Modeling of High Capacity Passive Cooling System

DTIC Science & Technology

2009-03-01

Pulsating Heat Pipes : Closed Loop Pulsating Heat Pipes , which is also known as Meandering Capillary Tube Heat Pipe or Closed Loop Oscillating Heat ... Pipe , has emerged in the recent years as a new electronics cooling technology. The Pulsating Heat Pipe is an innovating technology that has gained...horizontal orientation, the operating temperatures are lower. Pulsating heat pipes are capable of higher heat

A Comparison of Supercritical Carbon Dioxide Power Cycle Configurations with an Emphasis on CSP Applications (Presentation)

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

Neises, T.; Turchi, C.

2013-09-01

Recent research suggests that an emerging power cycle technology using supercritical carbon dioxide (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus supercritical or superheated steam cycles at temperatures relevant for CSP applications. Preliminary design-point modeling suggests that s-CO2 cycle configurations can be devised that have similar overall efficiency but different temperature and/or pressure characteristics. This paper employs a more detailed heat exchanger model than previous work to compare the recompression and partial cooling cycles, two cycles with high design-point efficiencies, and illustrates the potential advantages of the latter. Integration of themore » cycles into CSP systems is studied, with a focus on sensible heat thermal storage and direct s-CO2 receivers. Results show the partial cooling cycle may offer a larger temperature difference across the primary heat exchanger, thereby potentially reducing heat exchanger cost and improving CSP receiver efficiency.« less

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

Gerard, R.; Malekian, C.; Meessen, O.

The Leak Before Break (LBB) concept allows to eliminate from the design basis the double-ended guillotine break of the primary loop piping, provided it can be demonstrated by a fracture mechanics analysis that a through-wall flaw, of a size giving rise to a leakage still well detectable by the plant leak detection systems, remains stable even under accident conditions (including the Safe Shutdown Earthquake (SSE)). This concept was successfully applied to the primary loop piping of several Belgian Pressurized Water Reactor (PWR) units, operated by the Utility Electrabel. One of the main benefits is to permit justification of supports inmore » the primary loop and justification of the integrity of the reactor pressure vessel and internals in case of a Loss Of Coolant Accident (LOCA) in stretch-out conditions. For two of the Belgian PWR units, the LBB approach also made it possible to reduce the number of large hydraulic snubbers installed on the primary coolant pumps. Last but not least, the LBB concept also facilitates the steam generator replacement operations, by eliminating the need for some pipe whip restraints located close to the steam generator. In addition to the U.S. regulatory requirements, the Belgian safety authorities impose additional requirements which are described in details in a separate paper. An novel aspect of the studies performed in Belgium is the way in which residual loads in the primary loop are taken into account. Such loads may result from displacements imposed to close the primary loop in a steam generator replacement operation, especially when it is performed using the {open_quote}two cuts{close_quotes} technique. The influence of such residual loads on the LBB margins is discussed in details and typical results are presented.« less

Water cooling system for an air-breathing hypersonic test vehicle

NASA Technical Reports Server (NTRS)

Petley, Dennis H.; Dziedzic, William M.

1993-01-01

This study provides concepts for hypersonic experimental scramjet test vehicles which have low cost and low risk. Cryogenic hydrogen is used as the fuel and coolant. Secondary water cooling systems were designed. Three concepts are shown: an all hydrogen cooling system, a secondary open loop water cooled system, and a secondary closed loop water cooled system. The open loop concept uses high pressure helium (15,000 psi) to drive water through the cooling system while maintaining the pressure in the water tank. The water flows through the turbine side of the turbopump to pump hydrogen fuel. The water is then allowed to vent. In the closed loop concept high pressure, room temperature, compressed liquid water is circulated. In flight water pressure is limited to 6000 psi by venting some of the water. Water is circulated through cooling channels via an ejector which uses high pressure gas to drive a water jet. The cooling systems are presented along with finite difference steady-state and transient analysis results. The results from this study indicate that water used as a secondary coolant can be designed to increase experimental test time, produce minimum venting of fluid and reduce overall development cost.

Closed loop air cooling system for combustion turbines

DOEpatents

Huber, David John; Briesch, Michael Scot

1998-01-01

Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.

Closed loop air cooling system for combustion turbines

DOEpatents

Huber, D.J.; Briesch, M.S.

1998-07-21

Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts. 1 fig.

Modification of wood fiber using steam

Treesearch

Roger Rowell; Sandra Lange; Jim McSweeny; Mark Davis

2002-01-01

High temperature steam treatment of wood fiber in a closed press during fiberboard pressing and then cooling the fiberboard while still under pressure to below the glass transition temperature of lignin, greatly increased the dimensional stability and decreased the hemicellulose content of the fiberboards produced. For example, after pressing aspen fiber four minutes...

Geothermal energy control system and method

DOEpatents

Matthews, Hugh B.

1977-01-01

A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system. The bearing system employs liquid lubricated thrust and radial bearings with all bearing surfaces bathed in clean water serving as a lubricant and maintained under pressure to prevent entry into the bearings of contaminated geothermal fluid, an auxiliary thrust ball bearing arrangement comes into operation when starting or stopping the pumping system.

Core design of a direct-cycle, supercritical-water-cooled fast breeder reactor

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

Jevremovic, T.; Oka, Yoshiaki; Koshizuka, Seiichi

1994-10-01

The conceptual design of a direct-cycle fast breeder reactor (FBR) core cooled by supercritical water is carried out as a step toward a low-cost FBR plant. The supercritical water does not exhibit change of phase. The turbines are directly driven by the core outlet coolant. In comparison with a boiling water reactor (BWR), the recirculation systems, steam separators, and dryers are eliminated. The reactor system is much simpler than the conventional steam-cooled FBRs, which adopted Loeffler boilers and complicated coolant loops for generating steam and separating it from water. Negative complete and partial coolant void reactivity are provided without muchmore » deterioration in the breeding performances by inserting thin zirconium-hydride layers between the seeds and blankets in a radially heterogeneous core. The net electric power is 1245 MW (electric). The estimated compound system doubling time is 25 yr. The discharge burnup is 77.7 GWd/t, and the refueling period is 15 months with a 73% load factor. The thermal efficiency is high (41.5%), an improvement of 24% relative to a BWR's. The pressure vessel is not thick at 30.3 cm.« less

Downhole steam generator with improved preheating, combustion, and protection features

DOEpatents

Fox, R.L.

1981-01-07

For tertiary oil recovery, a downhole steam generator is designed which provides for efficient counterflow cooling of the combustion chamber walls and preheating of the fuel and water. Pressure-responsive doors are provided for closing and opening the outlet in response to flameout, thereby preventing flooding of the combustion chamber. (DLC)

Gas turbine cooling system

DOEpatents

Bancalari, Eduardo E.

2001-01-01

A gas turbine engine (10) having a closed-loop cooling circuit (39) for transferring heat from the hot turbine section (16) to the compressed air (24) produced by the compressor section (12). The closed-loop cooling system (39) includes a heat exchanger (40) disposed in the flow path of the compressed air (24) between the outlet of the compressor section (12) and the inlet of the combustor (14). A cooling fluid (50) may be driven by a pump (52) located outside of the engine casing (53) or a pump (54) mounted on the rotor shaft (17). The cooling circuit (39) may include an orifice (60) for causing the cooling fluid (50) to change from a liquid state to a gaseous state, thereby increasing the heat transfer capacity of the cooling circuit (39).

Downhole steam generator having a downhole oxidant compressor

DOEpatents

Fox, R.L.

1981-01-07

Am improved apparatus is described for the downhole injection of steam into boreholes, for tertiary oil recovery. It includes an oxidant supply, a fuel supply, an igniter, a water supply, an oxidant compressor, and a combustor assembly. The apparatus is designed for efficiency, preheating of the water, and cooling of the combustion chamber walls. The steam outlet to the borehole is provided with pressure-responsive doors for closing the outlet in response to flameout. (DLC)

Emergency cooling analysis for the loss of coolant malfunction

NASA Technical Reports Server (NTRS)

Peoples, J. A.

1972-01-01

This report examines the dynamic response of a conceptual space power fast-spectrum lithium cooled reactor to the loss of coolant malfunction and several emergency cooling concepts. The results show that, following the loss of primary coolant, the peak temperatures of the center most 73 fuel elements can range from 2556 K to the region of the fuel melting point of 3122 K within 3600 seconds after the start of the accident. Two types of emergency aftercooling concepts were examined: (1) full core open loop cooling and (2) partial core closed loop cooling. The full core open loop concept is a one pass method of supplying lithium to the 247 fuel pins. This method can maintain fuel temperature below the 1611 K transient damage limit but requires a sizable 22,680-kilogram auxiliary lithium supply. The second concept utilizes a redundant internal closed loop to supply lithium to only the central area of each hexagonal fuel array. By using this method and supplying lithium to only the triflute region, fuel temperatures can be held well below the transient damage limit.

Analysis of steam generator tube rupture transients with single failure

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

Trambauer, K.

The Gesellschaft fuer Reaktorsicherheit is engaged in the collection and evaluation of light water reactor operating experience as well as analyses for the risk study of the pressurized water reactor (PWR). Within these activities, thermohydraulic calculations have been performed to show the influence of different boundary conditions and disturbances on the steam generator tube rupture (SGTR) transients. The analyses of these calculations have focused on the measures and systems needed to cope with an SGTR. The reference plant for this analysis is a 1300-MW(e) PWR of Kraftwerk Union design with four loops, each containing a U-tube steam generator (SG) andmore » a reactor cooling pump (RCP). The thermal-hydraulic code DRUFAN-02 was used for the transient calculations.« less

Pressure intelligent control strategy of Waste heat recovery system of converter vapors

NASA Astrophysics Data System (ADS)

Feng, Xugang; Wu, Zhiwei; Zhang, Jiayan; Qian, Hong

2013-01-01

The converter gas evaporative cooling system is mainly used for absorbing heat in the high temperature exhaust gas which produced by the oxygen blowing reaction. Vaporization cooling steam pressure control system of converter is a nonlinear, time-varying, lagging behind, close coupling of multivariable control object. This article based on the analysis of converter operation characteristics of evaporation cooling system, of vaporization in a production run of pipe pressure variation and disturbance factors.For the dynamic characteristics of the controlled objects,we have improved the conventional PID control scheme.In Oxygen blowing process, we make intelligent control by using fuzzy-PID cascade control method and adjusting the Lance,that it can realize the optimization of the boiler steam pressure control.By design simulation, results show that the design has a good control not only ensures drum steam pressure in the context of security, enabling efficient conversion of waste heat.And the converter of 1800 flue gas through pipes and cool and dust removal also can be cooled to about 800. Therefore the converter haze evaporative cooling system has achieved to the converter haze temperature decrease effect and enhanced to the coal gas returns-ratio.

Centrifuge Testing of a Partially-Confined FC-72 Spray

DTIC Science & Technology

2006-11-01

induced body forces. Heat transfer associated with closed - loop spray cooling will be affected by acceleration body forces, the extent of which is not...impingement cooling, spray cooling, heat pipes , loop heat pipes , carbon foam impregnated with phase-change materials, and combinations of the above...reduced gravity and elevated gravity experiments to help prove viability of pulsating heat pipes (PHPs) for space applications. The PHPs, filled

A dynamic flare with anomalously dense flare loops

NASA Technical Reports Server (NTRS)

Svestka, Z.; Fontenla, J. M.; Machado, M. E.; Martin, S. F.; Neidig, D. F.

1986-01-01

The dynamic flare of November 6, 1980 developed a rich system of growing loops which could be followed in H-alpha for 1.5 hours. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of b-values for a hydrogen atom reveal that this requires electron densities in the loops to be close to 10 to the 12th per cu cm. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 10 to the 12th per cu cm if no nonthermal motions were present. It is now general knowledge that flare loops are initially observed in X-rays and become visible in H-alpha only after cooling. For such a high density a loop would cool through radiation from 10 to the 7th K to 10 to the 4th K within a few minutes so that the dense H-alpha loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in H-alpha. Therefore, the density must have been significantly smaller when the loops were formed and the flare loops were apparently both shrinking and becoming denser while cooling.

Posttest analysis of MIST Test 3109AA using TRAC-PF1/MOD1

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

Steiner, J.L.; Siebe, D.A.; Boyack, B.E.

This document discusses a posttest calculation and analysis of Multi-loop Integral System Test (MIST) 3109AA as the nominal test for the MIST program. It is a test of a small-break loss-of-coolant accident (SBLOCA) with a scaled 10-cm{sup 2} break in the B1 cold leg. The test exhibited the major post-SBLOCA phenomena, as expected, including depressurization to saturation, intermittent and interrupted loop flow, boiler-condenser mode cooling, refill, and postrefill cooldown. Full high-pressure injection and auxiliary feedwater were available, reactor coolant pumps were not available, and reactor-vessel vent valves and guard heaters were automatically controlled. Constant level control in the steam-generator secondariesmore » was used after steam-generator secondary refill and symmetric steam-generator pressure control was used. We performed the calculation using TRAC-PF1/MODI. Agreement between test data and the calculation was generally reasonable. All major trends and phenomena were correctly predicted. It is believed that the correct conclusions about trends and phenomena will be reached if the code is used in similar applications.« less

Posttest analysis of MIST Test 3109AA using TRAC-PF1/MOD1

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

Steiner, J.L.; Siebe, D.A.; Boyack, B.E.

This document discusses a posttest calculation and analysis of Multi-loop Integral System Test (MIST) 3109AA as the nominal test for the MIST program. It is a test of a small-break loss-of-coolant accident (SBLOCA) with a scaled 10-cm[sup 2] break in the B1 cold leg. The test exhibited the major post-SBLOCA phenomena, as expected, including depressurization to saturation, intermittent and interrupted loop flow, boiler-condenser mode cooling, refill, and postrefill cooldown. Full high-pressure injection and auxiliary feedwater were available, reactor coolant pumps were not available, and reactor-vessel vent valves and guard heaters were automatically controlled. Constant level control in the steam-generator secondariesmore » was used after steam-generator secondary refill and symmetric steam-generator pressure control was used. We performed the calculation using TRAC-PF1/MODI. Agreement between test data and the calculation was generally reasonable. All major trends and phenomena were correctly predicted. It is believed that the correct conclusions about trends and phenomena will be reached if the code is used in similar applications.« less

The pre-conceptual design of the nuclear island of ASTRID

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

Saez, M.; Menou, S.; Uzu, B.

The CEA is involved in a substantial effort on the ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) pre-conceptual design in cooperation with EDF, as experienced Sodium-cooled Fast Reactor (SFR) operator, AREVA, as experienced SFR Nuclear Island engineering company and components designer, ALSTOM POWER as energy conversion system designer and COMEX NUCLEAIRE as mechanical systems designer. The CEA is looking for other partnerships, in France and abroad. The ASTRID preliminary design is based on a sodium-cooled pool reactor of 1500 MWth generating about 600 MWe, which is required to guarantee the representativeness of the reactor core and the main componentsmore » with regard to future commercial reactors. ASTRID lifetime target is 60 years. Two Energy Conversion Systems are studied in parallel until the end of 2012: Rankine steam cycle or Brayton gas based energy conversion cycle. ASTRID design is guided by the following major objectives: improved safety, simplification of structures, improved In Service Inspection and Repair (ISIR), improved manufacturing conditions for cost reduction and increased quality, reduction of risks related to sodium fires and water/sodium reaction, and improved robustness against external hazards. The core is supported by a diagrid, which lay on a strong back to transfer the weight to the main vessel. AREVA is involved in a substantial effort in order to improve the core support structure in particular regarding the ISIR and the connection to primary pump. In the preliminary design, the primary system is formed by the main vessel and the upper closure comprising the reactor roof, two rotating plugs - used for fuel handling - and the components plugs located in the roof penetrations. The Above Core Structure deflects the sodium flow in the hot pool and provides support to core instrumentation and guidance of the control rod drive mechanisms. The number of the major components in the main vessel, primary pumps, Intermediate Heat Exchangers, and Decay Heat Exchangers are now under consideration. Under normal conditions, power release is achieved using the steam/water plant (in case of Rankine steam cycle) or the gas plant (in case of Brayton gas cycle). The diverse design and operating modes of Decay Heat Removal systems provide protection against common cause failures. A Decay Heat Removal system through the reactor vault is in particular studied with the objective to complement Direct Reactor Cooling systems. At this stage of the studies, the secondary system comprises four independent sodium loops (two and three sodium loops configurations are also investigated). Each loop includes one mechanical pump (or a large capacity Annular Linear Induction Electromagnetic Pump), and three modular Steam Generator Units characterized by once through straight tube units with a ferritic tube bundle; nevertheless, helical coil steam generator with tubes made of Alloy 800, and inverted type steam generator with a ferritic tube bundle are also investigated. The limited power of each modular Steam Generator Unit allows the whole secondary loop to withstand a large water/sodium reaction consecutive to the postulated simultaneous rupture of all the heat exchange tubes of one module. The arrangement of the components is based on the 'Regain' concept, in which the secondary pump is situated at a low level in the circuit; conventional arrangement, as SUPERPHENIX type, is a back-up option. Alternative arrangements based on gas cycles are also studied together with Na-gas heat exchanger design. This paper presents a status of the ASTRID pre-conceptual design. The most promising options are highlighted as well as less risky and back-up options. (authors)« less

Energy alternative for industry: the high-temperature gas-cooled reactor steamer

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

McMain, A.T. Jr.; Blok, F.J.

1978-04-01

Large industrial complexes are faced with new requirements that will lead to a transition from such fluid fuels as natural gas and oil to such solid fuels as coal and uranium for supply of industrial energy. Power plants using these latter fuels will be of moderate size (800 to 1200 MW(thermal)) and will generally have the capability of co-generating electric power and process steam. A study has been made regarding use of the 840-MW(thermal) Fort St. Vrain high-temperature gas-cooled reactor (HTGR) design for industrial applications. The initial conceptual design (referred to as the HTGR Steamer) is substantially simplified relative tomore » Fort St. Vrain in that outlet helium and steam temperatures are lower and the reheat section is deleted from the steam generators. The Steamer has four independent steam generating loops producing a total of 277 kg/s (2.2 x 10/sup 6/ lb/h) of prime steam at 4.5 MPa/672 K (650 psia/750/sup 0/F). The unit co-generates 46 MW(electric) and provides process steam at 8.31 MPa/762 K(1200 psia/912/sup 0/F). The basic configuration and much of the equipment are retained from the Fort St. Vrain design. The system has inherent safety features important for industrial applications. These and other features indicate that the HTGR Steamer is an industrial energy option deserving additional evaluation. Subsequent work will focus on parallel design optimization and application studies.« less

Performance of the dark energy camera liquid nitrogen cooling system

NASA Astrophysics Data System (ADS)

Cease, H.; Alvarez, M.; Alvarez, R.; Bonati, M.; Derylo, G.; Estrada, J.; Flaugher, B.; Flores, R.; Lathrop, A.; Munoz, F.; Schmidt, R.; Schmitt, R. L.; Schultz, K.; Kuhlmann, S.; Zhao, A.

2014-01-01

The Dark Energy Camera, the Imager and its cooling system was installed onto the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile in September 2012. The imager cooling system is a LN2 two-phase closed loop cryogenic cooling system. The cryogenic circulation processing is located off the telescope. Liquid nitrogen vacuum jacketed transfer lines are run up the outside of the telescope truss tubes to the imager inside the prime focus cage. The design of the cooling system along with commissioning experiences and initial cooling system performance is described. The LN2 cooling system with the DES imager was initially operated at Fermilab for testing, then shipped and tested in the Blanco Coudé room. Now the imager is operating inside the prime focus cage. It is shown that the cooling performance sufficiently cools the imager in a closed loop mode, which can operate for extended time periods without maintenance or LN2 fills.

Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

DOEpatents

Tomlinson, Leroy Omar; Smith, Raub Warfield

2002-01-01

In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

Rotating diffuser for pressure recovery in a steam cooling circuit of a gas turbine

DOEpatents

Eldrid, Sacheverel Q.; Salamah, Samir A.; DeStefano, Thomas Daniel

2002-01-01

The buckets of a gas turbine are steam-cooled via a bore tube assembly having concentric supply and spent cooling steam return passages rotating with the rotor. A diffuser is provided in the return passage to reduce the pressure drop. In a combined cycle system, the spent return cooling steam with reduced pressure drop is combined with reheat steam from a heat recovery steam generator for flow to the intermediate pressure turbine. The exhaust steam from the high pressure turbine of the combined cycle unit supplies cooling steam to the supply conduit of the gas turbine.

Liquid-cooling technology for gas turbines - Review and status

NASA Technical Reports Server (NTRS)

Van Fossen, G. J., Jr.; Stepka, F. S.

1978-01-01

After a brief review of past efforts involving the forced-convection cooling of gas turbines, the paper surveys the state of the art of the liquid cooling of gas turbines. Emphasis is placed on thermosyphon methods of cooling, including those utilizing closed, open, and closed-loop thermosyphons; other methods, including sweat, spray and stator cooling, are also discussed. The more significant research efforts, design data, correlations, and analytical methods are mentioned and voids in technology are summarized.

Pyrometer mount for a closed-circuit thermal medium cooled gas turbine

DOEpatents

Jones, Raymond Joseph; Kirkpatrick, Francis Lawrence; Burns, James Lee; Fulton, John Robert

2002-01-01

A steam-cooled second-stage nozzle segment has an outer band and an outer cover defining a plenum therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets of the stage forwardly of the nozzle stage, a pyrometer boss is electron beam-welded in an opening through the outer band and TIG-welded to the outer cover plate. By machining a hole through the boss and seating a linearly extending tube in the boss, a line of sight between a pyrometer mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature.

The development of a cryogenic over-pressure pump

NASA Astrophysics Data System (ADS)

Alvarez, M.; Cease, H.; Flaugher, B.; Flores, R.; Garcia, J.; Lathrop, A.; Ruiz, F.

2014-01-01

A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL).

Air-Cooled Design of a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization Systems

NASA Technical Reports Server (NTRS)

Mulloth, Lila M.; Affleck, Dave L.; Rosen, Micha; LeVan, M. Douglas; Wang, Yuan; Cavalcante, Celio L.

2004-01-01

The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no rapidly moving parts. This paper discusses the mechanical design and the results of thermal model validation tests of a TSAC that uses air as the cooling medium.

Multi-thermal observations of newly formed loops in a dynamic flare

NASA Technical Reports Server (NTRS)

Svestka, Zdenek F.; Fontenla, Juan M.; Machado, Marcos E.; Martin, Sara F.; Neidig, Donald F.

1987-01-01

The dynamic flare of November 6, 1980 (max at about 15:26 UT) developed a rich system of growing loops which could be followed in H-alpha for 1.5 hr. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of deviations from LTE populations for a hydrogen atom reveal that this requires electron densities in the loops close to, or in excess of 10 to the 12th/cu cm. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 10 to the 12th/cu cm if no nonthermal motions were present, or 5 x 10 to the 11th/cu cm for a turbulent velocity of about 12 km/s. It is now general knowledge that flare loops are initially observed in X-rays and become visible in H-alpha only after cooling. For such a high density, a loop would cool through radiation from 10 to the 7th to 10 to the 4th K within a few minutes so that the dense H-alpha loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in H-alpha. Therefore, it is suggested that the density must have been significantly lower when the loops were formed, and that the flare loops were apparently both shrinking and increasing in density while cooling.

Apparatus and methods for supplying auxiliary steam in a combined cycle system

DOEpatents

Gorman, William G.; Carberg, William George; Jones, Charles Michael

2002-01-01

To provide auxiliary steam, a low pressure valve is opened in a combined cycle system to divert low pressure steam from the heat recovery steam generator to a header for supplying steam to a second combined cycle's steam turbine seals, sparging devices and cooling steam for the steam turbine if the steam turbine and gas turbine lie on a common shaft with the generator. Cooling steam is supplied the gas turbine in the combined cycle system from the high pressure steam turbine. Spent gas turbine cooling steam may augment the low pressure steam supplied to the header by opening a high pressure valve whereby high and low pressure steam flows are combined. An attemperator is used to reduce the temperature of the combined steam in response to auxiliary steam flows above a predetermined flow and a steam header temperature above a predetermined temperature. The auxiliary steam may be used to start additional combined cycle units or to provide a host unit with steam turbine cooling and sealing steam during full-speed no-load operation after a load rejection.

77 FR 20059 - License Amendment To Increase the Maximum Reactor Power Level, Florida Power & Light Company...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-03

... surface evaporation. The canals are a closed recirculating loop that serves as the ultimate heat sink for...) for water discharges to an onsite closed-loop recirculation cooling canal system. The seasonal... to 90 [deg]F (21 [deg]C to 32 [deg]C). Additionally, the CCS water is hyper-saline (twice the...

Ground Source Geothermal District Heating and Cooling System

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

Lowe, James William

2016-10-21

Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reducemore » worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx« less

Testing of a Neon Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin Lee

2014-01-01

Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.

Debris trap in a turbine cooling system

DOEpatents

Wilson, Ian David

2002-01-01

In a turbine having a rotor and a plurality of stages, each stage comprising a row of buckets mounted on the rotor for rotation therewith; and wherein the buckets of at least one of the stages are cooled by steam, the improvement comprising at least one axially extending cooling steam supply conduit communicating with an at least partially annular steam supply manifold; one or more axially extending cooling steam feed tubes connected to the manifold at a location radially outwardly of the cooling steam supply conduit, the feed tubes arranged to supply cooling steam to the buckets of at least one of the plurality of stages; the manifold extending radially beyond the feed tubes to thereby create a debris trap region for collecting debris under centrifugal loading caused by rotation of the rotor.

Multi-Nozzle Spray Cooling in a Closed Loop (POSTPRINT)

DTIC Science & Technology

2011-03-01

characteristics and critical heat flux (CHF) at cooling surfaces (Sehmbey et al., 1992, Mudawar and Estes, 1996, Rini et al., 2002, Lin and Ponnappan, 2003...surface characteristics in evaporative spray cooling, Journal of Thermophysics and heat Transfer, 1992, Vol. 6, pp. 505-512. 3. Mudawar , I., and

Chemical Looping Autothermal Reforming at a 120 kW Pilot Rig

NASA Astrophysics Data System (ADS)

Bofhàr-Nordenkampf, Johannes; Pröll, Tobias; Kolbitsch, Philipp; Hofbauer, Hermann

Chemical looping with selective oxygen transport allows two step combustion or autothermal reforming without mixing of fuel and air. The reactor system consists of two reactors, an air reactor and a fuel reactor with a suitable oxygen carrier that transports the necessary oxygen for operation. In the present study, a highly active nickel based oxygen carrier is tested in a novel dual circulating fluidized bed (DCFB) system at a scale of 120 kW fuel power. The mean particle size of the oxygen carrier is 120 μm and the pilot rig is fueled with natural gas. For the investigated oxygen carrier high CH4 conversion is achieved. Air/fuel ratio is varied at three different fuel reactor temperatures. For chemical looping reforming one can observe synthesis gas composition close to thermodynamic equilibrium. In spite of the fact that no additional steam has been added to the fuel besides the one present through steam fluidization of the loop seals, coke formation does not occur at global stoichiometric air/fuel ratios above 0.46.

Breckinridge Project, initial effort

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

None

1982-01-01

The project cogeneration plant supplies electric power, process steam and treated boiler feedwater for use by the project plants. The plant consists of multiple turbine generators and steam generators connected to a common main steam header. The major plant systems which are required to produce steam, electrical power and treated feedwater are discussed individually. The systems are: steam, steam generator, steam generator fuel, condensate and feedwater deaeration, condensate and blowdown collection, cooling water, boiler feedwater treatment, coal handling, ash handling (fly ash and bottom ash), electrical, and control system. The plant description is based on the Phase Zero design basismore » established for Plant 31 in July of 1980 and the steam/condensate balance as presented on Drawing 31-E-B-1. Updating of steam requirements as more refined process information becomes available has generated some changes in the steam balance. Boiler operation with these updated requirements is reflected on Drawing 31-D-B-1A. The major impact of updating has been that less 600 psig steam generated within the process units requires more extraction steam from the turbine generators to close the 600 psig steam balance. Since the 900 psig steam generation from the boilers was fixed at 1,200,000 lb/hr, the additional extraction steam required to close the 600 psig steam balance decreased the quantity of electrical power available from the turbine generators. In the next phase of engineering work, the production of 600 psig steam will be augmented by increasing convection bank steam generation in the Plant 3 fired heaters by 140,000 to 150,000 lb/hr. This modification will allow full rated power generation from the turbine generators.« less

5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT ...

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

5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT BUILDING, FROM SOUTH. SHOWS CURRENT LEVEL OF DISREPAIR. December 4, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Heat-transfer analysis of double-pipe heat exchangers for indirect-cycle SCW NPP

NASA Astrophysics Data System (ADS)

Thind, Harwinder

SuperCritical-Water-cooled Reactors (SCWRs) are being developed as one of the Generation-IV nuclear-reactor concepts. SuperCritical Water (SCW) Nuclear Power Plants (NPPs) are expected to have much higher operating parameters compared to current NPPs, i.e., pressure of about 25 MPa and outlet temperature up to 625 °C. This study presents the heat transfer analysis of an intermediate Heat exchanger (HX) design for indirect-cycle concepts of Pressure-Tube (PT) and Pressure-Vessel (PV) SCWRs. Thermodynamic configurations with an intermediate HX gives a possibility to have a single-reheat option for PT and PV SCWRs without introducing steam-reheat channels into a reactor. Similar to the current CANDU and Pressurized Water Reactor (PWR) NPPs, steam generators separate the primary loop from the secondary loop. In this way, the primary loop can be completely enclosed in a reactor containment building. This study analyzes the heat transfer from a SCW primary (reactor) loop to a SCW and Super-Heated Steam (SHS) secondary (turbine) loop using a double-pipe intermediate HX. The numerical model is developed with MATLAB and NIST REFPROP software. Water from the primary loop flows through the inner pipe, and water from the secondary loop flows through the annulus in the counter direction of the double-pipe HX. The analysis on the double-pipe HX shows temperature and profiles of thermophysical properties along the heated length of the HX. It was found that the pseudocritical region has a significant effect on the temperature profiles and heat-transfer area of the HX. An analysis shows the effect of variation in pressure, temperature, mass flow rate, and pipe size on the pseudocritical region and the heat-transfer area of the HX. The results from the numerical model can be used to optimize the heat-transfer area of the HX. The higher pressure difference on the hot side and higher temperature difference between the hot and cold sides reduces the pseudocritical-region length, thus decreases the heat-transfer surface area of the HX.

Numerical analysis of radial inward flow turbine for CO2 based closed loop Brayton cycle

NASA Astrophysics Data System (ADS)

Kisan, Jadhav Amit; Govardhan, M.

2017-06-01

Last few decades have witnessed a phenomenal growth in the demand for power, which has driven the suppliers to find new sources of energy and increase the efficiency of power generation process. Power generation cycles are either steam based Rankine cycle or closed loop Brayton cycles providing an efficiency of 30 to 40%. An upcoming technology in this regard is the CO2 based Brayton cycle operating near the critical region which has applications in vast areas. Power generation of CO2 based Brayton cycle can vary from few kilowatts for waste heat recovery to hundreds of megawatts in sodium cooled fast reactors. A CO2 based Brayton cycle is being studied for power generation especially in mid-sized concentrated solar power plants by numerous research groups around the world. One of the main components of such a setting is its turbine. Simulating the flow conditions inside the turbine becomes very crucial in order to accurately predict the performance of the system. The flow inside radial inflow turbine is studied at various inlet temperatures and mass flow rates in order to predict the behavior of the turbine under various boundary conditions. The performance investigation of the turbine system is done on the basis of parameters such as total efficiency, pressure ratio, and power coefficient. Effect of different inlet stagnation temperature and exit mass flow rates on these parameters is also studied. Results obtained are encouraging for the use of CO2 as working fluid in Brayton cycle.

Case Study of The ARRA-Funded GSHP Demonstration at the Natural Sources Building, Montana Tech

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

Malhotra, Mini; Liu, Xiaobing

Under the American Recovery and Reinvestment Act (ARRA), 26 ground source heat pump (GSHP) projects were competitively selected in 2009 to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. One of the selected demonstration projects was proposed by Montana Tech of the University of Montana for a 56,000 sq ft, newly constructed, on-campus research facility – the Natural Resources Building (NRB) located in Butte, Montana. This demonstrated GSHP system consists of a 50 ton water-to-water heat pump and a closed-loop ground heat exchanger with two redundant 7.5 hp constant-speed pumps to use watermore » in the nearby flooded mines as a heat source or heat sink. It works in conjunction with the originally installed steam HX and an aircooled chiller to provide space heating and cooling. It is coupled with the existing hot water and chilled water piping in the building and operates in the heating or cooling mode based on the outdoor air temperature. The ground loop pumps operate in conjunction with the existing pumps in the building hot and chilled water loops for the operation of the heat pump unit. The goal of this demonstration project is to validate the technical and economic feasibility of the demonstrated commercial-scale GSHP system in the region, and illustrate the feasibility of using mine waters as the heat sink and source for GSHP systems. Should the demonstration prove satisfactory and feasible, it will encourage similar GSHP applications using mine water, thus help save energy and reduce carbon emissions. The actual performance of the system is analyzed with available measured data for January through July 2014. The annual energy performance is predicted and compared with a baseline scenario, with the heating and cooling provided by the originally designed systems. The comparison is made in terms of energy savings, operating cost savings, cost-effectiveness, and environmental benefits. Finally, limitations in conducting the analysis are identified and recommendations for improvement in the control and operation of such systems are made.« less

The NICMOS Cooling SYSTEM-5 Years of Successful On-Orbit Operation

NASA Astrophysics Data System (ADS)

Swift, W. L.; Dolan, F. X.; Zagarola, M. V.

2008-03-01

The NICMOS Cooling System consists of a closed-loop turbo-Brayton cryocooler coupled with a cryogenic circulator that provides refrigeration to the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The cryocooler heat is rejected to space through a capillary pumped loop connected to radiators mounted on the side of the telescope. The system was deployed and integrated with NICMOS by astronauts during STS-109 (Space Shuttle Columbia) in March 2002. It has operated nearly continuously without performance degradation since that time, maintaining NICMOS detectors at a constant temperature of 77 K. Miniature, high-speed turbomachines are used in the cryocooler and the circulator loop to provide vibration-free, long-life operation. A small centrifugal compressor and miniature turboalternator are key elements of the closed loop cryocooler. A miniature cryogenic centrifugal circulator in a separate pressurized neon loop transports heat from the NICMOS instrument to the cryocooler interface heat exchanger. This paper describes the development of the system, key operational features, ground and orbital tests prior to its deployment, and operational results during its five-year operational history on orbit.

