrifugation while using activation inhibitors was attributed to the remaining amount of the inhibitors. All other parameters tested were similar. The expression of CD62P was equivalent with both techniques, and centrifugation did not activate platelets more than filtration contrary to what was originally anticipated. In conclusion, platelet quality was comparable after washing by either technique but hollow fiber filtration does remove cryoprotectant more rapidly than does centrifugation.

Simulating Blade-Strike on Fish passing through Marine Hydrokinetic Turbines

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

Romero Gomez, Pedro DJ; Richmond, Marshall C.

2014-06-16

The study reported here evaluated the occurrence, frequency, and intensity of blade strike of fish on an axial-flow marine hydrokinetic turbine by using two modeling approaches: a conventional kinematic formulation and a proposed Lagrangian particle- based scheme. The kinematic model included simplifying assumptions of fish trajectories such as distribution and velocity. The proposed method overcame the need for such simplifications by integrating the following components into a computational fluid dynamics (CFD) model: (i) advanced eddy-resolving flow simulation, (ii) generation of ambient turbulence based on field data, (iii) moving turbine blades in highly transient flows, and (iv) Lagrangian particles to mimicmore » the potential fish pathways. The test conditions to evaluate the blade-strike probability and fish survival rate were: (i) the turbulent environment, (ii) the fish size, and (iii) the approaching flow velocity. The proposed method offered the ability to produce potential fish trajectories and their interaction with the rotating turbine. Depending upon the scenario, the percentile of particles that registered a collision event ranged from 6% to 19% of the released sample size. Next, by using a set of experimental correlations of the exposure-response of living fish colliding with moving blades, the simulated collision data were used as input variables to estimate the survival rate of fish passing through the operating turbine. The resulting survival rates were greater than 96% in all scenarios, which is comparable to or better than known survival rates for conventional hydropower turbines. The figures of strike probability and mortality rate were amplified by the kinematic model. The proposed method offered the advantage of expanding the evaluation of other mechanisms of stress and injury on fish derived from hydrokinetic turbines and related devices.« less

Microgravity Passive Phase Separator

NASA Technical Reports Server (NTRS)

Paragano, Matthew; Indoe, William; Darmetko, Jeffrey

2012-01-01

A new invention disclosure discusses a structure and process for separating gas from liquids in microgravity. The Microgravity Passive Phase Separator consists of two concentric, pleated, woven stainless- steel screens (25-micrometer nominal pore) with an axial inlet, and an annular outlet between both screens (see figure). Water enters at one end of the center screen at high velocity, eventually passing through the inner screen and out through the annular exit. As gas is introduced into the flow stream, the drag force exerted on the bubble pushes it downstream until flow stagnation or until it reaches an equilibrium point between the surface tension holding bubble to the screen and the drag force. Gas bubbles of a given size will form a front that is moved further down the length of the inner screen with increasing velocity. As more bubbles are added, the front location will remain fixed, but additional bubbles will move to the end of the unit, eventually coming to rest in the large cavity between the unit housing and the outer screen (storage area). Owing to the small size of the pores and the hydrophilic nature of the screen material, gas does not pass through the screen and is retained within the unit for emptying during ground processing. If debris is picked up on the screen, the area closest to the inlet will become clogged, so high-velocity flow will persist farther down the length of the center screen, pushing the bubble front further from the inlet of the inner screen. It is desired to keep the velocity high enough so that, for any bubble size, an area of clean screen exists between the bubbles and the debris. The primary benefits of this innovation are the lack of any need for additional power, strip gas, or location for venting the separated gas. As the unit contains no membrane, the transport fluid will not be lost due to evaporation in the process of gas separation. Separation is performed with relatively low pressure drop based on the large surface area of the separating screen. Additionally, there are no moving parts, and there are no failure modes that involve fluid loss. A patent application has been filed.

Modeling quasi-static poroelastic propagation using an asymptotic approach

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

Vasco, D.W.

2007-11-01

Since the formulation of poroelasticity (Biot(1941)) and its reformulation (Rice & Cleary(1976)), there have been many efforts to solve the coupled system of equations. Perhaps because of the complexity of the governing equations, most of the work has been directed towards finding numerical solutions. For example, Lewis and co-workers published early papers (Lewis & Schrefler(1978); Lewis et al.(1991)Lewis, Schrefler, & Simoni) concerned with finite-element methods for computing consolidation, subsidence, and examining the importance of coupling. Other early work dealt with flow in a deformable fractured medium (Narasimhan & Witherspoon 1976); Noorishad et al.(1984)Noorishad, Tsang, & Witherspoon. This effort eventually evolvedmore » into a general numerical approach for modeling fluid flow and deformation (Rutqvist et al.(2002)Rutqvist, Wu, Tsang, & Bodvarsson). As a result of this and other work, numerous coupled, computer-based algorithms have emerged, typically falling into one of three categories: one-way coupling, loose coupling, and full coupling (Minkoff et al.(2003)Minkoff, Stone, Bryant, Peszynska, & Wheeler). In one-way coupling the fluid flow is modeled using a conventional numerical simulator and the resulting change in fluid pressures simply drives the deformation. In loosely coupled modeling distinct geomechanical and fluid flow simulators are run for a sequence of time steps and at the conclusion of each step information is passed between the simulators. In full coupling, the fluid flow and geomechanics equations are solved simultaneously at each time step (Lewis & Sukirman(1993); Lewis & Ghafouri(1997); Gutierrez & Lewis(2002)). One disadvantage of a purely numerical approach to solving the governing equations of poroelasticity is that it is not clear how the various parameters interact and influence the solution. Analytic solutions have an advantage in that respect; the relationship between the medium and fluid properties is clear from the form of the solution. Unfortunately, analytic solutions are only available for highly idealized conditions, such as a uniform (Rudnicki(1986)) or one-dimensional (Simon et al.(1984)Simon, Zienkiewicz, & Paul; Gajo & Mongiovi(1995); Wang & Kumpel(2003)) medium. In this paper I derive an asymptotic, semi-analytic solution for coupled deformation and flow. The approach is similar to trajectory- or ray-based methods used to model elastic and electromagnetic wave propagation (Aki & Richards(1980); Kline & Kay(1979); Kravtsov & Orlov(1990); Keller & Lewis(1995)) and, more recently, diffusive propagation (Virieux et al.(1994)Virieux, Flores-Luna, & Gibert; Vasco et al.(2000)Vasco, Karasaki, & Keers; Shapiro et al.(2002)Shapiro, Rothert, Rath, & Rindschwentner; Vasco(2007)). The asymptotic solution is valid in the presence of smoothly-varying, heterogeneous flow properties. The situation I am modeling is that of a formation with heterogeneous flow properties and uniform mechanical properties. The boundaries of the layer may vary arbitrary and can define discontinuities in both flow and mechanical properties. Thus, using the techniques presented here, it is possible to model a stack of irregular layers with differing mechanical properties. Within each layer the hydraulic conductivity and porosity can vary smoothly but with an arbitrarily large magnitude. The advantages of this approach are that it produces explicit, semi-analytic expressions for the arrival time and amplitude of the Biot slow and fast waves, expressions which are valid in a medium with heterogeneous properties. As shown here, the semi-analytic expressions provide insight into the nature of pressure and deformation signals recorded at an observation point. Finally, the technique requires considerably fewer computer resources than does a fully numerical treatment.« less

Frequency-Domain Characterization of Optic Flow and Vision-Based Ocellar Sensing for Rotational Motion

DTIC Science & Technology

2017-04-01

complementary fusion: Fourth-order Butterworth filter was used to high -pass ocelli and low-pass optic flow. The normalized cutoff frequency had to be kept...information introduced by luminance change. The high - frequency cutoff was added to reject the flickering noise for indoor usage. The filtered signals from the...function of the low- pass filter is to attenuate high - frequency noise. The final band-pass filter transfer function is in Eq. 2. (()

Permeability estimations and frictional flow features passing through porous media comprised of structured microbeads

NASA Astrophysics Data System (ADS)

Shin, C.

2017-12-01

Permeability estimation has been extensively researched in diverse fields; however, methods that suitably consider varying geometries and changes within the flow region, for example, hydraulic fracture closing for several years, are yet to be developed. Therefore, in the present study a new permeability estimation method is presented based on the generalized Darcy's friction flow relation, in particular, by examining frictional flow parameters and characteristics of their variations. For this examination, computational fluid dynamics (CFD) simulations of simple hydraulic fractures filled with five layers of structured microbeads and accompanied by geometry changes and flow transitions are performed. Consequently, it was checked whether the main structures and shapes of each flow path are preserved, even for geometry variations within porous media. However, the scarcity and discontinuity of streamlines increase dramatically in the transient- and turbulent-flow regions. The quantitative and analytic examinations of the frictional flow features were also performed. Accordingly, the modified frictional flow parameters were successfully presented as similarity parameters of porous flows. In conclusion, the generalized Darcy's friction flow relation and friction equivalent permeability (FEP) equation were both modified using the similarity parameters. For verification, the FEP values of the other aperture models were estimated and then it was checked whether they agreed well with the original permeability values. Ultimately, the proposed and verified method is expected to efficiently estimate permeability variations in porous media with changing geometric factors and flow regions, including such instances as hydraulic fracture closings.

Thermal effectiveness of multiple shell and tube pass TEMA E heat exchangers

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

Pignotti, A.; Tamborenea, P.I.

1988-02-01

The thermal effectiveness of a TEMAE shell-and-tube heat exchanger, with one shell pass and an arbitrary number of tube passes, is determined under the usual simplifying assumptions of perfect transverse mixing of the shell fluid, no phase change, and temperature independence of the heat capacity rates and the heat transfer coefficient. A purely algebraic solution is obtained for the effectiveness as a functions of the heat capacity rate ratio and the number of heat transfer units. The case with M shell passes and N tube passes is easily expressed in terms of the single-shell-pass case.

Heat transfer within a flat micro heat pipe with extra liquid

NASA Astrophysics Data System (ADS)

Sprinceana, Silviu; Mihai, Ioan

2016-12-01

In the real functioning of flat micro heat pipe (FMHP), there can appear cases when the temperature from the vaporization zone can exceed a critical value caused by a sudden increase of the thermal flow. The heat transfer which is completed conductively through the copper wall of a FMHP vaporizer causes the vaporization of the work fluid. On the condenser, the condensation of the fluid vapors and the transfer of the condenser to the vaporizer can no longer be achieved. The solution proposed for enhancing heat transfer in the event of blockage phenomenon FMHP, it is the injection of a certain amount of working fluid in the vaporization zone. By this process the working fluid injected into the evaporator passes suddenly in the vapor, producing a cooling zone. The new product additional mass of vapor will leave the vaporization zone and will condense in condensation zone, thereby supplementing the amount of condensation. Thus resumes normal operating cycle of FMHP. For the experimental measurements made for the transfer of heat through the FMHP working fluid demineralized water, they were made two micro-capillary tubes of sintered copper layer. The first was filled with 1ml of demineralized water was dropped under vacuum until the internal pressure has reached a level of 1•104Pa. The second FMHP was filled with the same amount of working fluid was used and the same capillary inner layer over which was laid a polysynthetic material that will accrue an additional amount of fluid. In this case, the internal pressure was reduced to 1•104Pa.

Mapping bone interstitial fluid movement: Displacement of ferritin tracer during histological processing

PubMed Central

Ciani, Cesare; Doty, Stephen B.; Fritton, Susannah P.

2014-01-01

Bone interstitial fluid flow is thought to play a fundamental role in the mechanical stimulation of bone cells, either via shear stresses or cytoskeletal deformations. Recent evidence indicates that osteocytes are surrounded by a fiber matrix that may be involved in the mechanotransduction of external stimuli as well as in nutrient exchange. In our previous tracer studies designed to map how different-sized molecules travel through the bone porosities, we found that injected ferritin was confined to blood vessels and did not pass into the mineralized matrix. However, other investigators have shown that ferritin forms halo-shaped labeling that enters the mineralized matrix around blood vessels. This labeling is widely used to explain normal interstitial fluid movement in bone; in particular, it is said to demonstrate bulk centrifugal interstitial fluid movement away from a highly pressurized vascular porosity. In addition, appositional ferritin fronts are said to demonstrate centrifugal interstitial fluid movement from the medullary canal to the periosteal surface. The purpose of this study was to investigate the conflicting ferritin labeling results by evaluating the role of different histological processes in the formation of ferritin “halos.” Ferritin was injected into the rat vasculature and allowed to circulate for 5 min. Samples obtained from tibiae were reacted for different times with Perl's reagent and then were either paraffin-embedded or sectioned with a cryostat. Halo-like labeling surrounding vascular pores was found in all groups, ranging from 1.2–3.9% for the samples treated with the shortest histological processes (unembedded, frozen sections) to 5.6–15% for the samples treated with the longest histological processes (paraffin-embedded sections). These results indicate that different histological processing methods are able to create ferritin “halos,” with some processing methods allowing more redistribution of the ferritin tracer than others. Based on these results and the fact that “halo” labeling has not been found with any other tracer, as we seek to further delineate the movement of interstitial fluid and the role it plays in bone mechanotransduction, we believe that ferritin “halo” labeling should not be used to demonstrate physiological bone interstitial fluid flow. PMID:15964255

Mapping bone interstitial fluid movement: displacement of ferritin tracer during histological processing.

PubMed

Ciani, Cesare; Doty, Stephen B; Fritton, Susannah P

2005-09-01

Bone interstitial fluid flow is thought to play a fundamental role in the mechanical stimulation of bone cells, either via shear stresses or cytoskeletal deformations. Recent evidence indicates that osteocytes are surrounded by a fiber matrix that may be involved in the mechanotransduction of external stimuli as well as in nutrient exchange. In our previous tracer studies designed to map how different-sized molecules travel through the bone porosities, we found that injected ferritin was confined to blood vessels and did not pass into the mineralized matrix. However, other investigators have shown that ferritin forms halo-shaped labeling that enters the mineralized matrix around blood vessels. This labeling is widely used to explain normal interstitial fluid movement in bone; in particular, it is said to demonstrate bulk centrifugal interstitial fluid movement away from a highly pressurized vascular porosity. In addition, appositional ferritin fronts are said to demonstrate centrifugal interstitial fluid movement from the medullary canal to the periosteal surface. The purpose of this study was to investigate the conflicting ferritin labeling results by evaluating the role of different histological processes in the formation of ferritin "halos." Ferritin was injected into the rat vasculature and allowed to circulate for 5 min. Samples obtained from tibiae were reacted for different times with Perl's reagent and then were either paraffin-embedded or sectioned with a cryostat. Halo-like labeling surrounding vascular pores was found in all groups, ranging from 1.2-3.9% for the samples treated with the shortest histological processes (unembedded, frozen sections) to 5.6-15% for the samples treated with the longest histological processes (paraffin-embedded sections). These results indicate that different histological processing methods are able to create ferritin "halos," with some processing methods allowing more redistribution of the ferritin tracer than others. Based on these results and the fact that "halo" labeling has not been found with any other tracer, as we seek to further delineate the movement of interstitial fluid and the role it plays in bone mechanotransduction, we believe that ferritin "halo" labeling should not be used to demonstrate physiological bone interstitial fluid flow.

A kinetic approach to the study of absorption of solutes by isolated perfused small intestine

PubMed Central

Fisher, R. B.; Gardner, M. L. G.

1974-01-01

1. A new technique has been developed for making serial measurements of water and solute absorption from the lumen of isolated small intestine. 2. The isolated intestine is perfused in a single pass with a segmented flow of slugs of liquid separated by bubbles of oxygen-carbon dioxide mixture. Simultaneous collections are made of effluent from the lumen and of the fluid which is transported across the mucosa. This latter fluid appears to be a fair sample of the tissue fluid. 3. Conditions in the lumen can be changed within less than 5 min. The effects of two or more treatments applied to the same segment of intestine can be determined and the time course of a change in luminal conditions. 4. The rate of appearance of solutes on the serosal side depends on the rate of water absorption, and changes exponentially towards a steady state. The rate constant is a function of tissue fluid volume. 5. In the steady state the concentration of glucose in the tissue fluid is 71 mM when the luminal concentration is 28 mM, and is 45 mM when the luminal concentration is 8·3 mM. 6. For solutes such as glucose for which reflux from tissue fluid to lumen is small relative to flux from lumen to tissue fluid, the time of attainment of a steady state in secretion is usually 50-60 min. 7. For solutes such as sodium for which the reflux is relatively high, the steady state may be reached in 15-20 min. 8. The Km for glucose absorption (14-19 mM) is much lower than is found with unsegmented flow perfusion. 9. These findings emphasize problems in interpreting results from other types of intestinal preparation. 10. The rate of glucose absorption from the lumen falls only gradually when the luminal sodium concentration is reduced abruptly. In contrast the rate of glucose absorption falls suddenly when the luminal glucose concentration is reduced abruptly. This suggests that glucose absorption is not directly dependent on luminal sodium ions. ImagesPlate 1 PMID:4422346

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

DOEpatents

Ortiz, Marcos G.; Boucher, Timothy J.

1997-01-01

A system for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit.

Effects of coarse grain size distribution and fine particle content on pore fluid pressure and shear behavior in experimental debris flows

NASA Astrophysics Data System (ADS)

Kaitna, Roland; Palucis, Marisa C.; Yohannes, Bereket; Hill, Kimberly M.; Dietrich, William E.

2016-02-01

Debris flows are typically a saturated mixture of poorly sorted particles and interstitial fluid, whose density and flow properties depend strongly on the presence of suspended fine sediment. Recent research suggests that grain size distribution (GSD) influences excess pore pressures (i.e., pressure in excess of predicted hydrostatic pressure), which in turn plays a governing role in debris flow behaviors. We report a series of controlled laboratory experiments in a 4 m diameter vertically rotating drum where the coarse particle size distribution and the content of fine particles were varied independently. We measured basal pore fluid pressures, pore fluid pressure profiles (using novel sensor probes), velocity profiles, and longitudinal profiles of the flow height. Excess pore fluid pressure was significant for mixtures with high fines fraction. Such flows exhibited lower values for their bulk flow resistance (as measured by surface slope of the flow), had damped fluctuations of normalized fluid pressure and normal stress, and had velocity profiles where the shear was concentrated at the base of the flow. These effects were most pronounced in flows with a wide coarse GSD distribution. Sustained excess fluid pressure occurred during flow and after cessation of motion. Various mechanisms may cause dilation and contraction of the flows, and we propose that the sustained excess fluid pressures during flow and once the flow has stopped may arise from hindered particle settling and yield strength of the fluid, resulting in transfer of particle weight to the fluid. Thus, debris flow behavior may be strongly influenced by sustained excess fluid pressures controlled by particle settling rates.

Effects of Energy Dissipation Rate on Islets of Langerhans: Implications for Isolation and Transplantation

PubMed Central

Shenkman, Rustin M.; Godoy-Silva, Ruben; Papas, Klearchos K.; Chalmers, Jeffrey J.

2010-01-01

Acute physical stresses can occur in the procurement and isolation process and potentially can contribute to islet death or malfunction upon transplantation. A contractional flow device, previously used to subject suspended cells to well-defined hydrodynamic forces, has been modified and used to assess the vulnerability of porcine islets of Langerhans to hydrodynamic forces. The flow profiles and velocity gradients in this modified device were modeled using commercial CFD software and characterized, as in previous studies, with the scalar parameter, energy dissipation rate (EDR). Porcine islets were stressed in a single pass at various stress levels (i.e., values of EDR). Membrane integrity, oxygen uptake rate, caspase 3/7 activity, and insulin release were not affected by the levels of fluid stress tested up to an EDR of 2 × 103 W/m3. Visual observation of the stressed islets suggested that cells at the islet exterior were peeled away at EDR greater than 10,000 W/m3, however, this observation could not be confirmed using image analysis software, which determined the ratio of surface perimeter to total area. The result of this study suggests an upper limit in fluid stress to which islets can be subjected. Such upper limits assist in the design and operation of future islet processing equipment and processes. PMID:19191351

Bipotential continuum models for granular mechanics

NASA Astrophysics Data System (ADS)

Goddard, Joe

2014-03-01

Most currently popular continuum models for granular media are special cases of a generalized Maxwell fluid model, which describes the evolution of stress and internal variables such as granular particle fraction and fabric,in terms of imposed strain rate. It is shown how such models can be obtained from two scalar potentials, a standard elastic free energy and a ``dissipation potential'' given rigorously by the mathematical theory of Edelen. This allows for a relatively easy derivation of properly invariant continuum models for granular media and fluid-particle suspensions within a thermodynamically consistent framework. The resulting continuum models encompass all the prominent regimes of granular flow, ranging from the quasi-static to rapidly sheared, and are readily extended to include higher-gradient or Cosserat effects. Models involving stress diffusion, such as that proposed recently by Kamrin and Koval (PRL 108 178301), provide an alternative approach that is mentioned in passing. This paper provides a brief overview of a forthcoming review articles by the speaker (The Princeton Companion to Applied Mathematics, and Appl. Mech. Rev.,in the press, 2013).

Performance of a parallel code for the Euler equations on hypercube computers

NASA Technical Reports Server (NTRS)

Barszcz, Eric; Chan, Tony F.; Jesperson, Dennis C.; Tuminaro, Raymond S.

1990-01-01

The performance of hypercubes were evaluated on a computational fluid dynamics problem and the parallel environment issues were considered that must be addressed, such as algorithm changes, implementation choices, programming effort, and programming environment. The evaluation focuses on a widely used fluid dynamics code, FLO52, which solves the two dimensional steady Euler equations describing flow around the airfoil. The code development experience is described, including interacting with the operating system, utilizing the message-passing communication system, and code modifications necessary to increase parallel efficiency. Results from two hypercube parallel computers (a 16-node iPSC/2, and a 512-node NCUBE/ten) are discussed and compared. In addition, a mathematical model of the execution time was developed as a function of several machine and algorithm parameters. This model accurately predicts the actual run times obtained and is used to explore the performance of the code in interesting but yet physically realizable regions of the parameter space. Based on this model, predictions about future hypercubes are made.

Heat exchanger for reactor core and the like

DOEpatents

Kaufman, Jay S.; Kissinger, John A.

1986-01-01

A compact bayonet tube type heat exchanger which finds particular application as an auxiliary heat exchanger for transfer of heat from a reactor gas coolant to a secondary fluid medium. The heat exchanger is supported within a vertical cavity in a reactor vessel intersected by a reactor coolant passage at its upper end and having a reactor coolant return duct spaced below the inlet passage. The heat exchanger includes a plurality of relatively short length bayonet type heat exchange tube assemblies adapted to pass a secondary fluid medium therethrough and supported by primary and secondary tube sheets which are releasibly supported in a manner to facilitate removal and inspection of the bayonet tube assemblies from an access area below the heat exchanger. Inner and outer shrouds extend circumferentially of the tube assemblies and cause the reactor coolant to flow downwardly internally of the shrouds over the tube bundle and exit through the lower end of the inner shroud for passage to the return duct in the reactor vessel.

Late Quaternary history of contourite drifts and variations in Labrador Current flow, Flemish Pass, offshore eastern Canada

NASA Astrophysics Data System (ADS)

Marshall, Nicole R.; Piper, David J. W.; Saint-Ange, Francky; Campbell, D. Calvin

2014-10-01

Contourite drifts of alternating sand and mud, shaped by the Labrador Current, formed during the late Quaternary in Flemish Pass seaward of the Grand Banks of Newfoundland, Canada. The drifts preserve a record of Labrador Current flow variations through the last glacial maximum. A high-resolution seismic profile and a transect of four cores were collected across Beothuk drift on the southeast side of Flemish Pass. Downcore and lateral trends in grain size and sedimentation rate provide evidence that, between 16 and 13 ka, sediment was partitioned across Beothuk drift and the adjacent Flemish Pass floor by a strong current flow but, from 29 to 16 ka, sedimentation was more of a blanketing style, represented by draped reflections interpreted as being due to a weaker current. The data poorly resolve the low sedimentation rates since 13 ka, but the modern Labrador Current in Flemish Pass is the strongest it has been in at least the past 29 ka. Pre-29 ka current flow is interpreted based on reflection architecture in seismic profiles. A prominent drift on the southwestern side of Flemish Pass formed above a mid-Miocene erosion surface, but was buried by a mass-transport deposit after the penultimate glacial maximum and after drift deposition switched to eastern Flemish Pass. These findings illustrate the temporal complexity of drift sedimentation and provide the first detailed proxy for Labrador Current flow since the last glacial maximum.

Finite Element Analysis of MEMS Devices

NASA Technical Reports Server (NTRS)

Corrigan, Jennifer

2004-01-01

A side-slide actuator and a corrugated diaphragm actuator will be analyzed and optimized this summer. Coupled electrostatic and fluid analyses will also be initiated. Both the side-slide actuator and the corrugated diaphragm actuator will be used to regulate the flow of fuel in a jet engine. Many of the side-slide actuators will be placed on top of a fuel injector that is still in the developmental stage as well. The corrugated diaphragm actuator will also be used to regulate the flow of fuel in fuel injectors. A comparative analysis of the performance matrix of both actuators will be conducted. The side-slide actuator uses the concept of mechanical advantage to regulate the flow of fuel using electrostatic forces. It is made from Nickel, Silicon Carbide, and thin layers of Oxide. The slider will have a hole in the middle that will allow fuel to pass through the hole underneath it. The goal is to regulate the flow of fuel through the inlet. This means that the actuator needs to be designed so that when a voltage is applied to the push rod, the slider will deflect in the x-direction and be able to completely block the inlet and no fuel can pass through. Different voltage levels will be tested. The parameters that are being optimized are the thickness of the diaphragm, what kind of corrugation the diaphragm should have, the length, width, and thickness of the push rod, and what design should be used to return the slider. The current possibilities for a return rod are a built in spring on the slider, a return rod that acts like a spring, or a return rod that is identical to the push rod. The final actuator design should have a push rod that has rotational motion and no translation motion, a push rod thickness that prevents warping due to the slider, and a large ratio of the displacement on the bottom of the push rod to displacement on the top of the push rod. The corrugated diaphragm actuator was optimized last winter and this summer will be spent completing the optimization of the coupled electrostatic and fluid flow parameters. It was found that Nickel is the best material to use for the diaphragm because it has a higher yield strength and allows for a larger stress, deflection and applied pressure. The parameters that were optimized were the wavelength and thickness of the diaphragm.

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1997-06-24

A system is described for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit. 2 figs.

Cerebrospinal fluid flow abnormalities in patients with neoplastic meningitis. An evaluation using /sup 111/In-DTPA ventriculography

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

Grossman, S.A.; Trump, D.L.; Chen, D.C.

1982-11-01

Cerebrospinal fluid flow dynamics were evaluated by /sup 111/In-diethylenetriamine pentaacetic acid (/sup 111/In-DTPA) ventriculography in 27 patients with neoplastic meningitis. Nineteen patients (70 percent) had evidence of cerebrospinal fluid flow disturbances. These occurred as ventricular outlet obstructions, abnormalities of flow in the spinal canal, or flow distrubances over the cortical convexities. Tumor histology, physical examination, cerebrospinal fluid analysis, myelograms, and computerized axial tomographic scans were not sufficient to predict cerebrospinal fluid flow patterns. These data indicate that cerebrospinal fluid flow abnormalities are common in patients with neoplastic meningitis and that /sup 111/In-DTPA cerebrospinal fluid flow imaging is useful in characterizingmore » these abnormalities. This technique provides insight into the distribution of intraventricularly administered chemotherapy and may provide explanations for treatment failure and drug-induced neurotoxicity in patients with neoplastic meningitis.« less

Gas turbine engine exhaust diffuser including circumferential vane

DOEpatents

Orosa, John A.; Matys, Pawel

2015-05-19

A flow passage defined between an inner and an outer boundary for guiding a fluid flow in an axial direction. A flow control vane is supported at a radial location between the inner and outer boundaries. A fluid discharge opening is provided for discharging a flow of the compressed fluid from a trailing edge of the vane, and a fluid control surface is provided adjacent to the fluid discharge opening and extends in the axial direction at the trailing edge of the vane. The fluid control surface has a curved trailing edge forming a Coanda surface. The fluid discharge opening is selectively provided with a compressed fluid to produce a Coanda effect along the control surface. The Coanda effect has a component in the radial direction effecting a turning of the fluid flow in the flow path radially inward or outward toward one of the inner and outer boundaries.