Cooling system for a bearing of a turbine rotor

DOEpatents

Schmidt, Mark Christopher

2002-01-01

In a gas turbine, a bore tube assembly radially inwardly of an aft bearing conveys cooling steam to the buckets of the turbine and returns the cooling steam to a return. To cool the bearing and thermally insulate the bearing from the cooling steam paths, a radiation shield is spaced from the bore tube assembly by a dead air gap. Additionally, an air passageway is provided between the radiation shield and the inner surface of an aft shaft forming part of the rotor. Air is supplied from an inlet for flow along the passage and radially outwardly through bores in the aft shaft disk to cool the bearing and insulate it from transfer of heat from the cooling steam.

Steam exit flow design for aft cavities of an airfoil

DOEpatents

Storey, James Michael; Tesh, Stephen William

2002-01-01

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

Feasibility study on an energy-saving desiccant wheel system with CO2 heat pump

NASA Astrophysics Data System (ADS)

Liu, Yefeng; Meng, Deren; Chen, Shen

2018-02-01

In traditional desiccant wheel, air regeneration process occurs inside an open loop, and lots of energy is consumed. In this paper, an energy-saving desiccant wheel system with CO2 heat pump and closed loop air regeneration is proposed. The general theory and features of the desiccant wheel are analysed. The main feature of the proposed system is that the air regeneration process occurs inside a closed loop, and a CO2 heat pump is utilized inside this loop for the air regeneration process as well as supplying cooling for the process air. The simulation results show that the proposed system can save significant energy.

Developments in TurboBrayton Technology for Low Temperature Applications

NASA Technical Reports Server (NTRS)

Swift, W. L.; Zagarola, M. V.; Nellis, G. F.; McCormick, J. A.; Gibbon, Judy

1999-01-01

A single stage reverse Brayton cryocooler using miniature high-speed turbomachines recently completed a successful space shuttle test flight demonstrating its capabilities for use in cooling the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The NICMOS CryoCooler (NCC) is designed for a cooling load of about 8 W at 65 K, and comprises a closed loop cryocooler coupled to an independent cryogenic circulating loop. Future space applications involve instruments that will require 5 mW to 200 mW of cooling at temperatures between 4 K and 10 K. This paper discusses the extension of Turbo-Brayton technology to meet these requirements.

Spectroscopic Study of a Dark Lane and a Cool Loop in a Solar Limb Active Region by Hinode/EIS

NASA Astrophysics Data System (ADS)

Lee, K.; Imada, S.; Moon, Y.; Lee, J.

2012-12-01

We investigate a cool loop and a dark lane over a limb active region on 2007 March 14 by the Hinode/EUV Imaging Spectrometer (EIS). The cool loop is clearly seen in the EIS spectral lines formed at the transition region temperature (log T = 5.8). The dark lane is characterized by an elongated faint structure in coronal spectral lines (log T = 5.8 - 6.1) and rooted on a bright point. We examine their electron densities, Doppler velocities, and non-thermal velocities as a function of distance from the limb using the spectral lines formed at different temperatures (log T = 5.4 - 6.4). The electron densities of the cool loop and the dark lane are derived from the density sensitive line pairs of Mg VII, Fe XII, and Fe XIV spectra. Under the hydrostatic equilibrium and isothermal assumption, we determine their temperatures from the density scale height. Comparing the scale height temperatures to the peak formation temperatures of the spectral lines, we note that the scale height temperature of the cool loop is consistent with a peak formation temperature of the Mg VII (log T = 5.8) and the scale height temperature of the dark lane is close to a peak formation temperature of the Fe XII and Fe XIII (log T = 6.1 - 6.2). It is interesting to note that the structures of the cool loop and the dark lane are most visible in these temperature lines. While the non-thermal velocity in the cool loop slightly decreases (less than 7 km {s-1}) along the loop, that in the dark lane sharply falls off with height. The variation of non-thermal velocity with height in the cool loop and the dark lane is contrast to that in off-limb polar coronal holes which are considered as source of the fast solar wind. Such a decrease in the non-thermal velocity may be explained by wave damping near the solar surface or turbulence due to magnetic reconnection near the bright point.

Cooling circuit for steam and air-cooled turbine nozzle stage

DOEpatents

Itzel, Gary Michael; Yu, Yufeng

2002-01-01

The turbine vane segment includes inner and outer walls with a vane extending therebetween. The vane includes leading and trailing edge cavities and intermediate cavities. An impingement plate is spaced from the outer wall to impingement-cool the outer wall. Post-impingement cooling air flows through holes in the outer wall to form a thin air-cooling film along the outer wall. Cooling air is supplied an insert sleeve with openings in the leading edge cavity for impingement-cooling the leading edge. Holes through the leading edge afford thin-film cooling about the leading edge. Cooling air is provided the trailing edge cavity and passes through holes in the side walls of the vane for thin-film cooling of the trailing edge. Steam flows through a pair of intermediate cavities for impingement-cooling of the side walls. Post-impingement steam flows to the inner wall for impingement-cooling of the inner wall and returns the post-impingement cooling steam through inserts in other intermediate cavities for impingement-cooling the side walls of the vane.

Laser Cooling the Diatomic Molecule CaH

NASA Astrophysics Data System (ADS)

Velasquez, Joe, III; Di Rosa, Michael

2014-06-01

To laser-cool a species, a closed (or nearly closed) cycle is required to dissipate translational energy through many directed laser-photon absorption and subsequent randomly-directed spontaneous emission events. Many atoms lend themselves to such a closed-loop cooling cycle. Attaining laser-cooled molecular species is challenging because of their inherently complex internal structure, yet laser-cooling molecules could lead to studies in interesting chemical dynamics among other applications. Typically, laser-cooled atoms are assembled into molecules through photoassociation or Feschbach resonance. CaH is one of a few molecules whose internal structure is quite atom-like, allowing a nearly closed cycle without the need for many repumping lasers. We will also present our work-to-date on laser cooling this molecule. We employ traditional pulsed atomic/molecular beam techniques with a laser vaporization source to generate species with well-defined translational energies over a narrow range of velocity. In this way, we can apply laser-cooling to most species in the beam along a single dimension (the beam's axis). This project is funded by the LDRD program of the Los Alamos National Laboratory.

Steam cooling system for a gas turbine

DOEpatents

Wilson, Ian David; Barb, Kevin Joseph; Li, Ming Cheng; Hyde, Susan Marie; Mashey, Thomas Charles; Wesorick, Ronald Richard; Glynn, Christopher Charles; Hemsworth, Martin C.

2002-01-01

The steam cooling circuit for a gas turbine includes a bore tube assembly supplying steam to circumferentially spaced radial tubes coupled to supply elbows for transitioning the radial steam flow in an axial direction along steam supply tubes adjacent the rim of the rotor. The supply tubes supply steam to circumferentially spaced manifold segments located on the aft side of the 1-2 spacer for supplying steam to the buckets of the first and second stages. Spent return steam from these buckets flows to a plurality of circumferentially spaced return manifold segments disposed on the forward face of the 1-2 spacer. Crossover tubes couple the steam supply from the steam supply manifold segments through the 1-2 spacer to the buckets of the first stage. Crossover tubes through the 1-2 spacer also return steam from the buckets of the second stage to the return manifold segments. Axially extending return tubes convey spent cooling steam from the return manifold segments to radial tubes via return elbows.

Numerical investigation of the relationship between magnetic stiffness and minor loop size in the HTS levitation system

NASA Astrophysics Data System (ADS)

Yang, Yong; Li, Chengshan

2017-10-01

The effect of minor loop size on the magnetic stiffness has not been paid attention to by most researchers in experimental and theoretical studies about the high temperature superconductor (HTS) magnetic levitation system. In this work, we numerically investigate the average magnetic stiffness obtained by the minor loop traverses Δz (or Δx) varying from 0.1 mm to 2 mm in zero field cooling and field cooling regimes, respectively. The approximate values of the magnetic stiffness with zero traverse are obtained using the method of linear extrapolation. Compared with the average magnetic stiffness gained by any minor loop traverse, these approximate values are Not always close to the average magnetic stiffness produced by the smallest size of minor loops. The relative deviation ranges of average magnetic stiffness gained by the usually minor loop traverse (1 or 2 mm) are presented by the ratios of approximate values to average stiffness for different moving processes and two typical cooling conditions. The results show that most of average magnetic stiffness are remarkably influenced by the sizes of minor loop, which indicates that the magnetic stiffness obtained by a single minor loop traverse Δ z or Δ x, for example, 1 or 2 mm, can be generally caused a large deviation.

Bore tube assembly for steam cooling a turbine rotor

DOEpatents

DeStefano, Thomas Daniel; Wilson, Ian David

2002-01-01

An axial bore tube assembly for a turbine is provided to supply cooling steam to hot gas components of the turbine wheels and return the spent cooling steam. A pair of inner and outer tubes define a steam supply passage concentric about an inner return passage. The forward ends of the tubes communicate with an end cap assembly having sets of peripheral holes communicating with first and second sets of radial tubes whereby cooling steam from the concentric passage is supplied through the end cap holes to radial tubes for cooling the buckets and return steam from the buckets is provided through the second set of radial tubes through a second set of openings of the end cap into the coaxial return passage. A radial-to-axial flow transitioning device, including anti-swirling vanes is provided in the end cap. A strut ring adjacent the aft end of the bore tube assembly permits axial and radial thermal expansion of the inner tube relative to the outer tube.

Real-Time Closed Loop Modulated Turbine Cooling

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Culley, Dennis E.; Eldridge, Jeffrey; Jones, Scott; Woike, Mark; Cuy, Michael

2014-01-01

It has been noted by industry that in addition to dramatic variations of temperature over a given blade surface, blade-to-blade variations also exist despite identical design. These variations result from manufacturing variations, uneven wear and deposition over the life of the part as well as limitations in the uniformity of coolant distribution in the baseline cooling design. It is proposed to combine recent advances in optical sensing, actuation, and film cooling concepts to develop a workable active, closed-loop modulated turbine cooling system to improve by 10 to 20 the turbine thermal state over the flight mission, to improve engine life and to dramatically reduce turbine cooling air usage and aircraft fuel burn. A reduction in oxides of nitrogen (NOx) can also be achieved by using the excess coolant to improve mixing in the combustor especially for rotorcraft engines. Recent patents filed by industry and universities relate to modulating endwall cooling using valves. These schemes are complex, add weight and are limited to the endwalls. The novelty of the proposed approach is twofold 1) Fluidic diverters that have no moving parts are used to modulate cooling and can operate under a wide range of conditions and environments. 2) Real-time optical sensing to map the thermal state of the turbine has never been attempted in realistic engine conditions.

LM-research opportunities and activities at Beer-Sheva

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

Lesin, S.

1996-06-01

Energy conversion concepts based on liquid metal (LM) magnetohydrodynamic (MHD) technology was intensively investigated at the Center for MHD Studies (CMHDS), in the Ben-Gurion University of the Negev in Israel. LMMHD energy conversion systems operate in a closed cycle as follows: heat intended for conversion into electricity is added to a liquid metal contained in a closed loop of pipes. The liquid metal is mixed with vapor or gas introduced from outside so that a two-phase mixture is formed. The gaseous phase performs a thermodynamic cycle, converting a certain amount of heat into mechanical energy of the liquid metal. Thismore » energy is converted into electrical power as the metal flows across a magnetic field in the MHD channel. Those systems where the expanding thermodynamic fluid performs work against gravitational forces (natural circulation loops) and using heavy liquid metals are named ETGAR systems. A number of different heavy-metal facilities have been specially constructed and tested with fluid combinations of mercury and steam, mercury and nitrogen, mercury and freon, lead-bismuth and steam, and lead and steam. Since the experimental investigation of such flows is a very difficult task and all the known measurment methods are incomplete and not fully reliable, a variety of experimental approaches have been developed. In most experiments, instantaneous pressure distribution along the height of the upcomer were measured and the average void fraction was calculated numerically using the one-dimensional equation for the two-phase flow. The research carried out at the CMHDS led to significant improvements in the characterization of the two-phase phenomena expected in the riser of ETGAR systems. One of the most important outcomes is the development of a new empirical correlation which enables the reliable prediction of the velocity ratio between the LM and the steam (slip), the friction factor, as well as of the steam void fraction distribution along the riser.« less

Optimization of 200 MWth and 250 MWt Ship Based Small Long Life NPP

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

Fitriyani, Dian; Su'ud, Zaki

2010-06-22

Design optimization of ship-based 200 MWth and 250 MWt nuclear power reactors have been performed. The neutronic and thermo-hydraulic programs of the three-dimensional X-Y-Z geometry have been developed for the analysis of ship-based nuclear power plant. Quasi-static approach is adopted to treat seawater effect. The reactor are loop type lead bismuth cooled fast reactor with nitride fuel and with relatively large coolant pipe above reactor core, the heat from primary coolant system is directly transferred to watersteam loop through steam generators. Square core type are selected and optimized. As the optimization result, the core outlet temperature distribution is changing withmore » the elevation angle of the reactor system and the characteristics are discussed.« less

55. BOILER CHAMBER No. 1, LOOP B, STEAM DRUM AND ...

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

55. BOILER CHAMBER No. 1, LOOP B, STEAM DRUM AND DOWNCOMERS LOOKING EAST (LOCATION LLL) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

Heat tolerance of two Cladonia species and Campylopus praemorsus in a hot steam vent area of Hawaii.

PubMed

Kappen, Ludger; Smith, Clifford W

1980-01-01

Temperatures were measured in soil, Cladonia skottsbergii, Cl. oceanica, and Campylopus praemorsus growing in the almost barren geothermal area at Puhimau, Hawaii. The measurements were made in the early morning in winter when insolation and air temperatures were minimal and the geothermal effects were predominant. Measurements were made on healthy, dew moistened plants. Close to steam vents Campylopus praemorsus forms thick cushions on hot soil and temperatures up to 29.8°C are recorded in the active parts of the moss. Cladonia oceanica grows exclusively on moss in this area, but not as close to steam vents as the moss itself. Maximum temperatures were 27.2°C in stunted and 23°C in ramified growth forms. In this area Cl. skottsbergii normally colonizes tree stumps of Metrosideros only where the steam is already cool. Maximum temperatures were 23°C in normal thalli, through higher temperatures were measured in partly damaged or killed thalli overhanging the stump where they are immersed in hot steam. With respect to heat tolerance only Campylopus can be considered as adapted to the hot environment. Therefore it is able to colonize the hot dry soil while deriving its moisture from adjacent steam vents. The lichens, particularly Cl. skottsbergii, are not adapted and are as sensitive to heat as most other lichens. Therefore they can only survive where there is at most a small geothermal impact yet they are obviously dependent on moisture from the steam vents.

Irradiation Testing Vehicles for Fast Reactors from Open Test Assemblies to Closed Loops

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

Sienicki, James J.; Grandy, Christopher

A review of irradiation testing vehicle approaches and designs that have been incorporated into past Sodium-Cooled Fast Reactors (SFRs) or envisioned for incorporation has been carried out. The objective is to understand the essential features of the approaches and designs so that they can inform test vehicle designs for a future U.S. Fast Test Reactor. Fast test reactor designs examined include EBR-II, FFTF, JOYO, BOR-60, PHÉNIX, JHR, and MBIR. Previous designers exhibited great ingenuity in overcoming design and operational challenges especially when the original reactor plant’s mission changed to an irradiation testing mission as in the EBRII reactor plant. Themore » various irradiation testing vehicles can be categorized as: Uninstrumented open assemblies that fit into core locations; Instrumented open test assemblies that fit into special core locations; Self-contained closed loops; and External closed loops. A special emphasis is devoted to closed loops as they are regarded as a very desirable feature of a future U.S. Fast Test Reactor. Closed loops are an important technology for irradiation of fuels and materials in separate controlled environments. The impact of closed loops on the design of fast reactors is also discussed in this report.« less

Experimental study of condensate subcooling with the use of a model of an air-cooled condenser

NASA Astrophysics Data System (ADS)

Sukhanov, V. A.; Bezukhov, A. P.; Bogov, I. A.; Dontsov, N. Y.; Volkovitsky, I. D.; Tolmachev, V. V.

2016-01-01

Water-supply deficit is now felt in many regions of the world. This hampers the construction of new steam-turbine and combined steam-and-gas thermal power plants. The use of dry cooling systems and, specifically, steam-turbine air-cooled condensers (ACCs) expands the choice of sites for the construction of such power plants. The significance of condensate subcooling Δ t as a parameter that negatively affects the engineering and economic performance of steam-turbine plants is thereby increased. The operation and design factors that influence the condensate subcooling in ACCs are revealed, and the research objective is, thus, formulated properly. The indicated research was conducted through physical modeling with the use of the Steam-Turbine Air-Cooled Condenser Unit specialized, multipurpose, laboratory bench. The design and the combined schematic and measurement diagram of this test bench are discussed. The experimental results are presented in the form of graphic dependences of the condensate subcooling value on cooling ratio m and relative weight content ɛ' of air in steam at the ACC inlet at different temperatures of cooling air t ca ' . The typical ranges of condensate subcooling variation (4 ≤ Δ t ≤ 6°C, 2 ≤ Δ t ≤ 4°C, and 0 ≤ Δ t ≤ 2°C) are identified based on the results of analysis of the attained Δ t levels in the ACC and numerous Δ t reduction estimates. The corresponding ranges of cooling ratio variation at different temperatures of cooling air at the ACC inlet are specified. The guidelines for choosing the adjusted ranges of cooling ratio variation with account of the results of experimental studies of the dependences of the absolute pressure of the steam-air mixture in the top header of the ACC and the heat flux density on the cooling ratio at different temperatures of cooling air at the ACC inlet are given.

Water cooled steam jet

DOEpatents

Wagner, Jr., Edward P.

1999-01-01

A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed therebetween. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock.

60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND ...

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

60. BOILER CHAMBER No. 1, D LOOP STEAM GENERATOR AND MAIN COOLANT PUMP LOOKING NORTHEAST (LOCATION OOO) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

Closed Brayton cycle power conversion systems for nuclear reactors :

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

Wright, Steven A.; Lipinski, Ronald J.; Vernon, Milton E.

2006-04-01

This report describes the results of a Sandia National Laboratories internally funded research program to study the coupling of nuclear reactors to gas dynamic Brayton power conversion systems. The research focused on developing integrated dynamic system models, fabricating a 10-30 kWe closed loop Brayton cycle, and validating these models by operating the Brayton test-loop. The work tasks were performed in three major areas. First, the system equations and dynamic models for reactors and Closed Brayton Cycle (CBC) systems were developed and implemented in SIMULINKTM. Within this effort, both steady state and dynamic system models for all the components (turbines, compressors,more » reactors, ducting, alternators, heat exchangers, and space based radiators) were developed and assembled into complete systems for gas cooled reactors, liquid metal reactors, and electrically heated simulators. Various control modules that use proportional-integral-differential (PID) feedback loops for the reactor and the power-conversion shaft speed were also developed and implemented. The simulation code is called RPCSIM (Reactor Power and Control Simulator). In the second task an open cycle commercially available Capstone C30 micro-turbine power generator was modified to provide a small inexpensive closed Brayton cycle test loop called the Sandia Brayton test-Loop (SBL-30). The Capstone gas-turbine unit housing was modified to permit the attachment of an electrical heater and a water cooled chiller to form a closed loop. The Capstone turbine, compressor, and alternator were used without modification. The Capstone systems nominal operating point is 1150 K turbine inlet temperature at 96,000 rpm. The annular recuperator and portions of the Capstone control system (inverter) and starter system also were reused. The rotational speed of the turbo-machinery is controlled by adjusting the alternator load by using the electrical grid as the load bank. The SBL-30 test loop was operated at the manufacturers site (Barber-Nichols Inc.) and installed and operated at Sandia. A sufficiently detailed description of the loop is provided in this report along with the design characteristics of the turbo-alternator-compressor set to allow other researchers to compare their results with those measured in the Sandia test-loop. The third task consisted of a validation effort. In this task the test loop was operated and compared with the modeled results to develop a more complete understanding of this electrically heated closed power generation system and to validate the model. The measured and predicted system temperatures and pressures are in good agreement, indicating that the model is a reasonable representation of the test loop. Typical deviations between the model and the hardware results are less than 10%. Additional tests were performed to assess the capability of the Brayton engine to continue to remove decay heat after the reactor/heater is shutdown, to develop safe and effective control strategies, and to access the effectiveness of gas inventory control as an alternative means to provide load following. In one test the heater power was turned off to simulate a rapid reactor shutdown, and the turbomachinery was driven solely by the sensible heat stored in the heater for over 71 minutes without external power input. This is an important safety feature for CBC systems as it means that the closed Brayton loop will keep cooling the reactor without the need for auxiliary power (other than that needed to circulate the waste heat rejection coolant) provided the heat sink is available.« less

Proposed Performance Evaluation Acceptance Test for Heat Recovery Incinerators

DTIC Science & Technology

1988-08-01

steam and the cooling water (if used). = Qye + Qwe = Mass flow of steam or water x enthalpy change. Qye = Wye x (hout - hin) Qwe = Wwe x (hout - hin...cooling water (if used). = Qye + Qwe = . Mass flow of steam or water x enthalpy change. Qye = Wye x (hout - hin) Qwe = Wwe x (hout - hin) = Wwe x (tout...transferred to recovery liquid (e.g., steam) Btu/hr 0.293 W Qwe Heat in water (cooling or Btu/hr 0.293 W quench) r Waste - S Sulfur lb/lb - kg/kg t

Gas turbine combustor transition

DOEpatents

Coslow, Billy Joe; Whidden, Graydon Lane

1999-01-01

A method of converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit.

Gas turbine combustor transition

DOEpatents

Coslow, B.J.; Whidden, G.L.

1999-05-25

A method is described for converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit. 7 figs.

PARTIAL ECONOMIC STUDY OF STEAM COOLED HEAVY WATER MODERATED REACTORS

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

None

1960-04-01

Steam-cooled reactors are compared with CAHDU for costs of Calandria tubes, pressure tubes. heavy water moderator, heavy water reflector, fuel supply, heat exchanger, and turbine generator. A direct-cycle lightsteam-cooled heavy- water-moderated pressure-tube reactor formed the basic reactor design for the study. Two methods of steam circulation through the reactor were examined. In both cases the steam was generated outside the reactor and superheated in the reactor core. One method consisted of a series of reactor and steam generator passes. The second method consisted of the Loeffler cycle and its modifications. The fuel was assumed to be natural cylindrical UO/sub 2/more » pellets sheathed in a hypothetical material with the nuclear properties of Zircaloy, but able to function at temperatures to 900 deg F. For the conditions assumed, the longer the rod, the higher the outlet temperature and therefore the higher the efficiency. The turbine cycle efficiency was calculated on the assumption that suitable steam generators are available. As the neutron losses to the pressure tubes were significant, an economic analysis of insulated pressure tubes is included. A description of the physics program for steam-cooled reactors is included. Results indicated that power from the steam-cooled reactor would cost 1.4 mills/ kwh compared with 1.25 mills/kwh for CANDU. (M.C.G.)« less

Methods for disassembling, replacing and assembling parts of a steam cooling system for a gas turbine

DOEpatents

Wilson, Ian D.; Wesorick, Ronald R.

2002-01-01

The steam cooling circuit for a gas turbine includes a bore tube assembly supplying steam to circumferentially spaced radial tubes coupled to supply elbows for transitioning the radial steam flow in an axial direction along steam supply tubes adjacent the rim of the rotor. The supply tubes supply steam to circumferentially spaced manifold segments located on the aft side of the 1-2 spacer for supplying steam to the buckets of the first and second stages. Spent return steam from these buckets flows to a plurality of circumferentially spaced return manifold segments disposed on the forward face of the 1-2 spacer. Crossover tubes couple the steam supply from the steam supply manifold segments through the 1-2 spacer to the buckets of the first stage. Crossover tubes through the 1-2 spacer also return steam from the buckets of the second stage to the return manifold segments. Axially extending return tubes convey spent cooling steam from the return manifold segments to radial tubes via return elbows. The bore tube assembly, radial tubes, elbows, manifold segments and crossover tubes are removable from the turbine rotor and replaceable.

Carbon Dioxide Reduction Technology Trade Study

NASA Technical Reports Server (NTRS)

Jeng, Frank F.; Anderson, Molly S.; Abney, Morgan B.

2011-01-01

For long-term human missions, a closed-loop atmosphere revitalization system (ARS) is essential to minimize consumables. A carbon dioxide (CO2) reduction technology is used to reclaim oxygen (O2) from metabolic CO2 and is vital to reduce the delivery mass of metabolic O2. A key step in closing the loop for ARS will include a proper CO2 reduction subsystem that is reliable and with low equivalent system mass (ESM). Sabatier and Bosch CO2 reduction are two traditional CO2 reduction subsystems (CRS). Although a Sabatier CRS has been delivered to International Space Station (ISS) and is an important step toward closing the ISS ARS loop, it recovers only 50% of the available O2 in CO2. A Bosch CRS is able to reclaim all O2 in CO2. However, due to continuous carbon deposition on the catalyst surface, the penalties of replacing spent catalysts and reactors and crew time in a Bosch CRS are significant. Recently, technologies have been developed for recovering hydrogen (H2) from Sabatier-product methane (CH4). These include methane pyrolysis using a microwave plasma, catalytic thermal pyrolysis of CH4 and thermal pyrolysis of CH4. Further, development in Sabatier reactor designs based on microchannel and microlith technology could open up opportunities in reducing system mass and enhancing system control. Improvements in Bosch CRS conversion have also been reported. In addition, co-electrolysis of steam and CO2 is a new technology that integrates oxygen generation and CO2 reduction functions in a single system. A co-electrolysis unit followed by either a Sabatier or a carbon formation reactor based on Bosch chemistry could improve the overall competitiveness of an integrated O2 generation and CO2 reduction subsystem. This study evaluates all these CO2 reduction technologies, conducts water mass balances for required external supply of water for 1-, 5- and 10-yr missions, evaluates mass, volume, power, cooling and resupply requirements of various technologies. A system analysis and comparison among the technologies was made based on ESM, technology readiness level and reliability. Those technologies with potential were recommended for development.

Water cooled steam jet

DOEpatents

Wagner, E.P. Jr.

1999-01-12

A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed there between. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock. 2 figs.

Solar thermoelectric cooling using closed loop heat exchangers with macro channels

NASA Astrophysics Data System (ADS)

Atta, Raghied M.

2017-07-01

In this paper we describe the design, analysis and experimental study of an advanced coolant air conditioning system which cools or warms airflow using thermoelectric (TE) devices powered by solar cells. Both faces of the TE devices are directly connected to closed-loop highly efficient channels plates with macro scale channels and liquid-to-air heat exchangers. The hot side of the system consists of a pump that moves a coolant through the hot face of the TE modules, a radiator that drives heat away into the air, and a fan that transfer the heat over the radiator by forced convection. The cold side of the system consists also of a pump that moves coolant through the cold face of the TE modules, a radiator that drives cold away into the air, and a fan that blows cold air off the radiator. The system was integrated with solar panels, tested and its thermal performance was assessed. The experimental results verify the possibility of heating or cooling air using TE modules with a relatively high coefficient of performance (COP). The system was able to cool a closed space of 30 m3 by 14 °C below ambient within 90 min. The maximum COP of the whole system was 0.72 when the TE modules were running at 11.2 Å and 12 V. This improvement in the system COP over the air cooled heat sink is due to the improvement of the system heat exchange by means of channels plates.

Steam--water mixing and system hydrodynamics program. Task 4. Quarterly progress report, October 1, 1977--December 31, 1977. [PWR

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

Carbiener, W.A.; Cudnik, R.A.; Dykhuizen, R.C.

Experimental studies were conducted in a /sup 2///sub 15/-scale model of a four-loop pressurized water reactor at pressures to 75 psia to extend the understanding of steam-water interaction phenomena and processes associated with a loss-of-coolant accident. Plenum filling studies were conducted with hydraulic communication between the cold leg and core steam supplies and hot walls, with both fixed and ramped steam flows. Comparisons of correlational fits have been made for penetration data obtained with hydraulic communication, fixed cold leg steam, and no cold leg steam. Statistical tests applied to these correlational fits have indicated that the hydraulic communication and fixedmore » cold leg steam data can be considered to be a common data set. Comparing either of these data sets to the no cold leg steam data using the statistical test indicated that it was unlikely that these sets could be considered to be a common data set. The introduction of cold leg steam results in a slight decrease in penetration relative to that obtained without cold leg steam at the same value of subcooling of water entering the downcomer. A dimensionless parameter which is a weighted mean of a modified Froude number and the Weber number has been proposed as a scaling parameter for penetration data. This parameter contains an additional degree of freedom which allows data from different scales to collapse more closely to a single curve than current scaling parameters permit.« less

Heat transfer performance comparison of steam and air in gas turbine cooling channels with different rib angles

NASA Astrophysics Data System (ADS)

Shi, Xiaojun; Gao, Jianmin; Xu, Liang; Li, Fajin

2013-11-01

Using steam as working fluid to replace compressed air is a promising cooling technology for internal cooling passages of blades and vanes. The local heat transfer characteristics and the thermal performance of steam flow in wide aspect ratio channels ( W/ H = 2) with different angled ribs on two opposite walls have been experimentally investigated in this paper. The averaged Nusselt number ratios and the friction factor ratios of steam and air in four ribbed channels were also measured under the same test conditions for comparison. The Reynolds number range is 6,000-70,000. The rib angles are 90°, 60°, 45°, and 30°, respectively. The rib height to hydraulic diameter ratio is 0.047. The pitch-to-rib height ratio is 10. The results show that the Nusselt number ratios of steam are 1.19-1.32 times greater than those of air over the range of Reynolds numbers studied. For wide aspect ratio channels using steam as the coolant, the 60° angled ribs has the best heat transfer performance and is recommended for cooling design.

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, Paul W.; Bannister, Ronald L.

1995-01-01

A gas turbine system in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas.

Active cooling-based surface confinement system for thermal soil treatment

DOEpatents

Aines, R.D.; Newmark, R.L.

1997-10-28

A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders. 1 fig.

Active cooling-based surface confinement system for thermal soil treatment

DOEpatents

Aines, Roger D.; Newmark, Robin L.

1997-01-01

A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders.

Efforts to Reduce International Space Station Crew Maintenance Time in the Management of the Extravehicular Mobility Unit Transport Loop Water Quality

NASA Technical Reports Server (NTRS)

Etter,David; Rector, Tony; Boyle, robert; Zande, Chris Vande

2012-01-01

The EMU (Extravehicular Mobility Unit) contains a semi-closed-loop re-circulating water circuit (Transport Loop) to absorb heat into a LCVG (Liquid Coolant and Ventilation Garment) worn by the astronaut. A second, single-pass water circuit (Feed-water Loop) provides water to a cooling device (Sublimator) containing porous plates, and that water sublimates through the porous plates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. The quality of the EMU Transport Loop water is maintained through the use of a water processing kit (ALCLR - Airlock Cooling Loop Remediation) that is used to periodically clean and disinfect the water circuit. Opportunities to reduce crew time associated with ALCLR operations include a detailed review of the historical water quality data for evidence to support an extension to the implementation cycle. Furthermore, an EMU returned after 2-years of use on the ISS (International Space Station) is being used as a test bed to evaluate the results of extended and repeated ALCLR implementation cycles. Finally, design, use and on-orbit location enhancements to the ALCLR kit components are being considered to allow the implementation cycle to occur in parallel with other EMU maintenance and check-out activities, and to extend the life of the ALCLR kit components. These efforts are undertaken to reduce the crew-time and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a post- Shuttle 6-year service life.

Efforts to Reduce International Space Station Crew Maintenance for the Management of the Extravehicular Mobility Unit Transport Loop Water Quality

NASA Technical Reports Server (NTRS)

Steele, John W.; Etter, David; Rector, Tony; Boyle, Robert; Vandezande, Christopher

2013-01-01

The EMU (Extravehicular Mobility Unit) contains a semi-closed-loop re-circulating water circuit (Transport Loop) to absorb heat into a LCVG (Liquid Coolant and Ventilation Garment) worn by the astronaut. A second, single-pass water circuit (Feed-water Loop) provides water to a cooling device (Sublimator) containing porous plates, and that water sublimates through the porous plates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. The quality of the EMU Transport Loop water is maintained through the use of a water processing kit (ALCLR Airlock Cooling Loop Remediation) that is used to periodically clean and disinfect the water circuit. Opportunities to reduce crew time associated with on-orbit ALCLR operations include a detailed review of the historical water quality data for evidence to support an extension to the implementation cycle. Furthermore, an EMU returned after 2-years of use on the ISS (International Space Station) is being used as a test bed to evaluate the results of extended and repeated ALCLR implementation cycles. Finally, design, use and on-orbit location enhancements to the ALCLR kit components are being considered to allow the implementation cycle to occur in parallel with other EMU maintenance and check-out activities, and to extend the life of the ALCLR kit components. These efforts are undertaken to reduce the crew-time and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a post-Shuttle 6-year service life.

Mitigation of steam generator tube rupture in a pressurized water reactor with passive safety systems

DOEpatents

McDermott, D.J.; Schrader, K.J.; Schulz, T.L.

1994-05-03

The effects of steam generator tube ruptures in a pressurized water reactor are mitigated by reducing the pressure in the primary loop by diverting reactor coolant through the heat exchanger of a passive heat removal system immersed in the in containment refueling water storage tank in response to a high feed water level in the steam generator. Reactor coolant inventory is maintained by also in response to high steam generator level introducing coolant into the primary loop from core make-up tanks at the pressure in the reactor coolant system pressurizer. The high steam generator level is also used to isolate the start-up feed water system and the chemical and volume control system to prevent flooding into the steam header. 2 figures.

Mitigation of steam generator tube rupture in a pressurized water reactor with passive safety systems

DOEpatents

McDermott, Daniel J.; Schrader, Kenneth J.; Schulz, Terry L.

1994-01-01

The effects of steam generator tube ruptures in a pressurized water reactor are mitigated by reducing the pressure in the primary loop by diverting reactor coolant through the heat exchanger of a passive heat removal system immersed in the in containment refueling water storage tank in response to a high feed water level in the steam generator. Reactor coolant inventory is maintained by also in response to high steam generator level introducing coolant into the primary loop from core make-up tanks at the pressure in the reactor coolant system pressurizer. The high steam generator level is also used to isolate the start-up feed water system and the chemical and volume control system to prevent flooding into the steam header. 2 figures.

New Technique for Cryogenically Cooling Small Test Articles

NASA Technical Reports Server (NTRS)

Rodriquez, Karen M.; Henderson, Donald J.

2011-01-01

Convective heat removal techniques to rapidly cool small test articles to Earth-Moon L2 temperatures of 77 K were accomplished through the use of liquid nitrogen (LN2). By maintaining a selected pressure range on the saturation curve, test articles were cooled below the LN2 boiling point at ambient pressure in less than 30 min. Difficulties in achieving test pressures while maintaining the temperature tolerance necessitated a modification to the original system to include a closed loop conductive cold plate and cryogenic shroud

Real-time Kalman filter: Cooling of an optically levitated nanoparticle

NASA Astrophysics Data System (ADS)

Setter, Ashley; Toroš, Marko; Ralph, Jason F.; Ulbricht, Hendrik

2018-03-01

We demonstrate that a Kalman filter applied to estimate the position of an optically levitated nanoparticle, and operated in real-time within a field programmable gate array, is sufficient to perform closed-loop parametric feedback cooling of the center-of-mass motion to sub-Kelvin temperatures. The translational center-of-mass motion along the optical axis of the trapped nanoparticle has been cooled by 3 orders of magnitude, from a temperature of 300 K to a temperature of 162 ±15 mK.

Split radiator design for heat rejection optimization for a waste heat recovery system

DOEpatents

Ernst, Timothy C.; Nelson, Christopher R.

2016-10-18

A cooling system provides improved heat recovery by providing a split core radiator for both engine cooling and condenser cooling for a Rankine cycle (RC). The cooling system includes a radiator having a first cooling core portion and a second cooling core portion. An engine cooling loop is fluidly connected the second cooling core portion. A condenser of an RC has a cooling loop fluidly connected to the first cooling core portion. A valve is provided between the engine cooling loop and the condenser cooling loop adjustably control the flow of coolant in the condenser cooling loop into the engine cooling loop. The cooling system includes a controller communicatively coupled to the valve and adapted to determine a load requirement for the internal combustion engine and adjust the valve in accordance with the engine load requirement.

Cooling system for a gas turbine

DOEpatents

Wilson, Ian David; Salamah, Samir Armando; Bylina, Noel Jacob

2003-01-01

A plurality of arcuate circumferentially spaced supply and return manifold segments are arranged on the rim of a rotor for respectively receiving and distributing cooling steam through exit ports for distribution to first and second-stage buckets and receiving spent cooling steam from the first and second-stage buckets through inlet ports for transmission to axially extending return passages. Each of the supply and return manifold segments has a retention system for precluding substantial axial, radial and circumferential displacement relative to the rotor. The segments also include guide vanes for minimizing pressure losses in the supply and return of the cooling steam. The segments lie substantially equal distances from the centerline of the rotor and crossover tubes extend through each of the segments for communicating steam between the axially adjacent buckets of the first and second stages, respectively.

Management of the Post-Shuttle Extravehicular Mobility Unit (EMU) Water Circuits

NASA Technical Reports Server (NTRS)

Steele, John W.; Etter, David; Rector, Tony; Hill, Terry; Wells, Kevin

2011-01-01

The EMU incorporates two separate water circuits for the rejection of metabolic heat from the astronaut and the cooling of electrical components. The first (the Transport Water Loop) circulates in a semi-closed-loop manner and absorbs heat into a Liquid Coolant and Ventilation Garment (LCVG) warn by the astronaut. The second (the Feed Water Loop) provides water to a cooling device (Sublimator) with a porous plate, and that water subsequently sublimates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. Efforts are underway to streamline the use of a water processing kit (ALCLR) that is being used to periodically clean and disinfect the Transport Loop Water. Those efforts include a fine tuning of the duty cycle based on a review of prior performance data as well as an assessment of a fixed installation of this kit into the EMU backpack or within on-orbit EMU interface hardware. Furthermore, testing is being conducted to ensure compatibility between the International Space Station (ISS) Water Processor Assembly (WPA) effluent and the EMU Sublimator as a prelude to using the WPA effluent as influent to the EMU Feed Water loop. This work is undertaken to reduce the crew-time and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a post-Shuttle 6-year service life.

Staged regenerative sorption heat pump

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor)

1995-01-01

A regenerative adsorbent heat pump process and system for cooling and heating a space. A sorbent is confined in a plurality of compressors of which at least four are first stage and at least four are second stage. The first stage operates over a first pressure region and the second stage over a second pressure region which is higher than the first. Sorbate from the first stage enters the second stage. The sorbate loop includes a condenser, expansion valve, evaporator and the compressors. A single sorbate loop can be employed for single-temperature-control such as air conditioning and heating. Two sorbate loops can be used for two-temperature-control as in a refrigerator and freezer. The evaporator temperatures control the freezer and refrigerator temperatures. Alternatively the refrigerator temperature can be cooled by the freezer with one sorbate loop. A heat transfer fluid is circulated in a closed loop which includes a radiator and the compressors. Low temperature heat is exhausted by the radiator. High temperature heat is added to the heat transfer fluid entering the compressors which are desorbing vapor. Heat is transferred from compressors which are sorbing vapor to the heat transfer fluid, and from the heat transfer fluid to the compressors which are desorbing vapor. Each compressor is subjected to the following phases, heating to its highest temperature, cooling down from its highest temperature, cooling to its lowest temperature, and warming up from its lowest temperature. The phases are repeated to complete a cycle and regenerate heat.

Management of the Post-Shuttle Extravehicular Mobility Unit (EMU) Water Circuits

NASA Technical Reports Server (NTRS)

Steele, John W.; Etter, David; Rector, Tony; Hill, Terry; Wells, Kevin

2012-01-01

The EMU incorporates two separate water circuits for the rejection of metabolic heat from the astronaut and the cooling of electrical components. The first (the Transport Water Loop) circulates in a semi-closed-loop manner and absorbs heat into a Liquid Coolant and Ventilation Garment (LCVG) worn by the astronaut. The second (the Feed-water Loop) provides water to a cooling device (Sublimator) with a porous plate, and that water subsequently sublimates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. Efforts are underway to streamline the use of a water processing kit (ALCLR) that is being used to periodically clean and disinfect the Transport Loop Water. Those efforts include a fine tuning of the duty cycle based on a review of prior performance data as well as an assessment of a fixed installation of this kit into the EMU backpack, within on-orbit EMU interface hardware or as a stand-alone unit. Furthermore, testing is being conducted to ensure compatibility between the International Space Station (ISS) Water Processor Assembly (WPA) effluent and the EMU Sublimator as a prelude to using the WPA effluent as influent to the EMU Feed Water loop. This work is undertaken to reduce the crewtime and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a 6-year service life.

Retention sleeve for a thermal medium carrying tube in a gas turbine

DOEpatents

Lathrop, Norman Douglas; Czachor, Robert Paul

2003-01-01

Multiple tubes are connected to steam supply and spent cooling steam return manifolds for supplying cooling steam to buckets and returning spent cooling steam from the buckets to the manifolds, respectively. The tubes are prevented from axial movement in one direction by flanges engaging end faces of the spacer between the first and second-stage wheels. Retention sleeves are disposed about cantilevered ends of the tubes. One end of the retention sleeve engages an enlarged flange on the tube, while an opposite end is spaced axially from an end face of the adjoining wheel, forming a gap, enabling thermal expansion of the tubes and limiting axial displacement of the tube in the opposite direction.

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, P.W.; Bannister, R.L.

1995-07-11

A gas turbine system is described in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas. 4 figs.

Method for generating hydrogen for fuel cells

DOEpatents

Ahmed, Shabbir; Lee, Sheldon H. D.; Carter, John David; Krumpelt, Michael

2004-03-30

A method of producing a H.sub.2 rich gas stream includes supplying an O.sub.2 rich gas, steam, and fuel to an inner reforming zone of a fuel processor that includes a partial oxidation catalyst and a steam reforming catalyst or a combined partial oxidation and stream reforming catalyst. The method also includes contacting the O.sub.2 rich gas, steam, and fuel with the partial oxidation catalyst and the steam reforming catalyst or the combined partial oxidation and stream reforming catalyst in the inner reforming zone to generate a hot reformate stream. The method still further includes cooling the hot reformate stream in a cooling zone to produce a cooled reformate stream. Additionally, the method includes removing sulfur-containing compounds from the cooled reformate stream by contacting the cooled reformate stream with a sulfur removal agent. The method still further includes contacting the cooled reformate stream with a catalyst that converts water and carbon monoxide to carbon dioxide and H.sub.2 in a water-gas-shift zone to produce a final reformate stream in the fuel processor.

Fuel processor and method for generating hydrogen for fuel cells

DOEpatents

Ahmed, Shabbir [Naperville, IL; Lee, Sheldon H. D. [Willowbrook, IL; Carter, John David [Bolingbrook, IL; Krumpelt, Michael [Naperville, IL; Myers, Deborah J [Lisle, IL

2009-07-21

A method of producing a H.sub.2 rich gas stream includes supplying an O.sub.2 rich gas, steam, and fuel to an inner reforming zone of a fuel processor that includes a partial oxidation catalyst and a steam reforming catalyst or a combined partial oxidation and stream reforming catalyst. The method also includes contacting the O.sub.2 rich gas, steam, and fuel with the partial oxidation catalyst and the steam reforming catalyst or the combined partial oxidation and stream reforming catalyst in the inner reforming zone to generate a hot reformate stream. The method still further includes cooling the hot reformate stream in a cooling zone to produce a cooled reformate stream. Additionally, the method includes removing sulfur-containing compounds from the cooled reformate stream by contacting the cooled reformate stream with a sulfur removal agent. The method still further includes contacting the cooled reformate stream with a catalyst that converts water and carbon monoxide to carbon dioxide and H.sub.2 in a water-gas-shift zone to produce a final reformate stream in the fuel processor.

PRESSURE SYSTEM CONTROL

DOEpatents

Esselman, W.H.; Kaplan, G.M.

1961-06-20

The control of pressure in pressurized liquid systems, especially a pressurized liquid reactor system, may be achieved by providing a bias circuit or loop across a closed loop having a flow restriction means in the form of an orifice, a storage tank, and a pump connected in series. The subject invention is advantageously utilized where control of a reactor can be achieved by response to the temperature and pressure of the primary cooling system.

Fast reactor power plant design having heat pipe heat exchanger

DOEpatents

Huebotter, P.R.; McLennan, G.A.

1984-08-30

The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes. The thermal energy from the primary coolant is transferred to the water coolant by isothermal evaporation-condensation of the heat transfer medium between the heat pipe and U-tube walls, the heat transfer medium moving within the heat pipe primarily transversely between these walls.

Fast reactor power plant design having heat pipe heat exchanger

DOEpatents

Huebotter, Paul R.; McLennan, George A.

1985-01-01

The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes. The thermal energy from the primary coolant is transferred to the water coolant by isothermal evaporation-condensation of the heat transfer medium between the heat pipe and U-tube walls, the heat transfer medium moving within the heat pipe primarily transversely between these walls.

Apparatus for impingement cooling a side wall adjacent an undercut region of a turbine nozzle segment

DOEpatents

Burdgick, Steven Sebastian

2002-01-01

A gas turbine nozzle segment has outer and inner bands and vanes therebetween. Each band includes a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. Slots are formed through the inturned flange along the nozzle side wall. A plate having through-apertures extending between opposite edges thereof is disposed in each slot, the slots and plates being angled such that the cooling medium exiting the apertures in the second cavity lie close to the side wall for focusing and targeting cooling medium onto the side wall.

Fractional order PIλ controller synthesis for steam turbine speed governing systems.

PubMed

Chen, Kai; Tang, Rongnian; Li, Chuang; Lu, Junguo

2018-06-01

The current state of the art of fractional order stability theory is hardly to build connection between the time domain analysis and frequency domain synthesis. The existing tuning methodologies for fractional order PI λ D μ are not always satisfy the given gain crossover frequency and phase margin simultaneously. To overcome the drawbacks in the existing synthesis of fractional order controller, the synthesis of optimal fractional order PI λ controller for higher-order process is proposed. According to the specified phase margin, the corresponding upper boundary of gain crossover frequency and stability surface in parameter space are obtained. Sweeping the order parameter over λ∈(0,2), the complete set of stabilizing controller which guarantees both pre-specifying phase frequency characteristic can be collected. Whereafter, the optimal fractional order PI λ controller is applied to the speed governing systems of steam turbine generation units. The numerical simulation and hardware-in-the-loop simulation demonstrate the effectiveness and satisfactory closed-loop performance of obtained fractional order PI λ controller. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Design and Development of an air-cooled Temperature-Swing Adsorption Compressor for Carbon Dioxide

NASA Technical Reports Server (NTRS)

Mulloth, Lila M.

2003-01-01

The air revitalization system of the International Space Station (ISS) operates in an open loop mode and relies on the resupply of oxygen and other consumables from earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. We have a developed a temperature-swing adsorption compressor (TSAC) for performing these tasks that is energy efficient, quiet, and has no wearing parts. This paper discusses the design features of a TSAC hardware that uses air as the cooling medium and has Space Station application.

Development of a test device to characterize thermal protective performance of fabrics against hot steam and thermal radiation

NASA Astrophysics Data System (ADS)

Su, Yun; Li, Jun

2016-12-01

Steam burns severely threaten the life of firefighters in the course of their fire-ground activities. The aim of this paper was to characterize thermal protective performance of flame-retardant fabrics exposed to hot steam and low-level thermal radiation. An improved testing apparatus based on ASTM F2731-11 was developed in order to simulate the routine fire-ground conditions by controlling steam pressure, flow rate and temperature of steam box. The thermal protective performance of single-layer and multi-layer fabric system with/without an air gap was studied based on the calibrated tester. It was indicated that the new testing apparatus effectively evaluated thermal properties of fabric in hot steam and thermal radiation. Hot steam significantly exacerbated the skin burn injuries while the condensed water on the skin’s surface contributed to cool down the skin tissues during the cooling. Also, the absorbed thermal energy during the exposure and the cooling was mainly determined by the fabric’s configuration, the air gap size, the exposure time and the existence of hot steam. The research provides a effective method to characterize the thermal protection of fabric in complex conditions, which will help in optimization of thermal protection performance of clothing and reduction of steam burn.

On the possibility of connecting a non-operating main circulation pump with three pumps in operation without preliminary coast-down of power-generating unit No. 5 in the Novovoronezh nuclear power plant

NASA Astrophysics Data System (ADS)

Vitkovskii, I. L.; Nikonov, S. P.; Ryasnyi, S. I.

2014-02-01

The subject of this paper is a transient caused by connection of a standby loop to three operating circulation pumps at the initial reactor heat rate equal to 70% of the rated value without preliminarily reducing it to 30% of the rated level as required by the safe operation regulations. Failure of the following normal operation systems is supposed: the first- and the second-type warning protection systems, all quick-acting reducing devices releasing steam into the auxiliary manifold, the electric heaters of the pressurizer, the pressurizer injection system, the primary cooling circuit fluid makeup/blow-through systems, and the blocking systems to shut down the main circulation pump after the level in the steam generator is exceeded. In addition, it is supposed that, under transient conditions, the valves of the turbine regulation system will be in the position in which they were at the moment of the initial event until generation of the signal for positive closing of the turbine stop valves. The first signal to actuate the reactor emergency protection system (EPS) is skipped. The failure of all quick-acting reducing devices releasing steam into the atmosphere is assumed. In addition to equipment failure, at the moment when the main circulation pump is connected, the operator erroneously puts in a new setting to maintain the power allowable for four pumps in operation-in the calculations it was taken equal to 104% of the rated level at most considering the accuracy of evaluating and maintaining the reactor heat rate-and the working group of the reactor protection and control system (P&CS) starts moving upward. On reaching the set power level, the automatic reactor power regulator stops operating and the P&CS elements remain in the position in which they are at the moment. Compliance with the design safety criteria for the adopted scenario of the transient is demonstrated.

Combined cycle plants: Yesterday, today, and tomorrow (review)

NASA Astrophysics Data System (ADS)

Ol'khovskii, G. G.

2016-07-01

Gas turbine plants (GTP) for a long time have been developed by means of increasing the initial gas temperature and improvement of the turbo-machines aerodynamics and the efficiency of the critical components air cooling within the framework of a simple thermodynamic cycle. The application of watercooling systems that were used in experimental turbines and studied approximately 50 years ago revealed the fundamental difficulties that prevented the practical implementation of such systems in the industrial GTPs. The steam cooling researches have developed more substantially. The 300 MW power GTPs with a closedloop steam cooling, connected in parallel with the intermediate steam heating line in the steam cycle of the combined cycle plant (CCP) have been built, tested, and put into operation. The designs and cycle arrangements of such GTPs and entire combined cycle steam plants have become substantially more complicated without significant economic benefits. As a result, the steam cooling of gas turbines has not become widespread. The cycles—complicated by the intermediate air cooling under compression and reheat of the combustion products under expansion and their heat recovery to raise the combustion chamber entry temperature of the air—were used, in particular, in the domestic power GTPs with a moderate (700-800°C) initial gas turbine entry temperature. At the temperatures being reached to date (1300-1450°C), only one company, Alstom, applies in their 240-300 MW GTPs the recycled fuel cycle under expansion of gases in the turbine. Although these GTPs are reliable, there are no significant advantages in terms of their economy. To make a forecast of the further improvement of power GTPs, a brief review and assessment of the water cooling and steam cooling of hot components and complication of the GTP cycle by the recycling of fuel under expansion of gases in the turbine has been made. It is quite likely in the long term to reach the efficiency for the traditional GTPs of approximately 43% and 63% for PGUs at the initial gas temperature of 1600°C and less likely to increase the efficiency of these plants up to 45% and 65% by increasing the gas temperature up to 1700°C or by application of the steam cooling in the recycled fuel cycle.

Strategic need for a multi-purpose thermal hydraulic loop for support of advanced reactor technologies

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

O'Brien, James E.; Sabharwall, Piyush; Yoon, Su -Jong

2014-09-01

This report presents a conceptual design for a new high-temperature multi fluid, multi loop test facility for the INL to support thermal hydraulic, materials, and thermal energy storage research for nuclear and nuclear-hybrid applications. In its initial configuration, the facility will include a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed with this facility include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs)more » at prototypical operating conditions, flow and heat transfer issues related to core thermal hydraulics in advanced helium-cooled and salt-cooled reactors, and evaluation of corrosion behavior of new cladding materials and accident-tolerant fuels for LWRs at prototypical conditions. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST) facility. Research performed in this facility will advance the state of the art and technology readiness level of high temperature intermediate heat exchangers (IHXs) for nuclear applications while establishing the INL as a center of excellence for the development and certification of this technology. The thermal energy storage capability will support research and demonstration activities related to process heat delivery for a variety of hybrid energy systems and grid stabilization strategies. Experimental results obtained from this research will assist in development of reliable predictive models for thermal hydraulic design and safety codes over the range of expected advanced reactor operating conditions. Proposed/existing IHX heat transfer and friction correlations and criteria will be assessed with information on materials compatibility and instrumentation needs. The experimental database will guide development of appropriate predictive methods and be available for code verification and validation (V&V) related to these systems.« less

Effect of thermal barrier coatings on the performance of steam and water-cooled gas turbine/steam turbine combined cycle system

NASA Technical Reports Server (NTRS)

Nainiger, J. J.

1978-01-01

An analytical study was made of the performance of air, steam, and water-cooled gas-turbine/steam turbine combined-cycle systems with and without thermal-barrier coatings. For steam cooling, thermal barrier coatings permit an increase in the turbine inlet temperature from 1205 C (2200 F), resulting in an efficiency improvement of 1.9 percentage points. The maximum specific power improvement with thermal barriers is 32.4 percent, when the turbine inlet temperature is increased from 1425 C (2600 F) to 1675 C (3050 F) and the airfoil temperature is kept the same. For water cooling, the maximum efficiency improvement is 2.2 percentage points at a turbine inlet temperature of 1683 C (3062 F) and the maximum specific power improvement is 36.6 percent by increasing the turbine inlet temperature from 1425 C (2600 F) to 1730 C (3150 F) and keeping the airfoil temperatures the same. These improvements are greater than that obtained with combined cycles using air cooling at a turbine inlet temperature of 1205 C (2200 F). The large temperature differences across the thermal barriers at these high temperatures, however, indicate that thermal stresses may present obstacles to the use of coatings at high turbine inlet temperatures.

Thermal Vacuum Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin

2016-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and to verify its ability to cool large areas or components in the 3 degrees Kelvin temperature range. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by simply applying power to both the capillary pump and the evaporator plate without pre-conditioning. It could adapt to a rapid heat load change and quickly reach a new steady state. Heat removal between 10 megawatts and 140 megawatts was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Preliminary assessment of alternative PFBC power plant systems. Final report

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

Wysocki, J.; Rogali, R.

1980-07-01

This report presents the design and and economic comparisons of the following nominal 1000 MWe PFBC power plants for both eastern and western coal: Curtiss-Wright PFBC power plants with an air-cooled design; General Electric RFBC power plants with a steam-cooled design; and AEP/Stal-Laval PFBC power plants with a steam-cooled design. In addition, reference pulverized coal-fired (PCF) power plants are included for comparison purposes. The results of the analysis indicate: (1) The steam-cooled PFBC designs show potential savings of 10% and 11% over PCF plants for eastern and western coal, respectively, in terms of busbar power cost; (2) the air-cooled PFBCmore » designs show potential savings of 1% and 2% over PCF plants for eastern and western coal, respectively, in terms of busbar power cost.« less

Turbomachine rotor with improved cooling

DOEpatents

Hultgren, Kent Goran; McLaurin, Leroy Dixon; Bertsch, Oran Leroy; Lowe, Perry Eugene

1998-01-01

A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn.

Turbomachine rotor with improved cooling

DOEpatents

Hultgren, K.G.; McLaurin, L.D.; Bertsch, O.L.; Lowe, P.E.

1998-05-26

A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn. 5 figs.

Pressurized thermal shock: TEMPEST computer code simulation of thermal mixing in the cold leg and downcomer of a pressurized water reactor. [Creare 61 and 64

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

Eyler, L.L.; Trent, D.S.

The TEMPEST computer program was used to simulate fluid and thermal mixing in the cold leg and downcomer of a pressurized water reactor under emergency core cooling high-pressure injection (HPI), which is of concern to the pressurized thermal shock (PTS) problem. Application of the code was made in performing an analysis simulation of a full-scale Westinghouse three-loop plant design cold leg and downcomer. Verification/assessment of the code was performed and analysis procedures developed using data from Creare 1/5-scale experimental tests. Results of three simulations are presented. The first is a no-loop-flow case with high-velocity, low-negative-buoyancy HPI in a 1/5-scale modelmore » of a cold leg and downcomer. The second is a no-loop-flow case with low-velocity, high-negative density (modeled with salt water) injection in a 1/5-scale model. Comparison of TEMPEST code predictions with experimental data for these two cases show good agreement. The third simulation is a three-dimensional model of one loop of a full size Westinghouse three-loop plant design. Included in this latter simulation are loop components extending from the steam generator to the reactor vessel and a one-third sector of the vessel downcomer and lower plenum. No data were available for this case. For the Westinghouse plant simulation, thermally coupled conduction heat transfer in structural materials is included. The cold leg pipe and fluid mixing volumes of the primary pump, the stillwell, and the riser to the steam generator are included in the model. In the reactor vessel, the thermal shield, pressure vessel cladding, and pressure vessel wall are thermally coupled to the fluid and thermal mixing in the downcomer. The inlet plenum mixing volume is included in the model. A 10-min (real time) transient beginning at the initiation of HPI is computed to determine temperatures at the beltline of the pressure vessel wall.« less

Indirect-cycle FBR cooled by supercritical steam-concept and design

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

Yoshiaki, Oka; Tatjana, Jevremovic; Sei-ichi, Koshizuka

1993-01-01

Neutronic and thermal-hydraulic design of an in direct-cycle supercritical steam-cooled fast breeder reactor (SCFBR-I) is carried out to find a way to make low-cost FBRs (Ref. 1). The advantages of supercritical steam cooling are high thermal efficiency, low pumping power, simplified system (no primary steam generators and no Loeffler boilers), and the use of experienced technology in fossil-fired power plants. The design goals are fissile fuel breeding (compound system doubling time below 30 yr), 1000-M(electric) class out-put, high fuel discharge burnup, and a long refueling period. The coolant void reactivity should be negative throughout fuel lifetime because the loss-of-coolant accidentmore » is the design-basis accident. These goals have never been satisfied simultaneously in previous SCFBRs.« less

Clocking of stators in one and half stage of axial steam turbine

NASA Astrophysics Data System (ADS)

Němec, Martin; Jelínek, Tomáš; Milčák, Petr

2018-06-01

An investigation of one and half axial turbine stage configuration was carried out in a closed-loop wind tunnel. The investigation was addressed to that impact how the previous stage outlet flow field influences the flow structures in the next stator in steam multistage turbines. The stage - stator interaction has been studied in this work. The detailed measurement with a pneumatic probes and fast response pressure probes behind the rotor and the second stator were performed to gain the useful data to analyze the impact. The detailed flow field measurement was carried out in the nominal stage regime (given by the stage isentropic Mach number 0.3 and velocity ratio u/c 0.68). The clocking effect of the stators is discussed and detailed unsteady flow analysis is shown.

Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

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

Siriwardane, Ranjani; Benincosa, William; Riley, Jarrett

This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe 2O 3-alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier. Reactions of coal/steam/CuO-Fe 2O 3-alumina oxygen carrier and coal/steam/partially reduced CuO-Fe 2O 3-alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). Inmore » addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H 2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H 2 was also observed with the reduced oxygen carrier. CuO-Fe 2O 3-alumina reacted with coal during the temperature ramp to 850 °C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Here, the fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.« less

Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

DOE PAGES

Siriwardane, Ranjani; Benincosa, William; Riley, Jarrett; ...

2016-10-06

This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe 2O 3-alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier. Reactions of coal/steam/CuO-Fe 2O 3-alumina oxygen carrier and coal/steam/partially reduced CuO-Fe 2O 3-alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). Inmore » addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H 2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H 2 was also observed with the reduced oxygen carrier. CuO-Fe 2O 3-alumina reacted with coal during the temperature ramp to 850 °C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Here, the fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.« less

Coronal Structures in Cool Stars: XMM-NEWTON Hybrid Stars and Coronal Evolution

NASA Technical Reports Server (NTRS)

Dupree, Andrea K.; Mushotzky, Richard (Technical Monitor)

2003-01-01

This program addresses the evolution of stellar coronas by comparing a solar-like corona in the supergiant Beta Dra (G2 Ib-IIa) to the corona in the allegedly more evolved state of a hybrid star, alpha TrA (K2 II-III). Because the hybrid star has a massive wind, it appears likely that the corona will be cooler and less dense as the magnetic loop structures are no longer closed. By analogy with solar coronal holes, when the topology of the magnetic field is configured with open magnetic structures, both the coronal temperature and density are lower than in atmospheres dominated by closed loops. The hybrid stars assume a pivotal role in the definition of coronal evolution, atmospheric heating processes and mechanisms to drive winds of cool stars. We are attempting to determine if this model of coronal evolution is correct by using XMM-NEWTON RGS spectra for the 2 targets we were allocated through the Guest Observer program.

Hot spot detection system for vanes or blades of a combustion turbine

DOEpatents

Twerdochlib, Michael

1999-01-01

This invention includes a detection system that can determine if a turbine component, such as a turbine vane or blade, has exceeded a critical temperature, such as a melting point, along any point along the entire surface of the vane or blade. This system can be employed in a conventional combustion turbine having a compressor, a combustor and a turbine section. Included within this system is a chemical coating disposed along the entire interior surface of a vane or blade and a closed loop cooling system that circulates a coolant through the interior of the vane or blade. If the temperature of the vane or blade exceeds a critical temperature, the chemical coating will be expelled from the vane or blade into the coolant. Since while traversing the closed loop cooling system the coolant passes through a detector, the presence of the chemical coating in the coolant will be sensed by the system. If the chemical coating is detected, this indicates that the vane or blade has exceeded a critical temperature.

Tuning and performance evaluation of PID controller for superheater steam temperature control of 200 MW boiler using gain phase assignment algorithm

NASA Astrophysics Data System (ADS)

Begum, A. Yasmine; Gireesh, N.

2018-04-01

In superheater, steam temperature is controlled in a cascade control loop. The cascade control loop consists of PI and PID controllers. To improve the superheater steam temperature control the controller's gains in a cascade control loop has to be tuned efficiently. The mathematical model of the superheater is derived by sets of nonlinear partial differential equations. The tuning methods taken for study here are designed for delay plus first order transfer function model. Hence from the dynamical model of the superheater, a FOPTD model is derived using frequency response method. Then by using Chien-Hrones-Reswick Tuning Algorithm and Gain-Phase Assignment Algorithm optimum controller gains has been found out based on the least value of integral time weighted absolute error.

A SURVEY OF CONVENTIONAL STEAM BOILER EXPERIENCE APPLICABLE TO THE HTGR STEAM GENERATORS

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

Paget, J.A.

1959-10-01

BS>The steam generator of a high temperature gas-cooled reactor consists of tubular heating surface inside a shell which forms part of the primary He circuit of the reactor. When a tube fails in such a steam generator, moisture in the form of steam is released into the He steam and is carried through the reactor where it will cause corrosion and mass transfer of C in the core. A paramount consideration in the design of a steam generator for a high temperature gas-cooled reactor is the prevention of tube failures. Preference, therefore, should be given to a forced circulation design.more » The Loeffler Boiler would be the best from this standpoint alone since only steam enters the tubes, and its circulation rate can be maintained at an adequate value to insure cool tubes regardless of load fluctuations. The next type in the order of preference would be the forced recirculation boiler, since at least the boiier tubes always have an adequate cooling flow regardless of output. The third type in order of preference would be a Sulzer Type boiler since it has a separator to remove dissolved material from the water which is comparible in efficiency to a standard boiler drum and although the flow through evaporator and superheater fluctuates with load, the Sulzer Boiler can be operated as a forced recirculation boiler at low loads. The least desirable type would be a Benson or supercritical boiler which is completely dependent on input water purity for its survival. It is not claimed that Benson or supercritical boilers should not or will not be used in the future for gas-cooled reactors, but only that their use would be the least conservative choice from a tube failure standpoint at the present time. (auth)« less

POWER GENERATION FROM LIQUID METAL NUCLEAR FUEL

DOEpatents

Dwyer, O.E.

1958-12-23

A nuclear reactor system is described wherein the reactor is the type using a liquid metal fuel, such as a dispersion of fissile material in bismuth. The reactor is designed ln the form of a closed loop having a core sectlon and heat exchanger sections. The liquid fuel is clrculated through the loop undergoing flssion in the core section to produce heat energy and transferrlng this heat energy to secondary fluids in the heat exchanger sections. The fission in the core may be produced by a separate neutron source or by a selfsustained chain reaction of the liquid fuel present in the core section. Additional auxiliary heat exchangers are used in the system to convert water into steam which drives a turbine.

Experimental study on the heat transfer characteristics of a nuclear reactor containment wall cooled by gravitationally falling water

NASA Astrophysics Data System (ADS)

Pasek, Ari D.; Umar, Efrison; Suwono, Aryadi; Manalu, Reinhard E. E.

2012-06-01

Gravitationally falling water cooling is one of mechanism utilized by a modern nuclear Pressurized Water Reactor (PWR) for its Passive Containment Cooling System (PCCS). Since the cooling is closely related to the safety, water film cooling characteristics of the PCCS should be studied. This paper deals with the experimental study of laminar water film cooling on the containment model wall. The influences of water mass flow rate and wall heat rate on the heat transfer characteristic were studied. This research was started with design and assembly of a containment model equipped with the water cooling system, and calibration of all measurement devices. The containment model is a scaled down model of AP 1000 reactor. Below the containment steam is generated using electrical heaters. The steam heated the containment wall, and then the temperatures of the wall in several positions were measure transiently using thermocouples and data acquisition. The containment was then cooled by falling water sprayed from the top of the containment. The experiments were done for various wall heat rate and cooling water flow rate. The objective of the research is to find the temperature profile along the wall before and after the water cooling applied, prediction of the water film characteristic such as means velocity, thickness and their influence to the heat transfer coefficient. The result of the experiments shows that the wall temperatures significantly drop after being sprayed with water. The thickness of water film increases with increasing water flow rate and remained constant with increasing wall heat rate. The heat transfer coefficient decreases as film mass flow rate increase due to the increases of the film thickness which causes the increasing of the thermal resistance. The heat transfer coefficient increases slightly as the wall heat rate increases. The experimental results were then compared with previous theoretical studied.

Integrated Testing of a 4-Bed Molecular Sieve and a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization

NASA Technical Reports Server (NTRS)

Knox, James C.; Mulloth, Lila M.; Affleck, David L.

2004-01-01

Accumulation and subsequent compression of carbon dioxide that is removed from space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. This paper reports the integrated 4BMS and liquid-cooled TSAC testing conducted during the period of March 3 to April 18, 2003. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of CDRA.

Determination of the steam volume fraction in the event of loss of cooling of the spent fuel storage pool

NASA Astrophysics Data System (ADS)

Sledkov, R. M.; Galkin, I. Yu.; Stepanov, O. E.; Strebnev, N. A.

2017-01-01

When one solves engineering problems related to the cooling of fuel assemblies (FAs) in a spent fuel storage pool (SFSP) and the assessment of nuclear safety of FA storage in an SFSP in the initial event of loss of SFSP cooling, it is essential to determine the coolant density and, consequently, steam volume fractions φ in bundles of fuel elements at a pressure of 0.1-0.5 MPa. Such formulas for calculating φ that remain valid in a wide range of operating parameters and geometric shapes of channels and take the conditions of loss of SFSP cooling into account are currently almost lacking. The results of systematization and analysis of the available formulas for φ are reported in the present study. The calculated values were compared with the experimental data obtained in the process of simulating the conditions of FA cooling in an SFSP in the event of loss of its cooling. Six formulas for calculating the steam volume fraction, which were used in this comparison, were chosen from a total of 11 considered relations. As a result, the formulas producing the most accurate values of φ in the conditions of loss of SFSP cooling were selected. In addition, a relation that allows one to perform more accurate calculations of steam volume fractions in the conditions of loss of SFSP cooling was derived based on the Fedorov formula in the two-group approximation.

Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin

2016-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heaters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Testing of a Helium Loop Heat Pipe for Large Area Cryocooling

NASA Technical Reports Server (NTRS)

Ku, Jentung; Robinson, Franklin Lee

2015-01-01

Future NASA space telescopes and exploration missions require cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks. One device that can potentially be used to provide closed-loop cryocooling is the cryogenic loop heat pipe (CLHP). A CLHP has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A helium CLHP has been tested extensively in a thermal vacuum chamber using a cryocooler as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components in the 3K temperature range. A copper plate with attached electrical heters was used to simulate the heat source, and heat was collected by the CLHP evaporator and transferred to the cryocooler for ultimate heat rejection. The helium CLHP thermal performance test included cool-down from the ambient temperature, startup, capillary limit, heat removal capability, rapid power changes, and long duration steady state operation. The helium CLHP demonstrated robust operation under steady state and transient conditions. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully without pre-conditioning by simply applying power to both the capillary pump and the evaporator plate. It could adapt to rapid changes in the heat load, and reach a new steady state very quickly. Heat removal between 10mW and 140mW was demonstrated, yielding a power turn down ratio of 14. When the CLHP capillary limit was exceeded, the loop could resume its normal function by reducing the power to the capillary pump. Steady state operations up to 17 hours at several heat loads were demonstrated. The ability of the helium CLHP to cool large areas was therefore successfully verified.

Water Purification

NASA Technical Reports Server (NTRS)

1992-01-01

Silver ionization water purification technology was originally developed for Apollo spacecraft. It was later used to cleanse swimming pools and has now been applied to industrial cooling towers and process coolers. Sensible Technologies, Inc. has added two other technologies to the system, which occupies only six square feet. It is manufactured in three capacities, and larger models are custom built on request. The system eliminates scale, corrosion, algae, bacteria and debris, and because of the NASA technology, viruses and waterborne bacteria are also destroyed. Applications include a General Motors cooling tower, amusement parks, ice manufacture and a closed-loop process cooling system.

Method to prevent/mitigate steam explosions in casting pits

DOEpatents

Taleyarkhan, Rusi P.

1996-01-01

Steam explosions can be prevented or mitigated during a metal casting process by the placement of a perforated flooring system in the casting pit. An upward flow of compressed gas through this perforated flooring system is introduced during the casting process to produce a buffer layer between any spilled molten metal and the cooling water in the reservoir. This buffer layer provides a hydrodynamic layer which acts to prevent or mitigate steam explosions resulting from hot, molten metal being spilled into or onto the cooling water.

Heat transfer from an internal combustion (Otto-cycle) engine on the surface of Mars

NASA Technical Reports Server (NTRS)

Gwynne, Owen

1992-01-01

The cooling requirements for an average car sized engine (spark-ignition, V-6, four-stroke, naturally aspirated, about 200 kg, about 100 kW) were looked at for Mars. Several modes of cooling were considered, including forced convection, exhaust, radiation and closed loop systems. The primary goal was to determine the effect of the thinner Martian atmosphere on the cooling system. The results show that there was only a 6-percent difference in the cooling requirements. This difference was due mostly to the thinner atmosphere during forced convection and the heat capacity of the exhaust. A method using a single pass counter-flow heat exchanger is suggested to offset this difference in cooling requirements.

Heat transfer from an internal combustion (Otto-cycle) engine on the surface of Mars

NASA Astrophysics Data System (ADS)

Gwynne, Owen

1992-05-01

The cooling requirements for an average car sized engine (spark-ignition, V-6, four-stroke, naturally aspirated, about 200 kg, about 100 kW) were looked at for Mars. Several modes of cooling were considered, including forced convection, exhaust, radiation and closed loop systems. The primary goal was to determine the effect of the thinner Martian atmosphere on the cooling system. The results show that there was only a 6-percent difference in the cooling requirements. This difference was due mostly to the thinner atmosphere during forced convection and the heat capacity of the exhaust. A method using a single pass counter-flow heat exchanger is suggested to offset this difference in cooling requirements.

Component testing of a ground based gas turbine steam cooled rich-burn primary zone combustor for emissions control of nitrogeneous fuels

NASA Technical Reports Server (NTRS)

Schultz, D. F.

1986-01-01

This effort summarizes the work performed on a steam cooled, rich-burn primary zone, variable geometry combustor designed for combustion of nitrogeneous fuels such as heavy oils or synthetic crude oils. The steam cooling was employed to determine its feasibility and assess its usefulness as part of a ground based gas turbine bottoming cycle. Variable combustor geometry was employed to demonstrate its ability to control primary and secondary zone equivalence ratios and overall pressure drop. Both concepts proved to be highly successful in achieving their desired objectives. The steam cooling reduced peak liner temperatures to less than 800 K. This low temperature offers the potential of both long life and reduced use of strategic materials for liner fabrication. These degrees of variable geometry were successfully employed to control air flow distribution within the combustor. A variable blade angle axial flow air swirler was used to control primary zone air flow, while the secondary and tertiary zone air flows were controlled by rotating bands which regulated air flow to the secondary zone quench holes and the dilutions holes respectively.

Thermal Management Research for Power Generation. Delivery Order 0002 - Volume 2: Closed-Loop Spray Cooling of High-Power Semiconductor Lasers

DTIC Science & Technology

2002-12-01

surface temperature for a given heat flux [2]. Mudawar and Valentine conducted an experimental study of spray cooling to determine local quenching... Mudawar presented a CHF correlation with suitable dimensionless parameters that accurately predicted data for FC-72, FC-87 and water [5]. The 2...correlation by Estes and Mudawar had a strong dependence of CHF on volumetric flux and Sauter mean diameter. Sehmbey et al. developed a semiempirical

Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

NASA Astrophysics Data System (ADS)

Milman, O. O.; Ptakhin, A. V.; Kondratev, A. V.; Shifrin, B. A.; Yankov, G. G.

2016-05-01

The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.

Apparatus and methods for impingement cooling of an undercut region adjacent a side wall of a turbine nozzle segment

DOEpatents

Burdgick, Steven Sebastian; Itzel, Gary Michael

2001-01-01

A gas turbine nozzle segment has outer and inner bands. Each band includes a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. The inturned flange has a plurality of apertures for directing cooling steam to cool the side wall between adjacent nozzle segments.

A small-scale eruption leading to a blowout macrospicule jet in an on-disk coronal hole

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

Adams, Mitzi; Sterling, Alphonse C.; Moore, Ronald L.

2014-03-01

We examine the three-dimensional magnetic structure and dynamics of a solar EUV-macrospicule jet that occurred on 2011 February 27 in an on-disk coronal hole. The observations are from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) and the SDO Helioseismic and Magnetic Imager (HMI). The observations reveal that in this event, closed-field-carrying cool absorbing plasma, as in an erupting mini-filament, erupted and opened, forming a blowout jet. Contrary to some jet models, there was no substantial recently emerged, closed, bipolar-magnetic field in the base of the jet. Instead, over several hours, flux convergence and cancellation at the polarity inversionmore » line inside an evolved arcade in the base apparently destabilized the entire arcade, including its cool-plasma-carrying core field, to undergo a blowout eruption in the manner of many standard-sized, arcade-blowout eruptions that produce a flare and coronal mass ejection. Internal reconnection made bright 'flare' loops over the polarity inversion line inside the blowing-out arcade field, and external reconnection of the blowing-out arcade field with an ambient open field made longer and dimmer EUV loops on the outside of the blowing-out arcade. That the loops made by the external reconnection were much larger than the loops made by the internal reconnection makes this event a new variety of blowout jet, a variety not recognized in previous observations and models of blowout jets.« less

Integrated design of cryogenic refrigerator and liquid-nitrogen circulation loop for HTS cable

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Ryu, Ki Nam; Yang, Hyung Suk

2016-12-01

A new concept of cryogenic cooling system is proposed and investigated for application to long-length HTS cables. One of major obstacles to the cable length of 1 km or longer is the difficulty in circulating liquid nitrogen (LN) along the cables, since the temperature rise and pressure drop of LN flow could be excessively large. This study attempts a breakthrough by integrating the refrigerator with the LN circulation loop in order to eliminate the cryogenic LN pumps, and generate a large LN flow with the power of compressors at ambient temperature. A variety of thermodynamic structures are investigated on standard and modified Claude cycles, where nitrogen is used as refrigerant and the LN circulation loop is included as part of the closed cycle. Four proposed cycles are fully analyzed and optimized with a process simulator (Aspen HYSYS) to evaluate the FOM (figure of merit) and examine the feasibility. The modified dual-pressure cycle cooled with expander stream is recommended for long HTS cables.

Heat transfer analysis of catheters used for localized tissue cooling to attenuate reperfusion injury.

PubMed

Merrill, Thomas L; Mitchell, Jennifer E; Merrill, Denise R

2016-08-01

Recent revascularization success for ischemic stroke patients using stentrievers has created a new opportunity for therapeutic hypothermia. By using short term localized tissue cooling interventional catheters can be used to reduce reperfusion injury and improve neurological outcomes. Using experimental testing and a well-established heat exchanger design approach, the ɛ-NTU method, this paper examines the cooling performance of commercially available catheters as function of four practical parameters: (1) infusion flow rate, (2) catheter location in the body, (3) catheter configuration and design, and (4) cooling approach. While saline batch cooling outperformed closed-loop autologous blood cooling at all equivalent flow rates in terms of lower delivered temperatures and cooling capacity, hemodilution, systemic and local, remains a concern. For clinicians and engineers this paper provides insights for the selection, design, and operation of commercially available catheters used for localized tissue cooling. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Concentrating Solar Power Projects - Olivenza 1 | Concentrating Solar Power

Science.gov Websites

Manufacturer: Siemens Turbine Description: 5 extractions Output Type: Steam Rankine Power Cycle Pressure: 100.0 bar Cooling Method: Wet cooling Cooling Method Description: Cooling Towers

An investigation of a flow field in one and half axial turbine stage

NASA Astrophysics Data System (ADS)

Němec, Martin; Jelínek, Tomáš; Milčák, Petr

2017-09-01

An investigation of one and half axial turbine stage configuration was carried out in a closed-loop wind tunnel. The investigation was addressed to that impact how the previous stage outlet flow field influences a flow structures in the next stator in steam multistage turbines. The detailed measurement behind the rotor and the second stator was performed with a pneumatic probes to gain a useful data for an impact analysis. Various rotor shroud clearances were also tested to capture the shroud outlet flow field influences.

Model Predictive Control Based on System Re-Identification (MPC-SRI) to Control Bio-H2 Production from Biomass

NASA Astrophysics Data System (ADS)

Wahid, A.; Taqwallah, H. M. H.

2018-03-01

Compressors and a steam reformer are the important units in biohydrogen from biomass plant. The compressors are useful for achieving high-pressure operating conditions while the steam reformer is the main process to produce H2 gas. To control them, in this research used a model predictive control (MPC) expected to have better controller performance than conventional controllers. Because of the explicit model empowerment in MPC, obtaining a better model is the main objective before employing MPC. The common way to get the empirical model is through the identification system, so that obtained a first-order plus dead-time (FOPDT) model. This study has already improved that way since used the system re-identification (SRI) based on closed loop mode. Based on this method the results of the compressor pressure control and temperature control of steam reformer were that MPC based on system re-identification (MPC-SRI) has better performance than MPC without system re-identification (MPCWSRI) and the proportional-integral (PI) controller, by % improvement of 73% against MPCWSRI and 75% against the PI controller.

Method to prevent/mitigate steam explosions in casting pits

DOEpatents

Taleyarkhan, R.P.

1996-12-24

Steam explosions can be prevented or mitigated during a metal casting process by the placement of a perforated flooring system in the casting pit. An upward flow of compressed gas through this perforated flooring system is introduced during the casting process to produce a buffer layer between any spilled molten metal and the cooling water in the reservoir. This buffer layer provides a hydrodynamic layer which acts to prevent or mitigate steam explosions resulting from hot, molten metal being spilled into or onto the cooling water. 3 figs.

Hot spot detection system for vanes or blades of a combustion turbine

DOEpatents

Twerdochlib, M.

1999-02-02

This invention includes a detection system that can determine if a turbine component, such as a turbine vane or blade, has exceeded a critical temperature, such as a melting point, along any point along the entire surface of the vane or blade. This system can be employed in a conventional combustion turbine having a compressor, a combustor and a turbine section. Included within this system is a chemical coating disposed along the entire interior surface of a vane or blade and a closed loop cooling system that circulates a coolant through the interior of the vane or blade. If the temperature of the vane or blade exceeds a critical temperature, the chemical coating will be expelled from the vane or blade into the coolant. Since while traversing the closed loop cooling system the coolant passes through a detector, the presence of the chemical coating in the coolant will be sensed by the system. If the chemical coating is detected, this indicates that the vane or blade has exceeded a critical temperature. 5 figs.

Design study of steady-state 30-tesla liquid-neon-cooled magnet

NASA Technical Reports Server (NTRS)

Prok, G. M.; Brown, G. V.

1976-01-01

A design for a 30-tesla, liquid-neon-cooled magnet was reported which is capable of continuous operation. Cooled by nonboiling, forced-convection heat transfer to liquid neon flowing at 2.8 cu m/min in a closed, pressurized heat-transfer loop and structurally supported by a tapered structural ribbon, the tape-wound coils with a high-purity-aluminum conductor will produce over 30 teslas for 1 minute at 850 kilowatts. The magnet will have an inside diameter of 7.5 centimeters and an outside diameter of 54 centimeters. The minimum current density at design field will be 15.7 kA/sq cm.

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System

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

Ying, Alice; Popov, Emilian L

2011-01-01

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and tomore » provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.« less

Dry coolers and air-condensing units (Review)

NASA Astrophysics Data System (ADS)

Milman, O. O.; Anan'ev, P. A.

2016-03-01

The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that global trends have a significant influence on the application of dry coolers in Russia, in view of the fact that some TPP have a surface condensers arrangement. The reasons that these systems are currently less efficient than the direct steam condensation in an air-cooled condenser are explained. It is shown that, in some cases, it is more reasonable to use mixing-type condensers in combination with a dry cooler. Measures for a full import substitution of steam exhaust heat removal systems are mentioned.

Hybrid Stars and Coronal Evolution

NASA Technical Reports Server (NTRS)

Mushotzky, Richard (Technical Monitor); Dupree, Andrea K.

2004-01-01

This program addresses the evolution of stellar coronas by comparing a solar-like corona in the supergiant Dra (G2 Ib-IIa) to the corona in the allegedly more evolved state of a hybrid star, TrA (K2 11-111). Because the hybrid star has a massive wind, it appears likely that the corona will be cooler and less dense as the magnetic loop structures are no longer closed. By analogy with solar coronal holes, when the topology of the magnetic field is configured with open magnetic structures, both the coronal temperature and density are lower than in atmospheres dominated by closed loops. The hybrid stars assume a pivotal role in the definition of coronal evolution, atmospheric heating processes and mechanisms to drive winds of cool stars.

Thermal Propulsion Capture System Heat Exchanger Design

NASA Technical Reports Server (NTRS)

Richard, Evan M.

2016-01-01

One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

Optimization of steam generators of NPP with WWER in operation with variable load

NASA Astrophysics Data System (ADS)

Parchevskii, V. M.; Shchederkina, T. E.; Gur'yanova, V. V.

2017-11-01

The report addresses the issue of the optimal water level in the horizontal steam generators of NPP with WWER. On the one hand, the level needs to be kept at the lower limit of the allowable range, as gravity separation, steam will have the least humidity and the turbine will operate with higher efficiency. On the other hand, the higher the level, the greater the supply of water in the steam generator, and therefore the higher the security level of the unit, because when accidents involving loss of cooling of the reactor core, the water in the steam generators, can be used for cooling. To quantitatively compare the damage from higher level to the benefit of improving the safety was assessed of the cost of one cubic meter of water in the steam generators, the formulated objective function of optimal levels control. This was used two-dimensional separation characteristics of steam generators. It is demonstrated that the security significantly shifts the optimal values of the levels toward the higher values, and this bias is greater the lower the load unit.

Harwell high pressure heat transfer loop

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

Bennett, A.W.; Keeys, R.K.F.

1967-12-15

A detailed description is presented of the Harwell (Chemical Engineering and Process Technology Division) high pressure, steam-water heat transfer loop; this description is aimed at supplementing the information given in reports on individual experiments. The operating instructions for the loop are given in an appendix. (auth)

Downhole steam generator having a downhole oxidant compressor

DOEpatents

Fox, Ronald L.

1983-01-01

Apparatus and method for generation of steam in a borehole for penetration into an earth formation wherein a downhole oxidant compressor is used to compress relatively low pressure (atmospheric) oxidant, such as air, to a relatively high pressure prior to mixing with fuel for combustion. The multi-stage compressor receives motive power through a shaft driven by a gas turbine powered by the hot expanding combustion gases. The main flow of compressed oxidant passes through a velocity increasing nozzle formed by a reduced central section of the compressor housing. An oxidant bypass feedpipe leading to peripheral oxidant injection nozzles of the combustion chamber are also provided. The downhole compressor allows effective steam generation in deep wells without need for high pressure surface compressors. Feedback preheater means are provided for preheating fuel in a preheat chamber. Preheating of the water occurs in both a water feed line running from aboveground and in a countercurrent water flow channel surrounding the combustor assembly. The countercurrent water flow channels advantageously serve to cool the combustion chamber wall. 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 for closing and sealing the combustion chamber from entry of reservoir fluids in the event of a flameout.

Lubricating system for thermal medium delivery parts in a gas turbine

DOEpatents

Mashey, Thomas Charles

2002-01-01

Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coefficient of friction coating is provided at the interface of the tubes and support elements. On each surface, a first coating of a cobalt-based alloy is sprayed onto the surface at high temperature. A portion of the first coating is machined off to provide a smooth, hard surface. A second ceramic-based solid film lubricant is sprayed onto the first coating. By reducing the resistance to axial displacement of the tubes relative to the supporting elements due to thermal expansion, the service life of the tubes is substantially extended.

Numerical investigation on pulsating heat pipes with nitrogen or hydrogen

NASA Astrophysics Data System (ADS)

Y Han, D.; Sun, X.; Gan, Z. H.; Y Luo, R.; Pfotenhauer, J. M.; Jiao, B.

2017-12-01

With flexible structure and excellent performance, pulsating heat pipes (PHP) are regarded as a great solution to distribute cooling power for cryocoolers. The experiments on PHPs with cryogenic fluids have been carried out, indicating their efficient performances in cryogenics. There are large differences in physical properties between the fluids at room and cryogenic temperature, resulting in their different heat transfer and oscillation characteristics. Up to now, the numerical investigations on cryogenic fluids have rarely been carried out. In this paper, the model of the closed-loop PHP with multiple liquid slugs and vapor plugs is performed with nitrogen and hydrogen as working fluids, respectively. The effects of heating wall temperature on the performance of close-looped PHPs are investigated and compared with that of water PHP.

43 CFR 3276.13 - What additional information must I give BLM in the monthly report for flash and dry steam...

Code of Federal Regulations, 2014 CFR

2014-10-01

... flow into the turbine in klbs; for dual flash facilities, you must separate the steam flow into high...; (d) Auxiliary steam flow used for gas ejectors, steam seals, pumps, etc., in klbs; (e) Flow of condensate out of the plant (after the cooling towers) in klbs; and (f) Any other information we may require. ...

43 CFR 3276.13 - What additional information must I give BLM in the monthly report for flash and dry steam...

Code of Federal Regulations, 2012 CFR

2012-10-01

... flow into the turbine in klbs; for dual flash facilities, you must separate the steam flow into high...; (d) Auxiliary steam flow used for gas ejectors, steam seals, pumps, etc., in klbs; (e) Flow of condensate out of the plant (after the cooling towers) in klbs; and (f) Any other information we may require. ...

43 CFR 3276.13 - What additional information must I give BLM in the monthly report for flash and dry steam...

Code of Federal Regulations, 2011 CFR

2011-10-01

... flow into the turbine in klbs; for dual flash facilities, you must separate the steam flow into high...; (d) Auxiliary steam flow used for gas ejectors, steam seals, pumps, etc., in klbs; (e) Flow of condensate out of the plant (after the cooling towers) in klbs; and (f) Any other information we may require. ...

43 CFR 3276.13 - What additional information must I give BLM in the monthly report for flash and dry steam...

Code of Federal Regulations, 2013 CFR

2013-10-01

... flow into the turbine in klbs; for dual flash facilities, you must separate the steam flow into high...; (d) Auxiliary steam flow used for gas ejectors, steam seals, pumps, etc., in klbs; (e) Flow of condensate out of the plant (after the cooling towers) in klbs; and (f) Any other information we may require. ...

Simulation of a main steam line break with steam generator tube rupture using trace

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

Gallardo, S.; Querol, A.; Verdu, G.

A simulation of the OECD/NEA ROSA-2 Project Test 5 was made with the thermal-hydraulic code TRACE5. Test 5 performed in the Large Scale Test Facility (LSTF) reproduced a Main Steam Line Break (MSLB) with a Steam Generator Tube Rupture (SGTR) in a Pressurized Water Reactor (PWR). The result of these simultaneous breaks is a depressurization in the secondary and primary system in loop B because both systems are connected through the SGTR. Good approximation was obtained between TRACE5 results and experimental data. TRACE5 reproduces qualitatively the phenomena that occur in this transient: primary pressure falls after the break, stagnation ofmore » the pressure after the opening of the relief valve of the intact steam generator, the pressure falls after the two openings of the PORV and the recovery of the liquid level in the pressurizer after each closure of the PORV. Furthermore, a sensitivity analysis has been performed to know the effect of varying the High Pressure Injection (HPI) flow rate in both loops on the system pressures evolution. (authors)« less

Closed Loop Two-Phase Thermosyphon of Small Dimensions: a Review of the Experimental Results

NASA Astrophysics Data System (ADS)

Franco, Alessandro; Filippeschi, Sauro

2012-06-01

A bibliographical review on the heat and mass transfer in gravity assisted Closed Loop Two Phase Thermosyphons (CLTPT) with channels having a hydraulic diameter of the order of some millimetres and input power below 1 kW is proposed. The available experimental works in the literature are critically analysed in order to highlight the main results and the correlation between mass flow rate and heat input in natural circulation loops. A comparison of different experimental apparatuses and results is made. It is observed that the results are very different among them and in many cases the experimental data disagree with the conventional theory developed for an imposed flow rate. The paper analyses the main differences among the experimental devices and try to understand these disagreements. From the present analysis it is evident that further systematic studies are required to generate a meaningful body of knowledge of the heat and mass transport mechanism in these devices for practical applications in cooling devices or energy systems.

Integrated Testing of a 4-Bed Molecular Sieve, Air-Cooled Temperature Swing Adsorption Compressor, and Sabatier Engineering Development Unit

NASA Technical Reports Server (NTRS)

Knox, James C.; Miller, Lee; Campbell, Melissa; Mulloth, Lila; Varghese, Mini

2006-01-01

Accumulation and subsequent compression of carbon dioxide that is removed from the space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. The Sabatier Engineering Development Unit (EDU) processes waste CO2 to provide water to the crew. This paper reports the integrated 4BMS, air-cooled Temperature Swing Adsorption Compressor (TSAC), and Sabatier EDU testing. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of the 4BMS and Sabatier.

Safety and environmental aspects of organic coolants for fusion facilities

NASA Astrophysics Data System (ADS)

Natalizio, A.; Hollies, R. E.; Gierszewski, P.

1993-06-01

Organic coolants, such as OS-84, offer unique advantages for fusion reactor applications. These advantages are with respect to both reactor operation and safety. The key operational advantage is a coolant that can provide high temperature (350-400°C) at modest pressure (2-4 MPa). These temperatures are needed for conditioning the plasma-facing components and, in reactors, for achieving high thermodynamic conversion efficiencies (>40%). The key safety advantage of organic coolants is the low vapor pressure, which significantly reduces the containment pressurization transient (relative to water) following a loss of coolant event. Also, from an occupational dose viewpoint, organic coolants significantly reduce corrosion and erosion inside the cooling system and consequently reduce the quantity of activation products deposited in cooling system equipment. On the negative side, organic coolants undergo both pyrolytic and radiolytic decomposition, and are flammable. While the decomposition rate can be minimized by coolant system design (by reducing coolant inventories exposed to neutron flux and to high temperatures), decomposition products are formed and these degrade the coolant properties. Both heavy compounds and light gases are produced from the decomposition process, and both must be removed to maintain adequate coolant properties. As these hydrocarbons may become tritiated by permeation, or activated through impurities, their disposal could create an environmental concern. Because of this potential waste disposal problem, consideration has been given to the recycling of both the light and heavy products, thereby reducing the quantity of waste to be disposed. Preliminary assessments made for various fusion reactor designs, including ITER, suggest that it is feasible to use organic coolants for several applications. These applications range from first wall and blanket coolant (the most demanding with respect to decomposition), to shield and vacuum vessel cooling, to an intermediate cooling loop removing heat from a liquid metal loop and transferring it to a steam generator or heat exchanger.

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant

DOEpatents

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

Concentrating Solar Power Projects - Enerstar | Concentrating Solar Power |

Science.gov Websites

Capacity (Net): 50.0 MW Turbine Manufacturer: Man-Turbo Turbine Description: 3 extractions Output Type : Steam Rankine Power Cycle Pressure: 100.0 bar Cooling Method: Wet cooling Cooling Method Description

SELF-ORGANIZATION OF RECONNECTING PLASMAS TO MARGINAL COLLISIONALITY IN THE SOLAR CORONA

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

Imada, S.; Zweibel, E. G.

We explore the suggestions by Uzdensky and Cassak et al. that coronal loops heated by magnetic reconnection should self-organize to a state of marginal collisionality. We discuss their model of coronal loop dynamics with a one-dimensional hydrodynamic calculation. We assume that many current sheets are present, with a distribution of thicknesses, but that only current sheets thinner than the ion skin depth can rapidly reconnect. This assumption naturally causes a density-dependent heating rate which is actively regulated by the plasma. We report nine numerical simulation results of coronal loop hydrodynamics in which the absolute values of the heating rates aremore » different but their density dependences are the same. We find two regimes of behavior, depending on the amplitude of the heating rate. In the case that the amplitude of heating is below a threshold value, the loop is in stable equilibrium. Typically, the upper and less dense part of a coronal loop is collisionlessly heated and conductively cooled. When the amplitude of heating is above the threshold, the conductive flux to the lower atmosphere required to balance collisionless heating drives an evaporative flow which quenches fast reconnection, ultimately cooling and draining the loop until the cycle begins again. The key elements of this cycle are gravity and the density dependence of the heating function. Some additional factors are present, including pressure-driven flows from the loop top, which carry a large enthalpy flux and play an important role in reducing the density. We find that on average the density of the system is close to the marginally collisionless value.« less

A STRONGLY COUPLED REACTOR CORE ISOLATION COOLING SYSTEM MODEL FOR EXTENDED STATION BLACK-OUT ANALYSES

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

Zhao, Haihua; Zhang, Hongbin; Zou, Ling

2015-03-01

The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup cooling water to the reactor pressure vessel (RPV) when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. The RCIC system operates independently of AC power, service air, or external cooling water systems. The only required external energy source is from the battery to maintain the logic circuits to control the opening and/or closure of valves in the RCIC systems in order to control the RPV water level by shutting down the RCIC pump to avoidmore » overfilling the RPV and flooding the steam line to the RCIC turbine. It is generally considered in almost all the existing station black-out accidents (SBO) analyses that loss of the DC power would result in overfilling the steam line and allowing liquid water to flow into the RCIC turbine, where it is assumed that the turbine would then be disabled. This behavior, however, was not observed in the Fukushima Daiichi accidents, where the Unit 2 RCIC functioned without DC power for nearly three days. Therefore, more detailed mechanistic models for RCIC system components are needed to understand the extended SBO for BWRs. As part of the effort to develop the next generation reactor system safety analysis code RELAP-7, we have developed a strongly coupled RCIC system model, which consists of a turbine model, a pump model, a check valve model, a wet well model, and their coupling models. Unlike the traditional SBO simulations where mass flow rates are typically given in the input file through time dependent functions, the real mass flow rates through the turbine and the pump loops in our model are dynamically calculated according to conservation laws and turbine/pump operation curves. A simplified SBO demonstration RELAP-7 model with this RCIC model has been successfully developed. The demonstration model includes the major components for the primary system of a BWR, as well as the safety system components such as the safety relief valve (SRV), the RCIC system, the wet well, and the dry well. The results show reasonable system behaviors while exhibiting rich dynamics such as variable flow rates through RCIC turbine and pump during the SBO transient. The model has the potential to resolve the Fukushima RCIC mystery after adding the off-design two-phase turbine operation model and other additional improvements.« less

The formation flare loops by magnetic reconnection and chromospheric ablation

NASA Technical Reports Server (NTRS)

Forbes, T. G.; Malherbe, J. M.; Priest, E. R.

1989-01-01

Noncoplanar compressible reconnection theory is combined here with simple scaling arguments for ablation and radiative cooling to predict average properties of hot and cool flare loops as a function of the coronal vector magnetic field. For a coronal field strength of 100 G, the temperature of the hot flare loops decreases from 1.2 x 10 to the 7th K to 4.0 x 10 to the 6th K as the component of the coronal magnetic field perpendicular to the plane of the loops increases from 0 percent to 86 percent of the total field. When the perpendicular component exceeds 86 percent of the total field or when the altitude of the reconnection site exceeds 10 to the 6th km, flare loops no longer occur. Shock-enhanced radiative cooling triggers the formation of cool H-alpha flare loops with predicted densities of roughly 10 to the 13th/cu cm, and a small gap of roughly 1000 km is predicted to exist between the footpoints of the cool flare loops and the inner edges of the flare ribbons.

Cooling scheme for turbine hot parts

DOEpatents

Hultgren, Kent Goran; Owen, Brian Charles; Dowman, Steven Wayne; Nordlund, Raymond Scott; Smith, Ricky Lee

2000-01-01

A closed-loop cooling scheme for cooling stationary combustion turbine components, such as vanes, ring segments and transitions, is provided. The cooling scheme comprises: (1) an annular coolant inlet chamber, situated between the cylinder and blade ring of a turbine, for housing coolant before being distributed to the turbine components; (2) an annular coolant exhaust chamber, situated between the cylinder and the blade ring and proximate the annular coolant inlet chamber, for collecting coolant exhaust from the turbine components; (3) a coolant inlet conduit for supplying the coolant to said coolant inlet chamber; (4) a coolant exhaust conduit for directing coolant from said coolant exhaust chamber; and (5) a piping arrangement for distributing the coolant to and directing coolant exhaust from the turbine components. In preferred embodiments of the invention, the cooling scheme further comprises static seals for sealing the blade ring to the cylinder and flexible joints for attaching the blade ring to the turbine components.

Induced natural convection thermal cycling device

DOEpatents

Heung, Leung Kit [Aiken, SC

2002-08-13

A device for separating gases, especially isotopes, by thermal cycling of a separation column using a pressure vessel mounted vertically and having baffled sources for cold and heat. Coils at the top are cooled with a fluid such as liquid nitrogen. Coils at the bottom are either electrical resistance coils or a tubular heat exchange. The sources are shrouded with an insulated "top hat" and simultaneously opened and closed at the outlets to cool or heat the separation column. Alternatively, the sources for cold and heat are mounted separately outside the vessel and an external loop is provided for each circuit.

Steam-jet Chiller for Army Field Kitchens

DTIC Science & Technology

2009-08-01

Steam-Jet Test-Loop Schematic A vacuum pump removes air from the entire system on startup, and is occasionally used to expel air during...delivered to the tube and shell condenser. The steam is condensed and drains to the vacuum sump tank. 11 Periodically, the condensate pump ... Vacuum Roughing Pump The condenser must be held at vacuum to prevent air from insulating the condenser tubes or create a back-pressure that would

High-Performance Computing Data Center Efficiency Dashboard | Computational

Science.gov Websites

recovery water (ERW) loop Heat exchanger for energy recovery Thermosyphon Heat exchanger between ERW loop and cooling tower loop Evaporative cooling towers Learn more about our energy-efficient facility

Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

DOEpatents

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

2015-11-10

Methods are provided for facilitating cooling of an electronic component. The methods include providing: a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

Thermoelectric-enhanced, liquid-based cooling of a multi-component electronic system

DOEpatents

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

2015-05-12

Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled structure, a thermal conduction path coupling the electronic component and the liquid-cooled structure, a coolant loop in fluid communication with a coolant-carrying channel of the liquid-cooled structure, and an outdoor-air-cooled heat exchange unit coupled to facilitate heat transfer from the liquid-cooled structure via, at least in part, the coolant loop. The thermoelectric array facilitates transfer of heat from the electronic component to the liquid-cooled structure, and the heat exchange unit cools coolant passing through the coolant loop by dissipating heat from the coolant to outdoor ambient air. In one implementation, temperature of coolant entering the liquid-cooled structure is greater than temperature of the outdoor ambient air to which heat is dissipated.

PRELIMINARY HAZARDS SUMMARY REPORT FOR THE VALLECITOS SUPERHEAT REACTOR

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

Murray, J.L.