Electric fluid pump

DOEpatents

Van Dam, Jeremy Daniel; Turnquist, Norman Arnold; Raminosoa, Tsarafidy; Shah, Manoj Ramprasad; Shen, Xiaochun

2015-09-29

An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.

Visualization of various working fluids flow regimes in gravity heat pipe

NASA Astrophysics Data System (ADS)

Nemec, Patrik

Heat pipe is device working with phase changes of working fluid inside hermetically closed pipe at specific pressure. The phase changes of working fluid from fluid to vapour and vice versa help heat pipe to transport high heat flux. Amount of heat flux transferred by heat pipe, of course depends on kind of working fluid. The article deal about visualization of various working fluids flow regimes in glass gravity heat pipe by high speed camera and processes casing inside during heat pipe operation. Experiment working fluid flow visualization is performed with two glass heat pipes with different inner diameter (13 mm and 22 mm) filled with water, ethanol and fluorinert FC 72. The working fluid flow visualization explains the phenomena as a working fluid boiling, nucleation of bubbles, and vapour condensation on the wall, vapour and condensate flow interaction, flow down condensate film thickness on the wall occurred during the heat pipe operation.

Hyperfiltration wash water recovery subsystem - Design and test results. [for extended mission spacecraft such as space stations

NASA Technical Reports Server (NTRS)

Reysa, R. P.; Price, D. F.; Olcott, T.; Gaddis, J. L.

1983-01-01

The Hyperfiltration Wash Water Recovery (HWWR) subsystem, designed to offer low-power high-volume wash water purification for extended mission spacecraft, is discussed in terms of preprototype design and configuration. Heated wash water collected from the shower, hand wash, and laundry flows into a temperature-controlled (374 K) waste storage tank. Two parallel 25 micron absolute filters at the tank outlet remove large particles from the feed stream. A positive displacement feed pump delivers wash water to the hyperfiltration module at a constant flow rate of 0.20 lpm with discharge pressure variations from 4181-7239 Kpa. The hyperfiltration membrane module is a single-pass design including 36 porous stainless steel tubes, and is designed to provide an approximate water recovery rate of 90 percent. Permeate and brine water flows are monitored by flow meters, and removal of urea and ammonia is achieved by adding 15 percent NaOCl solution to the permeate fluid stream. An alternate module design using two diameters of tubing (allowing a smaller pressure drop and a larger membrane area) gave a superior predicted performance over the first module with larger tubing throughout.

Modeling of the static recrystallization for 7055 aluminum alloy by cellular automaton

NASA Astrophysics Data System (ADS)

Zhang, Tao; Lu, Shi-hong; Zhang, Jia-bin; Li, Zheng-fang; Chen, Peng; Gong, Hai; Wu, Yun-xin

2017-09-01

In order to simulate the flow behavior and microstructure evolution during the pass interval period of the multi-pass deformation process, models of static recovery (SR) and static recrystallization (SRX) by the cellular automaton (CA) method for the 7055 aluminum alloy were established. Double-pass hot compression tests were conducted to acquire flow stress and microstructure variation during the pass interval period. With the basis of the material constants obtained from the compression tests, models of the SR, incubation period, nucleation rate and grain growth were fitted by least square method. A model of the grain topology and a statistical computation of the CA results were also introduced. The effects of the pass interval time, temperature, strain, strain rate and initial grain size on the microstructure variation for the SRX of the 7055 aluminum alloy were studied. The results show that a long pass interval time, large strain, high temperature and large strain rate are beneficial for finer grains during the pass interval period. The stable size of the static recrystallized grain is not concerned with the initial grain size, but mainly depends on the strain rate and temperature. The SRX plays a vital role in grain refinement, while the SR has no effect on the variation of microstructure morphology. Using flow stress and microstructure comparisons of the simulated and experimental CA results, the established CA models can accurately predict the flow stress and microstructure evolution during the pass interval period, and provide guidance for the selection of optimized parameters for the multi-pass deformation process.

Determining the Coefficient of Discharge for a Draining Container

ERIC Educational Resources Information Center

Hicks, Ashley; Slaton, William

2014-01-01

The flow of fluids through open containers is a topic studied frequently in introductory physics classes. A fluid mechanics class delves deeper into the topic of fluid flow through open containers with holes or barriers. The flow of a fluid jet out of a sharp-edged orifice rarely has the same area as the orifice due to a fluid flow phenomenon…

Flow of two immiscible fluids in a periodically constricted tube: Transitions to stratified, segmented, churn, spray, or segregated flow

NASA Astrophysics Data System (ADS)

Fraggedakis, D.; Kouris, Ch.; Dimakopoulos, Y.; Tsamopoulos, J.

2015-08-01

We study the flow of two immiscible, Newtonian fluids in a periodically constricted tube driven by a constant pressure gradient. Our volume-of-fluid algorithm is used to solve the governing equations. First, the code is validated by comparing its predictions to previously reported results for stratified and pulsing flow. Then, it is used to capture accurately all the significant topological changes that take place. Initially, the fluids have a core-annular arrangement, which is found to either remain the same or change to a different arrangement depending on the fluid properties, the pressure driving the flow, or the flow geometry. The flow-patterns that appear are the core-annular, segmented, churn, spray, and segregated flow. The predicted scalings near pinching of the core fluid concur with similarity predictions and earlier numerical results [I. Cohen et al., "Two fluid drop snap-off problem: Experiments and theory," Phys. Rev. Lett. 83, 1147-1150 (1999)]. Flow-pattern maps are constructed in terms of the Reynolds and Weber numbers. Our result provides deeper insights into the mechanism of the pattern transitions and is in agreement with previous studies on core-annular flow [Ch. Kouris and J. Tsamopoulos, "Core-annular flow in a periodically constricted circular tube, I. Steady state, linear stability and energy analysis," J. Fluid Mech. 432, 31-68 (2001) and Ch. Kouris et al., "Comparison of spectral and finite element methods applied to the study of interfacial instabilities of the core-annular flow in an undulating tube," Int. J. Numer. Methods Fluids 39(1), 41-73 (2002)], segmented flow [E. Lac and J. D. Sherwood, "Motion of a drop along the centreline of a capillary in a pressure-driven flow," J. Fluid Mech. 640, 27-54 (2009)], and churn flow [R. Y. Bai et al., "Lubricated pipelining—Stability of core annular-flow. 5. Experiments and comparison with theory," J. Fluid Mech. 240, 97-132 (1992)].

Fish navigation of large dams emerges from their modulation of flow field experience

PubMed Central

Goodwin, R. Andrew; Politano, Marcela; Garvin, Justin W.; Nestler, John M.; Hay, Duncan; Anderson, James J.; Weber, Larry J.; Dimperio, Eric; Smith, David L.; Timko, Mark

2014-01-01

Navigating obstacles is innate to fish in rivers, but fragmentation of the world’s rivers by more than 50,000 large dams threatens many of the fish migrations these waterways support. One limitation to mitigating the impacts of dams on fish is that we have a poor understanding of why some fish enter routes engineered for their safe travel around the dam but others pass through more dangerous routes. To understand fish movement through hydropower dam environments, we combine a computational fluid dynamics model of the flow field at a dam and a behavioral model in which simulated fish adjust swim orientation and speed to modulate their experience to water acceleration and pressure (depth). We fit the model to data on the passage of juvenile Pacific salmonids (Oncorhynchus spp.) at seven dams in the Columbia/Snake River system. Our findings from reproducing observed fish movement and passage patterns across 47 flow field conditions sampled over 14 y emphasize the role of experience and perception in the decision making of animals that can inform opportunities and limitations in living resources management and engineering design. PMID:24706826

Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures

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

Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R.

Here, we present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 < T < 5000 K) and atmospheric pressure. The reactor consists of a glass tube that is attached to an inductively coupled argon plasma generator via an adaptor (ring flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after theymore » pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.« less

Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures

DOE PAGES

Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R.; ...

2017-09-11

Here, we present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 < T < 5000 K) and atmospheric pressure. The reactor consists of a glass tube that is attached to an inductively coupled argon plasma generator via an adaptor (ring flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after theymore » pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.« less

Hot Films on Ceramic Substrates for Measuring Skin Friction

NASA Technical Reports Server (NTRS)

Noffz, Greg; Leiser, Daniel; Bartlett, Jim; Lavine, Adrienne

2003-01-01

Hot-film sensors, consisting of a metallic film on an electrically nonconductive substrate, have been used to measure skin friction as far back as 1931. A hot film is maintained at an elevated temperature relative to the local flow by passing an electrical current through it. The power required to maintain the specified temperature depends on the rate at which heat is transferred to the flow. The heat transfer rate correlates to the velocity gradient at the surface, and hence, with skin friction. The hot-film skin friction measurement method is most thoroughly developed for steady-state conditions, but additional issues arise under transient conditions. Fabricating hot-film substrates using low-thermal-conductivity ceramics can offer advantages over traditional quartz or polyester-film substrates. First, a low conductivity substrate increases the fraction of heat convected away by the fluid, thus increasing sensitivity to changes in flow conditions. Furthermore, the two-part, composite nature of the substrate allows the installation of thermocouple junctions just below the hot film, which can provide an estimate of the conduction heat loss.

Low-pass filtered continuum streambed and bedload sediment mass balance laws for an alluvial, gravel-bed stream

NASA Astrophysics Data System (ADS)

DeTemple, B.; Wilcock, P.

2011-12-01

In an alluvial, gravel-bed stream governed by a plane-bed bedload transport regime, the physicochemical properties, size distribution, and granular architecture of the sediment grains that constitute the streambed surface influence many hydrodynamic, geomorphic, chemical, and ecological processes. Consequently, the abilities to accurately characterize the morphology and model the morphodynamics of the streambed surface and its interaction with the bedload above and subsurface below are necessary for a more complete understanding of how sediment, flow, organisms, and biogeochemistry interact. We report on our progress in the bottom-up development of low-pass filtered continuum streambed and bedload sediment mass balance laws for an alluvial, gravel-bed stream. These balance laws are assembled in a four stage process. First, the stream sediment-water system is conceptually abstracted as a nested, multi-phase, multi-species, structured continuum. Second, the granular surface of an aggregate of sediment grains is mathematically defined. Third, an integral approach to mass balance, founded in the continuum theory of multiphase flow, is used to formulate primordial, differential, instantaneous, local, continuum, mass balance laws applicable at any material point within a gravel-bed stream. Fourth, area averaging and time-after-area averaging, employing planform, low-pass filtering expressed as correlation or convolution integrals and based on the spatial and temporal filtering techniques found in the fields of multiphase flow, porous media flow, and large eddy simulation of turbulent fluid flow, are applied to smooth the primordial equations while maximizing stratigraphic resolution and preserving the definitions of relevant morphodynamic surfaces. Our approach unifies, corrects, contextualizes, and generalizes prior efforts at developing stream sediment continuity equations, including the top-down derivations of the surface layer (or "active layer") approach of Hirano [1971a,b] and probabilistic approach of Parker et al. [2000], as well as the bottom-up, low-pass filtered continuum approach of Coleman & Nikora [2009] which employed volume and volume-after-time averaging. It accommodates partial transport (e.g., Wilcock & McArdell [1997], Wilcock [1997a,b]). Additionally, it provides: (1) precise definitions of the geometry and kinematics of sediment in a gravel-bed stream required to collect and analyze the high resolution spatial and temporal datasets that are becoming ever more present in both laboratory and field investigations, (2) a mathematical framework for the use of tracer grains in gravel-bed streams, including the fate of streambed-emplaced tracers as well as the dispersion of tracers in the bedload, (3) spatial and temporal averaging uncompromised by the Reynolds rules necessary to assess the nature of scale separation, and (4) a kinematic foundation for hybrid Langrangian-Eulerian models of sediment morphodynamics.

Hydrocarbon fluid, ejector refrigeration system

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

Kowalski, G.J.; Foster, A.R.

1993-08-31

A refrigeration system is described comprising: a vapor ejector cycle including a working fluid having a property such that entropy of the working fluid when in a saturated vapor state decreases as pressure decreases, the vapor ejector cycle comprising: a condenser located on a common fluid flow path; a diverter located downstream from the condenser for diverting the working fluid into a primary fluid flow path and a secondary fluid flow path parallel to the primary fluid flow path; an evaporator located on the secondary fluid flow path; an expansion device located on the secondary fluid flow path upstream ofmore » the evaporator; a boiler located on the primary fluid flow path parallel to the evaporator for boiling the working fluid, the boiler comprising an axially extending core region having a substantially constant cross sectional area and a porous capillary region surrounding the core region, the core region extending a length sufficient to produce a near sonic velocity saturated vapor; and an ejector having an outlet in fluid communication with the inlet of the condenser and an inlet in fluid communication with the outlet of the evaporator and the outlet of the boiler and in which the flows of the working fluid from the evaporator and the boiler are mixed and the pressure of the working fluid is increased to at least the pressure of the condenser, the ejector inlet, located downstream from the axially extending core region, including a primary nozzle located sufficiently close to the outlet of the boiler to minimize a pressure drop between the boiler and the primary nozzle, the primary nozzle of the ejector including a converging section having an included angle and length preselected to receive the working fluid from the boiler as a near sonic velocity saturated vapor.« less

Shaded computer graphic techniques for visualizing and interpreting analytic fluid flow models

NASA Technical Reports Server (NTRS)

Parke, F. I.

1981-01-01

Mathematical models which predict the behavior of fluid flow in different experiments are simulated using digital computers. The simulations predict values of parameters of the fluid flow (pressure, temperature and velocity vector) at many points in the fluid. Visualization of the spatial variation in the value of these parameters is important to comprehend and check the data generated, to identify the regions of interest in the flow, and for effectively communicating information about the flow to others. The state of the art imaging techniques developed in the field of three dimensional shaded computer graphics is applied to visualization of fluid flow. Use of an imaging technique known as 'SCAN' for visualizing fluid flow, is studied and the results are presented.

Two part condenser for varying the rate of condensing and related method

DOEpatents

Dobos, James G.

2007-12-11

A heat transfer apparatus, such as a condenser, is provided. The apparatus includes a first component with a first heat transfer element that has first component inlet and outlet ports through which a first fluid may pass. A second component is also included and likewise has a second heat transfer element with second component inlet and outlet ports to pass a second fluid. The first component has a body that can receive a third fluid for heat transfer with the first heat transfer element. The first and second components are releasably attachable with one another so that when attached both the first and second heat transfer elements effect heat transfer with the third fluid. Attachment and removal of the first and second components allows for the heat transfer rate of the apparatus to be varied. An associated method is also provided.

Pressurized fluidized bed reactor

DOEpatents

Isaksson, J.

1996-03-19

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

Pressurized fluidized bed reactor

DOEpatents

Isaksson, Juhani

1996-01-01

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

Generating Inviscid and Viscous Fluid-Flow Simulations over an Aircraft Surface Using a Fluid-Flow Mesh

NASA Technical Reports Server (NTRS)

Rodriguez, David L. (Inventor); Sturdza, Peter (Inventor)

2013-01-01

Fluid-flow simulation over a computer-generated aircraft surface is generated using inviscid and viscous simulations. A fluid-flow mesh of fluid cells is obtained. At least one inviscid fluid property for the fluid cells is determined using an inviscid fluid simulation that does not simulate fluid viscous effects. A set of intersecting fluid cells that intersects the aircraft surface are identified. One surface mesh polygon of the surface mesh is identified for each intersecting fluid cell. A boundary-layer prediction point for each identified surface mesh polygon is determined. At least one boundary-layer fluid property for each boundary-layer prediction point is determined using the at least one inviscid fluid property of the corresponding intersecting fluid cell and a boundary-layer simulation that simulates fluid viscous effects. At least one updated fluid property for at least one fluid cell is determined using the at least one boundary-layer fluid property and the inviscid fluid simulation.

One-Way Particle Transport Using Oscillatory Flow in Asymmetric Traps.

PubMed

Lee, Jaesung; Burns, Mark A

2018-03-01

One challenge of integrating of passive, microparticles manipulation techniques into multifunctional microfluidic devices is coupling the continuous-flow format of most systems with the often batch-type operation of particle separation systems. Here, a passive fluidic technique-one-way particle transport-that can conduct microparticle operations in a closed fluidic circuit is presented. Exploiting pass/capture interactions between microparticles and asymmetric traps, this technique accomplishes a net displacement of particles in an oscillatory flow field. One-way particle transport is achieved through four kinds of trap-particle interactions: mechanical capture of the particle, asymmetric interactions between the trap and the particle, physical collision of the particle with an obstacle, and lateral shift of the particle into a particle-trapping stream. The critical dimensions for those four conditions are found by numerically solving analytical mass balance equations formulated using the characteristics of the flow field in periodic obstacle arrays. Visual observation of experimental trap-particle dynamics in low Reynolds number flow (<0.01) confirms the validity of the theoretical predictions. This technique can transport hundreds of microparticles across trap rows in only a few fluid oscillations (<500 ms per oscillation) and separate particles by their size differences. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical Simulation of Plume Transport in Channel Bend with Different Sediment Diameters

NASA Astrophysics Data System (ADS)

Kim, H. S.; Chen, H. C.

2017-12-01

The flow and transport of suspended sediment particles, in the form of plume, were simulated using an in-house Computational Fluid Dynamics (CFD) solver FANS3D (Finite Analytic Navier-Stokes code for 3D flow). The motivation for this investigation is to provide a means to simulate and visualize dispersal systems in a complex flow environment. The physical domain considered is a 90-degrees channel bend with wingwall abutments, which induces complex, three-dimensional flow characteristics. At the inlet of the channel, a sediment plume with the volumetric concentration of 1,000 parts per million (ppm) was constantly supplied. For simplicity, it was assumed that neither deposition nor erosion takes place inside the channel and settling sediment was made to pass through the bed surface. The effect of the sediment particle size was also analyzed using two different median diameters: 0.10 mm and 0.20 mm. It was shown that flow acceleration and vortices cause strong mixing inside the channel. The three-dimensional time series from the simulation captured increasing suspended sediment concentration downstream of the abutments, along the outer bank. When the median diameter was varied, the sediment concentration at certain locations differed by orders of magnitude, indicating that the settling velocity dominates the transport process for larger diameters.

Interfacial Area Development in Two-Phase Fluid Flow: Transient vs. Quasi-Static Flow Conditions

NASA Astrophysics Data System (ADS)

Meisenheimer, D. E.; Wildenschild, D.

2017-12-01

Fluid-fluid interfaces are important in multiphase flow systems in the environment (e.g. groundwater remediation, geologic CO2 sequestration) and industry (e.g. air stripping, fuel cells). Interfacial area controls mass transfer, and therefore reaction efficiency, between the different phases in these systems but they also influence fluid flow processes. There is a need to better understand this relationship between interfacial area and fluid flow processes so that more robust theories and models can be built for engineers and policy makers to improve the efficacy of many multiphase flow systems important to society. Two-phase flow experiments were performed in glass bead packs under transient and quasi-static flow conditions. Specific interfacial area was calculated from 3D images of the porous media obtained using the fast x-ray microtomography capability at the Advanced Photon Source. We present data suggesting a direct relationship between the transient nature of the fluid-flow experiment (fewer equilibrium points) and increased specific interfacial area. The effect of flow condition on Euler characteristic (a representative measure of fluid topology) will also be presented.

Mathematical modelling of cell layer growth in a hollow fibre bioreactor.

PubMed

Chapman, Lloyd A C; Whiteley, Jonathan P; Byrne, Helen M; Waters, Sarah L; Shipley, Rebecca J

2017-04-07

Generating autologous tissue grafts of a clinically useful volume requires efficient and controlled expansion of cell populations harvested from patients. Hollow fibre bioreactors show promise as cell expansion devices, owing to their potential for scale-up. However, further research is required to establish how to specify appropriate hollow fibre bioreactor operating conditions for expanding different cell types. In this study we develop a simple model for the growth of a cell layer seeded on the outer surface of a single fibre in a perfused hollow fibre bioreactor. Nutrient-rich culture medium is pumped through the fibre lumen and leaves the bioreactor via the lumen outlet or passes through the porous fibre walls and cell layer, and out via ports on the outer wall of the extra-capillary space. Stokes and Darcy equations for fluid flow in the fibre lumen, fibre wall, cell layer and extra-capillary space are coupled to reaction-advection-diffusion equations for oxygen and lactate transport through the bioreactor, and to a simple growth law for the evolution of the free boundary of the cell layer. Cells at the free boundary are assumed to proliferate at a rate that increases with the local oxygen concentration, and to die and detach from the layer if the local fluid shear stress or lactate concentration exceed critical thresholds. We use the model to predict operating conditions that maximise the cell layer growth for different cell types. In particular, we predict the optimal flow rate of culture medium into the fibre lumen and fluid pressure imposed at the lumen outlet for cell types with different oxygen demands and fluid shear stress tolerances, and compare the growth of the cell layer when the exit ports on the outside of the bioreactor are open with that when they are closed. Model simulations reveal that increasing the inlet flow rate and outlet fluid pressure increases oxygen delivery to the cell layer and, therefore, the growth rate of cells that are tolerant to high shear stresses, but may be detrimental for shear-sensitive cells. The cell layer growth rate is predicted to increase, and be less sensitive to the lactate tolerance of the cells, when the exit ports are opened, as the radial flow through the bioreactor is enhanced and the lactate produced by the cells cleared more rapidly from the cell layer. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparative study on the influence of depth, number and arrangement of dimples on the flow and heat transfer characteristics at turbulent flow regimes

NASA Astrophysics Data System (ADS)

Nazari, Saeed; Zamani, Mahdi; Moshizi, Sajad A.

2018-03-01

The ensuing study is dedicated to a series of numerical investigations concerning the effects of various geometric parameters of dimpled plates on the flow structure and heat transfer performance in a rectangular duct compared to the smooth plate. These parameters are the arrangement, number and depth of dimples. Two widely used staggered and square patterns in addition to a triangular arrangement, and three dimple depths (Δ = δ/d = 0.25, 0.375 and 0.5) have been chosen for this particular study. All studies have been conducted at three different Reynolds numbers Re = 25,000, 50,000 and 100,000. In order to capture the flow structures in the vicinity of dimples and contributing phenomena related to the boundary layer interactions, fully structured grids with y+ < 1 have been generated for all the cases. The realizable k t -ɛ two-layer model was selected as a proper turbulent model. It can be observed from the obtained results that higher effective area for heat transfer and a myriad of turbulent vortices mixing the hot fluid near the surface with the passing cold fluid generated from the downwind rims of dimples are the causes for improved average Nusselt number in the dimpled surface in comparison to the smooth plate. However, more pressure loss due to the higher friction drag and recirculation zones inside dimples will exist as a drawback in this system. Moreover, for all arrangements increasing dimple ratio Δ has a negative impact on the heat transfer augmentation and also deteriorates the pressure loss, which leads to this fact that Δ = 0.25 serves as the best option for the dimple depth.

Pressure balanced drag turbine mass flow meter

DOEpatents

Dacus, M.W.; Cole, J.H.

1980-04-23

The density of the fluid flowing through a tubular member may be measured by a device comprising a rotor assembly suspended within the tubular member, a fluid bearing medium for the rotor assembly shaft, independent fluid flow lines to each bearing chamber, and a scheme for detection of any difference between the upstream and downstream bearing fluid pressures. The rotor assembly reacts to fluid flow both by rotation and axial displacement; therefore concurrent measurements may be made of the velocity of blade rotation and also bearing pressure changes, where the pressure changes may be equated to the fluid momentum flux imparted to the rotor blades. From these parameters the flow velocity and density of the fluid may be deduced.

Pressure balanced drag turbine mass flow meter

DOEpatents

Dacus, Michael W.; Cole, Jack H.

1982-01-01

The density of the fluid flowing through a tubular member may be measured by a device comprising a rotor assembly suspended within the tubular member, a fluid bearing medium for the rotor assembly shaft, independent fluid flow lines to each bearing chamber, and a scheme for detection of any difference between the upstream and downstream bearing fluid pressures. The rotor assembly reacts to fluid flow both by rotation and axial displacement; therefore concurrent measurements may be made of the velocity of blade rotation and also bearing pressure changes, where the pressure changes may be equated to the fluid momentum flux imparted to the rotor blades. From these parameters the flow velocity and density of the fluid may be deduced.

Performance of three systems for warming intravenous fluids at different flow rates.

PubMed

Satoh, J; Yamakage, M; Wasaki, S I; Namiki, A

2006-02-01

This study compared the intravenous fluid warming capabilities of three systems at different flow rates. The devices studied were a water-bath warmer, a dry-heat plate warmer, and an intravenous fluid tube warmer Ambient temperature was controlled at 22 degrees to 24 degrees C. Normal saline (0.9% NaCl) at either room temperature (21 degrees to 23 degrees C) or at ice-cold temperature (3 degrees to 5 degrees C) was administered through each device at a range of flow rates (2 to 100 ml/min). To mimic clinical conditions, the temperature of the fluid was measured with thermocouples at the end of a one metre tube connected to the outflow of the warmer for the first two devices and at the end of the 1.2 m warming tubing for the intravenous fluid tube warmer The temperature of fluid delivered by the water bath warmer increased as the flow rate was increased up to 15 to 20 ml/min but decreased with greater flow rates. The temperature of the fluid delivered by the dry-heat plate warmer significantly increased as the flow rate was increased within the range tested (due to decreased cooling after leaving the device at higher flow rates). The temperature of fluid delivered by the intravenous fluid tube warmer did not depend on the flow rate up to 20 ml/min but significantly and fluid temperature-dependently decreased at higher flow rates (>30 ml/min). Under the conditions of our testing, the dry heat plate warmer delivered the highest temperature fluid at high flow rates.

Destabilization of confined granular packings due to fluid flow

NASA Astrophysics Data System (ADS)

Monloubou, Martin; Sandnes, Bjørnar

2016-04-01

Fluid flow through granular materials can cause fluidization when fluid drag exceeds the frictional stress within the packing. Fluid driven failure of granular packings is observed in both natural and engineered settings, e.g. soil liquefaction and flowback of proppants during hydraulic fracturing operations. We study experimentally the destabilization and flow of an unconsolidated granular packing subjected to a point source fluid withdrawal using a model system consisting of a vertical Hele-Shaw cell containing a water-grain mixture. The fluid is withdrawn from the cell at a constant rate, and the emerging flow patterns are imaged in time-lapse mode. Using Particle Image Velocimetry (PIV), we show that the granular flow gets localized in a narrow channel down the center of the cell, and adopts a Gaussian velocity profile similar to those observed in dry grain flows in silos. We investigate the effects of the experimental parameters (flow rate, grain size, grain shape, fluid viscosity) on the packing destabilization, and identify the physical mechanisms responsible for the observed complex flow behaviour.

Modification of the flow pass method as applied to problems of chemistry of planet atmospheres

NASA Technical Reports Server (NTRS)

Parshev, V. A.

1980-01-01

It was shown that the modified flow pass method possesses considerable effectiveness, both in the case when the coefficient of diffusion changes severely in the examined region and in the case when diffusion is the prevalent process, as compared with chemical reactions. The case when a regular pass proves inapplicable, or applicable in a limited interval of the decisive parameters, was examined.

Effect of Er,Cr:YSGG laser on human dentin fluid flow.