1961-02-01

BS>The Vallecitos Superheat Reactor (VSR) is a light-watermoderated, thermal-spectrum reactor, cooled by a combination of moderator boiling and forced convection cooling with saturated steam. The reactor core consists of 32 fuel hurdles containing 5300 lb of UO/sub 2/ enriched in U/sub 235/ to 3.6%. The fuel elements are arranged in individual process tubes that direct the cooling steam flow and separate the steam from the water moderator. The reactor vessel is designed for 1250 psig and operates at 960 to 1000 psig. With the reactor operating at 12.5 Mw(t), the maximum fuel cladding temperature is 1250 deg F and themore » cooling steam is superheated to an average temperature of about 810 deg F at 905 psig. Nu clear operation of the reactor is controlled by 12 control rods, actuated by drives mounted on the bottom of the reactor vessel. The water moderator recirculates inside the reactor vessel and through the core region by natural convection. Inherent safety features of the reactor include the negative core reactivity effects upon heating the UO/sub 2/ fuel (Doppler effect), upon increasing the temperature or void content of the moderator in the operating condition, and upon unflooding the fuel process tubes in the hot condition. Snfety features designed into the reactor and plant systems include a system of sensors and devices to detect petentially unsafe operating conditions and to initiate automatically the appropriate countermeasures, a set of fast and reliable control rods for scramming the reactor if a potentially unsafe condition occurs, a manually-actuated liquid neutron poison system, and an emergency cooling system to provide continued steam flow through the reactor core in the event the reactor becomes isolated from either its normal source of steam supply or discharge. The release of radioactivity to unrestricted areas is maintained within permissible limits by monitoring the radioactivity of wastes and controlling their release. The reactor and many of its auxiliaries are housed within a high-integrity essentially leak-tight containment vessel. (auth)« less

Use of joint-growth directions and rock textures to infer thermal regimes during solidification of basaltic lava flows

NASA Astrophysics Data System (ADS)

Degraff, James M.; Long, Philip E.; Aydin, Atilla

1989-09-01

Thermal contraction joints form in the upper and lower solidifying crusts of basaltic lava flows and grow toward the interior as the crusts thicken. Lava flows are thus divided by vertical joints that, by changes in joint spacing and form, define horizontal intraflow layers known as tiers. Entablatures are tiers with joint spacings less than about 40 cm, whereas colonnades have larger joint spacings. We use structural and petrographic methods to infer heat-transfer processes and to constrain environmental conditions that produce these contrasting tiers. Joint-surface morphology indicates overall joint-growth direction and thus identifies the level in a flow where the upper and lower crusts met. Rock texture provides information on relative cooling rates in the tiers of a flow. Lava flows without entablature have textures that develop by relatively slow cooling, and two joint sets that usually meet near their middles, which indicate mostly conductive cooling. Entablature-bearing flows have two main joint sets that meet well below their middles, and textures that indicate fast cooling of entablatures and slow cooling of colonnades. Entablatures always occur in the upper joint sets and sometimes alternate several times with colonnades. Solidification times of entablature-bearing flows, constrained by lower joint-set thicknesses, are much less than those predicted by a purely conductive cooling model. These results are best explained by a cooling model based on conductive heat transfer near a flow base and water-steam convection in the upper part of an entablature-bearing flow. Calculated solidification rates in the upper parts of such flows exceed that of the upper crust of Kilauea Iki lava lake, where water-steam convection is documented. Use of the solidification rates in an available model of water-steam convection yields permeability values that agree with measured values for fractured crystalline rock. We conclude, therefore, that an entablature forms when part of a flow cools very rapidly by water-steam convection. Flooding of the flow top by surface drainage most likely induces the convection. Colonnades form under conditions of slower cooling by conductive heat transfer in the absence of water.

Dynamically limiting energy consumed by cooling apparatus

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Schmidt, Roger R.; Schultz, Mark D.

2015-05-26

Cooling apparatuses and methods are provided which include one or more coolant-cooled structures associated with an electronics rack, a coolant loop coupled in fluid communication with one or more passages of the coolant-cooled structure(s), one or more heat exchange units coupled to facilitate heat transfer from coolant within the coolant loop, and N controllable components associated with the coolant loop or the heat exchange unit(s), wherein N.gtoreq.1. The N controllable components facilitate circulation of coolant through the coolant loop or transfer of heat from the coolant via the heat exchange unit(s). A controller is coupled to the N controllable components, and dynamically adjusts operation of the N controllable components, based on Z input parameters and one or more specified constraints, to provide a specified cooling to the coolant-cooled structure(s), while limiting energy consumed by the N controllable components, wherein Z.gtoreq.1.

Dynamically limiting energy consumed by cooling apparatus

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Schmidt, Roger R.; Schultz, Mark D.

2015-06-09

Cooling methods are provided which include providing: one or more coolant-cooled structures associated with an electronics rack, a coolant loop coupled in fluid communication with one or more passages of the coolant-cooled structure(s), one or more heat exchange units coupled to facilitate heat transfer from coolant within the coolant loop, and N controllable components associated with the coolant loop or the heat exchange unit(s), wherein N.gtoreq.1. The N controllable components facilitate circulation of coolant through the coolant loop or transfer of heat from the coolant via the heat exchange unit(s). A controller is also provided to dynamically adjust operation of the N controllable components, based on Z input parameters and one or more specified constraints, and provide a specified cooling to the coolant-cooled structure(s), while limiting energy consumed by the N controllable components, wherein Z.gtoreq.1.

Closed Loop Short Rotation Woody Biomass Energy Crops

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

Brower, Michael

CRC Development LLC is pursuing commercialization of shrub willow crops to evaluate and confirm estimates of yield, harvesting, transportation and renewable energy conversion costs and to provide a diverse resource in its supply portfolio.The goal of Closed Loop Short Rotation Woody Biomass Energy Crops is supply expansion in Central New York to facilitate the commercialization of willow biomass crops as part of the mix of woody biomass feedstocks for bioenergy and bioproducts. CRC Development LLC established the first commercial willow biomass plantation acreage in North America was established on the Tug Hill in the spring of 2006 and expanded inmore » 2007. This was the first 230- acres toward the goal of 10,000 regional acres. This project replaces some 2007-drought damaged acreage and installs a total of 630-acre new planting acres in order to demonstrate to regional agricultural producers and rural land-owners the economic vitality of closed loop short rotation woody biomass energy crops when deployed commercially in order to motivate new grower entry into the market-place. The willow biomass will directly help stabilize the fuel supply for the Lyonsdale Biomass facility, which produces 19 MWe of power and exports 15,000 pph of process steam to Burrows Paper. This project will also provide feedstock to The Biorefinery in New York for the manufacture of renewable, CO2-neutral liquid transportation fuels, chemicals and polymers. This project helps end dependency on imported fossil fuels, adds to region economic and environmental vitality and contributes to national security through improved energy independence.« less

Coronal Loop Evolution Observed with AIA and Hi-C

NASA Technical Reports Server (NTRS)

Mulu-Moore, Fana; Winebarger, A.; Cirtain, J.; Kobayashi, K.; Korreck, K.; Golub, L.; Kuzin. S.; Walsh, R.; DeForest, C.; DePontieu, B.;

Application of waterproof breathable fabric in thermal protective clothing exposed to hot water and steam

NASA Astrophysics Data System (ADS)

Su, Y.; Li, R.; Song, G.; Li, J.

2017-10-01

A hot water and steam tester was used to examine thermal protective performance of waterproof and breathable fabric against hot water and steam hazards. Time to cause skin burn and thermal energy absorbed by skin during exposure and cooling phases was employed to characterize the effect of configuration, placing order and properties of waterproof and breathable fabric on the thermal protective performance. The difference of thermal protective performance due to hot water and steam hazards was discussed. The result showed that the configuration of waterproof and breathable fabric presented a significant effect on the thermal protective performance of single- and double-layer fabric system, while the difference between different configurations in steam hazard was greater than that in hot water hazard. The waterproof and breathable fabric as outer layer provided better protection than that as inner layer. Increasing thickness and moisture regain improved the thermal protective performance of fabric system. Additionally, the thermal energy absorbed by skin during the cooling phase was affected by configuration, thickness and moisture regain of fabric. The findings will provide technical data to improve performance of thermal protective clothing in hot water and steam hazards.

Effect of steam generator configuration in a loss of the RHR during mid-loop operation at PKL facility

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

Villanueva, J. F.; Carlos, S.; Martorell, S.

The loss of the residual heat removal system in mid-loop conditions may occur with a non-negligible contribution to the plant risk, so the analysis of the accidental sequences and the actions to mitigate the accident are of great interest in shutdown conditions. In order to plan the appropriate measures to mitigate the accident is necessary to understand the thermal-hydraulic processes following the loss of the residual heat removal system during shutdown. Thus, transients of this kind have been simulated using best-estimate codes in different integral test facilities and compared with experimental data obtained in different facilities. In PKL (Primaerkreislauf-Versuchsanlage, primarymore » coolant loop test facility) test facility different series of experiments have been undertaken to analyze the plant response in shutdown. In this context, the E3 and F2 series consist of analyzing the loss of the residual heat removal system with a reduced inventory in the primary system. In particular, the experiments were developed to investigate the influence of the steam generators secondary side configuration on the plant response, what involves the consideration of different number of steam generators filled with water and ready for activation, on the heat transfer mechanisms inside the steam generators U-tubes. This work presents the results of such experiments calculated using, RELAP5/Mod 3.3. (authors)« less

Steam generator support system

DOEpatents

Moldenhauer, J.E.

1987-08-25

A support system for connection to an outer surface of a J-shaped steam generator for use with a nuclear reactor or other liquid metal cooled power source is disclosed. The J-shaped steam generator is mounted with the bent portion at the bottom. An arrangement of elongated rod members provides both horizontal and vertical support for the steam generator. The rod members are interconnected to the steam generator assembly and a support structure in a manner which provides for thermal distortion of the steam generator without the transfer of bending moments to the support structure and in a like manner substantially minimizes forces being transferred between the support structure and the steam generator as a result of seismic disturbances. 4 figs.

Steam generator support system

DOEpatents

Moldenhauer, James E.

1987-01-01

A support system for connection to an outer surface of a J-shaped steam generator for use with a nuclear reactor or other liquid metal cooled power source. The J-shaped steam generator is mounted with the bent portion at the bottom. An arrangement of elongated rod members provides both horizontal and vertical support for the steam generator. The rod members are interconnected to the steam generator assembly and a support structure in a manner which provides for thermal distortion of the steam generator without the transfer of bending moments to the support structure and in a like manner substantially minimizes forces being transferred between the support structure and the steam generator as a result of seismic disturbances.

A numerical simulation of magnetic reconnection and radiative cooling in line-tied current sheets

NASA Technical Reports Server (NTRS)

Forbes, T. G.; Malherbe, J. M.

1991-01-01

Radiative MHD equations are used for an optically thin plasma to carry out a numerical experiment related to the formation of 'postflare' loops. The numerical experiment starts with a current sheet that is in mechanical and thermal equilibrium but is unstable to both tearing-mode and thermal-condensation instabilities. The current sheet is line-tied at one end to a photospheric-like boundary and evolves asymmetrically. The effects of thermal conduction, resistivity variation, and gravity are ignored. In general, reconnection in the nonlinear stage of the tearing-mode instability can strongly affect the onset of condensations unless the radiative-cooling time scale is much smaller than the tearing-mode time scale. When the ambient plasma is less than 0.2, the reconnection enters a regime where the outflow from the reconnection region is supermagnetosonic with respect to the fast-mode wave speed. In the supermagnetosonic regime the most rapidly condensing regions occur downstream of a fast-mode shock that forms where the outflow impinges on closed loops attached to the photospheric-like boundary. A similar shock-induced condensation might occur during the formation of 'postflare' loops.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

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

Moisseytsev, A.; Sienicki, J. J.; Lv, Q.

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO 2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO 2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO 2 Brayton cycle is that it enablesmore » dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately« less

Mathematical Modeling – The Impact of Cooling Water Temperature Upsurge on Combined Cycle Power Plant Performance and Operation

NASA Astrophysics Data System (ADS)

Indra Siswantara, Ahmad; Pujowidodo, Hariyotejo; Darius, Asyari; Ramdlan Gunadi, Gun Gun

2018-03-01

This paper presents the mathematical modeling analysis on cooling system in a combined cycle power plant. The objective of this study is to get the impact of cooling water upsurge on plant performance and operation, using Engineering Equation Solver (EES™) tools. Power plant installed with total power capacity of block#1 is 505.95 MWe and block#2 is 720.8 MWe, where sea water consumed as cooling media at two unit condensers. Basic principle of analysis is heat balance calculation from steam turbine and condenser, concern to vacuum condition and heat rate values. Based on the result shown graphically, there were impact the upsurge of cooling water to increase plant heat rate and vacuum pressure in condenser so ensued decreasing plant efficiency and causing possibility steam turbine trip as back pressure raised from condenser.

Thermal Hydraulic Design and Analysis of a Water-Cooled Ceramic Breeder Blanket with Superheated Steam for CFETR

NASA Astrophysics Data System (ADS)

Cheng, Xiaoman; Ma, Xuebin; Jiang, Kecheng; Chen, Lei; Huang, Kai; Liu, Songlin

2015-09-01

The water-cooled ceramic breeder blanket (WCCB) is one of the blanket candidates for China fusion engineering test reactor (CFETR). In order to improve power generation efficiency and tritium breeding ratio, WCCB with superheated steam is under development. The thermal-hydraulic design is the key to achieve the purpose of safe heat removal and efficient power generation under normal and partial loading operation conditions. In this paper, the coolant flow scheme was designed and one self-developed analytical program was developed, based on a theoretical heat transfer model and empirical correlations. Employing this program, the design and analysis of related thermal-hydraulic parameters were performed under different fusion power conditions. The results indicated that the superheated steam water-cooled blanket is feasible. supported by the National Special Project for Magnetic Confined Nuclear Fusion Energy of China (Nos. 2013GB108004, 2014GB122000 and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

Free-cooling: A total HVAC design concept

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

Janeke, C.E.

1982-01-01

This paper discusses a total ''free cooling'' HVAC design concept in which mechanical refrigeration is practically obviated via the refined application of existing technological strategies and a new diffuser terminal. The principles being applied are as follows; Thermal Swing: This is the active contribution of programmed heat storage to overall HVAC system performance. Reverse Diffuser: This is a new air terminal design that facilitates manifesting the thermal storage gains. Developing the thermal storage equation system into a generalized simulation model, optimizing the thermal storage and operating strategies with a computer program and developing related algorithms are subsequently illustrated. Luminair Aspiration:more » This feature provides for exhausting all luminair heat totally out of the building envelope, via an exhaust duct system and insulated boots. Two/Three-Stage Evaporative Cooling: This concept comprises a system of air conditioning that entails a combination of closed and open loop evaporative cooling with standby refrigeration only.« less

Closed loop control of the induction heating process using miniature magnetic sensors

DOEpatents

Bentley, Anthony E.; Kelley, John Bruce; Zutavern, Fred J.

2003-05-20

A method and system for providing real-time, closed-loop control of the induction hardening process. A miniature magnetic sensor located near the outer surface of the workpiece measures changes in the surface magnetic field caused by changes in the magnetic properties of the workpiece as it heats up during induction heating (or cools down during quenching). A passive miniature magnetic sensor detects a distinct magnetic spike that appears when the saturation field, B.sub.sat, of the workpiece has been exceeded. This distinct magnetic spike disappears when the workpiece's surface temperature exceeds its Curie temperature, due to the sudden decrease in its magnetic permeability. Alternatively, an active magnetic sensor can measure changes in the resonance response of the monitor coil when the excitation coil is linearly swept over 0-10 MHz, due to changes in the magnetic permeability and electrical resistivity of the workpiece as its temperature increases (or decreases).

Membrane-Based Water Evaporator for a Space Suit

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; McCann, Charles J.; O'Connell, Mary K.; Andrea, Scott

2004-01-01

A membrane-based water evaporator has been developed that is intended to serve as a heat-rejection device for a space suit. This evaporator would replace the current sublimator that is sensitive to contamination of its feedwater. The design of the membrane-based evaporator takes advantage of recent advances in hydrophobic micropore membranes to provide robust heat rejection with much less sensitivity to contamination. The low contamination sensitivity allows use of the heat transport loop as feedwater, eliminating the need for the separate feedwater system used for the sublimator. A cross section of the evaporator is shown in the accompanying figure. The space-suit cooling loop water flows into a distribution plenum, through a narrow annulus lined on both sides with a hydrophobic membrane, into an exit plenum, and returns to the space suit. Two perforated metal tubes encase the membranes and provide structural strength. Evaporation at the membrane inner surface dissipates the waste heat from the space suit. The water vapor passes through the membrane, into a steam duct and is vented to the vacuum environment through a back-pressure valve. The back-pressure setting can be adjusted to regulate the heat-rejection rate and the water outlet temperature.

Preliminary analysis of the PreFlexMS molten salt once-through steam generator dynamics and control strategy

NASA Astrophysics Data System (ADS)

Trabucchi, Stefano; Casella, Francesco; Maioli, Tommaso; Elsido, Cristina; Franzini, Davide; Ramond, Mathieu

2017-06-01

Concentrated Solar Power plants (CSP) coupled with thermal storage have the potential to guarantee both flexible and continuous energy production, thus being competitive with conventional fossil fuel and hydro power plants, in terms of dispatchability and provision of ancillary services. Hence, the plant equipment and control design have to be focused on flexible operation on one hand, and on plant safety concerning the molten salt freezing on the other hand. The PreFlexMS European project aims to introduce a molten salt Once-Through Steam Generator (OTSG) within a Rankine cycle based power unit, a technology that has greater flexibility potential if compared to steam drum boilers, currently used in CSP plants. The dynamic modelling and simulation from the early design stages is, thus, of paramount importance, to assess the plant dynamic behavior and controllability, and to predict the achievable closed-loop dynamic performance, potentially saving money and time during the detailed design, construction and commissioning phases. The present paper reports the main results of the analysis carried out during the first part of the project, regarding the system analysis and control design. In particular, two different control systems have been studied and tested with the plant dynamic model: a decentralized control strategy based on PI controllers and a Linear Model Predictive Control (LMPC).

Modeling Cyclic Fatigue Hysteresis Loops of 2D Woven Ceramic Matrix Composites at Elevated Temperatures in Steam

PubMed Central

Li, Longbiao

2016-01-01

In this paper, the cyclic fatigue hysteresis loops of 2D woven SiC/SiC ceramic matrix composites (CMCs) at elevated temperatures in steam have been investigated. The interface slip between fibers and the matrix existing in matrix cracking modes 3 and 5, in which matrix cracking and interface debonding occurred in longitudinal yarns, is considered as the major reason for hysteresis loops of 2D woven CMCs. The hysteresis loops of 2D SiC/SiC composites corresponding to different peak stresses, test conditions, and loading frequencies have been predicted using the present analysis. The damage parameter, i.e., the proportion of matrix cracking mode 3 in the entire matrix cracking modes of the composite, and the hysteresis dissipated energy increase with increasing fatigue peak stress. With increasing cycle number, the interface shear stress in the longitudinal yarns decreases, leading to transition of interface slip types of matrix cracking modes 3 and 5. PMID:28773544

Fuel Cell Thermal Management Through Conductive Cooling Plates

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.; Burke, Kenneth A.

2008-01-01

An analysis was performed to evaluate the concept of utilizing conductive cooling plates to remove heat from a fuel cell stack, as opposed to a conventional internal cooling loop. The potential advantages of this type of cooling system are reduced stack complexity and weight and increased reliability through the reduction of the number of internal fluid seals. The conductive cooling plates would extract heat from the stack transferring it to an external coolant loop. The analysis was performed to determine the required thickness of these plates. The analysis was based on an energy balance between the thermal energy produced within the stack and the heat removal from the cooling plates. To accomplish the energy balance, the heat flow into and along the plates to the cooling fluid was modeled. Results were generated for various numbers of cells being cooled by a single cooling plate. The results provided cooling plate thickness, mass, and operating temperature of the plates. It was determined that utilizing high-conductivity pyrolitic graphite cooling plates can provide a specific cooling capacity (W/kg) equivalent to or potentially greater than a conventional internal cooling loop system.

A Novel Method for Preparing Auxetic Foam from Closed-cell Polymer Foam Based on Steam Penetration and Condensation (SPC) Process.

PubMed

Fan, Donglei; Li, Minggang; Qiu, Jian; Xing, Haiping; Jiang, Zhiwei; Tang, Tao

2018-05-31

Auxetic materials are a class of materials possessing negative Poisson's ratio. Here we establish a novel method for preparing auxetic foam from closed-cell polymer foam based on steam penetration and condensation (SPC) process. Using polyethylene (PE) closed-cell foam as an example, the resultant foams treated by SPC process present negative Poisson's ratio during stretching and compression testing. The effect of steam-treated temperature and time on the conversion efficiency of negative Poisson's ratio foam is investigated, and the mechanism of SPC method for forming re-entrant structure is discussed. The results indicate that the presence of enough steam within the cells is a critical factor for the negative Poisson's ratio conversion in the SPC process. The pressure difference caused by steam condensation is the driving force for the conversion from conventional closed-cell foam to the negative Poisson's ratio foam. Furthermore, the applicability of SPC process for fabricating auxetic foam is studied by replacing PE foam by polyvinyl chloride (PVC) foam with closed-cell structure or replacing water steam by ethanol steam. The results verify the universality of SPC process for fabricating auxetic foams from conventional foams with closed-cell structure. In addition, we explored potential application of the obtained auxetic foams by SPC process in the fabrication of shape memory polymer materials.

Investigation and mitigation of condensation induced water hammer by stratified flow experiments

NASA Astrophysics Data System (ADS)

Kadakia, Hiral J.

This research primarily focuses on the possibility of using stratified flow in preventing an occurrence of condensation induced water hammer (CIWH) in horizontal pipe involving steam and subcooled water. A two-phase flow loop simulating the passive safety systems of an advanced light water reactor was constructed and a series of stratified flow experiments were carried out involving a system of subcooled water, saturated water, and steam. Special instruments were designed to measure steam flow rate and subcooled liquid velocity. These experiments showed that when flow field conditions meet certain criteria CIWH does occur. Flow conditions used in experiments were typically observed in passive safety systems of an advanced light water cooled reactor. This research summarizes a) literature research and other experimental data that signify an occurrence of CIWH, b) experiments in an effort to show an occurrence of CIWH and the ability to prevent CIWH, c) qualitative and quantitative results to underline the mechanism of CIWH, d) experiments that show CIWH can be prevented under certain conditions, and e) guidelines for the safe operating conditions. Based on initial experiment results it was observed that Bernoulli's effect can play an important role in wave formation and instability. A separate effect table top experiment was constructed with plexi-glass. A series of entrance effect tests and stratified experiments were carried out with different fluids to study wave formation and wave bridging. Special test series experiments were carried out to investigate the presence of a saturated layer. The effect of subcooled water and steam flow on wedge length and depth were recorded. These experiments helped create a model which calculates wedge and depth of wedge for a given condition of steam and subcooled water. A very good comparison between the experiment results and the model was obtained. These experiments also showed that the presence of saturated layer can mitigate the CIWH. Flow conditions require to mitigate the CIWH must be such that subcooled water is laminar and steam flow rate is less than critical. Finally, a data bank of containing large number of experiments was created and guidelines for safe filling and draining of the system involving steam and subcooled water were created. Also several suggestions are provided to stop CIWH in case it does occur.

Evaluation of Heating Methods for Thermal Structural Testing of Large Structures

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Sikora, Joseph G.; Caldwell, Darrell L., Jr.

1998-01-01

An experimental study was conducted to evaluate different heating methods for thermal structural testing of large scale structures at temperatures up to 350 F as part of the High Speed Research program. The heating techniques evaluated included: radiative/convective, forced convective, and conductive. The radiative/convective heaters included finned strip heaters, and clear and frosted quartz lamps. The forced convective heating was accomplished by closed loop circulation of heated air. The conductive heater consisted of heating blankets. The tests were conducted on an 1/8 inch thick stainless steel plate in a custom-built oven. The criteria used for comparing the different heating methods included test specimen temperature uniformity, heater response time, and consumed power. The parameters investigated included air circulation in the oven, reflectance of oven walls, and the orientation of the test specimen and heaters (vertical and horizontal). It was found that reflectance of oven walls was not an important parameter. Air circulation was necessary to obtain uniform temperatures only for the vertically oriented specimen. Heating blankets provided unacceptably high temperature non-uniformities. Quartz lamps with internal air circulation had the lowest power consumption levels. Using frosted quartz lamps with closed loop circulation of cool air, and closed loop circulation of heated air provided the fastest response time.

Effect of soaking, boiling, and steaming on total phenolic contentand antioxidant activities of cool season food legumes.

PubMed

Xu, Baojun; Chang, Sam K C

2008-09-01

The effects of soaking, boiling and steaming processes on the total phenolic components and antioxidant activity in commonly consumed cool season food legumes (CSFL's), including green pea, yellow pea, chickpea and lentil were investigated. As compared to original unprocessed legumes, all processing steps caused significant (p<0.05) decreases in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH) in all tested CSFL's. All soaking and atmospheric boiling treatments caused significant (p<0.05) decreases in oxygen radical absorbing capacity (ORAC). However, pressure boiling and pressure steaming caused significant (p<0.05) increases in ORAC values. Steaming treatments resulted in a greater retention of TPC, DPPH, and ORAC values in all tested CSFL's as compared to boiling treatments. To obtain cooked legumes with similar palatability and firmness, pressure boiling shortened processing time as compared to atmospheric boiling, resulted in insignificant differences in TPC, DPPH for green and yellow pea. However, TPC and DPPH in cooked lentils differed significantly between atmospheric and pressure boiling. As compared to atmospheric processes, pressure processes significantly increased ORAC values in both boiled and steamed CSFL's. Greater TPC, DPPH and ORAC values were detected in boiling water than that in soaking and steaming water. Boiling also caused more solid loss than steaming. Steam processing exhibited several advantages in retaining the integrity of the legume appearance and texture of the cooked product, shortening process time, and greater retention of antioxidant components and activities. Copyright © 2008 Elsevier Ltd. All rights reserved.

Cooling system with automated seasonal freeze protection

DOEpatents

Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth, Jr., Michael J.; Iyengar, Madhusudan K.; Simons, Robert E.; Singh, Prabjit; Zhang, Jing

2016-05-24

An automated multi-fluid cooling system and method are provided for cooling an electronic component(s). The cooling system includes a coolant loop, a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

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

Llopis, C.; Mendizabal, R.; Perez, J.

An assessment of RELAP5/MOD2 cycle 36.04 against a load rejection from 100% to 50% power in Vandals II NPP (Spain) is presented. The work is inscribed in the framework of the Spanish contribution to ICAP Project. The model used in the simulation consists of a single loop, a steam generator and a steam line up to the steam header all of them enlarged on a scale of 3:1, and full-scaled reactor vessel and pressurizer. The results of the calculations have been in reasonable agreement with plant measurements.

Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

NASA Astrophysics Data System (ADS)

Fic, Adam; Składzień, Jan; Gabriel, Michał

2015-03-01

Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle), which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle). The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

Study of Fluid Cooling Loop System in Chinese Manned Spacecraft

NASA Astrophysics Data System (ADS)

Jiang, Jun; Xu, Jiwan; Fan, Hanlin; Huang, Jiarong

2002-01-01

change. To solve the questions, a fluid cooling loop system must be applied to Chinese manned spacecraft besides other conventional thermal control methods, such as thermal control coatings, multiplayer insulation blankets, heat pipes, electro-heating adjustment temperature devices, and so on. The paper will introduce the thermal design of inner and outer fluid loop including their constitution and fundamental, etc. The capability of heat transportation and the accuracy of control temperature for the fluid loop will be evaluated and analyzed. To insure the air temperature of sealed cabins within 21+/-4, the inlet liquid temperature of condensing heat exchanger needs to be controlled within 9+/-2. To insure this, the inlet liquid temperature of middle heat exchanger needs to be controlled within 8+/-1.8. The inlet temperature point is controlled by a subsidiary loop adjusting: when the computer receives feedbacks of the deviation and the variety rate of deviation from the controlled temperature point. It drives the temperature control valve to adjust the flow flux distribution between the main loop through radiator and the subsidiary loop which isn't through radiator to control the temperature of the mixed fluid within 8+/-1.8. The paper will also introduce thermal designs of key parts in the cooling loop, such as space radiators, heat exchangers and cooling plates. Thermal simulated tests on the ground and flight tests have been performed to verify correctness of thermal designs. rational and the loop system works order. It realizes the circulation of absorbing heat dissipation to the loop and transferring it to radiator then radiating it to space. (2) loop control system controls inlet temperature of middle heat exchanger within 8+/-1.8 under various thermal cases. Thermal design of the middle heat exchanger insures inlet temperature of condensing heat within 9+/-2. Thereby, the air temperature of sealed cabins is controlled within about 21+/-4 accurately. (3) The thermal designs of the key heat exchanging parts (such as radiator, heat exchangers and cooling plates) in the cooling loop are rational and effective, they meet the requirements of heat exchanging and assure the entire system work order.

METHOD AND APPARATUS FOR PRODUCING POWER

DOEpatents

Wollan, E.O.

1961-06-27

A neutronic reactor comprising two discrete zones; namely, an inner zone containing fissionable material and an outer zone containing fertile material is described. The inner zone is operated at a low temperature and is cooled by pressurized water. The outer zone is operated at a substantially higher temperature and is cooled by steam flashed from the inner zone. The reactor is particularly advantageous in that it produces high temperature steam; yet the materials of construction in the core (inner zone) are not restricted to materials capable of withstanding high temperature operation.

Posttest RELAP4 analysis of LOFT experiment L1-4

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

Grush, W.H.; Holmstrom, H.L.O.

Results of posttest analysis of LOFT loss-of-coolant experiment L1-4 with the RELAP4 code are presented. The results are compared with the pretest prediction and the test data. Differences between the RELAP4 model used for this analysis and that used for the pretest prediction are in the areas of initial conditions, nodalization, emergency core cooling system, broken loop hot leg, and steam generator secondary. In general, these changes made only minor improvement in the comparison of the analytical results to the data. Also presented are the results of a limited study of LOFT downcomer modeling which compared the performance of themore » conventional single downcomer model with that of the new split downcomer model. A RELAP4 sensitivity calculation with artificially elevated emergency core coolant temperature was performed to highlight the need for an ECC mixing model in RELAP4.« less

Low chemical concentrating steam generating cycle

DOEpatents

Mangus, James D.

1983-01-01

A steam cycle for a nuclear power plant having two optional modes of operation. A once-through mode of operation uses direct feed of coolant water to an evaporator avoiding excessive chemical concentration buildup. A recirculation mode of operation uses a recirculation loop to direct a portion of flow from the evaporator back through the evaporator to effectively increase evaporator flow.

DETERMINATION OF MAXIMUM PERMISSIBLE LEAKAGE FROM THE HRT PROCESS STEAM SYSTEM

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

Gift, E.H.

1959-01-30

Calculations were made to determine the radiation hazard to HRT personnel as a result of leakage to the atmosphere from the process steam system in the event of a heat exchanger tube rupture. These calculations show that with the present four-minute delay before dumping approximately 1020 lb of fuel solution may be transferred to the steam system. The radiation hazard from fission products in the atomosphere will be negligble if the steam killer blower is operating. If this blower is not operatin. a natural convection loop will be set up in the steam killer which will have a condensing capacitymore » of 4 lb/min of steam at atmospheric pressure. In this latter case. the inhalation hazard will be negligible when the leak rate through the steam stop valves is less than 4lb/ min. (auth)« less

The effect of compressive viscosity and thermal conduction on the longitudinal MHD waves

NASA Astrophysics Data System (ADS)

Bahari, K.; Shahhosaini, N.

2018-05-01

longitudinal Magnetohydrodynamic (MHD) oscillations have been studied in a slowly cooling coronal loop, in the presence of thermal conduction and compressive viscosity, in the linear MHD approximation. WKB method has been used to solve the governing equations. In the leading order approximation the dispersion relation has been obtained, and using the first order approximation the time dependent amplitude has been determined. Cooling causes the oscillations to amplify and damping mechanisms are more efficient in hot loops. In cool loops the oscillation amplitude increases with time but in hot loops the oscillation amplitude decreases with time. Our conclusion is that in hot loops the efficiency of the compressive viscosity in damping longitudinal waves is comparable to that of the thermal conduction.

The effect of compressive viscosity and thermal conduction on the longitudinal MHD waves

NASA Astrophysics Data System (ADS)

Bahari, K.; Shahhosaini, N.

2018-07-01

Longitudinal magnetohydrodynamic (MHD) oscillations have been studied in a slowly cooling coronal loop, in the presence of thermal conduction and compressive viscosity, in the linear MHD approximation. The WKB method has been used to solve the governing equations. In the leading order approximation the dispersion relation has been obtained, and using the first-order approximation the time-dependent amplitude has been determined. Cooling causes the oscillations to amplify and damping mechanisms are more efficient in hot loops. In cool loops the oscillation amplitude increases with time but in hot loops the oscillation amplitude decreases with time. Our conclusion is that in hot loops the efficiency of the compressive viscosity in damping longitudinal waves is comparable to that of the thermal conduction.

Evidence that the X-Ray Plasma in Microflares is in a Sequence of Subresolution Magnetic Tubes

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Falconer, D. A.; Porter, Jason G.

1998-01-01

We analyze the cooling of the X-ray emitting thermal plasma in microflares observed in active regions by the Yohkoh Soft X-ray Telescope. A typical microflare appears to be a transient brightening of an entire small magnetic loop, often having a diameter near the limit of resolution (approximately 2 x 10(exp 8) cm) (Shimizu 1995, PASJ, 47, 251). The X-ray plasma in the loop cools by emission of XUV radiation and by heat conduction to the cooler plasma at the feet of the loop. The cooling rate is determined by the plasma temperature and density and the loop length. The plasma density is determined from the observed X-ray brightness of the loop in combination with the temperature, the loop diameter, and the filling factor. The filling factor is the volume fraction of the loop occupied by the subset of magnetic tubes that is filled by the X-ray plasma and that contains practically all of the X-ray plasma present in the microflare loop. Taking typical values from the hundreds of microflares measured by Shimizu (1995) (X-ray brightness through the thin aluminum filter approximately 4 x 10(exp 3) DN/s/pixel, lifetime approximately 5 min, temperature approximately 6 x 10(exp 6) K, loop length approximately 10(exp 9) cm, loop diameter approximately 3 x 10(exp 8) cm), we find that for filling factors greater than approximately 1% (1) the cooling time is much shorter than the duration of the microflare, and (2) conductive cooling strongly dominates over radiative cooling. Because the cooling time is so short and because the conductive heat flux goes mainly into increasing the plasma density via chromospheric evaporation, we are compelled to conclude that (1) heating to X-ray temperatures continues through nearly the entire life of a microflare, (2) the heating keeps changing to different field lines, so that any one magnetic tube in the sequence of heated tubes emits X-rays only briefly in the life of the microflare, and (3) at any instant during the microflare the tubes filled with X-ray plasma occupy only a small fraction (less than approximately 10%) of the microflare loop. Hence, we expect that coronal X-ray images with spatial resolution 2-3 times better than from Yohkoh will show plenty of rapidly changing filamentary substructure in microflares.

Heating and Cooling of Coronal Loops with Turbulent Suppression of Parallel Heat Conduction.

PubMed

Bian, Nicolas; Emslie, A Gordon; Horne, Duncan; Kontar, Eduard P

2018-01-10

Using the "enthalpy-based thermal evolution of loops" (EBTEL) model, we investigate the hydrodynamics of the plasma in a flaring coronal loop in which heat conduction is limited by turbulent scattering of the electrons that transport the thermal heat flux. The EBTEL equations are solved analytically in each of the two (conduction-dominated and radiation-dominated) cooling phases. Comparison of the results with typical observed cooling times in solar flares shows that the turbulent mean free path λ T lies in a range corresponding to a regime in which classical (collision-dominated) conduction plays at most a limited role. We also consider the magnitude and duration of the heat input that is necessary to account for the enhanced values of temperature and density at the beginning of the cooling phase and for the observed cooling times. We find through numerical modeling that in order to produce a peak temperature ≃1.5 × 10 7 K and a 200 s cooling time consistent with observations, the flare-heating profile must extend over a significant period of time; in particular, its lingering role must be taken into consideration in any description of the cooling phase. Comparison with observationally inferred values of post-flare loop temperatures, densities, and cooling times thus leads to useful constraints on both the magnitude and duration of the magnetic energy release in the loop, as well as on the value of the turbulent mean free path λ T .

Experimental study of high-performance cooling system pipeline diameter and working fluid amount

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan; Hrabovsky, Peter; Papučík, Štefan

2016-03-01

This work deals with heat transfer resulting from the operation of power electronic components. Heat is removed from the mounting plate, which is the evaporator of the loop thermosyphon to the condenser and by natural convection is transferred to ambient. This work includes proposal of cooling device - loop thermosyphon, with its construct and follow optimization of cooling effect. Optimization proceeds by selecting the quantity of working fluid and selection of diameters vapour line and liquid line of loop thermosyphon.

Performance calculations for 200-1000 MWe MHD/steam power plants

NASA Technical Reports Server (NTRS)

Staiger, P. J.

1981-01-01

The effects of MHD generator length, level of oxygen enrichment, and oxygen production power on the performance of MHD/steam power plants ranging from 200 to 1000 MW in electrical output are investigated. The plants considered use oxygen enriched combustion air preheated to 1100 F. Both plants in which the MHD generator is cooled with low temperature and pressure boiler feedwater and plants in which the generator is cooled with high temperature and pressure boiler feedwater are considered. For plants using low temperature boiler feedwater for generator cooling the maximum thermodynamic efficiency is obtained with shorter generators and a lower level of oxygen enrichment compared to plants using high temperature boiler feedwater for generator cooling. The generator length at which the maximum plant efficiency occurs increases with power plant size for plants with a generator cooled by low temperature feedwater. Also shown is the relationship of the magnet stored energy requirement of the generator length and the power plant performance. Possible cost/performance tradeoffs between magnet cost and plant performance are indicated.

Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

NASA Astrophysics Data System (ADS)

Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

2016-05-01

A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes, results in lower values of Δ t (the temperature difference between internal and external coolant) for a given heat load.

Pretest analysis of natural circulation on the PWR model PACTEL with horizontal steam generators

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

Kervinen, T.; Riikonen, V.; Ritonummi, T.

A new tests facility - parallel channel tests loop (PACTEL)- has been designed and built to simulate the major components and system behavior of pressurized water reactors (PWRs) during postulated small- and medium-break loss-of-coolant accidents. Pretest calculations have been performed for the first test series, and the results of these calculations are being used for planning experiments, for adjusting the data acquisition system, and for choosing the optimal position and type of instrumentation. PACTEL is a volumetrically scaled (1:305) model of the VVER-440 PWR. In all the calculated cases, the natural circulation was found to be effective in removing themore » heat from the core to the steam generator. The loop mass flow rate peaked at 60% mass inventory. The straightening of the loop seals increased the mass flow rate significantly.« less

Passive containment cooling system

DOEpatents

Billig, P.F.; Cooke, F.E.; Fitch, J.R.

1994-01-25

A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA. 1 figure.

Passive containment cooling system

DOEpatents

Billig, Paul F.; Cooke, Franklin E.; Fitch, James R.

1994-01-01

A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA.

SNS Resonance Control Cooling Systems and Quadrupole Magnet Cooling Systems DIW Chemistry

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

Magda, Karoly

This report focuses on control of the water chemistry for the Spallation Neutron Source (SNS) Resonance Control Cooling System (RCCS)/Quadrupole Magnet Cooling System (QMCS) deionized water (DIW) cooling loops. Data collected from spring 2013 through spring 2016 are discussed, and an operations regime is recommended.It was found that the RCCS operates with an average pH of 7.24 for all lines (from 7.0 to 7.5, slightly alkaline), the average low dissolved oxygen is in the area of < 36 ppb, and the main loop average resistivity of is > 14 MΩ-cm. The QMCS was found to be operating in a similarmore » regime, with a slightly alkaline pH of 7.5 , low dissolved oxygen in the area of < 45 ppb, and main loop resistivity of 10 to 15 MΩ-cm. During data reading, operational corrections were done on the polishing loops to improve the water chemistry regime. Therefore some trends changed over time.It is recommended that the cooling loops operate in a regime in which the water has a resistivity that is as high as achievable, a dissolved oxygen concentration that is as low as achievable, and a neutral or slightly alkaline pH.« less

Mechanically-reattachable liquid-cooled cooling apparatus

DOEpatents

Arney, Susanne; Cheng, Jen-Hau; Kolodner, Paul R; Kota-Venkata, Krishna-Murty; Scofield, William; Salamon, Todd R; Simon, Maria E

2013-09-24

An apparatus comprising a rack having a row of shelves, each shelf supporting an electronics circuit board, each one of the circuit boards being manually removable from the shelve supporting the one of the circuit boards and having a local heat source thereon. The apparatus also comprises a cooler attached to the rack and being able to circulate a cooling fluid around a channel forming a closed loop. The apparatus further comprises a plurality of heat conduits, each heat conduit being located over a corresponding one of the circuit boards and forming a path to transport heat from the local heat source of the corresponding one of the circuit boards to the cooler. Each heat conduit is configured to be manually detachable from the cooler or the circuit board, without breaking a circulation pathway of the fluid through the cooler.

Temperature Swing Adsorption Compressor Development

NASA Technical Reports Server (NTRS)

Finn, John E.; Mulloth, Lila M.; Affleck, Dave L.

2001-01-01

Closing the oxygen loop in an air revitalization system based on four-bed molecular sieve and Sabatier reactor technology requires a vacuum pump-compressor that can take the low-pressure CO, from the 4BMS and compress and store for use by a Sabatier reactor. NASA Ames Research Center proposed a solid-state temperature-swing adsorption (TSA) compressor that appears to meet performance requirements, be quiet and reliable, and consume less power than a comparable mechanical compressor/accumulator combination. Under this task, TSA compressor technology is being advanced through development of a complete prototype system. A liquid-cooled TSA compressor has been partially tested, and the rest of the system is being fabricated. An air-cooled TSA compressor is also being designed.

Power converter having improved fluid cooling

DOEpatents

Meyer, Andreas A.; Radosevich, Lawrence D.; Beihoff, Bruce C.; Kehl, Dennis L.; Kannenberg, Daniel G.

2007-03-06

A thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support, which may be controlled in a closed-loop manner. Interfacing between circuits, circuit mounting structure, and the support provide for greatly enhanced cooling. The support may form a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

Quick connect coupling

NASA Technical Reports Server (NTRS)

Lomax, Curtis (Inventor); Webbon, Bruce (Inventor)

1995-01-01

A cooling apparatus includes a container filled with a quantity of coolant fluid initially cooled to a solid phase, a cooling loop disposed between a heat load and the container, a pump for circulating a quantity of the same type of coolant fluid in a liquid phase through the cooling loop, and a pair of couplings for communicating the liquid phase coolant fluid into the container in a direct interface with the solid phase coolant fluid.

Controls on Water Use for Thermoelectric Generation: Case Study Texas, U.S.

PubMed Central

2013-01-01

Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ∼0.43 million acre feet (maf; 0.53 km3), accounting for ∼4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km3) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ∼2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000. PMID:23937226

Controls on water use for thermoelectric generation: case study Texas, US.

PubMed

Scanlon, Bridget R; Reedy, Robert C; Duncan, Ian; Mullican, William F; Young, Michael

2013-10-01

Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ∼0.43 million acre feet (maf; 0.53 km(3)), accounting for ∼4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km(3)) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ∼2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000.

Cooling systems for ultra-high temperature turbines.

PubMed

Yoshida, T

2001-05-01

This paper describes an introduction of research and development activities on steam cooling in gas turbines at elevated temperature of 1500 C and 1700 C level, partially including those on water cooling. Descriptions of a new cooling system that employs heat pipes are also made. From the view point of heat transfer, its promising applicability is shown with experimental data and engine performance numerical evaluation.

Pressure suppression system

DOEpatents

Gluntz, D.M.

1994-10-04

A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein. 3 figs.

Pressure suppression system

DOEpatents

Gluntz, Douglas M.

1994-01-01

A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein.

Experimental research of heterogeneous nuclei in superheated steam

NASA Astrophysics Data System (ADS)

Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

2016-03-01

A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

The pressure and energy balance of the cool corona over sunspots

NASA Technical Reports Server (NTRS)

Foukal, P. V.

1976-01-01

The 22 largest sunspots observed with the Skylab SO55 spectrometer are studied for a relation between their EUV radiation and their umbral size or magnetic classification. The ultimate goal is to determine why the coronal plasma is so cool over a sunspot and how this cool plasma manages to support itself against gravity. Based on the time behavior of the EUV emission, a steady-state model is developed for the pressure and energy balance of the cool coronal-plasma loops over the spots. Analysis of the temperature structure in a typical loop indicates that the loop is exceedingly well insulated from the outside corona, that its energy balance is determined purely by internal heating and cooling processes, and that a heat input of about 0.0001 erg/cu cm per sec is required along the full length of the loop. It is proposed that: (1) coronal material flows steadily across the field lines at the tops of the loops and falls downward along both sides under gravity; (2) the corona is heated by mechanical-energy transport across the very thin transition region immediately over network-cell interiors; and (3) strong magnetic fields tend to inhibit mechanical-energy dissipation in the corona.

Energy transport in cooling device by magnetic fluid

NASA Astrophysics Data System (ADS)

Yamaguchi, Hiroshi; Iwamoto, Yuhiro

2017-06-01

Temperature sensitive magnetic fluid has a great potential with high performance heat transport ability as well as long distance energy (heat) transporting. In the present study experimental set-up was newly designed and constructed in order to measure basic heat transport characteristics under various magnetic field conditions. Angular dependence for the device (heat transfer section) was also taken into consideration for a sake of practical applications. The energy transfer characteristic (heat transport capability) in the magnetically-driven heat transport (cooling) device using the binary TSMF was fully investigated with the set-up. The obtained results indicate that boiling of the organic mixture (before the magnetic fluid itself reaching boiling point) effectively enhances the heat transfer as well as boosting the flow to circulate in the closed loop by itself. A long-distance heat transport of 5 m is experimentally confirmed, transferring the thermal energy of 35.8 W, even when the device (circulation loop) is horizontally placed. The highlighted results reveal that the proposed cooling device is innovative in a sense of transporting substantial amount of thermal energy (heat) as well as a long distance heat transport. The development of the magnetically-driven heat transport device has a great potential to be replaced for the conventional heat pipe in application of thermal engineering.

Materials for Advanced Ultra-supercritical (A-USC) Steam Turbines – A-USC Component Demonstration

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

Purgert, Robert; Phillips, Jeffrey; Hendrix, Howard

The work by the United States Department of Energy (U.S. DOE)/Ohio Coal Development Office (OCDO) advanced ultra-supercritical (A-USC) Steam Boiler and Turbine Materials Consortia from 2001 through September 2015 was primarily focused on lab scale and pilot scale materials testing. This testing included air- or steam-cooled “loops” that were inserted into existing utility boilers to gain exposure of these materials to realistic conditions of high temperature and corrosion due to the constituents in the coal. Successful research and development resulted in metallic alloy materials and fabrication processes suited for power generation applications with metal temperatures up to approximately 1472°F (800°C).more » These materials or alloys have shown, in extensive laboratory tests and shop fabrication studies, to have excellent applicability for high-efficiency low CO 2 transformational power generation technologies previously mentioned. However, as valuable as these material loops have been for obtaining information, their scale is significantly below that required to minimize the risk associated with a power company building a multi-billion dollar A-USC power plant. To decrease the identified risk barriers to full-scale implementation of these advanced materials, the U.S. DOE/OCDO A-USC Steam Boiler and Turbine Materials Consortia identified the key areas of the technology that need to be tested at a larger scale. Based upon the recommendations and outcome of a Consortia-sponsored workshop with the U.S.’s leading utilities, a Component Test (ComTest) Program for A-USC was proposed. The A-USC ComTest program would define materials performance requirements, plan for overall advanced system integration, design critical component tests, fabricate components for testing from advanced materials, and carry out the tests. The AUSC Component Test was premised on the program occurring at multiple facilities, with the operating temperatures, pressure and/or size of these components determining the optimum test location. The first step of the ComTest, the steam turbine test, was determined best suited for a site in Youngstown, Ohio. Efforts were also undertaken to identify and evaluate other potential sites for high pressure testing.« less

Height Dependence of Plasma Properties of a Dark Lane and a Cool Loop in a Solar Limb Active Region Observed by Hinode/EIS

NASA Astrophysics Data System (ADS)

Lee, K.; Imada, S.; Moon, Y.; Lee, J.

2013-12-01

We investigate spectral properties of a cool loop and a dark lane over a limb active region on 2007 March 14 by the Hinode/EUV Imaging Spectrometer. The cool loop is clearly seen in the spectral lines formed at the transition region temperature. The dark lane is characterized by an elongated faint structure in coronal spectral lines and rooted on a bright point. We determine their electron densities, Doppler velocities, and non-thermal velocities with height over the limb. We derived electron densities using the density sensitive line pairs of Mg VII, Si X, Fe XII, Fe XIII and Fe XIV spectra. Under the hydrostatic equilibrium and isothermal assumption, we determine their temperatures from the density scale height. Comparing the scale height temperatures to the peak formation temperatures of the spectral lines, we note that the scale height temperature of the cool loop is consistent with a peak formation temperature of the Fe XII and the scale height temperatures of the dark lane from each spectral lines are much lower than their peak formation temperatures. The non-thermal velocity in the cool loop slightly decreases along the loop while that in the dark lane sharply falls off with height. The variation of non-thermal velocity with height in the cool loop and the dark lane is contrast to that in off-limb polar coronal holes which are considered as source of the solar wind. Such a decrease in the non-thermal velocity may be explained by wave damping near the solar surface or turbulence due to magnetic reconnection near the bright point.

Temperature initiated passive cooling system

DOEpatents

Forsberg, Charles W.

1994-01-01

A passive cooling system for cooling an enclosure only when the enclosure temperature exceeds a maximum standby temperature comprises a passive heat transfer loop containing heat transfer fluid having a particular thermodynamic critical point temperature just above the maximum standby temperature. An upper portion of the heat transfer loop is insulated to prevent two phase operation below the maximum standby temperature.

Desulfurizing Coal With an Alkali Treatment

NASA Technical Reports Server (NTRS)

Ravindram, M.; Kalvinskas, J. J.

1987-01-01

Experimental coal-desulfurization process uses alkalies and steam in fluidized-bed reactor. With highly volatile, high-sulfur bituminous coal, process removed 98 percent of pyritic sulfur and 47 percent of organic sulfur. Used in coal liquefaction and in production of clean solid fuels and synthetic liquid fuels. Nitrogen or steam flows through bed of coal in reactor. Alkalies react with sulfur, removing it from coal. Nitrogen flow fluidizes bed while heating or cooling; steam is fluidizing medium during reaction.

Filmwise Condensation of Steam on Externally-Finned Horizontal Tubes.

DTIC Science & Technology

1983-12-01

via gravity to the boiler. The auxiliary condenser was constructed of two 9.5-mm (3/8-in) water- cooled ccpper lines helically coiled to a height of...34. " . .. . ’ . .- .. ’. .. .- . . . i . ’ -, - NPS69-83-003 - m NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS FILMWISE CONDENSATION OF STEAM ON EXTERNALLY-FINNED...and SubEtee) 5. TYPE OF REPORT & PERIOD COVERED Filmwise Condensation of Steam on Master Thesis; Externally-Finned Horizontal Tubes D e r1 6

Environmental Impacts of a Multi-Borehole Geothermal System: Model Sensitivity Study

NASA Astrophysics Data System (ADS)

Krol, M.; Daemi, N.

2017-12-01

Problems associated with fossil fuel consumption has increased worldwide interest in discovering and developing sustainable energy systems. One such system is geothermal heating, which uses the constant temperature of the ground to heat or cool buildings. Since geothermal heating offers low maintenance, high heating/cooling comfort, and a low carbon footprint, compared to conventional systems, there has been an increasing trend in equipping large buildings with geothermal heating. However, little is known on the potential environmental impact geothermal heating can have on the subsurface, such as the creation of subsurface thermal plumes or changes in groundwater flow dynamics. In the present study, the environmental impacts of a closed-loop, ground source heat pump (GSHP) system was examined with respect to different system parameters. To do this a three-dimensional model, developed using FEFLOW, was used to examine the thermal plumes resulting from ten years of operation of a vertical closed-loop GSHP system with multiple boreholes. A required thermal load typical of an office building located in Canada was calculated and groundwater flow and heat transport in the geological formation was simulated. Consequently, the resulting thermal plumes were studied and a sensitivity analysis was conducted to determine the effect of different parameters like groundwater flow and soil type on the development and movement of thermal plumes. Since thermal plumes can affect the efficiency of a GSHP system, this study provides insight into important system parameters.

Imitative modeling automatic system Control of steam pressure in the main steam collector with the influence on the main Servomotor steam turbine

NASA Astrophysics Data System (ADS)

Andriushin, A. V.; Zverkov, V. P.; Kuzishchin, V. F.; Ryzhkov, O. S.; Sabanin, V. R.

2017-11-01

The research and setting results of steam pressure in the main steam collector “Do itself” automatic control system (ACS) with high-speed feedback on steam pressure in the turbine regulating stage are presented. The ACS setup is performed on the simulation model of the controlled object developed for this purpose with load-dependent static and dynamic characteristics and a non-linear control algorithm with pulse control of the turbine main servomotor. A method for tuning nonlinear ACS with a numerical algorithm for multiparametric optimization and a procedure for separate dynamic adjustment of control devices in a two-loop ACS are proposed and implemented. It is shown that the nonlinear ACS adjusted with the proposed method with the regulators constant parameters ensures reliable and high-quality operation without the occurrence of oscillations in the transient processes the operating range of the turbine loads.

Cooling method with automated seasonal freeze protection

DOEpatents

Cambell, Levi; Chu, Richard; David, Milnes; Ellsworth, Jr, Michael; Iyengar, Madhusudan; Simons, Robert; Singh, Prabjit; Zhang, Jing

2016-05-31

An automated multi-fluid cooling method is provided for cooling an electronic component(s). The method includes obtaining a coolant loop, and providing a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

Spectroscopic Study of a Dark Lane and a Cool Loop in a Solar Limb Active Region by Hinode/EIS

NASA Astrophysics Data System (ADS)

Lee, Kyoung-Sun; Imada, S.; Moon, Y.-J.; Lee, Jin-Yi

2014-01-01

We investigated a cool loop and a dark lane over a limb active region on 2007 March 14 using the Hinode/EUV Imaging Spectrometer. The cool loop is clearly seen in the spectral lines formed at the transition region temperature. The dark lane is characterized by an elongated faint structure in the coronal spectral lines and is rooted on a bright point. We examined their electron densities, Doppler velocities, and nonthermal velocities as a function of distance from the limb. We derived electron densities using the density sensitive line pairs of Mg VII, Si X, Fe XII, Fe XIII, and Fe XIV spectra. We also compared the observed density scale heights with the calculated scale heights from each peak formation temperatures of the spectral lines under the hydrostatic equilibrium. We noted that the observed density scale heights of the cool loop are consistent with the calculated heights, with the exception of one observed cooler temperature; we also found that the observed scale heights of the dark lane are much lower than their calculated scale heights. The nonthermal velocity in the cool loop slightly decreases along the loop, while nonthermal velocity in the dark lane sharply falls off with height. Such a decrease in the nonthermal velocity may be explained by wave damping near the solar surface or by turbulence due to magnetic reconnection near the bright point.

System identification from closed-loop data with known output feedback dynamics

NASA Technical Reports Server (NTRS)

Phan, Minh; Juang, Jer-Nan; Horta, Lucas G.; Longman, Richard W.

1992-01-01

This paper presents a procedure to identify the open loop systems when it is operating under closed loop conditions. First, closed loop excitation data are used to compute the system open loop and closed loop Markov parameters. The Markov parameters, which are the pulse response samples, are then used to compute a state space representation of the open loop system. Two closed loop configurations are considered in this paper. The closed loop system can have either a linear output feedback controller or a dynamic output feedback controller. Numerical examples are provided to illustrate the proposed closed loop identification method.

Subresolution Fibrillation in X-Ray Microflares Observed by Yohkoh SXT

NASA Technical Reports Server (NTRS)

Moore, Ron; Falconer, David; Porter, Jason

1999-01-01

We analyze the cooling of the X-ray plasma in microflares observed in active regions by the Yohkoh Soft X-ray Telescope (SXT). A typical microflare appears to be a transient brightening of an entire small magnetic loop, often having a diameter near the limit of resolution (approx. 2 x 10(exp 8) cm). The plasma heated to X-ray temperatures in the body of the loop cools by emission of XUV radiation and by heat conduction to the cooler plasma at the feet of the loop. The cooling rate is determined by the plasma temperature and density and the loop length. The plasma density is determined from the observed X-ray brightness of the loop in combination with the temperature, the loop diameter, and the filling factor. The filling factor is the volume fraction of the loop occupied by the subset of magnetic tubes that is fluid by the X-ray plasma and that contains practically all of the X-ray plasma present in the microflare loop. Taking typical values from the hundreds of microflares measured by Shimizu (X-ray brightness through the thin aluminum filter - 4 x 10(exp 3) DN/s/pixeL lifetime approx. 5 min, temperature approx. 6 x 10(exp 6) K, loop length approx. 10(exp 9) cm, loop diameter approx. 3 x 10(exp 8) cm), we find that for filling factors greater than approx. 1%: (1) the cooling time is much shorter than the duration of the microflare, and (2) conductive cooling strongly dominates over radiative cooling. Because the cooling time is so short and because the conductive heat flux goes mainly into increasing the plasma density via chromospheric evaporation, we are compelled to conclude that: (1) heating to X-ray temperatures continues through nearly the entire lifetime of the microflare, (2) die heating keeps changing to different field lines, so that any one magnetic tube in the sequence of heated tubes emits X-rays only briefly in the life of the microflare, and (3) at any instant during the microflare the tubes filled with X-ray plasma occupy only a small fraction (approx. 10%) of the microflare loop. Hence, we expect that coronal X-ray images with spatial resolution 2-3 times better than from the Yohkoh SXT will show plenty of rapidly changing filamentary substructure in microflares. Our results also suggest that the heating in microflares may result from progressive reconnection similar to that inferred in many larger flares.

Al-Mn CVD-FBR coating on P92 steel as protection against steam oxidation at 650 °C: TGA-MS study

NASA Astrophysics Data System (ADS)

Castañeda, S. I.; Pérez, F. J.

2018-02-01

The initial stages oxidation of the P92 ferritic/martensitic steel with and without Al-Mn coating at 650 °C in Ar+40%H2O for 240 h were investigated by mass spectrometry (MS) and thermogravimetric analysis (TGA). TGA-MS measurements were conducted in a closed steam loop. An Al-Mn coating was deposited on P92 steel at 580 °C for 2 h by chemical vapour deposition in a fluidized bed reactor (CVD-FBR). The coating as-deposited was treated in the same reactor at 700 °C in Ar for 2h, in order to produce aluminide phases that form the protective alumina layer (Al2O3) during oxidation. MS measurements at 650 °C of the Al-Mn/P92 sample for 200 h indicated the presence of (Al-Mn-Cr-Fe-O) volatile species of small intensity. Uncoated P92 steel oxidized under the same steam oxidation conditions emitted greater intensities of volatile species of Cr, Fe and Mo in comparison with intensities from coated steel. TGA measurements verified that the mass gained by the coated sample was up to 300 times lower than for uncoated P92 steel. The morphology, composition and structure of samples by Scanning Electron Microscopy SEM, Backscattered Electron (BSE) detection, X-ray Energy Dispersive Spectrometry (EDAX) and X-ray Diffraction (XRD) are described.

Experimental investigation of biomimetic self-pumping and self-adaptive transpiration cooling.

PubMed

Jiang, Pei-Xue; Huang, Gan; Zhu, Yinhai; Xu, Ruina; Liao, Zhiyuan; Lu, Taojie

2017-09-01

Transpiration cooling is an effective way to protect high heat flux walls. However, the pumps for the transpiration cooling system make the system more complex and increase the load, which is a huge challenge for practical applications. A biomimetic self-pumping transpiration cooling system was developed inspired by the process of trees transpiration that has no pumps. An experimental investigation showed that the water coolant automatically flowed from the water tank to the hot surface with a height difference of 80 mm without any pumps. A self-adaptive transpiration cooling system was then developed based on this mechanism. The system effectively cooled the hot surface with the surface temperature kept to about 373 K when the heating flame temperature was 1639 K and the heat flux was about 0.42 MW m -2 . The cooling efficiency reached 94.5%. The coolant mass flow rate adaptively increased with increasing flame heat flux from 0.24 MW m -2 to 0.42 MW m -2 while the cooled surface temperature stayed around 373 K. Schlieren pictures showed a protective steam layer on the hot surface which blocked the flame heat flux to the hot surface. The protective steam layer thickness also increased with increasing heat flux.

Water for electricity in India: A multi-model study of future challenges and linkages to climate change mitigation

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

Srinivasan, Shweta; Kholod, Nazar; Chaturvedi, Vaibhav

This paper provides projections of water withdrawals and consumption for electricity generation in India through 2050. Based on the results from five energy-economic modeling teams, the paper explores the implications of economic growth, power plant cooling policies, and electricity CO2 emissions reductions on water withdrawals and consumption. To isolate modeling differences, the five teams used harmonized assumptions regarding economic and population growth, the distribution of power plants by cooling technologies, and withdrawals and consumption intensities. The results demonstrate the different but potentially complementary implications of cooling technology policies and efforts to reduce CO2 emissions. The application of closed-loop cooling technologiesmore » substantially reduces water withdrawals but increases consumption. The water implications of CO2 emissions reductions, depend critically on the approach to these reductions. Focusing on wind and solar power reduces consumption and withdrawals; a focus on nuclear power increases both; and a focus on hydroelectric power could increase consumptive losses through evaporation.« less

Properties of amylose complexes with hexadecyl amine and its hydrochloride salt prepared by steam jet cooking

USDA-ARS?s Scientific Manuscript database

Steam jet cooking of starch is an effective, commercially scalable method of preparing amylose for complexing with a variety of ligands. Previous work has shown that dispersions of amylose complexes prepared with fatty acids (such as palmitic) formed a variety of spherulites when cooled under diffe...

Temperature initiated passive cooling system

DOEpatents

Forsberg, C.W.

1994-11-01

A passive cooling system for cooling an enclosure only when the enclosure temperature exceeds a maximum standby temperature comprises a passive heat transfer loop containing heat transfer fluid having a particular thermodynamic critical point temperature just above the maximum standby temperature. An upper portion of the heat transfer loop is insulated to prevent two phase operation below the maximum standby temperature. 1 fig.

Cool transition region loops observed by the Interface Region Imaging Spectrograph

NASA Astrophysics Data System (ADS)

Huang, Z.; Xia, L.; Li, B.; Madjarska, M. S.

2015-12-01

An important class of loops in the solar atmosphere, cool transition region loops, have received little attention mainly due to instrumental limitations. We analyze a cluster of these loops in the on-disk active region NOAA 11934 recorded in a Si IV 1402.8 Å spectral raster and 1400Å slit-jaw (SJ) images taken by the Interface Region Imaging Spectrograph. We divide these loops into three groups and study their dynamics, evolution and interaction.The first group comprises geometrically relatively stable loops, which are finely scaled with 382~626 km cross-sections. Siphon flows in these loops are suggested by the Doppler velocities gradually changing from -10 km/s (blue-shifts) in one end to 20 km/s (red-shifts) in the other. Nonthermal velocities from 15 to 25 km/s were determined. The obtained physical properties suggest that these loops are impulsively heated by magnetic reconnection occurring at the blue-shifted footpoints where magnetic cancellation with a rate of 1015 Mx/s is found. The released magnetic energy is redistributed by the siphon flows. The second group corresponds to two active footpoints rooted in mixed-magnetic-polarity regions. Magnetic reconnection in both footpoints is suggested by explosive-event line profiles with enhanced wings up to 200 km/s and magnetic cancellation with a rate of ~1015 Mx/s. In the third group, an interaction between two cool loop systems is observed. Mixed-magnetic polarities are seen in their conjunction area where explosive-event line profiles and magnetic cancellation with a rate of 3×1015 Mx/s are found. This is a clear indication that magnetic reconnection occurs between these two loop systems. Our observations suggest that the cool transition region loops are heated impulsively most likely by sequences of magnetic reconnection events.

Cool Transition Region Loops Observed by the Interface Region Imaging Spectrograph

NASA Astrophysics Data System (ADS)

Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.

2015-09-01

We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops, a class of loops that has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si iv 1402.8 Å spectral raster and 1400 Å slit-jaw images. We divide the loops into three groups and study their dynamics. The first group comprises relatively stable loops, with 382-626 km cross-sections. Observed Doppler velocities are suggestive of siphon flows, gradually changing from -10 km s-1 at one end to 20 km s-1 at the other end of the loops. Nonthermal velocities of 15 ˜ 25 km s-1 were determined. Magnetic cancellation with a rate of 1015 Mx s-1 is found at the blueshifted footpoints. These physical properties suggest that these loops are impulsively heated by magnetic reconnection, and the siphon flows play an important role in the energy redistribution. The second group corresponds to two footpoints rooted in mixed-magnetic-polarity regions, where magnetic cancellation with a rate of 1015 Mx s-1 and explosive-event line profiles with enhanced wings of up to 200 km s-1 were observed. In the third group, interaction between two cool loop systems is observed. Evidence for magnetic reconnection between the two loop systems is reflected in the explosive-event line profiles and magnetic cancellation with a rate of 3× {10}15 Mx s-1 observed in the corresponding area. The IRIS has provided opportunity for in-depth investigations of cool transition region loops. Further numerical experiments are crucial for understanding their physics and their roles in the coronal heating processes.

Pump, and earth-testable spacecraft capillary heat transport loop using augmentation pump and check valves

NASA Technical Reports Server (NTRS)

Baker, David (Inventor)

1998-01-01

A spacecraft includes heat-generating payload equipment, and a heat transport system with a cold plate thermally coupled to the equipment and a capillary-wick evaporator, for evaporating coolant liquid to cool the equipment. The coolant vapor is coupled to a condenser and in a loop back to the evaporator. A heated coolant reservoir is coupled to the loop for pressure control. If the wick is not wetted, heat transfer will not begin or continue. A pair of check valves are coupled in the loop, and the heater is cycled for augmentation pumping of coolant to and from the reservoir. This augmentation pumping, in conjunction with the check valves, wets the wick. The wick liquid storage capacity allows the augmentation pump to provide continuous pulsed liquid flow to assure continuous vapor transport and a continuously operating heat transport system. The check valves are of the ball type to assure maximum reliability. However, any type of check valve can be used, including designs which are preloaded in the closed position. The check valve may use any ball or poppet material which resists corrosion. For optimum performance during testing on Earth, the ball or poppet would have neutral buoyancy or be configured in a closed position when the heat transport system is not operating. The ball may be porous to allow passage of coolant vapor.

Open cycle ocean thermal energy conversion steam control and bypass system

DOEpatents

Wittig, J. Michael; Jennings, Stephen J.

1980-01-01

Two sets of hinged control doors for regulating motive steam flow from an evaporator to a condenser alternatively through a set of turbine blades in a steam bypass around the turbine blades. The evaporator has a toroidal shaped casing situated about the turbine's vertical axis of rotation and an outlet opening therein for discharging motive steam into an annular steam flow path defined between the turbine's radially inner and outer casing structures. The turbine blades extend across the steam flow path intermediate the evaporator and condenser. The first set of control doors is arranged to prevent steam access to the upstream side of the turbine blades and the second set of control doors acts as a bypass around the blades so as to maintain equilibrium between the evaporator and condenser during non-rotation of the turbine. The first set of control doors preferably extend, when closed, between the evaporator casing and the turbine's outer casing and, when open, extend away from the axis of rotation. The second set of control doors preferably constitute a portion of the turbine's outer casing downstream from the blades when closed and extend, when open, toward the axis of rotation. The first and second sets of control doors are normally held in the open and closed positions respectively by locking pins which may be retracted upon detecting an abnormal operating condition respectively to permit their closing and opening and provide steam flow from the evaporator to the condenser.

Solar heating, cooling, and hot water systems installed at Richland, Washington

NASA Technical Reports Server (NTRS)

1979-01-01

The project described is part of the U. S. Department of Energy's solar demonstration program, and became operational in April 1978. The solar system uses 6,000 square feet of flat-plate liquid collectors in a closed loop to deliver solar energy through a liquid-liquid heat exchanger to the building heat-pump duct work or 9,000-gallon thermal energy storage tank. A 25-ton Arkla solar-driven absorption chiller provides the cooling, in conjunction with a 2,000 gallon chilled water storage tank and reflective ponds on three sides of the building surplus heat. A near-by building is essentially identical except for having conventional heat-pump heating and cooling, and can serve as an experimental control. An on-going public relations program was provided from the beginning of the program, and resulted in numerous visitors and tour groups.