PubMed

Al-Omari, Wael M; Palamara, Joseph E

2013-11-01

The aim of the current investigation was to assess the rate and magnitude of dentin fluid flow of dentinal surfaces irradiated with Er,Cr:YSGG laser. Twenty extracted third molars were sectioned, mounted, and irradiated with Er,Cr:YSGG laser at 3.5 and 4.5 W power settings. Specimens were connected to an automated fluid flow measurement apparatus (Flodec). The rate, magnitude, and direction of dentin fluid flow were recorded at baseline and after irradiation. Nonparametric Wilcoxon signed ranks repeated measure t test revealed a statistically significant reduction in fluid flow for all the power settings. The 4.5-W power output reduced the flow significantly more than the 3.5 W. The samples showed a baseline outward flow followed by inward flow due to irradiation then followed by decreased outward flow. It was concluded that Er,Cr:YSGG laser irradiation at 3.5 and 4.5 W significantly reduced dentinal fluid flow rate. The reduction was directly proportional to power output.

Effects of Shrouded Stator Cavity Flows on Multistage Axial Compressor Aerodynamic Performance

NASA Technical Reports Server (NTRS)

Wellborn, Steven R.; Okiishi, Theodore H.

1996-01-01

Experiments were performed on a low-speed multistage axial-flow compressor to assess the effects of shrouded stator cavity flows on aerodynamic performance. Five configurations, which involved changes in seal-tooth leakage rates and/or elimination of the shrouded stator cavities, were tested. Data collected enabled differences in overall individual stage and the third stage blade element performance parameters to be compared. The results show conclusively that seal-tooth leakage ran have a large impact on compressor aerodynamic performance while the presence of the shrouded stator cavities alone seemed to have little influence. Overall performance data revealed that for every 1% increase in the seal-tooth clearance to blade-height ratio the pressure rise dropped up to 3% while efficiency was reduced by 1 to 1.5 points. These observed efficiency penalty slopes are comparable to those commonly reported for rotor and cantilevered stator tip clearance variations. Therefore, it appears that in order to correctly predict overall performance it is equally important to account for the effects of seal-tooth leakage as it is to include the influence of tip clearance flows. Third stage blade element performance data suggested that the performance degradation observed when leakage was increased was brought about in two distinct ways. First, increasing seal-tooth leakage directly spoiled the near hub performance of the stator row in which leakage occurred. Second, the altered stator exit now conditions caused by increased leakage impaired the performance of the next downstream stage by decreasing the work input of the downstream rotor and increasing total pressure loss of the downstream stator. These trends caused downstream stages to progressively perform worse. Other measurements were acquired to determine spatial and temporal flow field variations within the up-and-downstream shrouded stator cavities. Flow within the cavities involved low momentum fluid traveling primarily in the circumferential direction at about 40% of the hub wheel speed. Measurements indicated that the flow within both cavities was much more complex than first envisioned. A vortical flow structure in the meridional plane, similar to a driven cavity, existed within the upstream cavity Furthermore, other spatial and temporal variations in Row properties existed. the most prominent being caused by the upstream potential influence of the downstream blade. This influence caused the fluid within cavities near the leading edges of either stator blades in space or rotor blades in time to be driven radially inward relative to fluid near blade mid-pitch. This influence also produced large unsteady velocity fluctuations in the downstream cavity because of the passing of the downstream rotor blade.

Alkaline phosphatase in osteoblasts is down-regulated by pulsatile fluid flow

NASA Technical Reports Server (NTRS)

Hillsley, M. V.; Frangos, J. A.

1997-01-01

It is our hypothesis that interstitial fluid flow plays a role in the bone remodeling response to mechanical loading. The fluid flow-induced expression of three proteins (collagen, osteopontin, and alkaline phosphatase) involved in bone remodeling was investigated. Rat calvarial osteoblasts subjected to pulsatile fluid flow at an average shear stress of 5 dyne/cm2 showed decreased alkaline phosphatase (AP) mRNA expression after only 1 hour of flow. After 3 hours of flow, AP mRNA levels had decreased to 30% of stationary control levels and remained at this level for an additional 5 hours of flow. Steady flow (4 dyne/cm2 fluid shear stress), in contrast, resulted in a delayed and less dramatic decrease in AP mRNA expression to 63% of control levels after 8 hours of flow. The reduced AP mRNA expression under pulsatile flow conditions was followed by reduced AP enzyme activity after 24 hours. No changes in collagen or osteopontin mRNA expression were detected over 8 hours of pulsatile flow. This is the first time fluid flow has been shown to affect gene expression in osteoblasts.

Analytical solution of two-fluid electro-osmotic flows of viscoelastic fluids.

PubMed

Afonso, A M; Alves, M A; Pinho, F T

2013-04-01

This paper presents an analytical model that describes a two-fluid electro-osmotic flow of stratified fluids with Newtonian or viscoelastic rheological behavior. This is the principle of operation of an electro-osmotic two-fluid pump as proposed by Brask et al. [Tech. Proc. Nanotech., 1, 190-193, 2003], in which an electrically non-conducting fluid is transported by the interfacial dragging viscous force of a conducting fluid that is driven by electro-osmosis. The electric potential in the conducting fluid and the analytical steady flow solution of the two-fluid electro-osmotic stratified flow in a planar microchannel are presented by assuming a planar interface between the two immiscible fluids with Newtonian or viscoelastic rheological behavior. The effects of fluid rheology, shear viscosity ratio, holdup and interfacial zeta potential are analyzed to show the viability of this technique, where an enhancement of the flow rate is observed as the shear-thinning effects are increased. Copyright © 2012 Elsevier Inc. All rights reserved.

Flow accelerated organic coating degradation

NASA Astrophysics Data System (ADS)

Zhou, Qixin

Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as well as promotes the migration of coating materials from the coating into the working fluid, where coatings experience more severe deterioration in their barrier property under flowing conditions. Pure water has shown to be a much more aggressive working fluid than electrolyte solutions. The flowing fluid over the coating surface could be used as an effective acceleration method.

Method and apparatus for controlling the flow rate of mercury in a flow system

DOEpatents

Grossman, Mark W.; Speer, Richard

1991-01-01

A method for increasing the mercury flow rate to a photochemical mercury enrichment utilizing an entrainment system comprises the steps of passing a carrier gas over a pool of mercury maintained at a first temperature T1, wherein the carrier gas entrains mercury vapor; passing said mercury vapor entrained carrier gas to a second temperature zone T2 having temperature less than T1 to condense said entrained mercury vapor, thereby producing a saturated Hg condition in the carrier gas; and passing said saturated Hg carrier gas to said photochemical enrichment reactor.

Hydraulic flow visualization method and apparatus

DOEpatents

Karidis, Peter G.

1984-01-01

An apparatus and method for visualizing liquid flow. Pulses of gas bubbles are introduced into a liquid flow stream and a strobe light is operated at a frequency related to the frequency of the gas pulses to shine on the bubbles as they pass through the liquid stream. The gas pulses pass through a probe body having a valve element, and a reciprocating valve stem passes through the probe body to operate the valve element. A stem actuating device comprises a slidable reciprocating member, operated by a crank arm. The actuated member is adjustable to adjust the amount of the valve opening during each pulse.

Magnetically stimulated fluid flow patterns

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

Martin, Jim; Solis, Kyle

2014-03-06

Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

Magnetically stimulated fluid flow patterns

ScienceCinema

Martin, Jim; Solis, Kyle

2018-05-23

Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

Localized arc filament plasma actuators for noise mitigation and mixing enhancement

NASA Technical Reports Server (NTRS)

Samimy, Mohammad (Inventor); Adamovich, Igor (Inventor)

2008-01-01

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

Localized arc filament plasma actuators for noise mitigation and mixing enhancement

NASA Technical Reports Server (NTRS)

Samimy, Mohammad (Inventor); Adamovich, Igor (Inventor)

2010-01-01

A device for controlling fluid flow. The device includes an arc generator coupled to electrodes. The electrodes are placed adjacent a fluid flowpath such that upon being energized by the arc generator, an arc filament plasma adjacent the electrodes is formed. In turn, this plasma forms a localized high temperature, high pressure perturbation in the adjacent fluid flowpath. The perturbations can be arranged to produce vortices, such as streamwise vortices, in the flowing fluid to control mixing and noise in such flows. The electrodes can further be arranged within a conduit configured to contain the flowing fluid such that when energized in a particular frequency and sequence, can excite flow instabilities in the flowing fluid. The placement of the electrodes is such that they are unobtrusive relative to the fluid flowpath being controlled.

Two-lane traffic-flow model with an exact steady-state solution.

PubMed

Kanai, Masahiro

2010-12-01

We propose a stochastic cellular-automaton model for two-lane traffic flow based on the misanthrope process in one dimension. The misanthrope process is a stochastic process allowing for an exact steady-state solution; hence, we have an exact flow-density diagram for two-lane traffic. In addition, we introduce two parameters that indicate, respectively, driver's driving-lane preference and passing-lane priority. Due to the additional parameters, the model shows a deviation of the density ratio for driving-lane use and a biased lane efficiency in flow. Then, a mean-field approach explicitly describes the asymmetric flow by the hop rates, the driving-lane preference, and the passing-lane priority. Meanwhile, the simulation results are in good agreement with an observational data, and we thus estimate these parameters. We conclude that the proposed model successfully produces two-lane traffic flow particularly with the driving-lane preference and the passing-lane priority.

Effect of viscoelasticity on the flow pattern and the volumetric flow rate in electroosmotic flows through a microchannel.

PubMed

Park, H M; Lee, W M

2008-07-01

Many lab-on-a-chip based microsystems process biofluids such as blood and DNA solutions. These fluids are viscoelastic and show extraordinary flow behaviors, not existing in Newtonian fluids. Adopting appropriate constitutive equations these exotic flow behaviors can be modeled and predicted reasonably using various numerical methods. In the present paper, we investigate viscoelastic electroosmotic flows through a rectangular straight microchannel with and without pressure gradient. It is shown that the volumetric flow rates of viscoelastic fluids are significantly different from those of Newtonian fluids under the same external electric field and pressure gradient. Moreover, when pressure gradient is imposed on the microchannel there appear appreciable secondary flows in the viscoelastic fluids, which is never possible for Newtonian laminar flows through straight microchannels. The retarded or enhanced volumetric flow rates and secondary flows affect dispersion of solutes in the microchannel nontrivially.

International Congress of Fluid Mechanics, 3rd, Cairo, Egypt, Jan. 2-4, 1990, Proceedings. Volumes 1, 2, 3, & 4

NASA Astrophysics Data System (ADS)

Nayfeh, A. H.; Mobarak, A.; Rayan, M. Abou

This conference presents papers in the fields of flow separation, unsteady aerodynamics, fluid machinery, boundary-layer control and stability, grid generation, vorticity dominated flows, and turbomachinery. Also considered are propulsion, waves and sound, rotor aerodynamics, computational fluid dynamics, Euler and Navier-Stokes equations, cavitation, mixing and shear layers, mixing layers and turbulent flows, and fluid machinery and two-phase flows. Also addressed are supersonic and reacting flows, turbulent flows, and thermofluids.

Isotachophoresis system having larger-diameter channels flowing into channels with reduced diameter and with selectable counter-flow

DOEpatents

Mariella, Jr., Raymond P.

2018-03-06

An isotachophoresis system for separating a sample containing particles into discrete packets including a flow channel, the flow channel having a large diameter section and a small diameter section; a negative electrode operably connected to the flow channel; a positive electrode operably connected to the flow channel; a leading carrier fluid in the flow channel; a trailing carrier fluid in the flow channel; and a control for separating the particles in the sample into discrete packets using the leading carrier fluid, the trailing carrier fluid, the large diameter section, and the small diameter section.

Interaction of pressure and momentum driven flows with thin porous media: Experiments and modeling

NASA Astrophysics Data System (ADS)

Naaktgeboren, Christian

Flow interaction with thin porous media arise in a variety of natural and man-made settings. Examples include flow through thin grids in electronics cooling, and NOx emissions reduction by means of ammonia injection grids, pulsatile aquatic propulsion with complex trailing anatomy (e.g., jellyfish with tentacles) and microbursts from thunderstorm activity over dense vegetation, unsteady combustion in or near porous materials, pulsatile jet-drying of textiles, and pulsed jet agitation of clothing for trace contaminant sampling. Two types of interactions with thin porous media are considered: (i) forced convection or pressure-driven flows, where fluid advection is maintained by external forces, and (ii) inertial or momentum-driven flows, in which fluid motion is generated but not maintained by external forces. Forced convection analysis through thin permeable media using a porous continuum approach requires the knowledge of porous medium permeability and form coefficients, K and C, respectively, which are defined by the Hazen-Dupuit-Darcy (HDD) equation. Their determination, however, requires the measurement of the pressure-drop per unit of porous medium length. The pressure-drop caused by fluid entering and exiting the porous medium, however, is not related to the porous medium length. Hence, for situations in which the inlet and outlet pressure-drops are not negligible, e.g., for short porous media, the definition of Kand C via the HDD equation becomes ambiguous. This aspect is investigated analytically and numerically using the flow through a restriction in circular pipe and parallel plates channels as preliminary models. Results show that inlet and outlet pressure-drop effects become increasingly important when the inlet and outlet fluid surface fraction φ decreases and the Reynolds number Re increases for both laminar and turbulent flow regimes. A conservative estimate of the minimum porous medium length beyond which the core pressure-drop predominates over the inlet and outlet pressure-drop is obtained by considering a least restrictive porous medium core. Finally, modified K and C are proposed and predictive equations, accurate to within 2.5%, are obtained for both channel configurations with Re ranging from 10-2 to 102 and φ from 6% to 95%. When momentum driven flows interact with thin porous media, the interaction of vortices with the media's complex structure gives way to a number of phenomena of fundamental and applied interest, such as unsteady flow separation. A special case that embodies many of the key features of these flows is the interaction of a vortex ring with a permeable flat surface. Although fundamental, this complex flow configuration has never been considered. The present investigation experimentally studies the fluid mechanics of the interaction of a vortex ring impinging directly on thin permeable flat targets. The vortex ring is formed in water using a piston-cylinder mechanism and visualized using planar laser-induced fluorescence (PLIF). The rings are formed for jet Reynolds numbers of 3000 and 6000, and piston stroke-to-diameter ratios of 1.0, 3.0, and 6.0. Thin screens of similar geometry having surface opening fractions of 44, 60, 69, and 79% are targeted by the rings. The flow that emerges downstream of the screens reforms into a new, "transmitted" vortex ring. For the lower porosity targets, features that are characteristic of vortex ring impingement on walls are also observed, such as primary vortex ring rebound and reversal, flow separation, formation of secondary vortices and mixing. As the interaction proceeds, however, the primary vortex ring and secondary vortices are drawn toward the symmetry axis of the flow by fluid passing through the permeable screen. Quantitative flow measurements using digital particle image velocimetry (DPIV), indicate the transmitted vortex ring has lower velocity and less (total) kinetic energy than the incident ring. Ring trajectories and total kinetic energy relationships between vortices upstream and downstream the porous targets as a function of the porosity are presented, based on the velocity field from the DPIV measurements. Results show that kinetic energy dissipation is more intense for the low porosity targets and that flows with higher initial kinetic energy impacting on the same target loose a smaller percentage of their initial energy.

Fluid-induced Blueschist Preservation on Syros, Cyclades, Southern Greece

NASA Astrophysics Data System (ADS)

Kleine, B. I.; Huet, B.; Skelton, A. D. L.

2012-04-01

Local examples of preservation of high-pressure, low-temperature (HP-LT) mineral assemblages within retrograde metamorphosed greenschist are recorded from the Cyclades, Greece. Several models have been proposed to explain the preservation of HP-LT rocks in these areas. On Sifnos, a capping effect of impermeable marble units below the preserved blueschists caused diversion of the upward, cross-layer infiltration of retrograde fluids [1]. On Tinos, blueschist preservation occurred due to retrograde fluid flow channelization along lithological contacts with high flux rates [2]. HP-LT minerals were preserved in regions adjacent to these contacts where fluid fluxes were smaller. We propose a different mechanism of blueschist preservation based on observations from a costal section near Fabrika on Syros. At this locality a high strain zone cuts through a retrograde greenschist. Along the fault a dark blue halo occurs within the greenschist. Whole rock analyses along a profile from the fault into the greenschist show that only the areas directly adjacent to the deformation zone show chemical evidence of metasomatism, whereas the areas further away are chemically similar to greenschist. Point counting of 1000 evenly spaced points in thin sections of the profile shows a clear blueschist to greenschist transition with a blueschist mineral assemblage (glaucophane+phengite+calcite) nearer to the metasomatic zone and a typical greenschist mineral assemblage (epidote+chlorite+albite) farther away. We propose the following model to explain preservation of HP-LT mineral assemblage in this locality. During retrograde metamorphism a water-rich fluid infiltrated the blueschist rock from below. This occurred close to the brittle-ductile transition. This fluid caused a reaction front to propagate into the overlying blueschist at which its mineral assemblage glaucophane+phengite+calcite was replaced by the greenschist mineral assemblage epidote+albite+chlorite. Upwards-flowing fluid passing through the reaction front is buffered to higher X(CO2) by the reaction glaucophane+phengite+calcite+H2O=albite+chlorite+epidote+quartz+CO2. This fluid travels faster along paths of structural weakness (e.g. shear zones, faults). If this fluid reaches colder regions more rapidly such that the fluid chemistry is unable to "keep up" with the position of the reaction equilibria as the temperature falls, X(CO2) will be effectively shifted back into the blueschist stability field and blueschist will be preserved, specifically within high flux regions, such as shear zones and faults. [1] Matthews & Schliestedt (1984), Contributions to Mineralogy and Petrology, 88, 150-163. [2] Breeding et al. (2003), Geochemistry Geophysics Geosystems, 4, 1-11.

Radiation receiver

DOEpatents

Hunt, A.J.

1983-09-13

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles. 5 figs.

Radiation receiver

DOEpatents

Hunt, Arlon J.

1983-01-01

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

Radiant energy collection and conversion apparatus and method

DOEpatents

Hunt, Arlon J.

1982-01-01

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

Radiant energy collection and conversion apparatus and method

DOEpatents

Hunt, A.J.

The apparatus for collecting radiant energy and converting to alternate energy forms includes a housing having an interior space and a radiation transparent window allowing solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past the window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

Non-Newtonian fluid flow in 2D fracture networks

NASA Astrophysics Data System (ADS)

Zou, L.; Håkansson, U.; Cvetkovic, V.

2017-12-01

Modeling of non-Newtonian fluid (e.g., drilling fluids and cement grouts) flow in fractured rocks is of interest in many geophysical and industrial practices, such as drilling operations, enhanced oil recovery and rock grouting. In fractured rock masses, the flow paths are dominated by fractures, which are often represented as discrete fracture networks (DFN). In the literature, many studies have been devoted to Newtonian fluid (e.g., groundwater) flow in fractured rock using the DFN concept, but few works are dedicated to non-Newtonian fluids.In this study, a generalized flow equation for common non-Newtonian fluids (such as Bingham, power-law and Herschel-Bulkley) in a single fracture is obtained from the analytical solutions for non-Newtonian fluid discharge between smooth parallel plates. Using Monte Carlo sampling based on site characterization data for the distribution of geometrical features (e.g., density, length, aperture and orientations) in crystalline fractured rock, a two dimensional (2D) DFN model is constructed for generic flow simulations. Due to complex properties of non-Newtonian fluids, the relationship between fluid discharge and the pressure gradient is nonlinear. A Galerkin finite element method solver is developed to iteratively solve the obtained nonlinear governing equations for the 2D DFN model. Using DFN realizations, simulation results for different geometrical distributions of the fracture network and different non-Newtonian fluid properties are presented to illustrate the spatial discharge distributions. The impact of geometrical structures and the fluid properties on the non-Newtonian fluid flow in 2D DFN is examined statistically. The results generally show that modeling non-Newtonian fluid flow in fractured rock as a DFN is feasible, and that the discharge distribution may be significantly affected by the geometrical structures as well as by the fluid constitutive properties.

The impact of fluid advection on gas hydrate stability: Investigations at sites of methane seepage offshore Costa Rica

NASA Astrophysics Data System (ADS)

Crutchley, G. J.; Klaeschen, D.; Planert, L.; Bialas, J.; Berndt, C.; Papenberg, C.; Hensen, C.; Hornbach, M. J.; Krastel, S.; Brueckmann, W.

2014-09-01

Fluid flow through marine sediments drives a wide range of processes, from gas hydrate formation and dissociation, to seafloor methane seepage including the development of chemosynthetic ecosystems, and ocean acidification. Here, we present new seismic data that reveal the 3D nature of focused fluid flow beneath two mound structures on the seafloor offshore Costa Rica. These mounds have formed as a result of ongoing seepage of methane-rich fluids. We show the spatial impact of advective heat flow on gas hydrate stability due to the channelled ascent of warm fluids towards the seafloor. The base of gas hydrate stability (BGHS) imaged in the seismic data constrains peak heat flow values to ∼60 mW m and ∼70 mW m beneath two separate seep sites known as Mound 11 and Mound 12, respectively. The initiation of pronounced fluid flow towards these structures was likely controlled by fault networks that acted as efficient pathways for warm fluids ascending from depth. Through the gas hydrate stability zone, fluid flow has been focused through vertical conduits that we suggest developed as migrating fluids generated their own secondary permeability by fracturing strata as they forced their way upwards towards the seafloor. We show that Mound 11 and Mound 12 (about 1 km apart on the seafloor) are sustained by independent fluid flow systems through the hydrate system, and that fluid flow rates across the BGHS are probably similar beneath both mounds. 2D seismic data suggest that these two flow systems might merge at approximately 1 km depth, i.e. much deeper than the BGHS. This study provides a new level of detail and understanding of how channelled, anomalously-high fluid flow towards the seafloor influences gas hydrate stability. Thus, gas hydrate systems have good potential for quantifying the upward flow of subduction system fluids to seafloor seep sites, since the fluids have to interact with and leave their mark on the hydrate system before reaching the seafloor.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John M.; Wing, Boswell A.; Penniston-Dorland, Sarah C.; Rumble, Douglas

2002-03-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux ~5,000 and ~300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John; Wing, Boswell; Penniston-Dorland, Sarah; Rumble, Douglas

2001-11-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux 5,000 and 300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

ENGINEERING BULLETIN: IN SITU SOIL FLUSHING

EPA Science Inventory

In situ soil flushing is the extraction of contaminants from the soil with water or other suitable aqueous solutions. Soil flushing is accomplished by passing the extraction fluid through in-place soils using an injection or infiltration process. Extraction fluids must be recover...

Reducing or stopping the uncontrolled flow of fluid such as oil from a well

DOEpatents

Hermes, Robert E

2014-02-18

The uncontrolled flow of fluid from an oil or gas well may be reduced or stopped by injecting a composition including 2-cyanoacrylate ester monomer into the fluid stream. Injection of the monomer results in a rapid, perhaps instantaneous, polymerization of the monomer within the flow stream of the fluid. This polymerization results in formation of a solid plug that reduces or stops the flow of additional fluid from the well.

Method for separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials

DOEpatents

Woodward, Jonathan

1998-01-01

A method for enzymatically separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials. The cellulosic material, such as newsprint, is introduced into a first chamber containing a plastic canvas basket. This first chamber is in fluid communication, via plastic tubing, with a second chamber containing cellobiase beads in a plastic canvas basket. Cellulase is then introduced into the first chamber. A programmable pump then controls the flow rate between the two chambers. The action of cellulase and stirring in the first chamber results in the production of a slurry of newsprint pulp in the first chamber. This slurry contains non-inked fibers, inked fibers, and some cellobiose. The inked fibers and cellobiose flow from the first chamber to the second chamber, whereas the non-inked fibers remain in the first chamber because they are too large to pass through the pores of the plastic canvas basket. The resulting non-inked and inked fibers are then recovered.

Method for separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials

DOEpatents

Woodward, J.

1998-12-01

A method for enzymatically separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials. The cellulosic material, such as newsprint, is introduced into a first chamber containing a plastic canvas basket. This first chamber is in fluid communication, via plastic tubing, with a second chamber containing cellobiase beads in a plastic canvas basket. Cellulase is then introduced into the first chamber. A programmable pump then controls the flow rate between the two chambers. The action of cellulase and stirring in the first chamber results in the production of a slurry of newsprint pulp in the first chamber. This slurry contains non-inked fibers, inked fibers, and some cellobiose. The inked fibers and cellobiose flow from the first chamber to the second chamber, whereas the non-inked fibers remain in the first chamber because they are too large to pass through the pores of the plastic canvas basket. The resulting non-inked and inked fibers are then recovered. 6 figs.

System for monitoring physical characteristics of fluids

NASA Technical Reports Server (NTRS)

Trinh, E. H.; Wang, T. G. (Inventor)

1983-01-01

An apparatus and method are described for measuring physical characteristics of fluid, by placing a drop of the fluid in a batch of a second fluid and passing acoustic waves through the bath. The applied frequency of the acoustic waves is varied, to determine the precise value of a frequency at which the drop undergoes resonant oscillations. The resonant frequency indicates the interfacial tension of the drop in the bath, and the interfacial tension can indicate physical properties of the fluid in the drop.

Enhanced heat transfer using nanofluids

DOEpatents

Choi, Stephen U. S.; Eastman, Jeffrey A.

2001-01-01

This invention is directed to a method of and apparatus for enhancing heat transfer in fluids such as deionized water. ethylene glycol, or oil by dispersing nanocrystalline particles of substances such as copper, copper oxide, aluminum oxide, or the like in the fluids. Nanocrystalline particles are produced and dispersed in the fluid by heating the substance to be dispersed in a vacuum while passing a thin film of the fluid near the heated substance. The fluid is cooled to control its vapor pressure.

Doppler optical coherence tomography imaging of local fluid flow and shear stress within microporous scaffolds

NASA Astrophysics Data System (ADS)

Jia, Yali; Bagnaninchi, Pierre O.; Yang, Ying; Haj, Alicia El; Hinds, Monica T.; Kirkpatrick, Sean J.; Wang, Ruikang K.

2009-05-01

Establishing a relationship between perfusion rate and fluid shear stress in a 3D cell culture environment is an ongoing and challenging task faced by tissue engineers. We explore Doppler optical coherence tomography (DOCT) as a potential imaging tool for in situ monitoring of local fluid flow profiles inside porous chitosan scaffolds. From the measured fluid flow profiles, the fluid shear stresses are evaluated. We examine the localized fluid flow and shear stress within low- and high-porosity chitosan scaffolds, which are subjected to a constant input flow rate of 0.5 ml.min-1. The DOCT results show that the behavior of the fluid flow and shear stress in micropores is strongly dependent on the micropore interconnectivity, porosity, and size of pores within the scaffold. For low-porosity and high-porosity chitosan scaffolds examined, the measured local fluid flow and shear stress varied from micropore to micropore, with a mean shear stress of 0.49+/-0.3 dyn.cm-2 and 0.38+/-0.2 dyn.cm-2, respectively. In addition, we show that the scaffold's porosity and interconnectivity can be quantified by combining analyses of the 3D structural and flow images obtained from DOCT.

Fluid Flow Phenomena during Welding

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

Zhang, Wei

2011-01-01

MOLTEN WELD POOLS are dynamic. Liquid in the weld pool in acted on by several strong forces, which can result in high-velocity fluid motion. Fluid flow velocities exceeding 1 m/s (3.3 ft/s) have been observed in gas tungsten arc (GTA) welds under ordinary welding conditions, and higher velocities have been measured in submerged arc welds. Fluid flow is important because it affects weld shape and is related to the formation of a variety of weld defects. Moving liquid transports heat and often dominates heat transport in the weld pool. Because heat transport by mass flow depends on the direction andmore » speed of fluid motion, weld pool shape can differ dramatically from that predicted by conductive heat flow. Temperature gradients are also altered by fluid flow, which can affect weld microstructure. A number of defects in GTA welds have been attributed to fluid flow or changes in fluid flow, including lack of penetration, top bead roughness, humped beads, finger penetration, and undercutting. Instabilities in the liquid film around the keyhole in electron beam and laser welds are responsible for the uneven penetration (spiking) characteristic of these types of welds.« less

Novel multi-functional fluid flow device for studying cellular mechanotransduction

PubMed Central

Lyons, James S.; Iyer, Shama R.; Lovering, Richard M.; Ward, Christopher W.; Stains, Joseph P.

2016-01-01

Cells respond to their mechanical environment by initiating multiple mechanotransduction signaling pathways. Defects in mechanotransduction have been implicated in a number of pathologies; thus, there is need for convenient and efficient methods for studying the mechanisms underlying these processes. A widely used and accepted technique for mechanically stimulating cells in culture is the introduction of fluid flow on cell monolayers. Here, we describe a novel, multifunctional fluid flow device for exposing cells to fluid flow in culture. This device integrates with common lab equipment including routine cell culture plates and peristaltic pumps. Further, it allows the fluid flow treated cells to be examined with outcomes at the cell and molecular level. We validated the device using the biologic response of cultured UMR-106 osteoblast-like cells in comparison to a commercially available system of laminar sheer stress to track live cell calcium influx in response to fluid flow. In addition, we demonstrate the fluid flow-dependent activation of phospho-ERK in these cells, consistent with the findings in other fluid flow devices. This device provides a low cost, multi-functional alternative to currently available systems, while still providing the ability to generate physiologically relevant conditions for studying processes involved in mechanotransduction in vitro. PMID:27887728

Fluid flow plate for decreased density of fuel cell assembly

DOEpatents

Vitale, Nicholas G.

1999-01-01

A fluid flow plate includes first and second outward faces. Each of the outward faces has a flow channel thereon for carrying respective fluid. At least one of the fluids serves as reactant fluid for a fuel cell of a fuel cell assembly. One or more pockets are formed between the first and second outward faces for decreasing density of the fluid flow plate. A given flow channel can include one or more end sections and an intermediate section. An interposed member can be positioned between the outward faces at an interface between an intermediate section, of one of the outward faces, and an end section, of that outward face. The interposed member can serve to isolate the reactant fluid from the opposing outward face. The intermediate section(s) of flow channel(s) on an outward face are preferably formed as a folded expanse.

Numerical Modelling of Three-Fluid Flow Using The Level-set Method

NASA Astrophysics Data System (ADS)

Li, Hongying; Lou, Jing; Shang, Zhi

2014-11-01

This work presents a numerical model for simulation of three-fluid flow involving two different moving interfaces. These interfaces are captured using the level-set method via two different level-set functions. A combined formulation with only one set of conservation equations for the whole physical domain, consisting of the three different immiscible fluids, is employed. Numerical solution is performed on a fixed mesh using the finite volume method. Surface tension effect is incorporated using the Continuum Surface Force model. Validation of the present model is made against available results for stratified flow and rising bubble in a container with a free surface. Applications of the present model are demonstrated by a variety of three-fluid flow systems including (1) three-fluid stratified flow, (2) two-fluid stratified flow carrying the third fluid in the form of drops and (3) simultaneous rising and settling of two drops in a stationary third fluid. The work is supported by a Thematic and Strategic Research from A*STAR, Singapore (Ref. #: 1021640075).

High precision high flow range control valve

DOEpatents

McCray, J.A.

1999-07-13

A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90 [degree] turn. In the preferred embodiment only one of the two fluid passageways contains a 90[degree] turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings. 12 figs.

High precision high flow range control valve

DOEpatents

McCray, John A.

1999-01-01

A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90.degree. turn. In the preferred embodiment only one of the two fluid passageways contains a 90.degree. turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings.

Nonlinear interaction and wave breaking with a submerged porous structure

NASA Astrophysics Data System (ADS)

Hsieh, Chih-Min; Sau, Amalendu; Hwang, Robert R.; Yang, W. C.

2016-12-01

Numerical simulations are performed to investigate interactive velocity, streamline, turbulent kinetic energy, and vorticity perturbations in the near-field of a submerged offshore porous triangular structure, as Stokes waves of different heights pass through. The wave-structure interaction and free-surface breaking for the investigated flow situations are established based on solutions of 2D Reynolds Averaged Navier-Stokes equations in a Cartesian grid in combination with K-ɛ turbulent closure and the volume of fluid methodology. The accuracy and stability of the adopted model are ascertained by extensive comparisons of computed data with the existing experimental and theoretical findings and through efficient predictions of the internal physical kinetics. Simulations unfold "clockwise" and "anticlockwise" rotation of fluid below the trough and the crest of the viscous waves, and the penetrated wave energy creates systematic flow perturbation in the porous body. The interfacial growths of the turbulent kinetic energy and the vorticity appear phenomenal, around the apex of the immersed structure, and enhanced significantly following wave breaking. Different values of porosity parameter and two non-porous cases have been examined in combination with varied incident wave height to reveal/analyze the nonlinear flow behavior in regard to local spectral amplification and phase-plane signatures. The evolution of leading harmonics of the undulating free-surface and the vertical velocity exhibits dominating roles of the first and the second modes in inducing the nonlinearity in the post-breaking near-field that penetrates well below the surface layer. The study further suggests the existence of a critical porosity that can substantially enhance the wave-shoaling and interface breaking.

Experimental investigation of the flow dynamics and rheology of complex fluids in pipe flow by hybrid multi-scale velocimetry

NASA Astrophysics Data System (ADS)

Haavisto, Sanna; Cardona, Maria J.; Salmela, Juha; Powell, Robert L.; McCarthy, Michael J.; Kataja, Markku; Koponen, Antti I.

2017-11-01

A hybrid multi-scale velocimetry method utilizing Doppler optical coherence tomography in combination with either magnetic resonance imaging or ultrasound velocity profiling is used to investigate pipe flow of four rheologically different working fluids under varying flow regimes. These fluids include water, an aqueous xanthan gum solution, a softwood fiber suspension, and a microfibrillated cellulose suspension. The measurement setup enables not only the analysis of the rheological (bulk) behavior of a studied fluid but gives simultaneously information on their wall layer dynamics, both of which are needed for analyzing and solving practical fluid flow-related problems. Preliminary novel results on rheological and boundary layer flow properties of the working fluids are reported and the potential of the hybrid measurement setup is demonstrated.

A New Modular Approach for Tightly Coupled Fluid/Structure Analysis

NASA Technical Reports Server (NTRS)

Guruswamy, Guru

2003-01-01

Static aeroelastic computations are made using a C++ executive suitable for closely coupled fluid/structure interaction studies. The fluid flow is modeled using the Euler/Navier Stokes equations and the structure is modeled using finite elements. FORTRAN based fluids and structures codes are integrated under C++ environment. The flow and structural solvers are treated as separate object files. The data flow between fluids and structures is accomplished using I/O. Results are demonstrated for transonic flow over partially flexible surface that is important for aerospace vehicles. Use of this development to accurately predict flow induced structural failure will be demonstrated.

FREE 17-HYDROXYCORTICOSTERIOD CONCENTRATION OF PAROTID FLUID FOLLOWING INTRAVENOUS ADMINISTRATION OF CORTISOL,

DTIC Science & Technology

In an attempt to determine the time required for adrenocortical steroids to pass from the bloodstream to parotid fluid, twenty subjects were given...intravenous injections of cortisol and parotid fluid was collected continuously for 120 minutes after injection. Additional studies were carried out...with intramuscular injections and oral administration of cortisol. The parotid fluid free 17-OHCS mean rose from 3.51 (S.D. = 1.57) to 21.34 (S.D

Shear Wave Splitting Inversion in a Complex Crust

NASA Astrophysics Data System (ADS)

Lucas, A.

2015-12-01

Shear wave splitting (SWS) inversion presents a method whereby the upper crust can be interrogated for fracture density. It is caused when a shear wave traverses an area of anisotropy, splits in two, with each wave experiencing a different velocity resulting in an observable separation in arrival times. A SWS observation consists of the first arrival polarization direction and the time delay. Given the large amount of data common in SWS studies, manual inspection for polarization and time delay is considered prohibitively time intensive. All automated techniques used can produce high amounts of observations falsely interpreted as SWS. Thus introducing error into the interpretation. The technique often used for removing these false observations is to manually inspect all SWS observations defined as high quality by the automated routine, and remove false identifications. We investigate the nature of events falsely identified compared to those correctly identified. Once this identification is complete we conduct a inversion for crack density from SWS time delay. The current body of work on linear SWS inversion utilizes an equation that defines the time delay between arriving shear waves with respect to fracture density. This equation makes the assumption that no fluid flow occurs as a result of the passing shear wave, a situation called squirt flow. We show that the assumption is not applicable in all geological situations. When it is not true, its use in an inversion produces a result which is negatively affected by the assumptions. This is shown to be the case at the test case of 6894 SWS observations gathered in a small area at Puna geothermal field, Hawaii. To rectify this situation, a series of new time delay formulae, applicable to linear inversion, are derived from velocity equations presented in literature. The new formula use a 'fluid influence parameter' which indicates the degree to which squirt flow is influencing the SWS. It is found that accounting for squirt flow better fits the data and is more applicable. The fluid influence factor that best describes the data can be identified prior to solving the inversion. Implementing this formula in a linear inversion has a significantly improved fit to the time delay observations than that of the current methods.

Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

NASA Technical Reports Server (NTRS)

Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

2010-01-01

This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

Thermohydrodynamic Analysis of Cryogenic Liquid Turbulent Flow Fluid Film Bearings

NASA Technical Reports Server (NTRS)

SanAndres, Luis

1996-01-01

Computational programs developed for the thermal analysis of tilting and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings are described. The motion of a cryogenic liquid on the thin film annular region of a fluid film bearing is described by a set of mass and momentum conservation, and energy transport equations for the turbulent bulk-flow velocities and pressure, and accompanied by thermophysical state equations for evaluation of the fluid material properties. Zeroth-order equations describe the fluid flow field for a journal static equilibrium position, while first-order (linear) equations govern the fluid flow for small amplitude-journal center translational motions. Solution to the zeroth-order flow field equations provides the bearing flow rate, load capacity, drag torque and temperature rise. Solution to the first-order equations determines the rotordynamic force coefficients due to journal radial motions.

Yield-stress fluids foams: flow patterns and controlled production in T-junction and flow-focusing devices.

PubMed

Laborie, Benoit; Rouyer, Florence; Angelescu, Dan E; Lorenceau, Elise

2016-11-23

We study the formation of yield-stress fluid foams in millifluidic flow-focusing and T-junction devices. First, we provide a phase diagram for the unsteady operating regimes of bubble production when the gas pressure and the yield-stress fluid flow rate are imposed. Three regimes are identified: a co-flow of gas and yield-stress fluid, a transient production of bubble and a flow of yield-stress fluid only. Taking wall slip into account, we provide a model for the pressure at the onset of bubble formation. Then, we detail and compare two simple methods to ensure steady bubble production: regulation of the gas pressure or flow-rate. These techniques, which are easy to implement, thus open pathways for controlled production of dry yield-stress fluid foams as shown at the end of this article.

A systems approach to theoretical fluid mechanics: Fundamentals

NASA Technical Reports Server (NTRS)

Anyiwo, J. C.

1978-01-01

A preliminary application of the underlying principles of the investigator's general system theory to the description and analyses of the fluid flow system is presented. An attempt is made to establish practical models, or elements of the general fluid flow system from the point of view of the general system theory fundamental principles. Results obtained are applied to a simple experimental fluid flow system, as test case, with particular emphasis on the understanding of fluid flow instability, transition and turbulence.

Intracellular Fluid Mechanics: Coupling Cytoplasmic Flow with Active Cytoskeletal Gel

NASA Astrophysics Data System (ADS)

Mogilner, Alex; Manhart, Angelika

2018-01-01

The cell is a mechanical machine, and continuum mechanics of the fluid cytoplasm and the viscoelastic deforming cytoskeleton play key roles in cell physiology. We review mathematical models of intracellular fluid mechanics, from cytoplasmic fluid flows, to the flow of a viscous active cytoskeletal gel, to models of two-phase poroviscous flows, to poroelastic models. We discuss application of these models to cell biological phenomena, such as organelle positioning, blebbing, and cell motility. We also discuss challenges of understanding fluid mechanics on the cellular scale.

Optimal design of wind barriers using 3D computational fluid dynamics simulations

NASA Astrophysics Data System (ADS)

Fang, H.; Wu, X.; Yang, X.

2017-12-01

Desertification is a significant global environmental and ecological problem that requires human-regulated control and management. Wind barriers are commonly used to reduce wind velocity or trap drifting sand in arid or semi-arid areas. Therefore, optimal design of wind barriers becomes critical in Aeolian engineering. In the current study, we perform 3D computational fluid dynamics (CFD) simulations for flow passing through wind barriers with different structural parameters. To validate the simulation results, we first inter-compare the simulated flow field results with those from both wind-tunnel experiments and field measurements. Quantitative analyses of the shelter effect are then conducted based on a series of simulations with different structural parameters (such as wind barrier porosity, row numbers, inter-row spacing and belt schemes). The results show that wind barriers with porosity of 0.35 could provide the longest shelter distance (i.e., where the wind velocity reduction is more than 50%) thus are recommended in engineering designs. To determine the optimal row number and belt scheme, we introduce a cost function that takes both wind-velocity reduction effects and economical expense into account. The calculated cost function show that a 3-row-belt scheme with inter-row spacing of 6h (h as the height of wind barriers) and inter-belt spacing of 12h is the most effective.

Two-stream modeling of plasmaspheric refilling

NASA Technical Reports Server (NTRS)

Guiter, S. M.; Gombosi, T. I.; Rasmussen, C. E.

1995-01-01

Plasmaspheric refilling on an L = 4 flux tube was studied by using a time-dependent, hydrodynamic plasmaspheric flow model in which the ion streams from the two hemispheres are treated as distinct fluids. In the model the continuity, momentum, and energy equations of a two-ion (O(+) and H(+)), quasi-neutral, currentless plasma are solved along a closed geomagnetic field line; diffusive equilibrium is not assumed. collisions between all stream pairs and with neutral species are included. The model includes a corotating, tilted dipole magnetic field and neutral winds. Ionospheric sources and sinks are accounted for in a self-consistent manner. Electrons are assumed to be heated by photoelectrons. The model flux tube extends from a 200-km altitude in one hemisphere to a 200-km altitude in the other hemisphere. Initially, the upwelling streams pass through each other practically unimpeded. When the streams approach the boundary in the conjugate ionosphere, a shock develops there, which moves upward and dissipates slowly; at about the same time a reverse shock develops in the hemisphere of origin, which moves upward. After about 1 hour, large shocks develop in each stream near the equator; these shocks move toward the equator and downward after crossing the equator. However, these shocks are probably artificial, because counterstreaming flows occur in each H(+) fluid, which the model can only handle by creating shocks.

Generalized Fluid System Simulation Program (GFSSP) Version 6 - General Purpose Thermo-Fluid Network Analysis Software

NASA Technical Reports Server (NTRS)

Majumdar, Alok; Leclair, Andre; Moore, Ric; Schallhorn, Paul

2011-01-01

GFSSP stands for Generalized Fluid System Simulation Program. It is a general-purpose computer program to compute pressure, temperature and flow distribution in a flow network. GFSSP calculates pressure, temperature, and concentrations at nodes and calculates flow rates through branches. It was primarily developed to analyze Internal Flow Analysis of a Turbopump Transient Flow Analysis of a Propulsion System. GFSSP development started in 1994 with an objective to provide a generalized and easy to use flow analysis tool for thermo-fluid systems.

New views of granular mass flows

USGS Publications Warehouse

Iverson, R.M.; Vallance, J.W.

2001-01-01

Concentrated grain-fluid mixtures in rock avalanches, debris flows, and pyroclastic flows do not behave as simple materials with fixed rheologies. Instead, rheology evolves as mixture agitation, grain concentration, and fluid-pressure change during flow initiation, transit, and deposition. Throughout a flow, however, normal forces on planes parallel to the free upper surface approximately balance the weight of the superincumbent mixture, and the Coulomb friction rule describes bulk intergranular shear stresses on such planes. Pore-fluid pressure can temporarily or locally enhance mixture mobility by reducing Coulomb friction and transferring shear stress to the fluid phase. Initial conditions, boundary conditions, and grain comminution and sorting can influence pore-fluid pressures and cause variations in flow dynamics and deposits.

Stirling cycle engine and refrigeration systems

NASA Technical Reports Server (NTRS)

Higa, W. H. (Inventor)

1976-01-01

A Stirling cycle heat engine is disclosed in which displacer motion is controlled as a function of the working fluid pressure P sub 1 and a substantially constant pressure P sub 0. The heat engine includes an auxiliary chamber at the constant pressure P sub 0. An end surface of a displacer piston is disposed in the auxiliary chamber. During the compression portion of the engine cycle when P sub 1 rises above P sub 0 the displacer forces the working fluid to pass from the cold chamber to the hot chamber of the engine. During the expansion portion of the engine cycle the heated working fluid in the hot chamber does work by pushing down on the engine's drive piston. As the working fluid pressure P sub 1 drops below P sub 0 the displacer forces most of the working fluid in the hot chamber to pass through the regenerator to the cold chamber. The engine is easily combinable with a refrigeration section to provide a refrigeration system in which the engine's single drive piston serves both the engine and the refrigeration section.

Concept of planetary gear system to control fluid mixture ratio

NASA Technical Reports Server (NTRS)

Mcgroarty, J. D.

1966-01-01

Mechanical device senses and corrects for fluid flow departures from the selected flow ratio of two fluids. This system has been considered for control of rocket engine propellant mixture control but could find use wherever control of the flow ratio of any two fluids is desired.

Viscoelastic fluid-structure interactions between a flexible cylinder and wormlike micelle solution

NASA Astrophysics Data System (ADS)

Dey, Anita A.; Modarres-Sadeghi, Yahya; Rothstein, Jonathan P.

2018-06-01

It is well known that when a flexible or flexibly mounted structure is placed perpendicular to the flow of a Newtonian fluid, it can oscillate due to the shedding of separated vortices at high Reynolds numbers. Unlike Newtonian fluids, the flow of viscoelastic fluids can become unstable even at infinitesimal Reynolds numbers due to a purely elastic flow instability that can occur at large Weissenberg numbers. Recent work has shown that these elastic flow instabilities can drive the motion of flexible sheets. The fluctuating fluid forces exerted on the structure from the elastic flow instabilities can lead to a coupling between an oscillatory structural motion and the state of stress in the fluid flow. In this paper, we present the results of an investigation into the flow of a viscoelastic wormlike micelle solution past a flexible circular cylinder. The time variation of the flow field and the state of stress in the fluid are shown using a combination of particle image tracking and flow-induced birefringence images. The static and dynamic responses of the flexible cylinder are presented for a range of flow velocities. The nonlinear dynamics of the structural motion is studied to better understand an observed transition from a symmetric to an asymmetric structural deformation and oscillation behavior.

Thermoelectric Generation Using Counter-Flows of Ideal Fluids

NASA Astrophysics Data System (ADS)

Meng, Xiangning; Lu, Baiyi; Zhu, Miaoyong; Suzuki, Ryosuke O.

2017-08-01

Thermoelectric (TE) performance of a three-dimensional (3-D) TE module is examined by exposing it between a pair of counter-flows of ideal fluids. The ideal fluids are thermal sources of TE module flow in the opposite direction at the same flow rate and generate temperature differences on the hot and cold surfaces due to their different temperatures at the channel inlet. TE performance caused by different inlet temperatures of thermal fluids are numerically analyzed by using the finite-volume method on 3-D meshed physical models and then compared with those using a constant boundary temperature. The results show that voltage and current of the TE module increase gradually from a beginning moment to a steady flow and reach a stable value. The stable values increase with inlet temperature of the hot fluid when the inlet temperature of cold fluid is fixed. However, the time to get to the stable values is almost consistent for all the temperature differences. Moreover, the trend of TE performance using a fluid flow boundary is similar to that of using a constant boundary temperature. Furthermore, 3-D contours of fluid pressure, temperature, enthalpy, electromotive force, current density and heat flux are exhibited in order to clarify the influence of counter-flows of ideal fluids on TE generation. The current density and heat flux homogeneously distribute on an entire TE module, thus indicating that the counter-flows of thermal fluids have high potential to bring about fine performance for TE modules.

Physical modeling of vortical cross-step flow in the American paddlefish, Polyodon spathula

PubMed Central

Brooks, Hannah; Haines, Grant E.; Lin, M. Carly

2018-01-01

Vortical cross-step filtration in suspension-feeding fish has been reported recently as a novel mechanism, distinct from other biological and industrial filtration processes. Although crossflow passing over backward-facing steps generates vortices that can suspend, concentrate, and transport particles, the morphological factors affecting this vortical flow have not been identified previously. In our 3D-printed models of the oral cavity for ram suspension-feeding fish, the angle of the backward-facing step with respect to the model’s dorsal midline affected vortex parameters significantly, including rotational, tangential, and axial speed. These vortices were comparable to those quantified downstream of the backward-facing steps that were formed by the branchial arches of preserved American paddlefish in a recirculating flow tank. Our data indicate that vortices in cross-step filtration have the characteristics of forced vortices, as the flow of water inside the oral cavity provides the external torque required to sustain forced vortices. Additionally, we quantified a new variable for ram suspension feeding termed the fluid exit ratio. This is defined as the ratio of the total open pore area for water leaving the oral cavity via spaces between branchial arches that are not blocked by gill rakers, divided by the total area for water entering through the gape during ram suspension feeding. Our experiments demonstrated that the fluid exit ratio in preserved paddlefish was a significant predictor of the flow speeds that were quantified anterior of the rostrum, at the gape, directly dorsal of the first ceratobranchial, and in the forced vortex generated by the first ceratobranchial. Physical modeling of vortical cross-step filtration offers future opportunities to explore the complex interactions between structural features of the oral cavity, vortex parameters, motile particle behavior, and particle morphology that determine the suspension, concentration, and transport of particles within the oral cavity of ram suspension-feeding fish. PMID:29561890

Fluid flows and forces in development: functions, features and biophysical principles

PubMed Central

Freund, Jonathan B.; Goetz, Jacky G.; Hill, Kent L.; Vermot, Julien

2012-01-01

Throughout morphogenesis, cells experience intracellular tensile and contractile forces on microscopic scales. Cells also experience extracellular forces, such as static forces mediated by the extracellular matrix and forces resulting from microscopic fluid flow. Although the biological ramifications of static forces have received much attention, little is known about the roles of fluid flows and forces during embryogenesis. Here, we focus on the microfluidic forces generated by cilia-driven fluid flow and heart-driven hemodynamics, as well as on the signaling pathways involved in flow sensing. We discuss recent studies that describe the functions and the biomechanical features of these fluid flows. These insights suggest that biological flow determines many aspects of cell behavior and identity through a specific set of physical stimuli and signaling pathways. PMID:22395739

Implementation of Finite Volume based Navier Stokes Algorithm Within General Purpose Flow Network Code

NASA Technical Reports Server (NTRS)

Schallhorn, Paul; Majumdar, Alok

2012-01-01

This paper describes a finite volume based numerical algorithm that allows multi-dimensional computation of fluid flow within a system level network flow analysis. There are several thermo-fluid engineering problems where higher fidelity solutions are needed that are not within the capacity of system level codes. The proposed algorithm will allow NASA's Generalized Fluid System Simulation Program (GFSSP) to perform multi-dimensional flow calculation within the framework of GFSSP s typical system level flow network consisting of fluid nodes and branches. The paper presents several classical two-dimensional fluid dynamics problems that have been solved by GFSSP's multi-dimensional flow solver. The numerical solutions are compared with the analytical and benchmark solution of Poiseulle, Couette and flow in a driven cavity.

Chaos analysis of viscoelastic chaotic flows of polymeric fluids in a micro-channel

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

Lim, C. P.; Lam, Y. C., E-mail: myclam@ntu.edu.sg; BioSystems and Micromechanics

2015-07-15

Many fluids, including biological fluids such as mucus and blood, are viscoelastic. Through the introduction of chaotic flows in a micro-channel and the construction of maps of characteristic chaos parameters, differences in viscoelastic properties of these fluids can be measured. This is demonstrated by creating viscoelastic chaotic flows induced in an H-shaped micro-channel through the steady infusion of a polymeric fluid of polyethylene oxide (PEO) and another immiscible fluid (silicone oil). A protocol for chaos analysis was established and demonstrated for the analysis of the chaotic flows generated by two polymeric fluids of different molecular weight but with similar relaxationmore » times. The flows were shown to be chaotic through the computation of their correlation dimension (D{sub 2}) and the largest Lyapunov exponent (λ{sub 1}), with D{sub 2} being fractional and λ{sub 1} being positive. Contour maps of D{sub 2} and λ{sub 1} of the respective fluids in the operating space, which is defined by the combination of polymeric fluids and silicone oil flow rates, were constructed to represent the characteristic of the chaotic flows generated. It was observed that, albeit being similar, the fluids have generally distinct characteristic maps with some similar trends. The differences in the D{sub 2} and λ{sub 1} maps are indicative of the difference in the molecular weight of the polymers in the fluids because the driving force of the viscoelastic chaotic flows is of molecular origin. This approach in constructing the characteristic maps of chaos parameters can be employed as a diagnostic tool for biological fluids and, more generally, chaotic signals.« less

Characterization of seismic properties across scales: from the laboratory- to the field scale

NASA Astrophysics Data System (ADS)

Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

2016-04-01

When exploring geothermal systems, the main interest is on factors controlling the efficiency of the heat exchanger. This includes the energy state of the pore fluids and the presence of permeable structures building part of the fluid transport system. Seismic methods are amongst the most common exploration techniques to image the deep subsurface in order to evaluate such a geothermal heat exchanger. They make use of the fact that a seismic wave caries information on the properties of the rocks in the subsurface through which it passes. This enables the derivation of the stiffness and the density of the host rock from the seismic velocities. Moreover, it is well-known that the seismic waveforms are modulated while propagating trough the subsurface by visco-elastic effects due to wave induced fluid flow, hence, delivering information about the fluids in the rock's pore space. To constrain the interpretation of seismic data, that is, to link seismic properties with the fluid state and host rock permeability, it is common practice to measure the rock properties of small rock specimens in the laboratory under in-situ conditions. However, in magmatic geothermal systems or in systems situated in the crystalline basement, the host rock is often highly impermeable and fluid transport predominately takes place in fracture networks, consisting of fractures larger than the rock samples investigated in the laboratory. Therefore, laboratory experiments only provide the properties of relatively intact rock and an up-scaling procedure is required to characterize the seismic properties of large rock volumes containing fractures and fracture networks and to study the effects of fluids in such fractured rock. We present a technique to parameterize fractured rock volumes as typically encountered in Icelandic magmatic geothermal systems, by combining laboratory experiments with effective medium calculations. The resulting models can be used to calculate the frequency-dependent bulk modulus K(ω) and shear modulus G(ω), from which the P- and S-wave velocities V P(ω) and V S(ω) and the quality factors QP(ω) and QS(ω) of fluid saturated fractured rock volumes can be estimated. These volumes are much larger and contain more complex structures than the rock samples investigated in the laboratory. Thus, the derived quantities describe the elastic and anelastic (energy loss due to wave induced fluid flow) short-term deformation induced by seismic waves at scales that are relevant for field-scale seismic exploration projects.

Fracture Characterization in the Astor Pass Geothermal Field, Nevada

NASA Astrophysics Data System (ADS)

Walsh, D. C.; Reeves, D. M.; Pohll, G.; Lyles, B. F.; Cooper, C. A.