Dual Rate Adaptive Control for an Industrial Heat Supply Process Using Signal Compensation Approach

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

Chai, Tianyou; Jia, Yao; Wang, Hong

The industrial heat supply process (HSP) is a highly nonlinear cascaded process which uses a steam valve opening as its control input, the steam flow-rate as its inner loop output and the supply water temperature as its outer loop output. The relationship between the heat exchange rate and the model parameters, such as steam density, entropy, and fouling correction factor and heat exchange efficiency are unknown and nonlinear. Moreover, these model parameters vary in line with steam pressure, ambient temperature and the residuals caused by the quality variations of the circulation water. When the steam pressure and the ambient temperaturemore » are of high values and are subjected to frequent external random disturbances, the supply water temperature and the steam flow-rate would interact with each other and fluctuate a lot. This is also true when the process exhibits unknown characteristic variations of the process dynamics caused by the unexpected changes of the heat exchange residuals. As a result, it is difficult to control the supply water temperature and the rates of changes of steam flow-rate well inside their targeted ranges. In this paper, a novel compensation signal based dual rate adaptive controller is developed by representing the unknown variations of dynamics as unmodeled dynamics. In the proposed controller design, such a compensation signal is constructed and added onto the control signal obtained from the linear deterministic model based feedback control design. Such a compensation signal aims at eliminating the unmodeled dynamics and the rate of changes of the currently sample unmodeled dynamics. A successful industrial application is carried out, where it has been shown that both the supply water temperature and the rate of the changes of the steam flow-rate can be controlled well inside their targeted ranges when the process is subjected to unknown variations of its dynamics.« less

SpalLoop

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

Sabau, Adrian; Wright, Ian

Boiler tubes in steam power plants experience tube blockages due to exfoliation of oxide grown on the inner side of the tubes. In extreme cases, significant tube blockages can lead to forced power plant outages. It is thus desired to predict through modeling the amount of tube blockage in order to inform power plant operators of possible forced outages. SpalLoop solves for the stress-strain equations in an axisymmetric geometry, tracking the stress/strain evolution during boiler operation including outages for the entire boiler tube length. At each operational outage, i.e., temperature excursions down to room temperature, the amount of exfoliated areamore » for the entire tube loop is estimated the amount of tube blockage is predicted based assumed blockage geometry and site. The SpaLLoop code contains modules developed for oxide growth, stress analysis, tube loop geometry, blockage area by taking into account the following phenomena and features, (a) Plant operation schedule with periodic alternate full-load and partial-load regimes and shut-downs, i.e., temperature excursions from high-load to room temperature, (b) axisymmetric formulation for cylindrical tubes, (c) oxide growth in a temperature gradient with multiple oxide layers, (d) geometry of a boiler tube with a single tube loop or two tube loops, (e) temperature variation along the tube length based on hot gas temperature distribution outside the tube and inlet steam temperature, (f) non-uniform oxide growth along the tube length according to the local steam tube temperature, (g) exfoliated area module: at each operational outage considered, the amount of exfoliated area and exfoliated volume along the tube is estimated, (h) blockage module: at each operational outage considered, the exfoliated volume/mass for each tube loop is estimated from which the amount of tube blockage is predicted based on given blockage geometry (length, location, and geometry). The computer program is written in FORTRAN90. Its modular structure was sought for allowing the best flexibility in updating the program by implementing new constitutive equations due to availability of new material property data and/or new physical phenomena.« less

The influence of EI-21 redox ion-exchange resins on the secondary-coolant circuit water chemistry of vehicular nuclear power installations

NASA Astrophysics Data System (ADS)

Moskvin, L. N.; Rakov, V. T.

2015-06-01

The results obtained from testing the secondary-coolant circuit water chemistry of full-scale land-based prototype bench models of vehicular nuclear power installations equipped with water-cooled water-moderated and liquid-metal reactor plants are presented. The influence of copper-containing redox ionexchange resins intended for chemically deoxygenating steam condensate on the working fluid circulation loop's water chemistry is determined. The influence of redox ion-exchange resins on the water chemistry is evaluated by generalizing an array of data obtained in the course of extended monitoring using the methods relating to physicochemical analysis of the quality of condensate-feedwater path media and the methods relating to metallographic analysis of the state of a faulty steam generator's tube system surfaces. The deoxygenating effectiveness of the normal state turbine condensate vacuum deaeration system is experimentally determined. The refusal from applying redox ion-exchange resins in the condensate polishing ion-exchange filters is formulated based on the obtained data on the adverse effect of copper-containing redox ionexchange resins on the condensate-feedwater path water chemistry and based on the data testifying a sufficient effect from using the normal state turbine condensate vacuum deaeration system. Data on long-term operation of the prototype bench model of a vehicular nuclear power installation without subjecting the turbine condensate to chemical deoxygenation are presented.

The THERMIE energy farm project

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

Lange, H.J. de; Barbucci, P.; Greil, C.

1998-07-01

At a site close to Pisa (Italy), a plant with a net power-output of approximately 12 MWe will be erected; it features an atmospheric, air-blown, circulating fluidized-bed (CFB) gasifier, integrated with a 10.9 MWe, single-shaft, heavy-duty gas-turbine, suited to burn the low-calorific value fuel-gas produced by the gasifier, and a heat-recovery steam-generator (HRSG), which provides steam to a 5 MWe condensing steam-turbine. The plant's net thermal-efficiency amounts to about 32%. Wet wood is shredded to chips, mixed with the agricultural residues and fed to a dryer. Here, flue gases from the HRSG are used to dry the fuel to themore » desired moisture content. The dried fuel is gasified in a CFB reactor to produce a fuel-gas. This fuel-gas is cooled in two stages during which the gasification air is preheated and steam is produced in a gas-cooler (GC). Then, it is washed in a wet-scrubber and compressed in several intercooled stages before it is delivered to the gas turbine model PGT10 B/1. The gas turbine adopts a newly developed, high-efficiency air-compressor and its special, dual-fuel combustion-chamber is now under development. The combined-cycle is completed with a dual pressure-level HRSG. The steam turbine is fed by the steam produced in the HRSG and the GC located in the gasification island. As a consequence of the changed agricultural market, the fuel will consist not only of short rotation forestry (SRF) but also of forestry and agricultural residues. The wood species include poplar, black locust, willow and chestnut, whereas the agricultural residues comprise olive stones and grape-seed flour. The financial viability of the project relies on the incentive provided by the Italian government with a premium price per kWh of electricity produced from renewables and on the financial contribution from the EU.« less

Pretest analysis document for Semiscale Test S-FS-1

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

Chen, T.H.

This report documents the pretest analysis calculation completed with the RELAP5/MOD2/CY21 code for Semiscale Test S-FS-1. The test will simulate the double-ended offset shear of the main steam line at the exit of the broken loop steam generator (downstream of the flow restrictor) and the subsequent plant recovery. The recovery portion of the test consists of a plant stabilization phase and a plant cooldown phase. The recovery procedures involve normal charging/letdown operation, pressurizer heater operation, secondary steam and feed of the unaffected steam generator, and pressurizer auxiliary spray. The test will be terminated after the unaffected steam generator and pressurizermore » pressures and liquid levels are stable, and the average priamry fluid temperature is stable at about 480 K (405/sup 0/F) for at least 10 minutes.« less

An optimal open/closed-loop control method with application to a pre-stressed thin duralumin plate

NASA Astrophysics Data System (ADS)

Nadimpalli, Sruthi Raju

The excessive vibrations of a pre-stressed duralumin plate, suppressed by a combination of open-loop and closed-loop controls, also known as open/closed-loop control, is studied in this thesis. The two primary steps involved in this process are: Step (I) with an assumption that the closed-loop control law is proportional, obtain the optimal open-loop control by direct minimization of the performance measure consisting of energy at terminal time and a penalty on open-loop control force via calculus of variations. If the performance measure also involves a penalty on closed-loop control effort then a Fourier based method is utilized. Step (II) the energy at terminal time is minimized numerically to obtain optimal values of feedback gains. The optimal closed-loop control gains obtained are used to describe the displacement and the velocity of open-loop, closed-loop and open/closed-loop controlled duralumin plate.

Magnetic loops, downflows, and convection in the solar corona

NASA Technical Reports Server (NTRS)

Foukal, P.

1978-01-01

Optical and extreme-ultraviolet observations of solar loop structures show that flows of cool plasma from condensations near the loop apex are a common property of loops associated with radiations whose maximum temperature is greater than approximately 7000 K and less than approximately 3,000,000 K. It is suggested that the mass balance of these structures indicates reconnection by means of plasma motion across field lines under rather general circumstances (not only after flares). It is shown that the cool material has lower gas pressure than the surrounding coronal medium. The density structure of the bright extreme ultraviolet loops suggests that downflows of cool gas result from isobaric condensation of plasma that is either out of thermal equilibrium with the local energy deposition rate into the corona, or is thermally unstable. The evidence is thought to indicate that magnetic fields act to induce a pattern of forced convection.

Refrigerant directly cooled capacitors

DOEpatents

Hsu, John S [Oak Ridge, TN; Seiber, Larry E [Oak Ridge, TN; Marlino, Laura D [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN

2007-09-11

The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

Evaluation of the Performance of O-rings Made with Different Elastomeric Polymers in Simulated Geothermal Environments at 300°C

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

Sugama, Toshifumi; Pyatina, Tatiana; Redline, Erica Marie

2014-12-01

This paper aims to evaluate the survival of O-rings made with six different elastomeric polymers, EPDM, type I- and II-FKM, FEPM, FFKM, and FSR, in five different simulated geothermal environments at 300°C. It further defines the relative strengths and weaknesses of the materials in each environment. The environments tested were: 1) non-aerated steam-cooling cycles, 2) aerated steam-cooling cycles, 3) water-based drilling fluid, 4) CO2-rich geo-brine fluid, and, 5) heat-cool water quenching cycles. Following exposure, the extent of oxidation, oxidationinduced degradation, thermal behaviors, micro-defects, permeation depths of ionic species present in environments throughout the O-ring, silicate-related scale-deposition, and changes in mechanicalmore » properties were assessed.« less

Method and apparatus for producing thermal vapor stream

DOEpatents

Cradeur, Robert R.; Sperry, John S.; Krajicek, Richard W.

1979-01-01

Method and apparatus for producing a thermal vapor stream for injecting into a subterranean formation for the recovery of liquefiable minerals therefrom, including a pressure vessel containing a high pressure combustion chamber for producing a heating gas for introduction into a heating gas injector. The heating gas injector is partly immersed in a steam generating section of the pressure vessel such that the heating gas is passed through the steam generating section to produce steam and combustion products which are directed between the pressure vessel and the combustion chamber for simultaneously cooling of the combustion chamber by further heating of the steam and combustion gases.

Spectroscopic study of a dark lane and a cool loop in a solar limb active region by Hinode/EIS

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

Lee, Kyoung-Sun; Imada, S.; Moon, Y.-J.

2014-01-10

We investigated a cool loop and a dark lane over a limb active region on 2007 March 14 using the Hinode/EUV Imaging Spectrometer. The cool loop is clearly seen in the spectral lines formed at the transition region temperature. The dark lane is characterized by an elongated faint structure in the coronal spectral lines and is rooted on a bright point. We examined their electron densities, Doppler velocities, and nonthermal velocities as a function of distance from the limb. We derived electron densities using the density sensitive line pairs of Mg VII, Si X, Fe XII, Fe XIII, and Femore » XIV spectra. We also compared the observed density scale heights with the calculated scale heights from each peak formation temperatures of the spectral lines under the hydrostatic equilibrium. We noted that the observed density scale heights of the cool loop are consistent with the calculated heights, with the exception of one observed cooler temperature; we also found that the observed scale heights of the dark lane are much lower than their calculated scale heights. The nonthermal velocity in the cool loop slightly decreases along the loop, while nonthermal velocity in the dark lane sharply falls off with height. Such a decrease in the nonthermal velocity may be explained by wave damping near the solar surface or by turbulence due to magnetic reconnection near the bright point.« less

The thermal circuit of a nuclear power station's unit built around a supercritical-pressure water-cooled reactor

NASA Astrophysics Data System (ADS)

Silin, V. A.; Zorin, V. M.; Tagirov, A. M.; Tregubova, O. I.; Belov, I. V.; Povarov, P. V.

2010-12-01

Main results obtained from calculations of the steam generator and thermal circuit of the steam turbine unit for a nuclear power unit with supercritical-pressure water coolant and integral layout are presented. The obtained characteristics point to the advisability of carrying out further developments of this promising nuclear power technology.

Chemical looping coal gasification with calcium ferrite and barium ferrite via solid--solid reactions

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

Siriwardane, Ranjani; Riley, Jarrett; Tian, Hanjing

Coal gasification to produce synthesis gas by chemical looping was investigated with two oxygen carriers, barium ferrite (BaFe2O4) and calcium ferrite (CaFe2O4). Thermo-gravimetric analysis (TGA) and fixed-bed flow reactor data indicated that a solid–solid interaction occurred between oxygen carriers and coal to produce synthesis gas. Both thermodynamic analysis and experimental data indicated that BaFe2O4 and CaFe2O4 have high reactivity with coal but have a low reactivity with synthesis gas, which makes them very attractive for the coal gasification process. Adding steam increased the production of hydrogen (H2) and carbon monoxide (CO), but carbon dioxide (CO2) remained low because these oxygenmore » carriers have minimal reactivity with H2 and CO. Therefore, the combined steam–oxygen carrier produced the highest quantity of synthesis gas. It appeared that neither the water–gas shift reaction nor the water splitting reaction promoted additional H2 formation with the oxygen carriers when steam was present. Wyodak coal, which is a sub-bituminous coal, had the best gasification yield with oxygen carrier–steam while Illinois #6 coal had the lowest. The rate of gasification and selectivity for synthesis gas production was significantly higher when these oxygen carriers were present during steam gasification of coal. The rates and synthesis gas yields during the temperature ramps of coal–steam with oxygen carriers were better than with gaseous oxygen.« less

Thermal gain of CHP steam generator plants and heat supply systems

NASA Astrophysics Data System (ADS)

Ziganshina, S. K.; Kudinov, A. A.

2016-08-01

Heating calculation of the surface condensate heat recovery unit (HRU) installed behind the BKZ-420-140 NGM boiler resulting in determination of HRU heat output according to fire gas value parameters at the heat recovery unit inlet and its outlet, heated water quantity, combustion efficiency per boiler as a result of installation of HRU, and steam condensate discharge from combustion products at its cooling below condensing point and HRU heat exchange area has been performed. Inspection results of Samara CHP BKZ-420-140 NGM power boilers and field tests of the surface condensate heat recovery unit (HRU) made on the bimetal calorifier base KCk-4-11 (KSk-4-11) installed behind station no. 2 Ulyanovsk CHP-3 DE-10-14 GM boiler were the basis of calculation. Integration of the surface condensation heat recovery unit behind a steam boiler rendered it possible to increase combustion efficiency and simultaneously decrease nitrogen oxide content in exit gases. Influence of the blowing air moisture content, the excess-air coefficient in exit gases, and exit gases temperature at the HRU outlet on steam condensate amount discharge from combustion products at its cooling below condensing point has been analyzed. The steam condensate from HRU gases is offered as heat system make-up water after degasification. The cost-effectiveness analysis of HRU installation behind the Samara CHP BKZ-420-140 NGM steam boiler with consideration of heat energy and chemically purified water economy has been performed. Calculation data for boilers with different heat output has been generalized.

Observations of Reconnection Flows in a Flare on the Solar Disk

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

Wang, Juntao; Simões, P. J. A.; Jeffrey, N. L. S.

Magnetic reconnection is a well-accepted part of the theory of solar eruptive events, though the evidence is still circumstantial. Intrinsic to the reconnection picture of a solar eruptive event, particularly in the standard model for two-ribbon flares (CSHKP model), are an advective flow of magnetized plasma into the reconnection region, expansion of field above the reconnection region as a flux rope erupts, retraction of heated post-reconnection loops, and downflows of cooling plasma along those loops. We report on a unique set of Solar Dynamics Observatory /Atmospheric Imaging Assembly imaging and Hinode /EUV Imaging Spectrometer spectroscopic observations of the disk flaremore » SOL2016-03-23T03:54 in which all four flows are present simultaneously. This includes spectroscopic evidence for a plasma upflow in association with large-scale expanding closed inflow field. The reconnection inflows are symmetric, and consistent with fast reconnection, and the post-reconnection loops show a clear cooling and deceleration as they retract. Observations of coronal reconnection flows are still rare, and most events are observed at the solar limb, obscured by complex foregrounds, making their relationship to the flare ribbons, cusp field, and arcades formed in the lower atmosphere difficult to interpret. The disk location and favorable perspective of this event have removed these ambiguities giving a clear picture of the reconnection dynamics.« less

Sources and potential application of waste heat utilization at a gas processing facility

NASA Astrophysics Data System (ADS)

Alshehhi, Alyas Ali

Waste heat recovery (WHR) has the potential to significantly improve the efficiency of oil and gas plants, chemical and other processing facilities, and reduce their environmental impact. In this Thesis a comprehensive energy audit at Abu Dhabi Gas Industries Ltd. (GASCO) ASAB gas processing facilities is undertaken to identify sources of waste heat and evaluate their potential for on-site recovery. Two plants are considered, namely ASAB0 and ASAB1. Waste heat evaluation criteria include waste heat grade (i.e., temperature), rate, accessibility (i.e., proximity) to potential on-site waste heat recovery applications, and potential impact of recovery on installation performance and safety. The operating parameters of key waste heat source producing equipment are compiled, as well as characteristics of the waste heat streams. In addition, potential waste heat recovery applications and strategies are proposed, focusing on utilities, i.e., enhancement of process cooling/heating, electrical/mechanical power generation, and steam production. The sources of waste heat identified at ASAB facilities consist of gas turbine and gas generator exhaust gases, flared gases, excess propane cooling capacity, excess process steam, process gas air-cooler heat dissipation, furnace exhaust gases and steam turbine outlet steam. Of the above waste heat sources, exhaust gases from five gas turbines and one gas generator at ASAB0 plant, as well as from four gas turbines at ASAB1 plant, were found to meet the rate (i.e., > 1 MW), grade (i.e., > 180°C), accessibility (i.e., < 50 m from potential on-site WHR applications) and minimal impact criteria on the performance and safety of existing installations, for potential waste heat recovery. The total amount of waste heat meeting these criteria were estimated at 256 MW and 289 MW at ASAB0 and ASAB1 plants, respectively, both of which are substantial. Of the 289 MW waste generated at ASAB1, approximately 173 MW are recovered by waste heat recovery steam generators (WHRSGs), leaving 116 MW unutilized. The following strategies were developed to recover the above waste heat. At ASAB0, it is proposed that exhaust gases from all five gas turbines be used to power a WHRSG. The steam generated by the WHRSG would both i) drive an absorption refrigeration unit for gas turbine inlet air cooling, which would result in additional electric or mechanical power generation, and pre-cooling of process gas, which could reduce the need for or eliminate air coolers, as well as reduce propane chiller load, and ii) serve for heating of lean gas, which would reduce furnace load. At ASAB1, it is proposed that exhaust gases from all four gas turbines be used to generate steam in WHRSG that would drive an absorption refrigeration unit for either gas turbine inlet air cooling for additional electric or mechanical power generation, or pre-cooling of process gas to eliminate air-coolers and reduce propane chiller cooling load. Considering the smaller amount of waste heat available at ASAB1 (116 MW) relative to ASAB0 (237 MW), these above two recovery options could not be implemented simultaneously at ASAB0. To permit the detailed design and techno-economic feasibility evaluation of the proposed waste heat recovery strategies in a subsequent study, the cooling loads and associated electric power consumption of ASAB0 process gas air-coolers were estimated at 21 MW and 1.9 MW, respectively, and 67 MW and 2.2 MW, respectively for ASAB1 plant. In addition, the heating loads and fuel consumption of ASAB0 furnaces used for lean gas re-generation were estimated at 24 MW and 0.0653 MMSCMD, respectively. In modeling work undertaken in parallel with this study at the Petroleum Institute, the waste heat recovery strategies proposed here were found to be thermodynamically and economically feasible, and to lead to substantial energy and cost savings, hence environmental benefits.

Evaluation of anticipatory signal to steam generator pressure control program for 700 MWe Indian pressurized heavy water reactor

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

Pahari, S.; Hajela, S.; Rammohan, H. P.

2012-07-01

700 MWe Indian Pressurized Heavy Water Reactor (IPHWR) is horizontal channel type reactor with partial boiling at channel outlet. Due to boiling, it has a large volume of vapor present in the primary loops. It has two primary loops connected with the help of pressurizer surge line. The pressurizer has a large capacity and is partly filled by liquid and partly by vapor. Large vapor volume improves compressibility of the system. During turbine trip or load rejection, pressure builds up in Steam Generator (SG). This leads to pressurization of Primary Heat Transport System (PHTS). To control pressurization of SG andmore » PHTS, around 70% of the steam generated in SG is dumped into the condenser by opening Condenser Steam Dump Valves (CSDVs) and rest of the steam is released to the atmosphere by opening Atmospheric Steam Discharge Valves (ASDVs) immediately after sensing the event. This is accomplished by adding anticipatory signal to the output of SG pressure controller. Anticipatory signal is proportional to the thermal power of reactor and the proportionality constant is set so that SG pressure controller's output jacks up to ASDV opening range when operating at 100% FP. To simulate this behavior for 700 MWe IPHWR, Primary and secondary heat transport system is modeled. SG pressure control and other process control program have also been modeled to capture overall plant dynamics. Analysis has been carried out with 3-D neutron kinetics coupled thermal hydraulic computer code ATMIKA.T to evaluate the effect of the anticipatory signal on PHT pressure and over all plant dynamics during turbine trip in 700 MWe IPHWR. This paper brings out the results of the analysis with and without considering anticipatory signal in SG pressure control program during turbine trip. (authors)« less

Impact of irrigation flow rate and intrapericardial fluid on cooled-tip epicardial radiofrequency ablation.

PubMed

Aryana, Arash; O'Neill, Padraig Gearoid; Pujara, Deep K; Singh, Steve K; Bowers, Mark R; Allen, Shelley L; d'Avila, André

2016-08-01

The optimal irrigation flow rate (IFR) during epicardial radiofrequency (RF) ablation has not been established. This study specifically examined the impact of IFR and intrapericardial fluid (IPF) accumulation during epicardial RF ablation. Altogether, 452 ex vivo RF applications (10 g for 60 seconds) delivered to the epicardial surface of bovine myocardium using 3 open-irrigated ablation catheters (ThermoCool SmartTouch, ThermoCool SmartTouch-SF, and FlexAbility) and 50 in vivo RF applications delivered (ThermoCool SmartTouch-SF) in 4 healthy adult swine in the presence or absence of IPF were examined. Ex vivo, RF was delivered at low (≤3 mL/min), reduced (5-7 mL/min), and high (≥10 mL/min) IFRs using intermediate (25-35 W) and high (35-45 W) power. In vivo, applications were delivered (at 9.3 ± 2.2 g for 60 seconds at 39 W) using reduced (5 mL/min) and high (15 mL/min) IFRs. Ex vivo, surface lesion diameter inversely correlated with IFR, whereas maximum lesion diameter and depth did not differ. While steam pops occurred more frequently at low IFR using high power (ThermoCool SmartTouch and ThermoCool SmartTouch-SF), tissue disruption was rare and did not vary with IFR. In vivo, charring/steam pop was not detected. Although there were no discernible differences in lesion size with IFR, surface lesion diameter, maximum diameter, depth, and volume were all smaller in the presence of IPF at both IFRs. Cooled-tip epicardial RF ablation created using reduced IFRs (5-7 mL/min) yields lesion sizes similar to those created using high IFRs (≥10 mL/min) without an increase in steam pop/tissue disruption, whereas the presence of IPF significantly reduces the lesion size. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Closed-Loop Control Better than Open-Loop Control of Profofol TCI Guided by BIS: A Randomized, Controlled, Multicenter Clinical Trial to Evaluate the CONCERT-CL Closed-Loop System

PubMed Central

Zhang, Xuena; Wu, Anshi; Yao, Shanglong; Xue, Zhanggang; Yue, Yun

2015-01-01

Background The CONCERT-CL closed-loop infusion system designed by VERYARK Technology Co., Ltd. (Guangxi, China) is an innovation using TCI combined with closed-loop controlled intravenous anesthesia under the guide of BIS. In this study we performed a randomized, controlled, multicenter study to compare closed-loop control and open-loop control of propofol by using the CONCERT-CL closed-loop infusion system. Methods 180 surgical patients from three medical centers undergone TCI intravenous anesthesia with propofol and remifentanil were randomly assigned to propofol closed-loop group and propofol opened-loop groups. Primary outcome was global score (GS, GS = (MDAPE+Wobble)/% of time of bispectral index (BIS) 40-60). Secondary outcomes were doses of the anesthetics and emergence time from anesthesia, such as, time to tracheal extubation. Results There were 89 and 86 patients in the closed-loop and opened-loop groups, respectively. GS in the closed-loop groups (22.21±8.50) were lower than that in the opened-loop group (27.19±15.26) (p=0.009). The higher proportion of time of BIS between 40 and 60 was also observed in the closed-loop group (84.11±9.50%), while that was 79.92±13.17% in the opened-loop group, (p=0.016). No significant differences in propofol dose and time of tracheal extubation were observed. The frequency of propofol regulation in the closed-loop group (31.55±9.46 times/hr) was obverse higher than that in the opened-loop group (6.84±6.21 times/hr) (p=0.000). Conclusion The CONCERT-CL closed-loop infusion system can automatically regulate the TCI of propofol, maintain the BIS value in an adequate range and reduce the workload of anesthesiologists better than open-loop system. Trial Registration ChiCTR ChiCTR-OOR-14005551 PMID:25886041

Solar production of intermediate temperature process heat. Phase I design. Final report. [For sugarcane processing plant in Hawaii

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

None

1980-08-01

This report is the final effort in the Phase I design of a solar industrial process heat system for the Hilo Coast Processing Company (HCPC) in Pepeekeo, Hawaii. The facility is used to wash, grind and extract sugar from the locally grown sugarcane and it operates 24 hours a day, 305 days per year. The major steam requirements in the industrial process are for the prime movers (mill turbines) in the milling process and heat for evaporating water from the extracted juices. Bagasse (the fibrous residue of milled sugarcane) supplied 84% of the fuel requirement for steam generation in 1979,more » while 65,000 barrels of No. 6 industrial fuel oil made up the remaining 16%. These fuels are burned in the power plant complex which produces 825/sup 0/F, 1,250 psi superheated steam to power a turbogenerator set which, in addition to serving the factory, generates from 7 to 16 megawatts of electricity that is exported to the local utility company. Extracted steam from the turbo-generator set supplies the plant's process steam needs. The system consists of 42,420 ft./sup 2/ of parabolic trough, single axis tracking, concentrating solar collectors. The collectors will be oriented in a North-South configuration and will track East-West. A heat transfer fluid (Gulf Synfluid 4cs) will be circulated in a closed loop fashion through the solar collectors and a series of heat exchangers. The inlet and outlet fluid temperatures for the collectors are 370/sup 0/F and 450/sup 0/F respectively. It is estimated that the net useable energy delivered to the industrial process will be 7.2 x 10/sup 9/ Btu's per year. With an HCPC boiler efficiency of 78% and 6.2 x 10/sup 6/ Btu's per barrel of oil, the solar energy system will displace 1489 barrels of oil per year. (WHK)« less

On a clean power generation system with the co-gasification of biomass and coal in a quadruple fluidized bed gasifier.

PubMed

Yan, Linbo; He, Boshu

2017-07-01

A clean power generation system was built based on the steam co-gasification of biomass and coal in a quadruple fluidized bed gasifier. The chemical looping with oxygen uncoupling technology was used to supply oxygen for the calciner. The solid oxide fuel cell and the steam turbine were combined to generate power. The calcium looping and mineral carbonation were used for CO 2 capture and sequestration. The aim of this work was to study the characteristics of this system. The effects of key operation parameters on the system total energy efficiency (ŋ ten ), total exergy efficiency (ŋ tex ) and carbon sequestration rate (R cs ) were detected. The energy and exergy balance calculations were implemented and the corresponding Sankey and Grassmann diagrams were drawn. It was found that the maximum energy and exergy losses occurred in the steam turbine. The system ŋ ten and ŋ tex could be ∼50% and ∼47%, and R cs could be over unit. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automatic design of conformal cooling channels in injection molding tooling

NASA Astrophysics Data System (ADS)

Zhang, Yingming; Hou, Binkui; Wang, Qian; Li, Yang; Huang, Zhigao

2018-02-01

The generation of cooling system plays an important role in injection molding design. A conformal cooling system can effectively improve molding efficiency and product quality. This paper provides a generic approach for building conformal cooling channels. The centrelines of these channels are generated in two steps. First, we extract conformal loops based on geometric information of product. Second, centrelines in spiral shape are built by blending these loops. We devise algorithms to implement the entire design process. A case study verifies the feasibility of this approach.

Utilization of municipal wastewater for cooling in thermoelectric power plants

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

Safari, Iman; Walker, Michael E.; Hsieh, Ming-Kai

2013-09-01

A process simulation model has been developed using Aspen Plus® with the OLI (OLI System, Inc.) water chemistry model to predict water quality in the recirculating cooling loop utilizing secondary- and tertiary-treated municipal wastewater as the source of makeup water. Simulation results were compared with pilot-scale experimental data on makeup water alkalinity, loop pH, and ammonia evaporation. The effects of various parameters including makeup water quality, salt formation, NH 3 and CO 2 evaporation mass transfer coefficients, heat load, and operating temperatures were investigated. The results indicate that, although the simulation model can capture the general trends in the loopmore » pH, experimental data on the rates of salt precipitation in the system are needed for more accurate prediction of the loop pH. It was also found that stripping of ammonia and carbon dioxide in the cooling tower can influence the cooling loop pH significantly. The effects of the NH 3 mass transfer coefficient on cooling loop pH appear to be more significant at lower values (e.g., k NH3 < 4×10 -3 m/s) when the makeup water alkalinity is low (e.g., <90 mg/L as CaCO 3). The effect of the CO2 mass transfer coefficient was found to be significant only at lower alkalinity values (e.g., k CO2<4×10 -6 m/s).« less

LCRE and SNAP 50-DR-1 programs. Engineering and progress report, April 1, 1963--June 30, 1963

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

None

BS>Declassified 6 Sep 1973. Information is presented concerning the LCRE kinetics, auxiliary systems, fuel, primary cooling system components, instrumentation, secondary cooling system, materials development, and fabrication; and SNAP-50/SPUR kinetics, fuel, primary system pump, steam generator, and materials development. (DCC)

An experimental study on the performance of closed loop pulsating heat pipe (CLPHP) with methanol as a working fluid

NASA Astrophysics Data System (ADS)

Rahman, Md. Lutfor; Nourin, Farah Nazifa; Salsabil, Zaimaa; Yasmin, Nusrat; Ali, Mohammad

2016-07-01

Thermal control is an important topic for thermal management of small electrical and electronic devices. Closed loop pulsating heat pipe (CLPHP) arises as the best solution for thermal control. The aim of this experimental study is to search a CLPHP of better thermal performance for cooling different electrical and electronic devices. In this experiment, methanol is used as working fluid. The effect of using methanol as a working fluid is studied on thermal performance in different filling ratios and angles of inclination. A copper capillary tube is used where the inner diameter is 2mm,outer diameter is 2.5mm and 250mm long. The CLPHP has 8 loops where the evaporation section is 50mm, adiabatic section is 120mm and condensation section is 80mm. The experiment is done using FR of 40%-70% with 10% of interval and angles of inclination 0° (vertical), 30°, 45°, 60° varying heat input. The results are compared on the basis of evaporator temperature, condenser temperature and their differences, thermal resistance, heat transfer co-efficient, power input and pulsating time. The results demonstrate the effect of methanol in different filling ratios and angles of inclination. M ethanol shows better performance at 30° inclination with 40% FR.

Active Control of High Frequency Combustion Instability in Aircraft Gas-Turbine Engines

NASA Technical Reports Server (NTRS)

Corrigan, Bob (Technical Monitor); DeLaat, John C.; Chang, Clarence T.

2003-01-01

Active control of high-frequency (greater than 500 Hz) combustion instability has been demonstrated in the NASA single-nozzle combustor rig at United Technologies Research Center. The combustor rig emulates an actual engine instability and has many of the complexities of a real engine combustor (i.e. actual fuel nozzle and swirler, dilution cooling, etc.) In order to demonstrate control, a high-frequency fuel valve capable of modulating the fuel flow at up to 1kHz was developed. Characterization of the fuel delivery system was accomplished in a custom dynamic flow rig developed for that purpose. Two instability control methods, one model-based and one based on adaptive phase-shifting, were developed and evaluated against reduced order models and a Sectored-1-dimensional model of the combustor rig. Open-loop fuel modulation testing in the rig demonstrated sufficient fuel modulation authority to proceed with closed-loop testing. During closed-loop testing, both control methods were able to identify the instability from the background noise and were shown to reduce the pressure oscillations at the instability frequency by 30%. This is the first known successful demonstration of high-frequency combustion instability suppression in a realistic aero-engine environment. Future plans are to carry these technologies forward to demonstration on an advanced low-emission combustor.

The IRIS Spool-Type Reactor Coolant Pump

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

Kujawski, J.M.; Kitch, D.M.; Conway, L.E.

2002-07-01

IRIS (International Reactor Innovative and Secure) is a light water cooled, 335 MWe power reactor which is being designed by an international consortium as part of the US DOE NERI Program. IRIS features an integral reactor vessel that contains all the major reactor coolant system components including the reactor core, the coolant pumps, the steam generators and the pressurizer. This integral design approach eliminates the large coolant loop piping, and thus eliminates large loss-of-coolant accidents (LOCAs) as well as the individual component pressure vessels and supports. In addition, IRIS is being designed with a long life core and enhanced safetymore » to address the requirements defined by the US DOE for Generation IV reactors. One of the innovative features of the IRIS design is the adoption of a reactor coolant pump (called 'spool' pump) which is completely contained inside the reactor vessel. Background, status and future developments of the IRIS spool pump are presented in this paper. (authors)« less

Investigation of the characteristics of a compact steam reformer integrated with a water-gas shift reactor

NASA Astrophysics Data System (ADS)

Seo, Yong-Seog; Seo, Dong-Joo; Seo, Yu-Taek; Yoon, Wang-Lai

The objective of this study is to investigate numerically a compact steam methane reforming (SMR) system integrated with a water-gas shift (WGS) reactor. Separate numerical models are established for the combustion part, SMR and WGS reaction bed. The concentration of species at the exits of the SMR and WGS bed, and the temperatures in the WGS bed are in good agreement with the measured data. Heat transfer to the catalyst beds and the catalytic reactions in the SMR and WGS catalyst bed are investigated as a function of the operation parameters. The conversion of methane at the exit of the SMR catalyst bed is calculated to be 87%, and the carbon monoxide concentration at the outlet of the WGS bed is estimated to be 0.45%. The effects of the cooling heat flux at the outside wall of the system and steam-to-carbon (S/C) ratio are also examined. As the cooling heat flux increases, both the methane conversion and carbon monoxide content are reduced in the SMR bed, and the carbon monoxide conversion is improved in the WGS bed. Both methane conversion and carbon dioxide reduction increase with increasing steam-to-carbon ratio.

Vacuum chamber with a supersonic flow aerodynamic window

DOEpatents

Hanson, Clark L.

1982-01-01

A supersonic flow aerodynamic window, whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Vacuum chamber with a supersonic-flow aerodynamic window

DOEpatents

Hanson, C.L.

1980-10-14

A supersonic flow aerodynamic window is disclosed whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Biophysics and clinical utility of irrigated-tip radiofrequency catheter ablation.