2011-12-01

The Astor Pass geothermal field, near Pyramid Lake, NV, is under study as a site of potential geothermal energy production. Three wells have been completed in the graben of this typical Basin and Range geologic setting. Lithologies include a layer of unconsolidated sediment (basin fill) underlain by various tertiary volcanic units and granodiorite and metavolcanic basement rock. Characterization of fractures within the relatively impermeable rock matrix is being conducted for the three wells. Statistical analysis of fracture orientation, densities, and spacing obtained from borehole imaging logs is used to determine stress orientation and to generate a statistically equivalent Discrete Fracture Network (DFN) model. Fractures at depth are compared to fracture data collected in nearby outcrops of the same lithologic stratigraphy. Fracture geometry and density is correlated to mechanically discrete layers within the stratigraphy to test whether variations in fracturing can be attributed to variations in Young's modulus. Correlation of fracture geometry and densities with spinner flowmeter logs and distributed temperature sensor records are made in an effort to identify potential flowing fracture zones intersecting the borehole. Mean fracture aperture is obtained from open fracture counts and reservoir-scale transmissivity values (computed from a 30 day pump test) in the absence of readily available aperture data. The goal of this thorough fracture characterization is to create a physically relevant model which may be coupled with a multipurpose fluid flow and thermal simulator for investigation of geothermal reservoir behavior, particularly at the borehole scale.

Influence of mantle viscosity structure and mineral grain size on fluid migration pathways in the mantle wedge.

NASA Astrophysics Data System (ADS)

Cerpa, N. G.; Wada, I.; Wilson, C. R.; Spiegelman, M. W.

2016-12-01

We develop a 2D numerical porous flow model that incorporates both grain size distribution and matrix compaction to explore the fluid migration (FM) pathways in the mantle wedge. Melt generation for arc volcanism is thought to be triggered by slab-derived fluids that migrate into the hot overlying mantle and reduce its melting temperature. While the narrow location of the arcs relative to the top of the slab ( 100±30 km) is a robust observation, the release of fluids is predicted to occur over a wide range of depth. Reconciling such observations and predictions remains a challenge for the geodynamic community. Fluid transport by porous flow depends on the permeability of the medium which in turn depends on fluid fraction and mineral grain size. The grain size distribution in the mantle wedge predicted by laboratory derived laws was found to be a possible mechanism to focusing of fluids beneath the arcs [Wada and Behn, 2015]. The viscous resistance of the matrix to the volumetric strain generates compaction pressure that affects fluid flow and can also focus fluids towards the arc [Wilson et al, 2014]. We thus have developed a 2D one-way coupled Darcy's-Stokes flow model (solid flow independent of fluid flow) for the mantle wedge that combines both effects. For the solid flow calculation, we use a kinematic-dynamic approach where the system is driven by the prescribed slab velocity. The solid rheology accounts for both dislocation and diffusion creep and we calculate the grain size distribution following Wada and Behn [2015]. In our fluid flow model, the permeability of the medium is grain size dependent and the matrix bulk viscosity depends on solid shear viscosity and fluid fraction. The fluid influx from the slab is imposed as a boundary condition at the base of the mantle wedge. We solve the discretized governing equations using the software package TerraFERMA. Applying a range of model parameter values, including slab age, slab dip, subduction rate, and fluid influx, we quantify the combined effects of grain size and compaction on fluid flow paths.

Effects of magnetic-fluid flow on structural instability of a carbon nanotube conveying nanoflow under a longitudinal magnetic field

NASA Astrophysics Data System (ADS)

Sadeghi-Goughari, Moslem; Jeon, Soo; Kwon, Hyock-Ju

2017-09-01

In drug delivery systems, carbon nanotubes (CNTs) can be used to deliver anticancer drugs into target site to kill metastatic cancer cells under the magnetic field guidance. Deep understanding of dynamic behavior of CNTs in drug delivery systems may enable more efficient use of the drugs while reducing systemic side effects. In this paper, we study the effect of magnetic-fluid flow on the structural instability of a CNT conveying nanoflow under a longitudinal magnetic field. The Navier-Stokes equation of magnetic-fluid flow is coupled with Euler-Bernoulli beam theory for modeling fluid structure interaction (FSI). Size effects of the magnetic fluid and the CNT are addressed through small-scale parameters including the Knudsen number (Kn) and the nonlocal parameter. Results show the positive role of magnetic properties of fluid flow on the structural stability of CNT. Specifically, magnetic force applied to the fluid flow has an effect of decreasing the structural stiffness of system while increasing the critical flow velocity. Furthermore, we discover that the nanoscale effects of CNT and fluid flow tend to amplify the influence of magnetic field on the vibrational behavior of the system.

Enhanced cell trapping throughput using DC-biased AC electric field in a dielectrophoresis-based fluidic device with densely packed silica beads.

PubMed

Lewpiriyawong, Nuttawut; Xu, Guolin; Yang, Chun

2018-03-01

This paper presents the use of DC-biased AC electric field for enhancing cell trapping throughput in an insulator-based dielectrophoretic (iDEP) fluidic device with densely packed silica beads. Cell suspension is carried through the iDEP device by a pressure-driven flow. Under an applied DC-biased AC electric field, DEP trapping force is produced as a result of non-uniform electric field induced by the gap of electrically insulating silica beads packed between two mesh electrodes that allow both fluid and cells to pass through. While the AC component is mainly to control the magnitude of DEP trapping force, the DC component generates local electroosmotic (EO) flow in the cavity between the beads and the EO flow can be set to move along or against the main pressure-driven flow. Our experimental and simulation results show that desirable trapping is achieved when the EO flow direction is along (not against) the main flow direction. Using our proposed DC-biased AC field, the device can enhance the trapping throughput (in terms of the flowrate of cell suspension) up to five times while yielding almost the same cell capture rates as compared to the pure AC field case. Additionally, the device was demonstrated to selectively trap dead yeast cells from a mixture of flowing live and dead yeast cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Device and method for measuring multi-phase fluid flow and density of fluid in a conduit having a gradual bend

DOEpatents

Ortiz, Marcos German; Boucher, Timothy J.

1998-01-01

A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Sample processor for chemical analysis

NASA Technical Reports Server (NTRS)

Boettger, Heinz G. (Inventor)

1980-01-01

An apparatus is provided which can process numerous samples that must be chemically analyzed by the application of fluids such as liquid reagents, solvents and purge gases, as well as the application of dumps for receiving the applied fluid after they pass across the sample, in a manner that permits numerous samples to be processed in a relatively short time and with minimal manpower. The processor includes a rotor which can hold numerous cartridges containing inert or adsorbent material for holding samples, and a pair of stators on opposite sides of the rotor. The stators form stations spaced along the path of the cartridges which lie in the rotor, and each station can include an aperture in one stator through which a fluid can be applied to a cartridge resting at that station, and an aperture in the other stator which can receive the fluid which has passed through the cartridge. The stators are sealed to the ends of the cartridges lying on the rotor, to thereby isolate the stations from one another.

Impacts of Fluid Dynamics Simulation in Study of Nasal Airflow Physiology and Pathophysiology in Realistic Human Three-Dimensional Nose Models

PubMed Central

Lee, Heow Peuh; Gordon, Bruce R.

2012-01-01

During the past decades, numerous computational fluid dynamics (CFD) studies, constructed from CT or MRI images, have simulated human nasal models. As compared to rhinomanometry and acoustic rhinometry, which provide quantitative information only of nasal airflow, resistance, and cross sectional areas, CFD enables additional measurements of airflow passing through the nasal cavity that help visualize the physiologic impact of alterations in intranasal structures. Therefore, it becomes possible to quantitatively measure, and visually appreciate, the airflow pattern (laminar or turbulent), velocity, pressure, wall shear stress, particle deposition, and temperature changes at different flow rates, in different parts of the nasal cavity. The effects of both existing anatomical factors, as well as post-operative changes, can be assessed. With recent improvements in CFD technology and computing power, there is a promising future for CFD to become a useful tool in planning, predicting, and evaluating outcomes of nasal surgery. This review discusses the possibilities and potential impacts, as well as technical limitations, of using CFD simulation to better understand nasal airflow physiology. PMID:23205221

Multiple capillary biochemical analyzer with barrier member

DOEpatents

Dovichi, N.J.; Zhang, J.Z.

1996-10-22

A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

Uncertainty Quantification and Certification Prediction of Low-Boom Supersonic Aircraft Configurations

NASA Technical Reports Server (NTRS)

West, Thomas K., IV; Reuter, Bryan W.; Walker, Eric L.; Kleb, Bil; Park, Michael A.

2014-01-01

The primary objective of this work was to develop and demonstrate a process for accurate and efficient uncertainty quantification and certification prediction of low-boom, supersonic, transport aircraft. High-fidelity computational fluid dynamics models of multiple low-boom configurations were investigated including the Lockheed Martin SEEB-ALR body of revolution, the NASA 69 Delta Wing, and the Lockheed Martin 1021-01 configuration. A nonintrusive polynomial chaos surrogate modeling approach was used for reduced computational cost of propagating mixed, inherent (aleatory) and model-form (epistemic) uncertainty from both the computation fluid dynamics model and the near-field to ground level propagation model. A methodology has also been introduced to quantify the plausibility of a design to pass a certification under uncertainty. Results of this study include the analysis of each of the three configurations of interest under inviscid and fully turbulent flow assumptions. A comparison of the uncertainty outputs and sensitivity analyses between the configurations is also given. The results of this study illustrate the flexibility and robustness of the developed framework as a tool for uncertainty quantification and certification prediction of low-boom, supersonic aircraft.

Multiple capillary biochemical analyzer with barrier member

DOEpatents

Dovichi, Norman J.; Zhang, Jian Z.

1996-01-01

A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

Design and Construction of a Shock Tube Experiment for Multiphase Instability Experiments

NASA Astrophysics Data System (ADS)

Middlebrooks, John; Black, Wolfgang; Avgoustopoulos, Constantine; Allen, Roy; Kathakapa, Raj; Guo, Qiwen; McFarland, Jacob

2016-11-01

Hydrodynamic instabilities are important phenomena that have a wide range of practical applications in engineering and physics. One such instability, the shock driven multiphase instability (SDMI), arises when a shockwave accelerates an interface between two particle-gas mixtures with differing multiphase properties. The SDMI is present in high energy explosives, scramjets, and supernovae. A practical way of studying shock wave driven instabilities is through experimentation in a shock tube laboratory. This poster presentation will cover the design and data acquisition process of the University of Missouri's Fluid Mixing Shock Tube Laboratory. In the shock tube, a pressure generated shockwave is passed through a multiphase interface, creating the SDMI instability. This can be photographed for observation using high speed cameras, lasers, and advance imaging techniques. Important experimental parameters such as internal pressure and temperature, and mass flow rates of gases can be set and recorded by remotely controlled devices. The experimental facility provides the University of Missouri's Fluid Mixing Shock Tube Laboratory with the ability to validate simulated experiments and to conduct further inquiry into the field of shock driven multiphase hydrodynamic instabilities. Advisor.

High fluid shear strain causes injury in silver shark: Preliminary implications for Mekong hydropower turbine design

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

Baumgartner, L. J.; Thorncraft, G.; Phonekhampheng, O.

Fluid shear arises when two bodies of water, travelling at different velocities, intersect. Fish entrained at the interface of these two water masses will experience shear stress; which can be harmful. The stress magnitude is dependent on waterbody mass and velocity; with the fish impact largely related to body size. Elevated shear stress occurs where rapidly flowing water passes near spillways, across screens, within turbine draft tubes or other passage routes. A flume was used to determine critical tolerances of silver shark (Balantiocheilos melanopterus) to different shear stress rates generated by a high velocity jet. Fish experienced higher levels ofmore » injury and mortality as shear stress was increased. Excessive shear forces had damaging impacts on fish. Mortality occurred at shear levels higher that 600/s. It is important that developers should attempt to model potential shear profiles expected during turbine passage in selected designs. These data will be critical to determine potential impacts on fish. If the likelihood of adverse impact is high, then alternative designs which have lower shear stress could be explored.« less

PRATHAM: Parallel Thermal Hydraulics Simulations using Advanced Mesoscopic Methods

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

Joshi, Abhijit S; Jain, Prashant K; Mudrich, Jaime A

2012-01-01

At the Oak Ridge National Laboratory, efforts are under way to develop a 3D, parallel LBM code called PRATHAM (PaRAllel Thermal Hydraulic simulations using Advanced Mesoscopic Methods) to demonstrate the accuracy and scalability of LBM for turbulent flow simulations in nuclear applications. The code has been developed using FORTRAN-90, and parallelized using the message passing interface MPI library. Silo library is used to compact and write the data files, and VisIt visualization software is used to post-process the simulation data in parallel. Both the single relaxation time (SRT) and multi relaxation time (MRT) LBM schemes have been implemented in PRATHAM.more » To capture turbulence without prohibitively increasing the grid resolution requirements, an LES approach [5] is adopted allowing large scale eddies to be numerically resolved while modeling the smaller (subgrid) eddies. In this work, a Smagorinsky model has been used, which modifies the fluid viscosity by an additional eddy viscosity depending on the magnitude of the rate-of-strain tensor. In LBM, this is achieved by locally varying the relaxation time of the fluid.« less

VISCOPLASTIC FLUID MODEL FOR DEBRIS FLOW ROUTING.

USGS Publications Warehouse

Chen, Cheng-lung

1986-01-01

This paper describes how a generalized viscoplastic fluid model, which was developed based on non-Newtonian fluid mechanics, can be successfully applied to routing a debris flow down a channel. The one-dimensional dynamic equations developed for unsteady clear-water flow can be used for debris flow routing if the flow parameters, such as the momentum (or energy) correction factor and the resistance coefficient, can be accurately evaluated. The writer's generalized viscoplastic fluid model can be used to express such flow parameters in terms of the rheological parameters for debris flow in wide channels. A preliminary analysis of the theoretical solutions reveals the importance of the flow behavior index and the so-called modified Froude number for uniformly progressive flow in snout profile modeling.

Late Noachian fluvial erosion on Mars: Cumulative water volumes required to carve the valley networks and grain size of bed-sediment

NASA Astrophysics Data System (ADS)

Rosenberg, Eliott N.; Head, James W., III

2015-11-01

Our goal is to quantify the cumulative water volume that was required to carve the Late Noachian valley networks on Mars. We employ an improved methodology in which fluid/sediment flux ratios are based on empirical data, not assumed. We use a large quantity of data from terrestrial rivers to assess the variability of actual fluid/sediment flux sediment ratios. We find the flow depth by using an empirical relationship to estimate the fluid flux from the estimated channel width, and then using estimated grain sizes (theoretical sediment grain size predictions and comparison with observations by the Curiosity rover) to find the flow depth to which the resulting fluid flux corresponds. Assuming that the valley networks contained alluvial bed rivers, we find, from their current slopes and widths, that the onset of suspended transport occurs near the sand-gravel boundary. Thus, any bed sediment must have been fine gravel or coarser, whereas fine sediment would be carried downstream. Subsequent to the cessation of fluvial activity, aeolian processes have partially redistributed fine-grain particles in the valleys, often forming dunes. It seems likely that the dominant bed sediment size was near the threshold for suspension, and assuming that this was the case could make our final results underestimates, which is the same tendency that our other assumptions have. Making this assumption, we find a global equivalent layer (GEL) of 3-100 m of water to be the most probable cumulative volume that passed through the valley networks. This value is similar to the ∼34 m water GEL currently on the surface and in the near-surface in the form of ice. Note that the amount of water required to carve the valley networks could represent the same water recycled through a surface valley network hydrological system many times in separate or continuous precipitation/runoff/collection/evaporation/precipitation cycles.

Sampling device for withdrawing a representative sample from single and multi-phase flows

DOEpatents

Apley, Walter J.; Cliff, William C.; Creer, James M.

1984-01-01

A fluid stream sampling device has been developed for the purpose of obtaining a representative sample from a single or multi-phase fluid flow. This objective is carried out by means of a probe which may be inserted into the fluid stream. Individual samples are withdrawn from the fluid flow by sampling ports with particular spacings, and the sampling parts are coupled to various analytical systems for characterization of the physical, thermal, and chemical properties of the fluid flow as a whole and also individually.

Method and apparatus for measuring the mass flow rate of a fluid

DOEpatents

Evans, Robert P.; Wilkins, S. Curtis; Goodrich, Lorenzo D.; Blotter, Jonathan D.

2002-01-01

A non invasive method and apparatus is provided to measure the mass flow rate of a multi-phase fluid. An accelerometer is attached to a pipe carrying a multi-phase fluid. Flow related measurements in pipes are sensitive to random velocity fluctuations whose magnitude is proportional to the mean mass flow rate. An analysis of the signal produced by the accelerometer shows a relationship between the mass flow of a fluid and the noise component of the signal of an accelerometer. The noise signal, as defined by the standard deviation of the accelerometer signal allows the method and apparatus of the present invention to non-intrusively measure the mass flow rate of a multi-phase fluid.

Safety drain system for fluid reservoir

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Cronise, Raymond J. (Inventor)

2012-01-01

A safety drain system includes a plurality of drain sections, each of which defines distinct fluid flow paths. At least a portion of the fluid flow paths commence at a side of the drain section that is in fluid communication with a reservoir's fluid. Each fluid flow path at the side communicating with the reservoir's fluid defines an opening having a smallest dimension not to exceed approximately one centimeter. The drain sections are distributed over at least one surface of the reservoir. A manifold is coupled to the drain sections.

Flow control using audio tones in resonant microfluidic networks: towards cell-phone controlled lab-on-a-chip devices.

PubMed

Phillips, Reid H; Jain, Rahil; Browning, Yoni; Shah, Rachana; Kauffman, Peter; Dinh, Doan; Lutz, Barry R

2016-08-16

Fluid control remains a challenge in development of portable lab-on-a-chip devices. Here, we show that microfluidic networks driven by single-frequency audio tones create resonant oscillating flow that is predicted by equivalent electrical circuit models. We fabricated microfluidic devices with fluidic resistors (R), inductors (L), and capacitors (C) to create RLC networks with band-pass resonance in the audible frequency range available on portable audio devices. Microfluidic devices were fabricated from laser-cut adhesive plastic, and a "buzzer" was glued to a diaphragm (capacitor) to integrate the actuator on the device. The AC flowrate magnitude was measured by imaging oscillation of bead tracers to allow direct comparison to the RLC circuit model across the frequency range. We present a systematic build-up from single-channel systems to multi-channel (3-channel) networks, and show that RLC circuit models predict complex frequency-dependent interactions within multi-channel networks. Finally, we show that adding flow rectifying valves to the network creates pumps that can be driven by amplified and non-amplified audio tones from common audio devices (iPod and iPhone). This work shows that RLC circuit models predict resonant flow responses in multi-channel fluidic networks as a step towards microfluidic devices controlled by audio tones.

Lagrangian analysis of premixed turbulent combustion in hydrogen-air flames

NASA Astrophysics Data System (ADS)

Darragh, Ryan; Poludnenko, Alexei; Hamlington, Peter

2016-11-01

Lagrangian analysis has long been a tool used to analyze non-reacting turbulent flows, and has recently gained attention in the reacting flow and combustion communities. The approach itself allows one to separate local molecular effects, such as those due to reactions or diffusion, from turbulent advective effects along fluid pathlines, or trajectories. Accurate calculation of these trajectories can, however, be rather difficult due to the chaotic nature of turbulent flows and the added complexity of reactions. In order to determine resolution requirements and verify the numerical algorithm, extensive tests are described in this talk for prescribed steady, unsteady, and chaotic flows, as well as for direct numerical simulations (DNS) of non-reacting homogeneous isotropic turbulence. The Lagrangian analysis is then applied to DNS of premixed hydrogen-air flames at two different turbulence intensities for both single- and multi-step chemical mechanisms. Non-monotonic temperature and fuel-mass fraction evolutions are found to exist along trajectories passing through the flame brush. Such non-monotonicity is shown to be due to molecular diffusion resulting from large spatial gradients created by turbulent advection. This work was supported by the Air Force Office of Scientific Research (AFOSR) under Award No. FA9550-14-1-0273, and the Department of Defense (DoD) High Performance Computing Modernization Program (HPCMP) under a Frontier project award.

Active flow control for a NACA-0012 profile

NASA Astrophysics Data System (ADS)

Oualli, H.; Mekadem, M.; Boukrif, M.; Saad, S.; Bouabdallah, A.; Gad-El-Hak, M.

2015-11-01

Active flow control is applied on a NACA-0012 profile. The experiments are carried out in a wind tunnel, and flow visualizations are conducted using high-resolution visible-light and infrared cameras. Numerical LES finite-volume code is used to complement the physical experiments. The symmetric wing is clipped into two parts, and those parts extend and retract along the chord according to the same sinusoidal law we optimized last year for a circular/elliptical cylinder (B. Am. Phys. Soc., vol. 59, no. 20, p. 319, 2014). The Reynolds number varies in the range of 500-100,000, which is typical of UAVs and micro-UAVs. The nascent cavity resulting from the oscillatory motion of the profile segments is kept open allowing the passage of fluid between the intrados and extrados. The pulsatile motion is characterized by an amplitude and frequency, and the airfoil's angle of attack is changed in the range of 0-30 deg. For certain amplitude and frequency, the drag coefficient is increased over the uncontrolled case by a factor of 300. But when the cavity is covered to prevent the flow from passing through the cavity, the drag coefficient becomes negative, and significant thrust is produced. The results are promising to achieve rapid deceleration and acceleration of UAVs.

Investigation of heat transfer and flow using ribs within gas turbine blade cooling passage: Experimental and hybrid LES/RANS modeling

NASA Astrophysics Data System (ADS)

Kumar, Sourabh

Gas turbines are extensively used for aircraft propulsion, land based power generation and various industrial applications. Developments in innovative gas turbine cooling technology enhance the efficiency and power output, with an increase in turbine rotor inlet temperatures. These advancements of turbine cooling have allowed engine design to exceed normal material temperature limits. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream are based on the increase of heat transfer areas and on promotion of turbulence of the cooling flow. In this study, it is obtained by casting repeated continuous V and broken V shaped ribs on one side of the two pass square channel into the core of blade. Despite extensive research on ribs, only few papers have validated the numerical data with experimental results in two pass channel. In the present study, detailed experimental investigation is carried out for two pass square channels with 180° turn. Detailed heat transfer distribution occurring in the ribbed passage is reported for steady state experiment. Four different combinations of 60° and Broken 60° V ribs in channel are considered. Thermocouples are used to obtain the temperature on the channel surface and local heat transfer coefficients are obtained for various Reynolds numbers, within the turbulent flow regime. Area averaged data are calculated in order to compare the overall performance of the tested ribbed surface and to evaluate the degree of heat transfer enhancement induced by the ribs with. Flow within the channels is characterized by heat transfer enhancing ribs, bends, rotation and buoyancy effects. Computational Fluid Dynamics (CFD) simulations were carried out for the same geometries using different turbulence models such as k-o Shear stress transport (SST) and Reynolds stress model (RSM). These CFD simulations were based on advanced computing in order to improve the accuracy of three dimensional metal temperature prediction which can be applied routinely in the design stage of turbine cooled vanes and blades. This study presents an attempt to collect information about Nusselt number inside the ribbed duct and a series of measurement is performed in steady state eliminating the error sources inherently connected with transient method. A Large Eddy Simulation (LES) is carried out on the best V and Broken V rib arrangements to analyze the flow pattern inside the channel. A novel method is devised to analyze the results obtained from CFD simulation. Hybrid LES/Reynolds Averaged Navier Strokes (RANS) modeling is used to modify Reynolds stresses using Algebraic Stress Model (ASM).

The effect of dentinal fluid flow during loading in various directions--simulation of fluid-structure interaction.

PubMed

Su, Kuo-Chih; Chang, Chih-Han; Chuang, Shu-Fen; Ng, Eddie Yin-Kwee

2013-06-01

This study uses a fluid-structure interaction (FSI) simulation to evaluate the fluid flow in a dental intrapulpal chamber induced by the deformation of the tooth structure during loading in various directions. The FSI is used for the biomechanics simulation of dental intrapulpal responses with the force loading gradually increasing from 0 to 100N at 0°, 30°, 45°, 60°, and 90° on the tooth surface in 1s, respectively. The effect of stress or deformation on tooth and fluid flow changes in the pulp chamber are evaluated. A horizontal loading force on a tooth may induce tooth structure deformation, which increases fluid flow velocity in the coronal pulp. Thus, horizontal loading on a tooth may easily induce tooth pain. This study suggests that experiments to investigate the relationship between loading in various directions and dental pain should avoid measuring the bulk pulpal fluid flow from radicular pulp, but rather should measure the dentinal fluid flow in the dentinal tubules or coronal pulp. The FSI analysis used here could provide a powerful tool for investigating problems with coupled solid and fluid structures in dental biomechanics. Copyright © 2012 Elsevier Ltd. All rights reserved.

Forensic Fluid Dynamics and the Indian Spring (1991) cave collapse problem

NASA Astrophysics Data System (ADS)

Nof, D.

2013-05-01

The collapse of the Indian spring cave (Florida) in 1991 was unique because it occurred while cave divers were in the cave. For the most part, the submerged cave is large enough to accommodate a passing truck so the cave divers were not in touch with its walls and it is hard to imagine why would it naturally collapse just when the divers were in it. Recently, Nof and Paldor (2010) resolved this apparent paradox by suggesting that resonance in the air pockets in the cavern, created by breathing (open circuit) divers, may have contributed to the collapse. In this scenario, divers present in the cavern during the dive may have (unknowingly) caused the collapse through the pressurized air/gas that they release with each breath. When the breathing period of the diver(s) matches the natural oscillations period of the "cave oscillator", the ensuing resonance causes the air pressure in the pockets to increase uncontrollably. Here, we place the above theory on a more solid ground. To do so, we first extended the resonance theory from our original two-pockets, symmetrical U-tube model (with two identical branches that were not specifically identified within the cave system) to a one (identified) pocket in the cavern and a very broad basin (identified, of course) that serves as the other branch of the U-tube. Our methodology is to apply familiar fluid dynamics principles to the situation that occurred in the cave. We did so, step-by-step, on the basis of our interviews with four out of the five surviving cave-divers. Namely, we dissected their testimonies to arrive at a physically plausible scenario determined on basis of a fluid dynamics application to the natural flow in the cave and the flow induced by the compressed air released by the divers as well as the collapsed mud. We found that the oscillation period was larger than what we earlier calculated (still relevant to the case, nevertheless), and that, in contrast to what most cave divers believe, there was a temporary flow blocking during the collapse but no total flow reversal within the cave. Observed swirling in the basin during the collapse is attributed to a dipole flow corresponding to an inflow and outflow from the cave.

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

Wu, H.L.; Spronsen, G. van; Klaus, E.H.

A simulation model of the dynamics of a by-pass pig and related two-phase flow behavior along with field trials of the pig in a dry-gas pipeline have revealed significant gains in use of a by-pass pig in modifying gas and liquid production rates. The method can widen the possibility of applying two-phase flow pipeline transportation to cases in which separator or slug-catcher capacity is limited by practicality or cost. Pigging two-phase pipelines normally generates large liquid slug volumes in front of the pig. These require large separators or slug catchers. Using a high by-pass pig to disperse the liquid andmore » reduce the maximum liquid production rate before pig arrival has been investigated by Shell Exploration and Production companies. A simulation model of the dynamics of the pig and related two-phase flow behavior in the pipeline was used to predict the performance of by-pass pigs. Field trials in a dry-gas pipeline were carried out to provide friction data and to validate the model. The predicted mobility of the high by-pass pig in the pipeline and risers was verified and the beneficial effects due to the by-pass concept exceeded the prediction of the simplified model.« less

Influence of blood flow on adsorption of beta2-microglobulin onto AN69 dialyzer membrane.

PubMed

Kandus, A; Malovrh, M; Bren, A F

1997-08-01

Adsorption onto the dialyzer membrane is a contributing factor to the elimination of beta2-microglobulin (beta2M) from the sera of uremic patients. The purpose of this prospective study was to ascertain the influence of the blood flow rate on adsorption of beta2M onto the polyacrylonitrile (AN69) hollow-fiber dialyzer membrane in 8 patients during regular hemodialysis (HD). Blood first passed through a low-flux polysulfone dialyzer and then through an AN69 dialyzer, which was not in contact with the dialysis fluid. During the investigation period (first hour of the HD session), the blood flow rate was 100 ml/ min (first part of the study), 200 ml/min (second part of the study), and 300 ml/min (third part of the study). Ultrafiltration was not performed during the investigation period. At the start of the HD sessions, the serum concentration of beta2M in the afferent blood line did not differ significantly among the 3 parts of the study. Serum beta2M was measured in samples taken from the afferent and efferent blood lines of the AN69 dialyzer at 5, 10, 15, 30, 45, and 60 min. The serum beta2M concentration decreased significantly in blood that had passed through the AN69 dialyzer. This decrease, indicating membrane adsorption, was maximal during the first part and minimal during the third part of study. The decrease in the contact time between the blood and the AN69 could be the underlying cause. The calculated quantities of beta2M adsorbed onto the AN69 membrane (44.2 +/- 10.2, 43.2 +/- 12.1, and 42.6 +/- 17.3 mg) did not differ significantly among the 3 parts of the study. These results suggest that an increase in blood flow rate from 100 to 300 ml/min did not significantly affect the quantity of beta2M adsorbed onto the AN69 membrane.

High-throughput biological small-angle X-ray scattering with a robotically loaded capillary cell

PubMed Central

Nielsen, S. S.; Møller, M.; Gillilan, R. E.

2012-01-01

With the rise in popularity of biological small-angle X-ray scattering (BioSAXS) measurements, synchrotron beamlines are confronted with an ever-increasing number of samples from a wide range of solution conditions. To meet these demands, an increasing number of beamlines worldwide have begun to provide automated liquid-handling systems for sample loading. This article presents an automated sample-loading system for BioSAXS beamlines, which combines single-channel disposable-tip pipetting with a vacuum-enclosed temperature-controlled capillary flow cell. The design incorporates an easily changeable capillary to reduce the incidence of X-ray window fouling and cross contamination. Both the robot-control and the data-processing systems are written in Python. The data-processing code, RAW, has been enhanced with several new features to form a user-friendly BioSAXS pipeline for the robot. The flow cell also supports efficient manual loading and sample recovery. An effective rinse protocol for the sample cell is developed and tested. Fluid dynamics within the sample capillary reveals a vortex ring pattern of circulation that redistributes radiation-damaged material. Radiation damage is most severe in the boundary layer near the capillary surface. At typical flow speeds, capillaries below 2 mm in diameter are beginning to enter the Stokes (creeping flow) regime in which mixing due to oscillation is limited. Analysis within this regime shows that single-pass exposure and multiple-pass exposure of a sample plug are functionally the same with regard to exposed volume when plug motion reversal is slow. The robot was tested on three different beamlines at the Cornell High-Energy Synchrotron Source, with a variety of detectors and beam characteristics, and it has been used successfully in several published studies as well as in two introductory short courses on basic BioSAXS methods. PMID:22509071

Flow of two immiscible fluids in a periodically constricted tube: Transitions to stratified, segmented, churn, spray or segregated flow

NASA Astrophysics Data System (ADS)

Tsamopoulos, John; Fraggedakis, Dimitris; Dimakopoulos, Yiannis

2015-11-01

We study the flow of two immiscible, Newtonian fluids in a periodically constricted tube driven by a constant pressure gradient. Our Volume-of-Fluid algorithm is used to solve the governing equations. First the code is validated by comparing its predictions to previously reported results for stratified and pulsing flow. Then it is used to capture accurately all the significant topological changes that take place. Initially, the fluids have a core-annular arrangement, which is found to either remain the same or change to a different arrangement depending on the fluid properties, the pressure driving the flow or the flow geometry. The flow-patterns that appear are the core-annular, segmented, churn, spray and segregated flow. The predicted scalings near pinching of the core fluid concur with similarity predictions and earlier numerical results (Cohen et al. (1999)). Flow-pattern maps are constructed in terms of the Reynolds and Weber numbers. Our results provide deeper insights in the mechanism of the pattern transitions and are in agreement with previous studies on core-annular flow (Kouris & Tsamopoulos (2001 & 2002)), segmented flow (Lac & Sherwood (2009)) and churn flow (Bai et al. (1992)). GSRT of Greece through the program ``Excellence'' (Grant No. 1918, entitled ``FilCoMicrA'').

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

Ploskey, Gene R.; Weiland, Mark A.; Faber, Derrek M.

This report describes a 2008 acoustic telemetry survival study conducted by the Pacific Northwest National Laboratory for the Portland District of the U.S. Army Corps of Engineers. The study estimated the survival of juvenile Chinook salmon and steelhead passing Bonneville Dam (BON) and its spillway. Of particular interest was the relative survival of smolts detected passing through end spill bays 1-3 and 16-18, which had deep flow deflectors immediately downstream of spill gates, versus survival of smolts passing middle spill bays 4-15, which had shallow flow deflectors.

Monodisperse granular flows in viscous dispersions in a centrifugal acceleration field

NASA Astrophysics Data System (ADS)

Cabrera, Miguel Angel; Wu, Wei

2016-04-01

Granular flows are encountered in geophysical flows and innumerable industrial applications with particulate materials. When mixed with a fluid, a complex network of interactions between the particle- and fluid-phase develops, resulting in a compound material with a yet unclear physical behaviour. In the study of granular suspensions mixed with a viscous dispersion, the scaling of the stress-strain characteristics of the fluid phase needs to account for the level of inertia developed in experiments. However, the required model dimensions and amount of material becomes a main limitation for their study. In recent years, centrifuge modelling has been presented as an alternative for the study of particle-fluid flows in a reduced scaled model in an augmented acceleration field. By formulating simple scaling principles proportional to the equivalent acceleration Ng in the model, the resultant flows share many similarities with field events. In this work we study the scaling principles of the fluid phase and its effects on the flow of granular suspensions. We focus on the dense flow of a monodisperse granular suspension mixed with a viscous fluid phase, flowing down an inclined plane and being driven by a centrifugal acceleration field. The scaled model allows the continuous monitoring of the flow heights, velocity fields, basal pressure and mass flow rates at different Ng levels. The experiments successfully identify the effects of scaling the plastic viscosity of the fluid phase, its relation with the deposition of particles over the inclined plane, and allows formulating a discussion on the suitability of simulating particle-fluid flows in a centrifugal acceleration field.

Simultaneous Multiple-Location Separation Control

NASA Technical Reports Server (NTRS)

Greenblatt, David (Inventor)

2009-01-01

A method of controlling a shear layer for a fluid dynamic body introduces first periodic disturbances into the fluid medium at a first flow separation location. Simultaneously, second periodic disturbances are introduced into the fluid medium at a second flow separation location. A phase difference between the first and second periodic disturbances is adjusted to control flow separation of the shear layer as the fluid medium moves over the fluid dynamic body.

Bernoulli's Principle Applied to Brain Fluids: Intracranial Pressure Does Not Drive Cerebral Perfusion or CSF Flow.

PubMed

Schmidt, Eric; Ros, Maxime; Moyse, Emmanuel; Lorthois, Sylvie; Swider, Pascal

2016-01-01

In line with the first law of thermodynamics, Bernoulli's principle states that the total energy in a fluid is the same at all points. We applied Bernoulli's principle to understand the relationship between intracranial pressure (ICP) and intracranial fluids. We analyzed simple fluid physics along a tube to describe the interplay between pressure and velocity. Bernoulli's equation demonstrates that a fluid does not flow along a gradient of pressure or velocity; a fluid flows along a gradient of energy from a high-energy region to a low-energy region. A fluid can even flow against a pressure gradient or a velocity gradient. Pressure and velocity represent part of the total energy. Cerebral blood perfusion is not driven by pressure but by energy: the blood flows from high-energy to lower-energy regions. Hydrocephalus is related to increased cerebrospinal fluid (CSF) resistance (i.e., energy transfer) at various points. Identification of the energy transfer within the CSF circuit is important in understanding and treating CSF-related disorders. Bernoulli's principle is not an abstract concept far from clinical practice. We should be aware that pressure is easy to measure, but it does not induce resumption of fluid flow. Even at the bedside, energy is the key to understanding ICP and fluid dynamics.

Multiphase flow in geometrically simple fracture intersections

USGS Publications Warehouse

Basagaoglu, H.; Meakin, P.; Green, C.T.; Mathew, M.; ,

2006-01-01

A two-dimensional lattice Boltzmann (LB) model with fluid-fluid and solid-fluid interaction potentials was used to study gravity-driven flow in geometrically simple fracture intersections. Simulated scenarios included fluid dripping from a fracture aperture, two-phase flow through intersecting fractures and thin-film flow on smooth and undulating solid surfaces. Qualitative comparisons with recently published experimental findings indicate that for these scenarios the LB model captured the underlying physics reasonably well.

Solids mass flow determination

DOEpatents

Macko, Joseph E.

1981-01-01

Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.

Centrifugal adsorption system

NASA Technical Reports Server (NTRS)

Gonda, Steve R. (Inventor); Tsao, Yow-Min D. (Inventor); Lee, Wenshan (Inventor)

2006-01-01

A gas-liquid separator uses a helical passageway to impart a spiral motion to a fluid passing therethrough. The centrifugal force generated by the spiraling motion urges the liquid component of the fluid radially outward which forces the gas component radially inward. The gas component is then separated through a gas-permeable, liquid-impervious membrane and discharged through a central passageway. A filter material captures target substances contained in the fluid.

Does the endolymph pass through the base of the cupula?

NASA Astrophysics Data System (ADS)

Jijiwa, H.; Watanabe, N.; Hattori, T.; Matuda, F.; Hashiba, M.; Mizuno, Y.; Shindo, M.; Watanabe, S.

2001-08-01

Whether the endolymph of the semicircular canal passes the cupular partition or not was examined using the lateral semicircular canal system of adult pigeons (Columba livia). By applying various pressures by means of injection of a dye solution through the membranous canal, it was found that the dye solution was seen to pass the cupula even under very low pressures when the pressure was increased gradually. When pulled by a magnet, the ultrafine particles of the dextran magnetite contained in the injected fluid were found to pass through the subcupular space without evident increase of the ampullary pressure.

Generating Inviscid and Viscous Fluid Flow Simulations over a Surface Using a Quasi-simultaneous Technique

NASA Technical Reports Server (NTRS)

Sturdza, Peter (Inventor); Martins-Rivas, Herve (Inventor); Suzuki, Yoshifumi (Inventor)

2014-01-01

A fluid-flow simulation over a computer-generated surface is generated using a quasi-simultaneous technique. The simulation includes a fluid-flow mesh of inviscid and boundary-layer fluid cells. An initial fluid property for an inviscid fluid cell is determined using an inviscid fluid simulation that does not simulate fluid viscous effects. An initial boundary-layer fluid property a boundary-layer fluid cell is determined using the initial fluid property and a viscous fluid simulation that simulates fluid viscous effects. An updated boundary-layer fluid property is determined for the boundary-layer fluid cell using the initial fluid property, initial boundary-layer fluid property, and an interaction law. The interaction law approximates the inviscid fluid simulation using a matrix of aerodynamic influence coefficients computed using a two-dimensional surface panel technique and a fluid-property vector. An updated fluid property is determined for the inviscid fluid cell using the updated boundary-layer fluid property.

The 'upstream wake' of swimming and flying animals and its correlation with propulsive efficiency.

PubMed

Peng, Jifeng; Dabiri, John O

2008-08-01

The interaction between swimming and flying animals and their fluid environments generates downstream wake structures such as vortices. In most studies, the upstream flow in front of the animal is neglected. In this study, we demonstrate the existence of upstream fluid structures even though the upstream flow is quiescent or possesses a uniform incoming velocity. Using a computational model, the flow generated by a swimmer (an oscillating flexible plate) is simulated and a new fluid mechanical analysis is applied to the flow to identify the upstream fluid structures. These upstream structures show the exact portion of fluid that is going to interact with the swimmer. A mass flow rate is then defined based on the upstream structures, and a metric for propulsive efficiency is established using the mass flow rate and the kinematics of the swimmer. We propose that the unsteady mass flow rate defined by the upstream fluid structures can be used as a metric to measure and objectively compare the efficiency of locomotion in water and air.

Persistent Homology to describe Solid and Fluid Structures during Multiphase Flow

NASA Astrophysics Data System (ADS)

Herring, A. L.; Robins, V.; Liu, Z.; Armstrong, R. T.; Sheppard, A.

2017-12-01

The question of how to accurately and effectively characterize essential fluid and solid distributions and structures is a long-standing topic within the field of porous media and fluid transport. For multiphase flow applications, considerable research effort has been made to describe fluid distributions under a range of conditions; including quantification of saturation levels, fluid-fluid pressure differences and interfacial areas, and fluid connectivity. Recent research has effectively used topological metrics to describe pore space and fluid connectivity, with researchers demonstrating links between pore-scale nonwetting phase topology to fluid mobilization and displacement mechanisms, relative permeability, fluid flow regimes, and thermodynamic models of multiphase flow. While topology is clearly a powerful tool to describe fluid distribution, topological metrics by definition provide information only on the connectivity of a phase, not its geometry (shape or size). Physical flow characteristics, e.g. the permeability of a fluid phase within a porous medium, are dependent on the connectivity of the pore space or fluid phase as well as the size of connections. Persistent homology is a technique which provides a direct link between topology and geometry via measurement of topological features and their persistence from the signed Euclidean distance transform of a segmented digital image (Figure 1). We apply persistent homology analysis to measure the occurrence and size of pore-scale topological features in a variety of sandstones, for both the dry state and the nonwetting phase fluid during two-phase fluid flow (drainage and imbibition) experiments, visualized with 3D X-ray microtomography. The results provide key insights into the dominant topological features and length scales of a media which control relevant field-scale engineering properties such as fluid trapping, absolute permeability, and relative permeability.

Fluid-cooled heat sink with improved fin areas and efficiencies for use in cooling various devices

DOEpatents

Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant

2015-04-21

The disclosure provides a fluid-cooled heat sink having a heat transfer base and a plurality of heat transfer fins in thermal communication with the heat transfer base, where the heat transfer base and the heat transfer fins form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

Thin-channel electrospray emitter

DOEpatents

Van Berkel, Gary J.

2004-08-31

An electrospray device includes a high voltage electrode chamber. The high voltage electrode chamber includes an inlet for receiving a fluid to be ionized and for directing the fluid into the chamber and at least one electrode having an exposed surface within the chamber. A flow channel directs fluid over a surface of the electrode and out of the chamber. The length of the flow channel over the electrode is greater than the height of the flow channel over the electrode, thereby producing enhanced mass transport to the working electrode resulting in improved electrolysis efficiency. An outlet is provided for transmitting the fluid out from the electrode chamber. A method of creating charged droplets includes flowing a fluid over an electrode where the length over the electrode is greater than the height of the fluid flowing over the electrode.

Meshless Lagrangian SPH method applied to isothermal lid-driven cavity flow at low-Re numbers

NASA Astrophysics Data System (ADS)

Fraga Filho, C. A. D.; Chacaltana, J. T. A.; Pinto, W. J. N.

2018-01-01

SPH is a recent particle method applied in the cavities study, without many results available in the literature. The lid-driven cavity flow is a classic problem of the fluid mechanics, extensively explored in the literature and presenting a considerable complexity. The aim of this paper is to present a solution from the Lagrangian viewpoint for this problem. The discretization of the continuum domain is performed using the Lagrangian particles. The physical laws of mass, momentum and energy conservation are presented by the Navier-Stokes equations. A serial numerical code, written in Fortran programming language, has been used to perform the numerical simulations. The application of the SPH and comparison with the literature (mesh methods and a meshless collocation method) have been done. The positions of the primary vortex centre and the non-dimensional velocity profiles passing through the geometric centre of the cavity have been analysed. The numerical Lagrangian results showed a good agreement when compared to the results found in the literature, specifically for { Re} < 100.00 . Suggestions for improvements in the SPH model presented are listed, in the search for better results for flows with higher Reynolds numbers.

Downhole steam generator with improved preheating, combustion and protection features

DOEpatents

Fox, Ronald L.

1983-01-01

An apparatus for generation of steam in a borehole for penetration into an earth formation wherein feedback preheater means are provided for the fuel and water before entering the combustor assembly. First, combustion gases are conducted from the combustion chamber to locations in proximity to the water and fuel supplies. Secondly, both hot combustion gases and steam are conducted from the borehole back to the water and fuel supply. The water used for conversion to steam is passed in a countercurrent manner through a plurality of annular water flow channels surrounding the combustion chamber. In this manner, the water is preheated, and the combustion chamber is cooled simultaneously, thereby minimizing thermal stresses and deterioration of the walls of the combustion chamber. The water is injected through slotted inlets along the combustion chamber wall to provide an unstable boundary layer and stripping of the water from the wall for efficient steam generation. Pressure responsive doors are provided at the steam outlet of the combustor assembly. The outlet doors and fluid flow functions may be controlled by a diagnostic/control module. The module is positioned in the water flow channel to maintain a relatively constant, controlled temperature.

Non-Darcian flow of shear-thinning fluids through packed beads: Experiments and predictions using Forchheimer's law and Ergun's equation

NASA Astrophysics Data System (ADS)

Rodríguez de Castro, Antonio; Radilla, Giovanni

2017-02-01

The flow of shear-thinning fluids through unconsolidated porous media is present in a number of important industrial applications such as soil depollution, Enhanced Oil Recovery or filtration of polymeric liquids. Therefore, predicting the pressure drop-flow rate relationship in model porous media has been the scope of major research efforts during the last decades. Although the flow of Newtonian fluids through packs of spherical particles is well understood in most cases, much less is known regarding the flow of shear-thinning fluids as high molecular weight polymer aqueous solutions. In particular, the experimental data for the non-Darcian flow of shear-thinning fluids are scarce and so are the current approaches for their prediction. Given the relevance of non-Darcian shear-thinning flow, the scope of this work is to perform an experimental study to systematically evaluate the effects of fluid shear rheology on the flow rate-pressure drop relationships for the non-Darcian flow through different packs of glass spheres. To do so, xanthan gum aqueous solutions with different polymer concentrations are injected through four packs of glass spheres with uniform size under Darcian and inertial flow regimes. A total of 1560 experimental data are then compared with predictions coming from different methods based on the extension of widely used Ergun's equation and Forchheimer's law to the case of shear thinning fluids, determining the accuracy of these predictions. The use of a proper definition for Reynolds number and a realistic model to represent the rheology of the injected fluids results in the porous media are shown to be key aspects to successfully predict pressure drop-flow rate relationships for the inertial shear-thinning flow in packed beads.

New Analysis Scheme of Flow-Acoustic Coupling for Gas Ultrasonic Flowmeter with Vortex near the Transducer.

PubMed

Sun, Yanzhao; Zhang, Tao; Zheng, Dandan

2018-04-10

Ultrasonic flowmeters with a small or medium diameter are widely used in process industries. The flow field disturbance on acoustic propagation caused by a vortex near the transducer inside the sensor as well as the mechanism and details of flow-acoustic interaction are needed to strengthen research. For that reason, a new hybrid scheme is proposed; the theories of computational fluid dynamics (CFD), wave acoustics, and ray acoustics are used comprehensively by a new step-by-step method. The flow field with a vortex near the transducer, and its influence on sound propagation, receiving, and flowmeter performance are analyzed in depth. It was found that, firstly, the velocity and vortex intensity distribution were asymmetric on the sensor cross-section and acoustic path. Secondly, when passing through the vortex zone, the central ray trajectory was deflected significantly. The sound pressure on the central line of the sound path also changed. Thirdly, the pressure deviation becomes larger with as the flow velocity increases. The deviation was up to 17% for different velocity profiles in a range of 0.6 m/s to 53 m/s. Lastly, in comparison to the theoretical value, the relative deviation of the instrument coefficient for the velocity profile with a vortex near the transducer reached up to -17%. In addition, the rationality of the simulation was proved by experiments.

New Analysis Scheme of Flow-Acoustic Coupling for Gas Ultrasonic Flowmeter with Vortex near the Transducer

PubMed Central

Zhang, Tao; Zheng, Dandan

2018-01-01

Ultrasonic flowmeters with a small or medium diameter are widely used in process industries. The flow field disturbance on acoustic propagation caused by a vortex near the transducer inside the sensor as well as the mechanism and details of flow-acoustic interaction are needed to strengthen research. For that reason, a new hybrid scheme is proposed; the theories of computational fluid dynamics (CFD), wave acoustics, and ray acoustics are used comprehensively by a new step-by-step method. The flow field with a vortex near the transducer, and its influence on sound propagation, receiving, and flowmeter performance are analyzed in depth. It was found that, firstly, the velocity and vortex intensity distribution were asymmetric on the sensor cross-section and acoustic path. Secondly, when passing through the vortex zone, the central ray trajectory was deflected significantly. The sound pressure on the central line of the sound path also changed. Thirdly, the pressure deviation becomes larger with as the flow velocity increases. The deviation was up to 17% for different velocity profiles in a range of 0.6 m/s to 53 m/s. Lastly, in comparison to the theoretical value, the relative deviation of the instrument coefficient for the velocity profile with a vortex near the transducer reached up to −17%. In addition, the rationality of the simulation was proved by experiments. PMID:29642577

Turbulence generation through intense kinetic energy sources

NASA Astrophysics Data System (ADS)

Maqui, Agustin F.; Donzis, Diego A.

2016-06-01

Direct numerical simulations (DNS) are used to systematically study the development and establishment of turbulence when the flow is initialized with concentrated regions of intense kinetic energy. This resembles both active and passive grids which have been extensively used to generate and study turbulence in laboratories at different Reynolds numbers and with different characteristics, such as the degree of isotropy and homogeneity. A large DNS database was generated covering a wide range of initial conditions with a focus on perturbations with some directional preference, a condition found in active jet grids and passive grids passed through a contraction as well as a new type of active grid inspired by the experimental use of lasers to photo-excite the molecules that comprise the fluid. The DNS database is used to assert under what conditions the flow becomes turbulent and if so, the time required for this to occur. We identify a natural time scale of the problem which indicates the onset of turbulence and a single Reynolds number based exclusively on initial conditions which controls the evolution of the flow. It is found that a minimum Reynolds number is needed for the flow to evolve towards fully developed turbulence. An extensive analysis of single and two point statistics, velocity as well as spectral dynamics and anisotropy measures is presented to characterize the evolution of the flow towards realistic turbulence.

Device and method for measuring multi-phase fluid flow and density of fluid in a conduit having a gradual bend

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1998-10-27

A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Geothermal state and fluid flow within ODP Hole 843B: results from wireline logging

NASA Astrophysics Data System (ADS)

Wiggins, Sean M.; Hildebrand, John A.; Gieskes, Joris M.

2002-02-01

Borehole fluid temperatures were measured with a wireline re-entry system in Ocean Drilling Program Hole 843B, the site of the Ocean Seismic Network Pilot Experiment. These temperature data, recorded more than 7 years after drilling, are compared to temperature data logged during Leg 136, approximately 1 day after drilling had ceased. Qualitative interpretations of the temperature data suggest that fluid flowed slowly downward in the borehole immediately following drilling, and flowed slowly upward 7 years after drilling. Quantitative analysis suggests that the upward fluid flow rate in the borehole is approximately 1 m/h. Slow fluid flow interpreted from temperature data only, however, requires estimates of other unmeasured physical properties. If fluid flows upward in Hole 843B, it may have led to undesirable noise for the borehole seismometer emplaced in this hole as part of the Ocean Seismic Network Pilot Experiment. Estimates of conductive heat flow from ODP Hole 843B are 51 mW/m 2 for the sediment and the basalt. These values are lower than the most recent Hawaiian Arch seafloor heat flow studies.

Fluidic Oscillator Array for Synchronized Oscillating Jet Generation

NASA Technical Reports Server (NTRS)

Koklu, Mehti (Inventor)

2017-01-01

A fluidic oscillator array includes a plurality of fluidic-oscillator main flow channels. Each main flow channel has an inlet and an outlet. Each main flow channel has first and second control ports disposed at opposing sides thereof, and has a first and a second feedback ports disposed at opposing sides thereof. The feedback ports are located downstream of the control ports with respect to a direction of a fluid flow through the main flow channel. The system also includes a first fluid accumulator in fluid communication with each first control port and each first feedback port, and a second fluid accumulator in fluid communication with each second control port and each second feedback port.

Fluidic Oscillator Array for Synchronized Oscillating Jet Generation

NASA Technical Reports Server (NTRS)

Koklu, Mehti (Inventor)

2016-01-01

A fluidic oscillator array includes a plurality of fluidic-oscillator main flow channels. Each main flow channel has an inlet and an outlet. Each main flow channel has first and second control ports disposed at opposing sides thereof, and has a first and a second feedback ports disposed at opposing sides thereof. The feedback ports are located downstream of the control ports with respect to a direction of a fluid flow through the main flow channel. The system also includes a first fluid accumulator in fluid communication with each first control port and each first feedback port, and a second fluid accumulator in fluid communication with each second control port and each second feedback port.

Magnetic heat pump flow director

NASA Technical Reports Server (NTRS)

Howard, Frank S. (Inventor)

1995-01-01

A fluid flow director is disclosed. The director comprises a handle body and combed-teeth extending from one side of the body. The body can be formed of a clear plastic such as acrylic. The director can be used with heat exchangers such as a magnetic heat pump and can minimize the undesired mixing of fluid flows. The types of heat exchangers can encompass both heat pumps and refrigerators. The director can adjust the fluid flow of liquid or gas along desired flow directions. A method of applying the flow director within a magnetic heat pump application is also disclosed where the comb-teeth portions of the director are inserted into the fluid flow paths of the heat pump.

Exhaust bypass flow control for exhaust heat recovery

DOEpatents

Reynolds, Michael G.

2015-09-22

An exhaust system for an engine comprises an exhaust heat recovery apparatus configured to receive exhaust gas from the engine and comprises a first flow passage in fluid communication with the exhaust gas and a second flow passage in fluid communication with the exhaust gas. A heat exchanger/energy recovery unit is disposed in the second flow passage and has a working fluid circulating therethrough for exchange of heat from the exhaust gas to the working fluid. A control valve is disposed downstream of the first and the second flow passages in a low temperature region of the exhaust heat recovery apparatus to direct exhaust gas through the first flow passage or the second flow passage.

Device and method for measuring fluid flow in a conduit having a gradual bend

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1998-11-10

A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend

DOEpatents

Ortiz, M.G.

1998-02-10

A system is described for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Device and method for measuring fluid flow in a conduit having a gradual bend

DOEpatents

Ortiz, Marcos German; Boucher, Timothy J

1998-01-01

A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend

DOEpatents

Ortiz, Marcos German

1998-01-01

A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Rankine cycle load limiting through use of a recuperator bypass

DOEpatents

Ernst, Timothy C.

2011-08-16

A system for converting heat from an engine into work includes a boiler coupled to a heat source for transferring heat to a working fluid, a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator with one flow path that routes working fluid from the turbine to the condenser, and another flow path that routes liquid working fluid from the condenser to the boiler, the recuperator being configured to transfer heat to the liquid working fluid, and a bypass valve in parallel with the second flow path. The bypass valve is movable between a closed position, permitting flow through the second flow path and an opened position, under high engine load conditions, bypassing the second flow path.

Personal cooling air filtering device

DOEpatents

Klett, James [Knoxville, TN; Conway, Bret [Denver, NC

2002-08-13

A temperature modification system for modifying the temperature of fluids includes at least one thermally conductive carbon foam element, the carbon foam element having at least one flow channel for the passage of fluids. At least one temperature modification device is provided, the temperature modification device thermally connected to the carbon foam element and adapted to modify the temperature of the carbon foam to modify the temperature of fluids flowing through the flow channels. Thermoelectric and/or thermoionic elements can preferably be used as the temperature modification device. A method for the reversible temperature modification of fluids includes the steps of providing a temperature modification system including at least one thermally conductive carbon foam element having flow channels and at least one temperature modification device, and flowing a fluid through the flow channels.

Physical and hydrologic characteristics of Matlacha Pass, southwestern Florida

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

Kane, R.L.; Russell, G.M.

1994-03-01

Matlacha Pass is part of the connected inshore waters of the Charlotte Harbor estuary in southwestern Florida. Bathymetry indicates that depths in the main channel of the pass range from 4 to 14 feet below sea level. The channel averages about 8 feet deep in the northern part of the pass and about 5 feet deep in the southern part. Additionally, depths average about 4 feet in a wide section of the middle of the pass and about 2 feet along the mangrove swamps near the shoreline. Tidal flow within Matlacha Pass varies depending on aquatic vegetation densities, oyster beds,more » and tidal flats. Surface-water runoff occurs primarily during the wet season (May to September), with most of the flow entering the Matlacha Pass through two openings in the spreader canal system near the city of Matlacha. Freshwater flow into the pass from the north Cape Coral spreader canal system averaged 113 cubic feet per second from October 1987 to September 1992. Freshwater inflow from the Aries Canal of the south Cape Coral spreader canal system averaged 14.1 cubic feet per second from October 1989 to September 1992. Specific conductance throughout Matlacha Pass ranged from less than 1,000 to 57,000 microsiemens per centimeter. Specific conductance, collected from a continuous monitoring data logger in the middle of the pass from February to September 1992, averaged 36,000 microsiemens per centimeter at 2 feet below the water surface and 40,000 microsiemens per centimeter at 2 feet above the bottom. During both the wet and dry seasons, specific conductance indicated that the primary mixing of tidal waters and freshwater inflow occurs in the mangrove swamps along the shoreline.« less

Fluid mechanics in fluids at rest.

PubMed

Brenner, Howard

2012-07-01

Using readily available experimental thermophoretic particle-velocity data it is shown, contrary to current teachings, that for the case of compressible flows independent dye- and particle-tracer velocity measurements of the local fluid velocity at a point in a flowing fluid do not generally result in the same fluid velocity measure. Rather, tracer-velocity equality holds only for incompressible flows. For compressible fluids, each type of tracer is shown to monitor a fundamentally different fluid velocity, with (i) a dye (or any other such molecular-tagging scheme) measuring the fluid's mass velocity v appearing in the continuity equation and (ii) a small, physicochemically and thermally inert, macroscopic (i.e., non-Brownian), solid particle measuring the fluid's volume velocity v(v). The term "compressibility" as used here includes not only pressure effects on density, but also temperature effects thereon. (For example, owing to a liquid's generally nonzero isobaric coefficient of thermal expansion, nonisothermal liquid flows are to be regarded as compressible despite the general perception of liquids as being incompressible.) Recognition of the fact that two independent fluid velocities, mass- and volume-based, are formally required to model continuum fluid behavior impacts on the foundations of contemporary (monovelocity) fluid mechanics. Included therein are the Navier-Stokes-Fourier equations, which are now seen to apply only to incompressible fluids (a fact well-known, empirically, to experimental gas kineticists). The findings of a difference in tracer velocities heralds the introduction into fluid mechanics of a general bipartite theory of fluid mechanics, bivelocity hydrodynamics [Brenner, Int. J. Eng. Sci. 54, 67 (2012)], differing from conventional hydrodynamics in situations entailing compressible flows and reducing to conventional hydrodynamics when the flow is incompressible, while being applicable to both liquids and gases.

Correlations for Vapor Nucleating Critical Embryo Parameters

NASA Astrophysics Data System (ADS)

Magnusson, Lars-Erik; Koropchak, John A.; Anisimov, Michael P.; Poznjakovskiy, Valeriy M.; de la Mora, Juan Fernandez

2003-12-01

Condensation nucleation light scattering detection in principle works by converting the effluent of the chromatographic separation into an aerosol and then selectively evaporating the mobile phase, leaving less volatile analytes and nonvolatile impurities as dry aerosol particles. The dry particles produced are then exposed to an environment that is saturated with the vapors of an organic solvent (commonly n-butanol). The blend of aerosol particles and organic vapor is then cooled so that conditions of vapor supersaturation are achieved. In principle, the vapor then condenses onto the dry particles, growing each particle (ideally) from as small as a few nanometers in diameter into a droplet with a diameter up to about 10 μm. The grown droplets are then passed through a beam of light, and the light scattered by the droplets is detected and used as the detector response. This growth and detection step is generally carried out using commercial continuous-flow condensation nucleus counters. In the present research, the possibility of using other fluids than the commonly used n-butanol is investigated. The Kelvin equation and the Nucleation theorem [Anisimov et al. (1978)] are used to evaluate a range of fluids for efficacy of growing small particles by condensation nucleation. Using the available experimental data on vapor nucleation, the correlations of Kelvin diameters (the critical embryo sizes) and the bulk surface tension with dielectric constants of working liquids are found. A simple method for choosing the most efficient fluid, within a class of fluids, for growth of small particles is suggested.

Porous materials for thermal management under extreme conditions.

PubMed

Clyne, T W; Golosnoy, I O; Tan, J C; Markaki, A E

2006-01-15

A brief analysis is presented of how heat transfer takes place in porous materials of various types. The emphasis is on materials able to withstand extremes of temperature, gas pressure, irradiation, etc. i.e. metals and ceramics, rather than polymers. A primary aim is commonly to maximize either the thermal resistance (i.e. provide insulation) or the rate of thermal equilibration between the material and a fluid passing through it (i.e. to facilitate heat exchange). The main structural characteristics concern porosity (void content), anisotropy, pore connectivity and scale. The effect of scale is complex, since the permeability decreases as the structure is refined, but the interfacial area for fluid-solid heat exchange is, thereby, raised. The durability of the pore structure may also be an issue, with a possible disadvantage of finer scale structures being poor microstructural stability under service conditions. Finally, good mechanical properties may be required, since the development of thermal gradients, high fluid fluxes, etc. can generate substantial levels of stress. There are, thus, some complex interplays between service conditions, pore architecture/scale, fluid permeation characteristics, convective heat flow, thermal conduction and radiative heat transfer. Such interplays are illustrated with reference to three examples: (i) a thermal barrier coating in a gas turbine engine; (ii) a Space Shuttle tile; and (iii) a Stirling engine heat exchanger. Highly porous, permeable materials are often made by bonding fibres together into a network structure and much of the analysis presented here is oriented towards such materials.

Concentric catalytic combustor

DOEpatents

Bruck, Gerald J [Oviedo, FL; Laster, Walter R [Oviedo, FL

2009-03-24

A catalytic combustor (28) includes a tubular pressure boundary element (90) having a longitudinal flow axis (e.g., 56) separating a first portion (94) of a first fluid flow (e.g., 24) from a second portion (95) of the first fluid flow. The pressure boundary element includes a wall (96) having a plurality of separate longitudinally oriented flow paths (98) annularly disposed within the wall and conducting respective portions (100, 101) of a second fluid flow (e.g., 26) therethrough. A catalytic material (32) is disposed on a surface (e.g., 102, 103) of the pressure boundary element exposed to at least one of the first and second portions of the first fluid flow.

Microelectromechanical flow control apparatus

DOEpatents

Okandan, Murat [NE Albuquerque, NM

2009-06-02

A microelectromechanical (MEM) flow control apparatus is disclosed which includes a fluid channel formed on a substrate from a first layer of a nonconducting material (e.g. silicon nitride). A first electrode is provided on the first layer of the nonconducting material outside the flow channel; and a second electrode is located on a second layer of the nonconducting material above the first layer. A voltage applied between the first and second electrodes deforms the fluid channel to increase its cross-sectional size and thereby increase a flow of a fluid through the channel. In certain embodiments of the present invention, the fluid flow can be decreased or stopped by applying a voltage between the first electrode and the substrate. A peristaltic pumping of the fluid through the channel is also possible when the voltage is applied in turn between a plurality of first electrodes and the substrate. A MEM flow control assembly can also be formed by providing one or more MEM flow control devices on a common substrate together with a submicron filter. The MEM flow control assembly can optionally include a plurality of pressure sensors for monitoring fluid pressure and determining flow rates through the assembly.

Hybrid: Passing

Science.gov Websites

accelerating or when additional power is needed, the gasoline engine and electric motor are both used to propel . The car is passing another vehicle. There are red arrows flowing from the gasoline engine to the front wheels. There are blue arrows flowing from the battery to the electric engine to the front wheels. Main

Analysis of the NASA/MSFC Airborne Doppler Lidar results from San Gorgonio Pass, California

NASA Technical Reports Server (NTRS)

Cliff, W. C.; Skarda, J. R.; Renne, D. S.; Sandusky, W. F.

1984-01-01

Two days during July of 1981 the NASA/MSFC Airborne Doppler Lidar System (ADLS) was flown aboard the NASA/AMES Convair 990 on the east side of San Gorgonio Pass California, near Palm Springs, to measure and investigate the accelerated atmospheric wind field discharging from the pass. The vertical and horizontal extent of the fast moving atmospheric flow discharging from the San Gorgonio Pass were examined. Conventional ground measurements were also taken during the tests to assist in validating the ADLS results. This particular region is recognized as a high wind resource region and, as such, a knowledge of the horizontal and vertical extent of this flow was of interest for wind energy applications. The statistics of the atmospheric flow field itself as it discharges from the pass and then spreads out over the desert were also of scientific interests. This data provided the first spatial data for ensemble averaging of spatial correlations to compute longitudinal and lateral integral length scales in the longitudinal and lateral directions for both components.

Numerical modeling of fluid migration in subduction zones

NASA Astrophysics Data System (ADS)

Walter, M. J.; Quinteros, J.; Sobolev, S. V.

2015-12-01

It is well known that fluids play a crucial role in subduction evolution. For example, mechanical weakening along tectonic interfaces, due to high fluid pressure, may enable oceanic subduction. Hence, the fluid content seems to be a critical parameter for subduction initiation. Studies have also shown a correlation between the location of slab dehydration and intermediate seismic activity. Furthermore, expelled fluids from the subduction slab affect the melting temperature, consequently, contributing to partial melting in the wedge above the down-going plate and extensive volcanism. In summary, fluids have a great impact on tectonic processes and therefore should be incorporated into geodynamic numerical models. Here we use existing approaches to couple and solve fluid flow equations in the SLIM-3D thermo-mechanical code. SLIM-3D is a three-dimensional thermo-mechanical code capable of simulating lithospheric deformation with elasto-visco-plastic rheology. It has been successfully applied to model geodynamic processes at different tectonic settings, including subduction zones. However, although SLIM-3D already includes many features, fluid migration has not been incorporated into the model yet. To this end, we coupled solid and fluid flow assuming that fluids flow through a porous and deformable solid. Thereby, we introduce a two-phase flow into the model, in which the Stokes flow is coupled with the Darcy law for fluid flow. Ultimately, the evolution of porosity is governed by a compaction pressure and the advection of the porous solid. We show the details of our implementation of the fluid flow into the existing thermo-mechanical finite element code and present first results of benchmarks and experiments. We are especially interested in the coupling of subduction processes and the evolution of the magmatic arc. Thereby, we focus on the key factors controlling magma emplacement and its influence on subduction processes.

Numerical Temperature And Fluid-Flow Modelling For The Topographic Effects On Hydrothermal Circulation; A case study in Lucy Strike Vent Field

NASA Astrophysics Data System (ADS)

Erçetin, Engin; Düşünür Doǧan, Doǧa

2017-04-01

The aim of the study is to present a numerical temperature and fluid-flow modelling for the topographic effects on hydrothermal circulation. Bathymetry can create a major disturbance on fluid flow pattern. ANSYS Fluent Computational fluid dynamics software is used for simulations. Coupled fluid flow and temperature quations are solved using a 2-Dimensional control volume finite difference approach. Darcy's law is assumed to hold, the fluid is considered to be anormal Boussinesq incompressible fluid neglecting inertial effects. Several topographic models were simulated and both temperature and fluid flow calculations obtained for this study. The preliminary simulations examine the effect of a ingle bathymetric high on a single plume and the secondary study of simulations investigates the effect of multiple bathymetric highs on multiple plume. The simulations were also performed for the slow spreading Lucky Strike segment along the Mid-Atlantic Ridge (MAR), one of the best studied regions along the MAR, where a 3.4 km deep magma chamber extending 6 km along-axis is found at its center. The Lucky Strike segment displays a transitional morphology between that of the FAMOUS - North FAMOUS segments, which are characterized by well-developed axial valleys typical of slow-spreading segments, and that of the Menez Gwen segment, characterized by an axial high at the segment center. Lucky Strike Segment hosts a central volcano and active vent field located at the segment center and thus constitutes an excellent case study to simulate the effects of bathymetry on fluid flow. Results demonstrate that bathymetric relief has an important influence on hydrothermal flow. Subsurface pressure alterations can be formed by bathymetric highs, for this reason, bathymetric relief ought to be considered while simulating hydrothermal circulation systems. Results of this study suggest the dominant effect of bathymetric highs on fluid flow pattern and Darcy velocities will be presented. Keywords: Hydrothermal Circulation, Lucky Strike, Bathymetry - Topography, Vent Location, Fluid Flow, Numerical Modelling

A system for measuring bubble voidage and frequency around tubes immersed in a fluidized bed of particles

NASA Astrophysics Data System (ADS)

Whitty, Kevin J.; Siddoway, Michael

2010-07-01

Gas-solid fluidized beds are common in chemical processing and energy production industries. These types of reactors frequently have banks of tubes immersed within the bed to provide heating or cooling, and it is important that the fluid dynamics within these bundles is efficient and uniform. This paper presents a simple, low-cost method for quantitatively analyzing the behavior of gas bubbles within banks of tubes in a fluidized bed cold flow model. Two probes, one containing an infrared emitter and one containing an infrared (IR) detector, are placed into adjacent glass tubes such that the emitter and detector face each other. As bubbles pass through the IR beam, the detector signal increases due to less solid material blocking the path between the emitter and detector. By calibrating the signal response to known voidage of the material, one can measure the bubble voidage at various locations within the tube bundle. The rate and size of bubbles passing through the beam can also be determined by high frequency data collection and subsequent analysis. This technique allows one to develop a map of bubble voidage within a fluidized bed, which can be useful for model validation and system optimization.

Pressurized fluidized bed reactor and a method of operating the same

DOEpatents

Isaksson, J.

1996-02-20

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

Pressurized fluidized bed reactor and a method of operating the same

DOEpatents

Isaksson, Juhani

1996-01-01

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

A system for measuring bubble voidage and frequency around tubes immersed in a fluidized bed of particles.

PubMed

Whitty, Kevin J; Siddoway, Michael

2010-07-01

Gas-solid fluidized beds are common in chemical processing and energy production industries. These types of reactors frequently have banks of tubes immersed within the bed to provide heating or cooling, and it is important that the fluid dynamics within these bundles is efficient and uniform. This paper presents a simple, low-cost method for quantitatively analyzing the behavior of gas bubbles within banks of tubes in a fluidized bed cold flow model. Two probes, one containing an infrared emitter and one containing an infrared (IR) detector, are placed into adjacent glass tubes such that the emitter and detector face each other. As bubbles pass through the IR beam, the detector signal increases due to less solid material blocking the path between the emitter and detector. By calibrating the signal response to known voidage of the material, one can measure the bubble voidage at various locations within the tube bundle. The rate and size of bubbles passing through the beam can also be determined by high frequency data collection and subsequent analysis. This technique allows one to develop a map of bubble voidage within a fluidized bed, which can be useful for model validation and system optimization.

Composition Pulse Time-Of-Flight Mass Flow Sensor

DOEpatents

Mosier, Bruce P.; Crocker, Robert W.; Harnett, Cindy K. l

2004-01-13

A device for measuring fluid flow rates over a wide range of flow rates (<1 nL/min to >10 .mu.L/min) and at pressures at least as great as 10,000 psi. The invention is particularly adapted for use in microfluidic systems. The device operates by producing compositional variations in the fluid, or pulses, that are subsequently detected downstream from the point of creation to derive a flow rate. Each pulse, comprising a small fluid volume, whose composition is different from the mean composition of the fluid, can be created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species. Measurements of the conductivity of the fluid can be used to detect the arrival time of the pulses, from which the fluid flow rate can be determined

Fluid-cooled heat sink for use in cooling various devices

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

Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth

The disclosure provides a fluid-cooled heat sink having a heat transfer base, a shroud, and a plurality of heat transfer fins in thermal communication with the heat transfer base and the shroud, where the heat transfer base, heat transfer fins, and the shroud form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop ofmore » the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.« less

Multiscale Modeling of Multiphase Fluid Flow

DTIC Science & Technology

2016-08-01

the disparate time and length scales involved in modeling fluid flow and heat transfer. Molecular dynamics simulations were carried out to provide a...fluid dynamics methods were used to investigate the heat transfer process in open-cell micro-foam with phase change material; enhancement of natural...Computational fluid dynamics, Heat transfer, Phase change material in Micro-foam, Molecular Dynamics, Multiphase flow, Multiscale modeling, Natural

Bone tissue engineering: the role of interstitial fluid flow

NASA Technical Reports Server (NTRS)

Hillsley, M. V.; Frangos, J. A.

1994-01-01

It is well established that vascularization is required for effective bone healing. This implies that blood flow and interstitial fluid (ISF) flow are required for healing and maintenance of bone. The fact that changes in bone blood flow and ISF flow are associated with changes in bone remodeling and formation support this theory. ISF flow in bone results from transcortical pressure gradients produced by vascular and hydrostatic pressure, and mechanical loading. Conditions observed to alter flow rates include increases in venous pressure in hypertension, fluid shifts occurring in bedrest and microgravity, increases in vascularization during the injury-healing response, and mechanical compression and bending of bone during exercise. These conditions also induce changes in bone remodeling. Previously, we hypothesized that interstitial fluid flow in bone, and in particular fluid shear stress, serves to mediate signal transduction in mechanical loading- and injury-induced remodeling. In addition, we proposed that a lack or decrease of ISF flow results in the bone loss observed in disuse and microgravity. The purpose of this article is to review ISF flow in bone and its role in osteogenesis.

Monitoring Subsurface Fluid Flow Using Perfluorocarbon Tracers: Another Tool Potentially Available for Subsurface Fluid Flow Assessments

EPA Pesticide Factsheets

Perfluorocarbon Tracers (PFTs) Complement stable Isotopes and Geochemistry for Verifying, Assessing or Modeling Fluid Flow. Geochemistry, Isotopes and PFT’s complement Geophysics to monitor and verify plume movement, leakage to shallow aquifers or surface

Low pressure drop, multi-slit virtual impactor

DOEpatents

Bergman, Werner

2002-01-01

Fluid flow is directed into a multiplicity of slit nozzles positioned so that the fluid flow is directed into a gap between the nozzles and (a) a number of receiving chambers and (b) a number of exhaust chambers. The nozzles and chambers are select so that the fluid flow will be separated into a first particle flow component with larger and a second particle flow component with the smaller particles.

A Parallel-Plate Flow Chamber for Mechanical Characterization of Endothelial Cells Exposed to Laminar Shear Stress

PubMed Central

Wong, Andrew K.; LLanos, Pierre; Boroda, Nickolas; Rosenberg, Seth R.; Rabbany, Sina Y.

2017-01-01

Shear stresses induced by laminar fluid flow are essential to properly recapitulate the physiological microenvironment experienced by endothelial cells (ECs). ECs respond to these stresses via mechanotransduction by modulating their phenotype and biomechanical characteristics, which can be characterized by Atomic Force Microscopy (AFM). Parallel Plate Flow Chambers (PPFCs) apply unidirectional laminar fluid flow to EC monolayers in vitro. Since ECs in sealed PPFCs are inaccessible to AFM probes, cone-and-plate viscometers (CPs) are commonly used to apply shear stress. This paper presents a comparison of the efficacies of both methods. Computational Fluid Dynamic simulation and validation testing using EC responses as a metric have indicated limitations in the use of CPs to apply laminar shear stress. Monolayers subjected to laminar fluid flow in a PPFC respond by increasing cortical stiffness, elongating, and aligning filamentous actin in the direction of fluid flow to a greater extent than CP devices. Limitations using CP devices to provide laminar flow across an EC monolayer suggest they are better suited when studying EC response for disturbed flow conditions. PPFC platforms allow for exposure of ECs to laminar fluid flow conditions, recapitulating cellular biomechanical behaviors, whereas CP platforms allow for mechanical characterization of ECs under secondary flow. PMID:28989541

Composition pulse time-of-flight mass flow sensor

DOEpatents

Harnett, Cindy K [Livermore, CA; Crocker, Robert W [Fremont, CA; Mosier, Bruce P [San Francisco, CA; Caton, Pamela F [Berkeley, CA; Stamps, James F [Livermore, CA

2007-06-05

A device for measuring fluid flow rates over a wide range of flow rates (<1 nL/min to >10 .mu.L/min) and at pressures at least as great as 2,000 psi. The invention is particularly adapted for use in microfluidic systems. The device operates by producing compositional variations in the fluid, or pulses, that are subsequently detected downstream from the point of creation to derive a flow rate. Each pulse, comprising a small fluid volume, whose composition is different from the mean composition of the fluid, can be created by electrochemical means, such as by electrolysis of a solvent, electrolysis of a dissolved species, or electrodialysis of a dissolved ionic species. Measurements of the conductivity of the fluid can be used to detect the arrival time of the pulses, from which the fluid flow rate can be determined. A pair of spaced apart electrodes can be used to produce the electrochemical pulse. In those instances where it is desired to measure a wide range of fluid flow rates a three electrode configuration in which the electrodes are spaced at unequal distances has been found to be desirable.

Unsteady magnetohydrodynamics micropolar fluid in boundary layer flow past a sphere influenced by magnetic fluid

NASA Astrophysics Data System (ADS)

Pratomo, Rizky Verdyanto; Widodo, Basuki; Adzkiya, Dieky

2017-12-01

Research about fluid flow was very interesting because have a lot of advantages and it can be applied in many aspects of life. The study on fluid flow which is now widely studied is on magnetohydrodynamic (MHD). Magnetohydrodynamic is a conductive and electrical in a magnetic field. This paper considers the effect of unsteady magnetic fields on the flow of magneto-hydrodynamic fluid on the boundary layer that flows past a sphere in micropolar fluid influenced by magnetic field. Our approach is as follows. First, we construct a mathematical model and then the system of equations obtained will be solved numerically using the Keller-Box scheme. Then the system is simulated to assess its effect on the fluid flow velocity profile and the profile of microrotation particles. The result of this research indicates, that when the magnetic parameters increase, then velocity profile increases. If material parameters increase, then velocity profile decreases and magnetic parameters increase for n = 0. For n = 0.5, if magnetic parameters increase, then microrotation profile decreases.

LOx breathing system with gas permeable-liquid impermeable heat exchange and delivery hose

DOEpatents

Hall, M.N.

1996-04-30

Life support apparatus is composed of: a garment for completely enclosing a wearer and constructed for preventing passage of gas from the environment surrounding the garment; a portable receptacle holding a quantity of an oxygen-containing fluid in liquid state, the fluid being in a breathable gaseous state when at standard temperature and pressure; a fluid flow member secured within the garment and coupled to the receptacle for conducting the fluid in liquid state from the receptacle to the interior of the garment; and a fluid flow control device connected for causing fluid to flow from the receptacle to the fluid flow member at a rate determined by the breathable air requirement of the wearer, wherein fluid in liquid state is conducted into the interior of the garment at a rate to be vaporized and heated to a breathable temperature by body heat produced by the wearer. 6 figs.

Facilitatory effect of AC-iontophoresis of lidocaine hydrochloride on the permeability of human enamel and dentine in extracted teeth.

PubMed

Ikeda, Hideharu; Suda, Hideaki

2013-04-01

The objectives of the present study were to quantitatively evaluate chemical permeability through human enamel/dentine using conductometry and to clarify if alternating current (AC) iontophoresis facilitates such permeability. Electrical impedance of different concentrations of lidocaine hydrochloride was measured using a bipolar platinum impedance probe. A quadratic curve closely fitted to the response functions between conductance and lidocaine hydrochloride. For analysis of the passage of lidocaine hydrochloride through human enamel/dentine, eight premolars that were extracted for orthodontic treatment were sectioned at the cemento-enamel junction. The tooth crowns were held between two chambers with a double O-ring. The enamel-side chamber was filled with lidocaine hydrochloride, and the pulp-side chamber was filled with extrapure water. Two platinum plate electrodes were set at the end of each chamber to pass alternating current. A simulated interstitial pulp pressure was applied to the pulp-side chamber. The change in the concentration of lidocaine hydrochloride in the pulp-side chamber was measured every 2min using a platinum recording probe positioned at the centre of the pulp-side chamber. Passive entry without iontophoresis was used as a control. The level of lidocaine hydrochloride that passed through enamel/dentine against the dentinal fluid flow increased with time. Electrical conductance (G, mho) correlated closely to the concentration (x, mmol/L) of lidocaine hydrochloride (G=2.16x(2)+0.0289x+0.000376, r(2)=0.999). Lidocaine hydrochloride can pass through enamel/dentine. Conductometry showed that the level of lidocaine hydrochloride that passed through enamel/dentine was increased by AC iontophoresis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Unbalanced-flow, fluid-mixing plug with metering capabilities

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Van Buskirk, Paul D. (Inventor)

2009-01-01

A fluid mixer plug has holes formed therethrough such that a remaining portion is closed to fluid flow. The plug's inlet face defines a central circuit region and a ring-shaped region with the ring-shaped region including at least some of the plug's remaining portion so-closed to fluid flow. This remaining portion or closed region at each radius R of the ring shaped region satisfies a radius independent, flow-based relationship. Entry openings are defined in the plug's inlet face in correspondence with the holes. The entry openings define an open flow area at each radius of the ring-shaped region. The open flow area at each such radius satisfies the inverse of the flow-based relationship defining the closed regions of the plug.

Axisymmetric flows from fluid injection into a confined porous medium

NASA Astrophysics Data System (ADS)

Guo, Bo; Zheng, Zhong; Celia, Michael A.; Stone, Howard A.

2016-02-01

We study the axisymmetric flows generated from fluid injection into a horizontal confined porous medium that is originally saturated with another fluid of different density and viscosity. Neglecting the effects of surface tension and fluid mixing, we use the lubrication approximation to obtain a nonlinear advection-diffusion equation that describes the time evolution of the sharp fluid-fluid interface. The flow behaviors are controlled by two dimensionless groups: M, the viscosity ratio of displaced fluid relative to injected fluid, and Γ, which measures the relative importance of buoyancy and fluid injection. For this axisymmetric geometry, the similarity solution involving R2/T (where R is the dimensionless radial coordinate and T is the dimensionless time) is an exact solution to the nonlinear governing equation for all times. Four analytical expressions are identified as asymptotic approximations (two of which are new solutions): (i) injection-driven flow with the injected fluid being more viscous than the displaced fluid (Γ ≪ 1 and M < 1) where we identify a self-similar solution that indicates a parabolic interface shape; (ii) injection-driven flow with injected and displaced fluids of equal viscosity (Γ ≪ 1 and M = 1), where we find a self-similar solution that predicts a distinct parabolic interface shape; (iii) injection-driven flow with a less viscous injected fluid (Γ ≪ 1 and M > 1) for which there is a rarefaction wave solution, assuming that the Saffman-Taylor instability does not occur at the reservoir scale; and (iv) buoyancy-driven flow (Γ ≫ 1) for which there is a well-known self-similar solution corresponding to gravity currents in an unconfined porous medium [S. Lyle et al. "Axisymmetric gravity currents in a porous medium," J. Fluid Mech. 543, 293-302 (2005)]. The various axisymmetric flows are summarized in a Γ-M regime diagram with five distinct dynamic behaviors including the four asymptotic regimes and an intermediate regime. The implications of the regime diagram are discussed using practical engineering projects of geological CO2 sequestration, enhanced oil recovery, and underground waste disposal.

Coaxial screen filter

DOEpatents

Schneider, William R.

1989-01-01

Methods and apparatus for removing a pollutant such as dust (33) from a fluid stream (34). A nested array of fibers (35) is provided in a substantially annular container (36) having openings in its inner (32) and outer (31) cylindrical sides of such size as to retain the fibers (35) within the container while permitting fluid (34) to pass through easily, and the pollutant-containing fluid stream (34) is passed through at least a substantial portion of the container (36) from a region (37) outside the outer side (31) to a region (38) inside the inner side (32). Thus a substantial fraction of the pollutant (33) is separated from the fluid stream (34) in a portion of the nested array (35) generally nearer to the outer side (31) of the container (36) than to the inner side (31). From time to time the container (36) is rotated about its axis to remove a substantial fraction of the separated pollutant (33) from the nested array (35), by tumbling action and by the force of gravity, through the openings in the outer side (31) of the container (36). To assist in this removal, purging fluid (41) may be directed back through the container (36) from the inner side (32) during the tumbling.

Modification of equation of motion of fluid-conveying pipe for laminar and turbulent flow profiles

NASA Astrophysics Data System (ADS)

Guo, C. Q.; Zhang, C. H.; Païdoussis, M. P.

2010-07-01

Considering the non-uniformity of the flow velocity distribution in fluid-conveying pipes caused by the viscosity of real fluids, the centrifugal force term in the equation of motion of the pipe is modified for laminar and turbulent flow profiles. The flow-profile-modification factors are found to be 1.333, 1.015-1.040 and 1.035-1.055 for laminar flow in circular pipes, turbulent flow in smooth-wall circular pipes and turbulent flow in rough-wall circular pipes, respectively. The critical flow velocities for divergence in the above-mentioned three cases are found to be 13.4%, 0.74-1.9% and 1.7-2.6%, respectively, lower than that with plug flow, while those for flutter are even lower, which could reach 36% for the laminar flow profile. By introducing two new concepts of equivalent flow velocity and equivalent mass, fluid-conveying pipe problems with different flow profiles can be solved with the equation of motion for plug flow.

Thermally conductive porous element-based recuperators

NASA Technical Reports Server (NTRS)

Du, Jian Hua (Inventor); Chow, Louis C (Inventor); Lin, Yeong-Ren (Inventor); Wu, Wei (Inventor); Kapat, Jayanta (Inventor); Notardonato, William U. (Inventor)

2012-01-01

A heat exchanger includes at least one hot fluid flow channel comprising a first plurality of open cell porous elements having first gaps there between for flowing a hot fluid in a flow direction and at least one cold fluid flow channel comprising a second plurality of open cell porous elements having second gaps therebetween for flowing a cold fluid in a countercurrent flow direction relative to the flow direction. The thermal conductivity of the porous elements is at least 10 W/mK. A separation member is interposed between the hot and cold flow channels for isolating flow paths associated these flow channels. The first and second plurality of porous elements at least partially overlap one another to form a plurality of heat transfer pairs which transfer heat from respective ones of the first porous elements to respective ones of the second porous elements through the separation member.

Miniaturized pressurization system

DOEpatents

Whitehead, John C.; Swink, Don G.

1991-01-01

The invention uses a fluid stored at a low pressure and provides the fluid at a high pressure. The invention allows the low pressure fluid to flow to a fluid bore of a differential pump and from the pump to a fluid pressure regulator. After flowing through the regulator the fluid is converted to a gas which is directed to a gas bore of the differential pump. By controlling the flow of gas entering and being exhausted from the gas bore, the invention provides pressure to the fluid. By setting the regulator, the high pressure fluid can be set at predetermined values. Because the invention only needs a low pressure fluid, the inventive apparatus has a low mass, and therefore would be useful in rocket propulsion systems.

Intracellular fluid flow in rapidly moving cells

PubMed Central

Keren, Kinneret; Yam, Patricia T.; Kinkhabwala, Anika; Mogilner, Alex; Theriot, Julie A.

2010-01-01

Cytosolic fluid dynamics have been implicated in cell motility1–5 because of the hydrodynamic forces they induce and because of their influence on transport of components of the actin machinery to the leading edge. To investigate the existence and the direction of fluid flow in rapidly moving cells, we introduced inert quantum dots into the lamellipodia of fish epithelial keratocytes and analysed their distribution and motion. Our results indicate that fluid flow is directed from the cell body towards the leading edge in the cell frame of reference, at about 40% of cell speed. We propose that this forward-directed flow is driven by increased hydrostatic pressure generated at the rear of the cell by myosin contraction, and show that inhibition of myosin II activity by blebbistatin reverses the direction of fluid flow and leads to a decrease in keratocyte speed. We present a physical model for fluid pressure and flow in moving cells that quantitatively accounts for our experimental data. PMID:19767741

Design and Development of Low-Cost Water Tunnel for Educational Purpose

NASA Astrophysics Data System (ADS)

Zahari, M.; Dol, S. S.

2015-04-01

The hydrodynamic behaviour of immersed body is essential in fluid dynamics study. Water tunnel is an example of facility required to provide a controlled condition for fluid flow research. The operational principle of water tunnel is quite similar to the wind tunnel but with different working fluid and higher flow-pumping capacity. Flow visualization in wind tunnel is more difficult to conduct as turbulent flows in wind dissipate quickly whilst water tunnel is more suitable for such purpose due to higher fluid viscosity and wide variety of visualization techniques can be employed. The present work focusses on the design and development of open flow water tunnel for the purpose of studying vortex-induced vibration from turbulent vortex shedding phenomenon. The water tunnel is designed to provide a steady and uniform flow speed within the test section area. Construction details are discussed for development of low-cost water tunnel for quantitative and qualitative fluid flow measurements. The water tunnel can also be used for educational purpose such as fluid dynamics class activity to provide quick access to visualization medium for better understanding of various turbulence motion learnt in class.

MANUFACTURE OF UF$sub 4$

DOEpatents

Calcott, W.S.

1959-10-13

The manufacture of uranium tetrafluoride from urarium dioxide is described. Uranium dioxide is heated to about 500 deg C in a reactor. Anhydrous hydrogen fluoride is passed through the reactor in contact with uranium dioxide for several hours, the flow of hydrogen fluoride is discontinued, and hydrogen passed through the reactor for less than an hour. The flow of hydrogen fluoride is resumed for several hours, and then nitrogen is passed for a few minutes to expel unreacted hydrogen fluoride as water vapor. The reactor is cooled to room temperature and the uranium tetrafluoride removed.

Axial compartmentation of descending and ascending thin limbs of Henle's loops

PubMed Central

Westrick, Kristen Y.; Serack, Bradley; Dantzler, William H.

2013-01-01

In the inner medulla, radial organization of nephrons and blood vessels around collecting duct (CD) clusters leads to two lateral interstitial regions and preferential intersegmental fluid and solute flows. As the descending (DTLs) and ascending thin limbs (ATLs) pass through these regions, their transepithelial fluid and solute flows are influenced by variable transepithelial solute gradients and structure-to-structure interactions. The goal of this study was to quantify structure-to-structure interactions, so as to better understand compartmentation and flows of transepithelial water, NaCl, and urea and generation of the axial osmotic gradient. To accomplish this, we determined lateral distances of AQP1-positive and AQP1-negative DTLs and ATLs from their nearest CDs, so as to gauge interactions with intercluster and intracluster lateral regions and interactions with interstitial nodal spaces (INSs). DTLs express reduced AQP1 and low transepithelial water permeability along their deepest segments. Deep AQP1-null segments, prebend segments, and ATLs lie equally near to CDs. Prebend segments and ATLs abut CDs and INSs throughout much of their descent and ascent, respectively; however, the distal 30% of ATLs of the longest loops lie distant from CDs as they approach the outer medullary boundary and have minimal interaction with INSs. These relationships occur regardless of loop length. Finally, we show that ascending vasa recta separate intercluster AQP1-positive DTLs from descending vasa recta, thereby minimizing dilution of gradients that drive solute secretion. We hypothesize that DTLs and ATLs enter and exit CD clusters in an orchestrated fashion that is important for generation of the corticopapillary solute gradient by minimizing NaCl and urea loss. PMID:23195680

Axial compartmentation of descending and ascending thin limbs of Henle's loops.

PubMed

Westrick, Kristen Y; Serack, Bradley; Dantzler, William H; Pannabecker, Thomas L

2013-02-01

In the inner medulla, radial organization of nephrons and blood vessels around collecting duct (CD) clusters leads to two lateral interstitial regions and preferential intersegmental fluid and solute flows. As the descending (DTLs) and ascending thin limbs (ATLs) pass through these regions, their transepithelial fluid and solute flows are influenced by variable transepithelial solute gradients and structure-to-structure interactions. The goal of this study was to quantify structure-to-structure interactions, so as to better understand compartmentation and flows of transepithelial water, NaCl, and urea and generation of the axial osmotic gradient. To accomplish this, we determined lateral distances of AQP1-positive and AQP1-negative DTLs and ATLs from their nearest CDs, so as to gauge interactions with intercluster and intracluster lateral regions and interactions with interstitial nodal spaces (INSs). DTLs express reduced AQP1 and low transepithelial water permeability along their deepest segments. Deep AQP1-null segments, prebend segments, and ATLs lie equally near to CDs. Prebend segments and ATLs abut CDs and INSs throughout much of their descent and ascent, respectively; however, the distal 30% of ATLs of the longest loops lie distant from CDs as they approach the outer medullary boundary and have minimal interaction with INSs. These relationships occur regardless of loop length. Finally, we show that ascending vasa recta separate intercluster AQP1-positive DTLs from descending vasa recta, thereby minimizing dilution of gradients that drive solute secretion. We hypothesize that DTLs and ATLs enter and exit CD clusters in an orchestrated fashion that is important for generation of the corticopapillary solute gradient by minimizing NaCl and urea loss.

A computational fluid dynamics modeling study of guide walls for downstream fish passage

USGS Publications Warehouse

Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

2017-01-01

A partial-depth, impermeable guidance structure (or guide wall) for downstream fish passage is typically constructed as a series of panels attached to a floating boom and anchored across a water body (e.g. river channel, reservoir, or power canal). The downstream terminus of the wall is generally located nearby to a fish bypass structure. If guidance is successful, the fish will avoid entrainment in a dangerous intake structure (i.e. turbine intakes) while passing from the headpond to the tailwater of a hydroelectric facility through a safer passage route (i.e. the bypass). The goal of this study is to determine the combination of guide wall design parameters that will most likely increase the chance of surface-oriented fish being successfully guided to the bypass. To evaluate the flow field immediately upstream of a guide wall, a parameterized computational fluid dynamics model of an idealized power canal was constructed in © ANSYS Fluent v 14.5 (ANSYS Inc., 2012). The design parameters investigated were the angle and depth of the guide wall and the average approach velocity in the power canal. Results call attention to the importance of the downward to sweeping flow ratio and demonstrate how a change in guide wall depth and angle can affect this important hydraulic cue to out-migrating fish. The key findings indicate that a guide wall set at a small angle (15° is the minimum in this study) and deep enough such that sweeping flow dominant conditions prevail within the expected vertical distribution of fish approaching the structure will produce hydraulic conditions that are more likely to result in effective passage.

Computational modelling of the flow of viscous fluids in carbon nanotubes

NASA Astrophysics Data System (ADS)

Khosravian, N.; Rafii-Tabar, H.

2007-11-01

Carbon nanotubes will have extensive application in all areas of nano-technology, and in particular in the field of nano-fluidics, wherein they can be used for molecular separation, nano-scale filtering and as nano-pipes for conveying fluids. In the field of nano-medicine, nanotubes can be functionalized with various types of receptors to act as bio-sensors for the detection and elimination of cancer cells, or be used as bypasses and even neural connections. Modelling fluid flow inside nanotubes is a very challenging problem, since there is a complex interplay between the motion of the fluid and the stability of the walls. A critical issue in the design of nano-fluidic devices is the induced vibration of the walls, due to the fluid flow, which can promote structural instability. It has been established that the resonant frequencies depend on the flow velocity. We have studied, for the first time, the flow of viscous fluids through multi-walled carbon nanotubes, using the Euler-Bernoulli classical beam theory to model the nanotube as a continuum structure. Our aim has been to compute the effect of the fluid flow on the structural stability of the nanotubes, without having to consider the details of the fluid-walls interaction. The variations of the resonant frequencies with the flow velocity are obtained for both unembedded nanotubes, and when they are embedded in an elastic medium. It is found that a nanotube conveying a viscous fluid is more stable against vibration-induced buckling than a nanotube conveying a non-viscous fluid, and that the aspect ratio plays the same role in both cases.

The two-dimensional pattern of metamorphic fluid flow at Mary Kathleen, Australia: Fluid focusing, transverse dispersion, and implications for modeling fluid flow

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

Cartwright, I.

The pattern of [delta][sup 18]O values in layered Corella calc-silicate rocks adjacent to a scapolitized metadolerite dike at Timberu in the Mary Kathleen fold belt illustrates some of the complexities of two-dimensional metamorphic fluid flow. Fluids flowing from the dike ([delta][sup 18]O = 9-10%) into the calc-silicate rocks lowered calcite [delta][sup 18]O values form 19-20% to as low as 10.3%. Time-integrate advectite fluid fluxes varied from 0.72 to > 8.1 m[sup 3]/m[sup 2] over a 4.5-m lateral distance, and there are two distinct channels of higher fluid flux. If the duration of fluid flow was similar across the outcrop, intrinsicmore » permeabilities varied laterally by at least an order of magnitude. Fluid flow was largely focused across lithological layering, with rare excursions parallel to layering, suggesting that (up to 1 m) to those at the isotopic front ([approximately]1.2 m), indicating that the coefficients of transverse and longitudinal dispersion are of similar orders of magnitude. Localities in other terrains probably show similar complex patterns of isotopic resetting that in two dimensions correspond to the predictions of the advective-dispersive transport models, but which are difficult to interpret using a one-dimensional analysis. Transverse dispersion during channeled fluid flow will potentially reset O-isotope ratios adjacent to the channels and cause decoupling of geochemical parameters during advective and dispersive transport. 43 refs., 5 figs., 2 tabs.« less

Value for controlling flow of cryogenic fluid

DOEpatents

Knapp, Philip A.

1996-01-01

A valve is provided for accurately controlling the flow of cryogenic fluids such as liquid nitrogen. The valve comprises a combination of disc and needle valves affixed to a valve stem in such a manner that the disc and needle are free to rotate about the stem, but are constrained in lateral and vertical movements. This arrangement provides accurate and precise fluid flow control and positive fluid isolation.

Poiseuille equation for steady flow of fractal fluid

NASA Astrophysics Data System (ADS)

Tarasov, Vasily E.

2016-07-01

Fractal fluid is considered in the framework of continuous models with noninteger dimensional spaces (NIDS). A recently proposed vector calculus in NIDS is used to get a description of fractal fluid flow in pipes with circular cross-sections. The Navier-Stokes equations of fractal incompressible viscous fluids are used to derive a generalization of the Poiseuille equation of steady flow of fractal media in pipe.

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.

Numerical study of soap-film flow by nonuniform alternating electric fields

NASA Astrophysics Data System (ADS)

Nasiri, M.; Shirsavar, R.; Mollaei, S.; Ramos, A.

2017-02-01

Fluid flow of suspended liquid films induced by non-uniform alternating electric fields has been reported. The electric fields were generated by two rod-like electrodes perpendicular to the fluid surface. The observed fluid flow was explained qualitatively by considering a charge induction mechanism, where the electric field actuates on the charge induced on the film surface. In this paper we perform a numerical study of this fluid flow taking into account the charge induction mechanism. The numerical results are compared with experiments and good agreement is found. Finally, we propose the application of the device as a new kind of two dimensional fluid pump.

Numerical study of soap-film flow by nonuniform alternating electric fields.

PubMed

Nasiri, M; Shirsavar, R; Mollaei, S; Ramos, A

2017-02-01

Fluid flow of suspended liquid films induced by non-uniform alternating electric fields has been reported. The electric fields were generated by two rod-like electrodes perpendicular to the fluid surface. The observed fluid flow was explained qualitatively by considering a charge induction mechanism, where the electric field actuates on the charge induced on the film surface. In this paper we perform a numerical study of this fluid flow taking into account the charge induction mechanism. The numerical results are compared with experiments and good agreement is found. Finally, we propose the application of the device as a new kind of two dimensional fluid pump.

Instability patterns in a miscible core annular flow

NASA Astrophysics Data System (ADS)

D'Olce, Marguerite; Martin, Jerome; Rakotomalala, Nicole; Salin, Dominique; Talon, Laurent

2006-11-01

Laboratoire FAST, batiment 502, campus universitaire, 91405 Orsay Cedex (France). Experiments are performed with two miscible fluids of equal density but different viscosities. The fluids are injected co-currently and concentrically into a cylindrical pipe. The so-obtained base state is an axisymmetric parallel flow, for which the ratio of the flow rates of the two fluids monitors the relative amount (and so the radius) of the fluids. Depending on this relative amount and on the total flow rate of the fluids, unstable axisymmetric patterns such as mushrooms and pearls are observed. We delineate the diagram of occurrence of the two patterns and characterize the instabilities.

Ultrasonic flow metering system

DOEpatents

Gomm, Tyler J.; Kraft, Nancy C.; Mauseth, Jason A.; Phelps, Larry D.; Taylor, Steven C.

2002-01-01

A system for determining the density, flow velocity, and mass flow of a fluid comprising at least one sing-around circuit that determines the velocity of a signal in the fluid and that is correlatable to a database for the fluid. A system for determining flow velocity uses two of the inventive circuits with directional transmitters and receivers, one of which is set at an angle to the direction of flow that is different from the others.

Dye laser amplifier including a low turbulence, stagnation-free dye flow configuration

DOEpatents

Davin, J.

1992-12-01

A large (high flow rate) dye laser amplifier in which a continuous replenished supply of dye is excited by a first light beam, specifically a copper vapor laser beam, in order to amplify the intensity of a second different light beam, specifically a dye beam, passing through the dye is disclosed herein. This amplifier includes a dye cell defining a dye chamber through which a continuous stream of dye is caused to pass at a flow rate of for example 30 gallons/minute, a specifically designed support vessel for containing the dye cell and a screen device for insuring that the dye stream passes into the dye cell in a substantially turbulent free, stagnation-free manner. 9 figs.

Pre-Darcy Flow in Porous Media

NASA Astrophysics Data System (ADS)

Dejam, Morteza; Hassanzadeh, Hassan; Chen, Zhangxin

2017-10-01

Fluid flow in porous media is very important in a wide range of science and engineering applications. The entire establishment of fluid flow application in porous media is based on the use of an experimental law proposed by Darcy (1856). There are evidences in the literature that the flow of a fluid in consolidated and unconsolidated porous media does not follow Darcy law at very low fluxes, which is called pre-Darcy flow. In this paper, the unsteady flow regimes of a slightly compressible fluid under the linear and radial pre-Darcy flow conditions are modeled and the corresponding highly nonlinear diffusivity equations are solved analytically by aid of a generalized Boltzmann transformation technique. The influence of pre-Darcy flow on the pressure diffusion for homogeneous porous media is studied in terms of the nonlinear exponent and the threshold pressure gradient. In addition, the pressure gradient, flux, and cumulative production per unit area are compared with the classical solution of the diffusivity equation based on Darcy flow. The presented results advance our understanding of fluid flow in low-permeability media such as shale and tight formations, where pre-Darcy is the dominant flow regime.

Microwave fluid flow meter

DOEpatents

Billeter, Thomas R.; Philipp, Lee D.; Schemmel, Richard R.

1976-01-01

A microwave fluid flow meter is described utilizing two spaced microwave sensors positioned along a fluid flow path. Each sensor includes a microwave cavity having a frequency of resonance dependent upon the static pressure of the fluid at the sensor locations. The resonant response of each cavity with respect to a variation in pressure of the monitored fluid is represented by a corresponding electrical output which can be calibrated into a direct pressure reading. The pressure drop between sensor locations is then correlated as a measure of fluid velocity. In the preferred embodiment the individual sensor cavities are strategically positioned outside the path of fluid flow and are designed to resonate in two distinct frequency modes yielding a measure of temperature as well as pressure. The temperature response can then be used in correcting for pressure responses of the microwave cavity encountered due to temperature fluctuations.

Working fluid selection for space-based two-phase heat transport systems

NASA Technical Reports Server (NTRS)

Mclinden, Mark O.

1988-01-01

The working fluid for externally-mounted, space-based two-phase heat transport systems is considered. A sequence of screening criteria involving freezing and critical point temperatures and latent heat of vaporization and vapor density are applied to a data base of 860 fluids. The thermal performance of the 52 fluids which pass this preliminary screening are then ranked according to their impact on the weight of a reference system. Upon considering other nonthermal criteria (flammability, toxicity, and chemical stability) a final set of 10 preferred fluids is obtained. The effects of variations in system parameters is investigated for these 10 fluids by means of a factorial design.

Method and apparatus for nitrogen oxide determination

DOEpatents

Hohorst, Frederick A.

1990-01-01

Method and apparatus for determining nitrogen oxide content in a high temperature process gas, which involves withdrawing a sample portion of a high temperature gas containing nitrogen oxide from a source to be analyzed. The sample portion is passed through a restrictive flow conduit, which may be a capillary or a restriction orifice. The restrictive flow conduit is heated to a temperature sufficient to maintain the flowing sample portion at an elevated temperature at least as great as the temperature of the high temperature gas source, to thereby provide that deposition of ammonium nitrate within the restrictive flow conduit cannot occur. The sample portion is then drawn into an aspirator device. A heated motive gas is passed to the aspirator device at a temperature at least as great as the temperature of the high temperature gas source. The motive gas is passed through the nozzle of the aspirator device under conditions sufficient to aspirate the heated sample portion through the restrictive flow conduit and produce a mixture of the sample portion in the motive gas at a dilution of the sample portion sufficient to provide that deposition of ammonium nitrate from the mixture cannot occur at reduced temperature. A portion of the cooled dilute mixture is then passed to analytical means capable of detecting nitric oxide.

Modeling steady-state dynamics of macromolecules in exponential-stretching flow using multiscale molecular-dynamics-multiparticle-collision simulations.

PubMed

Ghatage, Dhairyasheel; Chatterji, Apratim

2013-10-01

We introduce a method to obtain steady-state uniaxial exponential-stretching flow of a fluid (akin to extensional flow) in the incompressible limit, which enables us to study the response of suspended macromolecules to the flow by computer simulations. The flow field in this flow is defined by v(x) = εx, where v(x) is the velocity of the fluid and ε is the stretch flow gradient. To eliminate the effect of confining boundaries, we produce the flow in a channel of uniform square cross section with periodic boundary conditions in directions perpendicular to the flow, but simultaneously maintain uniform density of fluid along the length of the tube. In experiments a perfect elongational flow is obtained only along the axis of symmetry in a four-roll geometry or a filament-stretching rheometer. We can reproduce flow conditions very similar to extensional flow near the axis of symmetry by exponential-stretching flow; we do this by adding the right amounts of fluid along the length of the flow in our simulations. The fluid particles added along the length of the tube are the same fluid particles which exit the channel due to the flow; thus mass conservation is maintained in our model by default. We also suggest a scheme for possible realization of exponential-stretching flow in experiments. To establish our method as a useful tool to study various soft matter systems in extensional flow, we embed (i) spherical colloids with excluded volume interactions (modeled by the Weeks-Chandler potential) as well as (ii) a bead-spring model of star polymers in the fluid to study their responses to the exponential-stretched flow and show that the responses of macromolecules in the two flows are very similar. We demonstrate that the variation of number density of the suspended colloids along the direction of flow is in tune with our expectations. We also conclude from our study of the deformation of star polymers with different numbers of arms f that the critical flow gradient ε(c) at which the star undergoes the coil-to-stretch transition is independent of f for f = 2,5,10, and 20.

Cooling system having dual suction port compressor

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

Wu, Guolian

2017-08-29

A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portionmore » of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.« less

Refrigeration system having dual suction port compressor

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

Wu, Guolian

A cooling system for appliances, air conditioners, and other spaces includes a compressor, and a condenser that receives refrigerant from the compressor. The system also includes an evaporator that receives refrigerant from the condenser. Refrigerant received from the condenser flows through an upstream portion of the evaporator. A first portion of the refrigerant flows to the compressor without passing through a downstream portion of the evaporator, and a second portion of the refrigerant from the upstream portion of the condenser flows through the downstream portion of the evaporator after passing through the upstream portion of the evaporator. The second portionmore » of the refrigerant flows to the compressor after passing through the downstream portion of the evaporator. The refrigeration system may be configured to cool an appliance such as a refrigerator and/or freezer, or it may be utilized in air conditioners for buildings, motor vehicles, or other such spaces.« less

The stress heat-flow paradox and thermal results from Cajon Pass

USGS Publications Warehouse

Lachenbruch, A.H.; Sass, J.H.

1988-01-01

Conventional friction models predict a substantial thermal anomaly associated with active traces of strike-slip faults, but no such anomaly is observed from over 100 heat-flow determinations along 1000 km of the San Andreas fault. The Cajon Pass well is being drilled to bring deep heat-flow and stress data to bear on this paradox. Preliminary stress results from Cajon Pass and a new interpretation of regional data by Mark D. Zoback and colleagues suggests that the maximum compressive stress near the fault is almost normal to the trace, and hence the resolved shear stress is low and the fault, weak. The heat-flow data show large variability with depth, probably from three-dimensional structure, and an overall decrease from over 90 mW/m2 in the upper kilometer to less than 80 mW/m2 in the lower 300 m with no evidence of advective heat transfer. -from Authors

Online capacitive densitometer

DOEpatents

Porges, K.G.

1988-01-21

This invention is an apparatus for measuring fluid density of mixed phase fluid flow. The apparatus employs capacitive sensing of the mixed phased flow combined with means for uniformizing the electric field between the capacitor plates to account for flow line geometry. From measurement of fluid density, the solids feedrate can be ascertained. 7 figs.

Online capacitive densitometer

DOEpatents

Porges, Karl G.

1990-01-01

This invention is an apparatus for measuring fluid density of mixed phase fluid flow. The apparatus employs capacitive sensing of the mixed phased flow combined with means for uniformizing the electric field between the capacitor plates to account for flow line geometry. From measurement of fluid density, the solids feedrate can be ascertained.

Thermal transient anemometer

DOEpatents

Bailey, James L.; Vresk, Josip

1989-01-01

A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings

NASA Technical Reports Server (NTRS)

Andres, Luis San

1993-01-01

A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.

Finite element analysis in fluids; Proceedings of the Seventh International Conference on Finite Element Methods in Flow Problems, University of Alabama, Huntsville, Apr. 3-7, 1989

NASA Technical Reports Server (NTRS)

Chung, T. J. (Editor); Karr, Gerald R. (Editor)

1989-01-01

Recent advances in computational fluid dynamics are examined in reviews and reports, with an emphasis on finite-element methods. Sections are devoted to adaptive meshes, atmospheric dynamics, combustion, compressible flows, control-volume finite elements, crystal growth, domain decomposition, EM-field problems, FDM/FEM, and fluid-structure interactions. Consideration is given to free-boundary problems with heat transfer, free surface flow, geophysical flow problems, heat and mass transfer, high-speed flow, incompressible flow, inverse design methods, MHD problems, the mathematics of finite elements, and mesh generation. Also discussed are mixed finite elements, multigrid methods, non-Newtonian fluids, numerical dissipation, parallel vector processing, reservoir simulation, seepage, shallow-water problems, spectral methods, supercomputer architectures, three-dimensional problems, and turbulent flows.