PubMed

Houmsse, Mahmoud; Daoud, Emile G

2012-01-01

Catheter ablation by radiofrequency (RF) energy has successfully eliminated cardiac tachyarrhythmias. RF ablation lesions are created by thermal energy. Electrode catheters with 4-mm-tips have been adequate to ablate arrhythmias located near the endocardium; however, the 4-mm-tip electrode does not readily ablate deeper tachyarrhythmia substrate. With 8- and 10-mm-tip RF electrodes, ablation lesions were larger; yet, these catheters are associated with increased risk for coagulum, char and thrombus formation, as well as myocardial steam rupture. Cooled-tip catheter technology was designed to cool the electrode tip, prevent excessive temperatures at the electrode tip-tissue interface, and thus allow continued delivery of RF current into the surrounding tissue. This ablation system creates larger and deeper ablation lesions and minimizes steam pops and thrombus formation. The purpose of this article is to review cooled-tip RF ablation biophysics and outcomes of clinical studies as well as to discuss future technological improvements.

Natural Circulation Level Optimization and the Effect during ULOF Accident in the SPINNOR Reactors

NASA Astrophysics Data System (ADS)

Abdullah, Ade Gafar; Su'ud, Zaki; Kurniadi, Rizal; Kurniasih, Neny; Yulianti, Yanti

2010-12-01

Natural circulation level optimization and the effect during loss of flow accident in the 250 MWt MOX fuelled small Pb-Bi Cooled non-refueling nuclear reactors (SPINNOR) have been performed. The simulation was performed using FI-ITB safety code which has been developed in ITB. The simulation begins with steady state calculation of neutron flux, power distribution and temperature distribution across the core, hot pool and cool pool, and also steam generator. When the accident is started due to the loss of pumping power the power distribution and the temperature distribution of core, hot pool and cool pool, and steam generator change. Then the feedback reactivity calculation is conducted, followed by kinetic calculation. The process is repeated until the optimum power distribution is achieved. The results show that the SPINNOR reactor has inherent safety capability against this accident.

Partial Reflection and Trapping of a Fast-mode Wave in Solar Coronal Arcade Loops

NASA Astrophysics Data System (ADS)

Kumar, Pankaj; Innes, D. E.

2015-04-01

We report on the first direct observation of a fast-mode wave propagating along and perpendicular to cool (171 Å) arcade loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA). The wave was associated with an impulsive/compact flare near the edge of a sunspot. The EUV wavefront expanded radially outward from the flare center and decelerated in the corona from 1060 to 760 km s-1 within ˜3-4 minutes. Part of the EUV wave propagated along a large-scale arcade of cool loops and was partially reflected back to the flare site. The phase speed of the wave was about 1450 km s-1, which is interpreted as a fast-mode wave. A second overlying loop arcade, orientated perpendicular to the cool arcade, is heated and becomes visible in the AIA hot channels. These hot loops sway in time with the EUV wave, as it propagated to and fro along the lower loop arcade. We suggest that an impulsive energy release at one of the footpoints of the arcade loops causes the onset of an EUV shock wave that propagates along and perpendicular to the magnetic field.

US PWR steam generator management: An overview

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

Welty, C.S. Jr.

1997-02-01

This paper provides an overview on the status of steam generator management activities in US PWRs, and includes: (1) an overview of the impact of steam generator problems; (2) a brief discussion of historical damage trends and the current damage mechanism of most concern; (3) a discussion of the elements of {open_quotes}steam generator management{close_quotes}; and (4) a description of the approach being followed to implement a degradation-specific protocol for tubing inspection and repair. This paper was prepared in conjunction with another paper presented during the Plenary Session of this Conference, {open_quotes}Steam Generator Degradation: Current Mitigation Strategies for Controlling Corrosion{close_quotes}, andmore » is provided as a supplement to that material.« less

The Concept and Analytical Investigation of CO2 and Steam Co-Electrolysis for Resource Utilization in Space Exploration

NASA Technical Reports Server (NTRS)

McKellar, Michael G.; Stoots, Carl M.; Sohal, Manohar S.; Mulloth, Lila M.; Luna, Bernadette; Abney, Morgan B.

2010-01-01

CO2 acquisition and utilization technologies will have a vital role in designing sustainable and affordable life support and in situ fuel production architectures for human and robotic exploration of Moon and Mars. For long-term human exploration to be practical, reliable technologies have to be implemented to capture the metabolic CO2 from the cabin air and chemically reduce it to recover oxygen. Technologies that enable the in situ capture and conversion of atmospheric CO2 to fuel are essential for a viable human mission to Mars. This paper describes the concept and mathematical analysis of a closed-loop life support system based on combined electrolysis of CO2 and steam (co-electrolysis). Products of the coelectrolysis process include oxygen and syngas (CO and H2) that are suitable for life support and synthetic fuel production, respectively. The model was developed based on the performance of a co-electrolysis system developed at Idaho National Laboratory (INL). Individual and combined process models of the co-electrolysis and Sabatier, Bosch, Boudouard, and hydrogenation reactions are discussed and their performance analyses in terms of oxygen production and CO2 utilization are presented.

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

Antolin, P.; Rouppe van der Voort, L., E-mail: patrick.antolin@astro.uio.no, E-mail: v.d.v.l.rouppe@astro.uio.no

Observed in cool chromospheric lines, such as H{alpha} or Ca II H, coronal rain corresponds to cool and dense plasma falling from coronal heights. Considered as a peculiar sporadic phenomenon of active regions, it has not received much attention since its discovery more than 40 years ago. Yet, it has been shown recently that a close relationship exists between this phenomenon and the coronal heating mechanism. Indeed, numerical simulations have shown that this phenomenon is most likely due to a loss of thermal equilibrium ensuing from a heating mechanism acting mostly toward the footpoints of loops. We present here onemore » of the first high-resolution spectroscopic observations of coronal rain, performed with the CRisp Imaging Spectro Polarimeter (CRISP) instrument at the Swedish Solar Telescope. This work constitutes the first attempt to assess the importance of coronal rain in the understanding of the coronal magnetic field in active regions. With the present resolution, coronal rain is observed to literally invade the entire field of view. A large statistical set is obtained in which dynamics (total velocities and accelerations), shapes (lengths and widths), trajectories (angles of fall of the blobs), and thermodynamic properties (temperatures) of the condensations are derived. Specifically, we find that coronal rain is composed of small and dense chromospheric cores with average widths and lengths of {approx}310 km and {approx}710 km, respectively, average temperatures below 7000 K, displaying a broad distribution of falling speeds with an average of {approx}70 km s{sup -1}, and accelerations largely below the effective gravity along loops. Through estimates of the ion-neutral coupling in the blobs we show that coronal rain acts as a tracer of the coronal magnetic field, thus supporting the multi-strand loop scenario, and acts as a probe of the local thermodynamic conditions in loops. We further elucidate its potential in coronal heating. We find that the cooling in neighboring strands occurs simultaneously in general suggesting a similar thermodynamic evolution among strands, which can be explained by a common footpoint heating process. Constraints for coronal heating models of loops are thus provided. Estimates of the fraction of coronal volume with coronal rain give values between 7% and 30%. Estimates of the occurrence time of the phenomenon in loops set times between 5 and 20 hr, implying that coronal rain may be a common phenomenon, in agreement with the frequent observations of cool downflows in extreme-ultraviolet lines. The coronal mass drain rate in the form of coronal rain is estimated to be on the order of 5 Multiplication-Sign 10{sup 9} g s{sup -1}, a significant quantity compared to the estimate of mass flux into the corona from spicules.« less

Parametric performance analysis of steam-injected gas turbine with a thermionic-energy-converter-lined combustor

NASA Technical Reports Server (NTRS)

Choo, Y. K.; Burns, R. K.

1982-01-01

The performance of steam-injected gas turbines having combustors lined with thermionic energy converters (STIG/TEC systems) was analyzed and compared with that of two baseline systems; a steam-injected gas turbine (without a TEC-lined combustor) and a conventional combined gas turbine/steam turbine cycle. Common gas turbine parameters were assumed for all of the systems. Two configurations of the STIG/TEC system were investigated. In both cases, steam produced in an exhaust-heat-recovery boiler cools the TEC collectors. It is then injected into the gas combustion stream and expanded through the gas turbine. The STIG/TEC system combines the advantage of gas turbine steam injection with the conversion of high-temperature combustion heat by TEC's. The addition of TEC's to the baseline steam-injected gas turbine improves both its efficiency and specific power. Depending on system configuration and design parameters, the STIG/TEC system can also achieve higher efficiency and specific power than the baseline combined cycle.

Catalyst evaluation for high-purity H2 production by sorption-enhanced steam-methane reforming coupled to a Ca/Cu process

NASA Astrophysics Data System (ADS)

Navarro, M. V.; López, J. M.; García, T.; Grasa, G.; Murillo, R.

2017-09-01

The operational limits of a commercial nickel-based catalyst under the conditions of a sorption-enhanced steam-methane reforming process coupled to a Ca/Cu chemical loop are investigated for high-purity H2 production in a cyclic operation. The performance of the reforming catalyst is tested by means of a high number of oxidation-reduction-reforming cycles. After 100 oxidation-reduction cycles, this catalyst retains its exceptional reforming activity. The methane conversion values are close to the thermodynamic equilibrium under very demanding conditions: temperature between 500 °C - 700 °C and mass hourly space velocity of 8.8 kgCH4 h-1 kgcat-1. After 200 cycles, the sample shows reduction in its reforming activity in line with a lower dispersion of the Ni species. Sintering of Ni nanocrystals is evidenced during the oxidation-reduction multi-cycles. The performance of the catalyst after 200 oxidation-reduction cycles mixed with a CaO-based CO2 sorbent is studied under optimal conditions calculated for the sorption-enhanced reforming process coupled to a Ca/Cu cycle (temperature of 650 °C, steam/methane ratio of 4, sorbent/catalyst ratio of 4 and space velocity of 0.75 kgCH4 h-1 kgcat-1). Remarkably, an equilibrium value over 92 vol.% H2 concentration is achieved, highlighting this catalyst as a promising candidate for the next steps of the process development.

Decay Heat Removal from a GFR Core by Natural Convection

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

Williams, Wesley C.; Hejzlar, Pavel; Driscoll, Michael J.

2004-07-01

One of the primary challenges for Gas-cooled Fast Reactors (GFR) is decay heat removal after a loss of coolant accident (LOCA). Due to the fact that thermal gas cooled reactors currently under design rely on passive mechanisms to dissipate decay heat, there is a strong motivation to accomplish GFR core cooling through natural phenomena. This work investigates the potential of post-LOCA decay heat removal from a GFR core to a heat sink using an external convection loop. A model was developed in the form of the LOCA-COLA (Loss of Coolant Accident - Convection Loop Analysis) computer code as a meansmore » for 1D steady state convective heat transfer loop analysis. The results show that decay heat removal by means of gas cooled natural circulation is feasible under elevated post-LOCA containment pressure conditions. (authors)« less

Structure and Dynamics of Cool Flare Loops Observed by the Interface Region Imaging Spectrograph

NASA Astrophysics Data System (ADS)

Mikuła, K.; Heinzel, P.; Liu, W.; Berlicki, A.

2017-08-01

Flare loops were well observed with the Interface Region Imaging Spectrograph (IRIS) during the gradual phase of two solar flares on 2014 March 29 and 2015 June 22. Cool flare loops are visible in various spectral lines formed at chromospheric and transition-region temperatures and exhibit large downflows which correspond to the standard scenario. The principal aim of this work is to analyze the structure and dynamics of cool flare loops observed in Mg II lines. Synthetic profiles of the Mg II h line are computed using the classical cloud model and assuming a uniform background intensity. In this paper, we study novel IRIS NUV observations of such loops in Mg II h and k lines and also show the behavior of hotter lines detected in the FUV channel. We obtained the spatial evolution of the velocities: near the loop top, the flow velocities are small and they are increasing toward the loop legs. Moreover, from slit-jaw image (SJI) movies, we observe some plasma upflows into the loops, which are also detectable in Mg II spectra. The brightness of the loops systematically decreases with increasing flow velocity, and we ascribe this to the effect of Doppler dimming, which works for Mg II lines. Emission profiles of Mg II were found to be extremely broad, and we explain this through the large unresolved non-thermal motions.

Structure and Dynamics of Cool Flare Loops Observed by the Interface Region Imaging Spectrograph

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

Mikuła, K.; Berlicki, A.; Heinzel, P.

Flare loops were well observed with the Interface Region Imaging Spectrograph ( IRIS ) during the gradual phase of two solar flares on 2014 March 29 and 2015 June 22. Cool flare loops are visible in various spectral lines formed at chromospheric and transition-region temperatures and exhibit large downflows which correspond to the standard scenario. The principal aim of this work is to analyze the structure and dynamics of cool flare loops observed in Mg ii lines. Synthetic profiles of the Mg ii h line are computed using the classical cloud model and assuming a uniform background intensity. In thismore » paper, we study novel IRIS NUV observations of such loops in Mg ii h and k lines and also show the behavior of hotter lines detected in the FUV channel. We obtained the spatial evolution of the velocities: near the loop top, the flow velocities are small and they are increasing toward the loop legs. Moreover, from slit-jaw image (SJI) movies, we observe some plasma upflows into the loops, which are also detectable in Mg ii spectra. The brightness of the loops systematically decreases with increasing flow velocity, and we ascribe this to the effect of Doppler dimming, which works for Mg ii lines. Emission profiles of Mg ii were found to be extremely broad, and we explain this through the large unresolved non-thermal motions.« less

Disinfection of Cystoscopes by Subatmospheric Steam and Steam and Formaldehyde at 80°C

PubMed Central

Alder, V. G.; Gingell, J. C.; Mitchell, J. P.

1971-01-01

A new method of disinfection adapted for endoscopic instruments uses low temperature steam at 80°C or steam and formaldehyde at 80°C. The process has considerable advantages over existing methods and more closely approaches the ideal requirements. ImagesFIG. 3FIG. 4FIG. 5 PMID:5569551

Methods of increasing thermal efficiency of steam and gas turbine plants

NASA Astrophysics Data System (ADS)

Vasserman, A. A.; Shutenko, M. A.

2017-11-01

Three new methods of increasing efficiency of turbine power plants are described. Increasing average temperature of heat supply in steam turbine plant by mixing steam after overheaters with products of combustion of natural gas in the oxygen. Development of this idea consists in maintaining steam temperature on the major part of expansion in the turbine at level, close to initial temperature. Increasing efficiency of gas turbine plant by way of regenerative heating of the air by gas after its expansion in high pressure turbine and before expansion in the low pressure turbine. Due to this temperature of air, entering combustion chamber, is increased and average temperature of heat supply is consequently increased. At the same time average temperature of heat removal is decreased. Increasing efficiency of combined cycle power plant by avoiding of heat transfer from gas to wet steam and transferring heat from gas to water and superheated steam only. Steam will be generated by multi stage throttling of the water from supercritical pressure and temperature close to critical, to the pressure slightly higher than condensation pressure. Throttling of the water and separation of the wet steam on saturated water and steam does not require complicated technical devices.

Steam inhalation or humidified oxygen for acute bronchiolitis in children up to three years of age.

PubMed

Umoren, Rachel; Odey, Friday; Meremikwu, Martin M

2011-01-19

Acute bronchiolitis is a common respiratory infection and a major cause of morbidity in young children. It is treated with bronchodilators (for example, salbutamol), corticosteroids or humidified air (steam inhalation or cool mist). Steam inhalation is preferred in low-income countries as it is inexpensive and easily available. It is thought to act as a secretolytic agent to lighten secretions in the respiratory tract and relieve respiratory distress. To evaluate the effect of steam inhalation or humidified oxygen to relieve respiratory distress and to evaluate adverse events in children up to three years old with acute bronchiolitis. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 1) which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1950 to February Week 4, 2010), EMBASE.com (1974 to March 2010), CINAHL (1981 to March 2010), AMED (1985 to March 2010), Web of Science (2000 to March 2010) and LILACS (1982 to March 2010). Randomised controlled trials involving children up to three years old with bronchiolitis comparing steam inhalation (or cool mist) or humidified oxygen against bronchodilators, corticosteroids or placebo; alone or in combination. Two review authors independently assessed trial quality and extracted data. Only one study (156 children aged between seven weeks and 24 months with signs and symptoms of bronchiolitis) met the eligibility criteria for inclusion. Participants were randomised into three groups: nebulised salbutamol, nebulised saline and mist in a tent. The results showed a significant decrease in respiratory distress symptom (RDS) score in the nebulised salbutamol group but no significant decrease in the RDS score in the mist in a tent or nebulised saline groups. The study did not report on adverse effects of the interventions. Steam inhalation (or cool mist therapy) is commonly used to treat acute bronchiolitis in resource-constrained settings. One study was eligible for inclusion and found that nebulised salbutamol was an effective intervention for young children with bronchiolitis but mist in a tent did not lead to a significant decrease in RDS score. Since only one study was analysed it would be misleading to conclude that mist therapy is ineffective in children with bronchiolitis. We conclude that there is insufficient evidence to inform practice regarding using steam inhalation or mist therapy for acute bronchiolitis in children up to three years old.

Nonpneumonic, short-incubation-period Legionellosis (Pontiac fever) in men who cleaned a steam turbine condenser.

PubMed

Fraser, D W; Deubner, D C; Hill, D L; Gilliam, D K

1979-08-17

Pontiac fever affected ten men who had cleaned a steam turbine condenser with compressed air. Previous epidemics of Pontiac fever and Legionnaires' disease--both caused by Legionella Pneumophila (proposed sp. nov.)--involved "airborne spread" from air-conditioning cooling towers or evaporative condensers. Aerosols of contaminated water in heat-rejection systems appear to be important sources of epidemic legionellosis.

Gas-Cooled Reactor Programs annual progress report for period ending December 31, 1973. [HTGR fuel reprocessing, fuel fabrication, fuel irradiation, core materials, and fission product distribution; GCFR fuel irradiation and steam generator modeling

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

Kasten, P.R.; Coobs, J.H.; Lotts, A.L.

1976-04-01

Progress is summarized in studies relating to HTGR fuel reprocessing, refabrication, and recycle; HTGR fuel materials development and performance testing; HTGR PCRV development; HTGR materials investigations; HTGR fuel chemistry; HTGR safety studies; and GCFR irradiation experiments and steam generator modeling.

Downhole steam quality measurement

DOEpatents

Lee, D.O.; Montoya, P.C.; Muir, J.F.; Wayland, J.R. Jr.

1985-06-19

The present invention relates to an empirical electrical method for remote sensing of steam quality utilizing flow-through grids which allow measurement of the electrical properties of a flowing two-phase mixture. The measurement of steam quality in the oil field is important to the efficient application of steam assisted recovery of oil. Because of the increased energy content in higher quality steam it is important to maintain the highest possible steam quality at the injection sandface. The effectiveness of a steaming operation without a measure of steam quality downhole close to the point of injection would be difficult to determine. Therefore, a need exists for the remote sensing of steam quality.

Optical Design of the Developmental Cryogenic Active Telescope Testbed (DCATT)

NASA Technical Reports Server (NTRS)

Davila, Pam; Wilson, Mark; Young, Eric W.; Lowman, Andrew E.; Redding, David C.

1997-01-01

In the summer of 1996, three Study teams developed conceptual designs and mission architectures for the Next Generation Space Telescope (NGST). Each group highlighted areas of technology development that need to be further advanced to meet the goals of the NGST mission. The most important areas for future study included: deployable structures, lightweight optics, cryogenic optics and mechanisms, passive cooling, and on-orbit closed loop wavefront sensing and control. NASA and industry are currently planning to develop a series of ground testbeds and validation flights to demonstrate many of these technologies. The Deployed Cryogenic Active Telescope Testbed (DCATT) is a system level testbed to be developed at Goddard Space Flight Center in three phases over an extended period of time. This testbed will combine an actively controlled telescope with the hardware and software elements of a closed loop wavefront sensing and control system to achieve diffraction limited imaging at 2 microns. We will present an overview of the system level requirements, a discussion of the optical design, and results of performance analyses for the Phase 1 ambient concept for DCATT,

Non-Nuclear Validation Test Results of a Closed Brayton Cycle Test-Loop

NASA Astrophysics Data System (ADS)

Wright, Steven A.

2007-01-01

Both NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, or for next generation nuclear power plants on earth. Although open Brayton cycles are in use for many applications (combined cycle power plants, aircraft engines), only a few closed Brayton cycles have been tested. Experience with closed Brayton cycles coupled to nuclear reactors is even more limited and current projections of Brayton cycle performance are based on analytic models. This report describes and compares experimental results with model predictions from a series of non-nuclear tests using a small scale closed loop Brayton cycle available at Sandia National Laboratories. A substantial amount of testing has been performed, and the information is being used to help validate models. In this report we summarize the results from three kinds of tests. These tests include: 1) test results that are useful for validating the characteristic flow curves of the turbomachinery for various gases ranging from ideal gases (Ar or Ar/He) to non-ideal gases such as CO2, 2) test results that represent shut down transients and decay heat removal capability of Brayton loops after reactor shut down, and 3) tests that map a range of operating power versus shaft speed curve and turbine inlet temperature that are useful for predicting stable operating conditions during both normal and off-normal operating behavior. These tests reveal significant interactions between the reactor and balance of plant. Specifically these results predict limited speed up behavior of the turbomachinery caused by loss of load, the conditions for stable operation, and for direct cooled reactors, the tests reveal that the coast down behavior during loss of power events can extend for hours provided the ultimate heat sink remains available.

Thermally Simulated 32kW Direct-Drive Gas-Cooled Reactor: Design, Assembly, and Test

NASA Astrophysics Data System (ADS)

Godfroy, Thomas J.; Kapernick, Richard J.; Bragg-Sitton, Shannon M.

2004-02-01

One of the power systems under consideration for nuclear electric propulsion is a direct-drive gas-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the reactor to the Brayton system via a circulated closed loop gas. To allow early utilization, system designs must be relatively simple, easy to fabricate, and easy to test using non-nuclear heaters to closely mimic heat from fission. This combination of attributes will allow pre-prototypic systems to be designed, fabricated, and tested quickly and affordably. The ability to build and test units is key to the success of a nuclear program, especially if an early flight is desired. The ability to perform very realistic non-nuclear testing increases the success probability of the system. In addition, the technologies required by a concept will substantially impact the cost, time, and resources required to develop a successful space reactor power system. This paper describes design features, assembly, and test matrix for the testing of a thermally simulated 32kW direct-drive gas-cooled reactor in the Early Flight Fission - Test Facility (EFF-TF) at Marshall Space Flight Center. The reactor design and test matrix are provided by Los Alamos National Laboratories.

66. TURBINE BUILDING (LOCATION N), FIRST LEVEL, B AND D ...

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

66. TURBINE BUILDING (LOCATION N), FIRST LEVEL, B AND D LOOP STEAM HEATERS FROM NORTH - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

67. TURBINE BUILDING (LOCATION N), FIRST LEVEL, B AND D ...

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

67. TURBINE BUILDING (LOCATION N), FIRST LEVEL, B AND D LOOP STEAM HEATERS FROM NORTHWEST - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

MSG test report: removal of residual sodium. [LMFBR

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

Harty, R.B.

1974-03-08

This report presents the results of cleaning activities performed to remove residual sodium from the AI Modular Steam Generator. A description of the cleaning loop, cleaning procedure, results, and visual inspection are included.

Green Chemical Treatments for Heating and Cooling Systems

DTIC Science & Technology

2006-09-01

Legionella pneumophila bacterium, which causes Legion- naire’s Disease. 2.3 Steam Line Treatment The third and final product in the Green Chemistry...ER D C/ CE R L TR -0 6 -2 9 Green Chemical Treatments for Heating and Cooling Systems Susan A. Drozdz and Vincent F. Hock September...CERL TR-06-29 September 2006 Green Chemical Treatments for Heating and Cooling Systems Susan A. Drozdz and Vincent F. Hock Construction

Magnetization reversal mechanism for Co nanoparticles revealed by a magnetic hysteresis scaling technique

NASA Astrophysics Data System (ADS)

Kobayashi, Satoru; Sato, Takuma; Li, Zhang; Dong, Xing-Long; Murakami, Takeshi

2018-05-01

We report results of magnetic hysteresis scaling of minor loops for cobalt nanoparticles with variable mean particle size of 53 and 95 nm. A power-law scaling with an exponent of 1.40±0.05 was found to hold true between minor-loop remanence and hysteresis loss in the wide temperature range of 10 - 300 K, irrespective of particle size and cooling field. A coefficient deduced from the scaling law steeply increases with decreasing temperature and exhibits a cooling field dependence below T ˜ 150 K. The value obtained after field cooling at 5 T was lower than that after zero-field cooling, being opposite to a behavior of major-loop coercivity. These observations were explained from the viewpoint of the exchange coupling between ferromagnetic Co core and antiferromagnetic CoO shell, which becomes effective below T ˜ 150 K.

Economic analysis of condensers for water recovery in steam injected gas turbines

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

De Paepe, M.; Huvenne, P.; Dick, E.

1998-07-01

Steam injection cycles are interesting for small power ranges because of the high efficiency and the relatively low investment costs. A big disadvantage is the consumption of water by the cycle. Water recovery is seldom realized in industrial practice. In this paper an analysis of the technical and economical possibilities of water recovery by condensation of water out of the exhaust gases is made. Three gas turbines are considered : the Kawasaki M1A-13CC (2.3 MWe), the Allison 501KH (6.8 MWe) and the General Electric LM1600 (17 MWe). For every gas turbine two types of condensers are designed. In the watermore » cooled condenser finned tubes are used to cool the exhaust gases, flowing at the outside of the tubes. The water itself flows at the inside of the tubes and is cooled by a water to air cooler. In the air cooled condenser the exhaust gases flow at the inside of the tubes and the cooling air at the outside. The investment costs of the condensers is compared to the costs of the total installation. The investment costs are relatively smaller if the produced power goes up. The water cooled condenser with water to air cooler is cheaper than the air cooled condenser. Using a condenser results in higher exploitation costs due to the fans and pumps. It is shown that the air cooled condenser has lower exploitation costs than the water cooled one. Pay back time of the total installation does not significantly vary compared to the installation without recovery. Water prices are determined for which water recovery is profitable. For the water cooled condenser the turning point lies at 2.2 Euro/m; for the air cooled condenser this is 0.6 Euro/m.« less

Evaluation of a Passive Heat Exchanger Based Cooling System for Fuel Cell Applications

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.; Burke, Kenneth A.

2011-01-01

Fuel cell cooling is conventionally performed with an actively controlled, dedicated coolant loop that exchanges heat with a separate external cooling loop. To simplify this system the concept of directly cooling a fuel cell utilizing a coolant loop with a regenerative heat exchanger to preheat the coolant entering the fuel cell with the coolant exiting the fuel cell was analyzed. The preheating is necessary to minimize the temperature difference across the fuel cell stack. This type of coolant system would minimize the controls needed on the coolant loop and provide a mostly passive means of cooling the fuel cell. The results indicate that an operating temperature of near or greater than 70 C is achievable with a heat exchanger effectiveness of around 90 percent. Of the heat exchanger types evaluated with the same type of fluid on the hot and cold side, a counter flow type heat exchanger would be required which has the possibility of achieving the required effectiveness. The number of heat transfer units required by the heat exchanger would be around 9 or greater. Although the analysis indicates the concept is feasible, the heat exchanger design would need to be developed and optimized for a specific fuel cell operation in order to achieve the high effectiveness value required.

High temperature skin friction measurement

NASA Technical Reports Server (NTRS)

Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

1989-01-01

Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

Investigation into the Cyclic Strength of the Bodies of Steam Shutoff Valves from 10Kh9MFB-Sh Steel

NASA Astrophysics Data System (ADS)

Skorobogatykh, V. N.; Kunavin, S. A.; Prudnikov, D. A.; Shchenkova, I. A.; Bazhenov, A. M.; Zadoinyi, V. A.; Starkovskii, G. L.

2018-02-01

Steam shutoff valves are operated under complex loading conditions at thermal and nuclear power stations. In addition to exposure to high temperature and stresses resulting in fatigue, these valves are subjected to cyclic loads in heating-up-cooling down, opening-closing, etc. cycles. The number of these cycles to be specified in designing the valves should not exceed the maximum allowable value. Hence, the problem of cyclic failure rate of steam shutoff valve bodies is critical. This paper continues the previous publications about properties of the construction material for steam shutoff valve bodies (grade 10Kh9MFB-Sh steel) produced by electroslag melting and gives the results of investigation into the cyclic strength of this material. Fatigue curves for the steal used for manufacturing steam shutoff valve bodies are presented. The experimental data are compared with the calculated fatigue curves plotted using the procedures outlined in PNAE G-002-986 and RD 10-249-98. It is confirmed that these procedures may be used in designing valve bodies from 10Kh9MFB-Sh steel. The effect of the cyclic damage after preliminary cyclic loading of the specimens according to the prescribed load conditions on the high-temperature strength of the steel is examined. The influence of cyclic failure rate on the long-term strength was investigated using cylindrical specimens with a smooth working section in the as-made conditions and after two regimes of preliminary cyclic loading (training) at a working temperature of 570°C and the number of load cycles exceeding the design value, which was 2 × 103 cycles. The experiments corroborated that the material (10Kh9MFB-Sh steel) of the body manufactured by the method of electroslag melting had high resistance to cyclic failure rate. No effect of cyclic damages in the metal of the investigated specimens on the high-temperature strength has been found.

Summary Report On Design And Development Of High Temperature Gas-Cooled Power Pile

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

McCullough, C. R.

1947-09-15

This report presents a description of a design for an experimental nuclear power plant utilizing a high temperature gas-cooled power pile as the energy source. The plant consists of the pile, a heat exchanger or boiler, a conventional steam turbine generator and their associated auxiliaries. Helium gas under pressure transfers heat from the pile to the boiler which generates steam for driving the generator. The plant is rated at a normal output of 12,000 kilowatts of heat and an electrical output of 2400 kilowatts. Provision is made for operation up to 20,000 kilowatts of heat (4000 kilowatts of electrical output)more » in the event operation of the plants proves this possible.« less

Reactor core isolation cooling system

DOEpatents

Cooke, F.E.

1992-12-08

A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom. 1 figure.

Reactor core isolation cooling system

DOEpatents

Cooke, Franklin E.

1992-01-01

A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

Credit BG. View west of Test Stand "D" complex, with ...

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

Credit BG. View west of Test Stand "D" complex, with ends of Dd (left) and Dy (right) station ejectors in view. Steam piping from accumulator (sphere) to ejectors is apparent; long horizontal loops in the pipes permit expansion and contraction without special joints. The small platform straddling the Dd ejector (near the accumulator) was originally constructed for a "Hyprox" steam generator which supplied steam to the Dd ejector before the accumulator and Dy stand were built. Note ejectors on top of interstage condenser in Test Stand "D" tower. Metal shed in far right background is for storage - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

THE COLD SHOULDER: EMISSION MEASURE DISTRIBUTIONS OF ACTIVE REGION CORES

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

Schmelz, J. T.; Pathak, S., E-mail: jschmelz@memphis.edu

2012-09-10

The coronal heating mechanism for active region core loops is difficult to determine because these loops are often not resolved and cannot be studied individually. Rather, we concentrate on the 'inter-moss' areas between loop footpoints. We use observations from the Hinode EUV Imaging Spectrometer and the X-Ray Telescope to calculate the emission measure distributions of eight inter-moss areas in five different active regions. The combined data sets provide both high- and low-temperature constraints and ensure complete coverage in the temperature range appropriate for active regions. For AR 11113, the emission can be modeled with heating events that occur on timescalesmore » less than the cooling time. The loops in the core regions appear to be close to equilibrium and are consistent with steady heating. The other regions studied, however, appear to be dominated by nanoflare heating. Our results are consistent with the idea that active region age is an important parameter in determining whether steady or nanoflare heating is primarily responsible for the core emission, that is, older regions are more likely to be dominated by steady heating, while younger regions show more evidence of nanoflares.« less

Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

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

Michael G. McKellar; Manohar S. Sohal; Lila Mulloth

2010-03-01

NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developedmore » and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon dioxide is split instead of water, which has a lower heat of formation. Hydrogenation with co-electrolysis offers the best overall power performance for two reasons: it requires no external water, and it produces its own water, which reduces the power requirement for co-electrolysis.« less

Assessment of the SRI Gasification Process for Syngas Generation with HTGR Integration -- White Paper

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

A.M. Gandrik

2012-04-01

This white paper is intended to compare the technical and economic feasibility of syngas generation using the SRI gasification process coupled to several high-temperature gas-cooled reactors (HTGRs) with more traditional HTGR-integrated syngas generation techniques, including: (1) Gasification with high-temperature steam electrolysis (HTSE); (2) Steam methane reforming (SMR); and (3) Gasification with SMR with and without CO2 sequestration.

The international water conference proceedings

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

Guseman, J.R.

1984-10-01

This book provides information on computer applications to water chemistry control, groundwater, membrane technology, instrumentation/analytical techniques and ion exchange. Other topics of discussion include cooling water, biocontrol, the hydraulic properties of ion exchange resins, steam electric power plant aqueous discharges and colorimetric determination of trace benzotriazole or tolytriazole. Water chemistry guidelines for large steam generating power plants is discussed, as well as wastewater treatment, boiler water conditioning and ion exchange/computer related topics.

Propellant actuated nuclear reactor steam depressurization valve

DOEpatents

Ehrke, Alan C.; Knepp, John B.; Skoda, George I.

1992-01-01

A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

Nuclear light bulb

NASA Technical Reports Server (NTRS)

Latham, Tom

1991-01-01

The nuclear light bulb engine is a closed cycle concept. The nuclear light bulb concept provides containment by keeping the nuclear fuel fluid mechanically suspended in a cylindrical geometry. Thermal heat passes through an internally cooled, fused-silica, transparent wall and heats hydrogen propellant. The seeded hydrogen propellant absorbs radiant energy and is expanded through a nozzle. Internal moderation was used in the configuration which resulted in a reduced critical density requirement. This result was supported by criticality experiments. A reference engine was designed that had seven cells and was sized to fit in what was then predicted to be the shuttle bay mass and volume limitations. There were studies done of nozzle throat cooling schemes to remove the radiant heat. Elements of the nuclear light bulb program included closed loop critical assembly tests done at Los Alamos with UF6 confined by argon buffer gas. It was shown that the fuel region could be seeded with constituents that would block UV radiation from the uranium plasma. A combination of calculations and experiments showed that internal moderation produced a critical mass reduction. Other aspects of the research are presented.

Advanced technology cogeneration system conceptual design study: Closed cycle gas turbines

NASA Technical Reports Server (NTRS)

Mock, E. A. T.; Daudet, H. C.

1983-01-01

The results of a three task study performed for the Department of Energy under the direction of the NASA Lewis Research Center are documented. The thermal and electrical energy requirements of three specific industrial plants were surveyed and cost records for the energies consumed were compiled. Preliminary coal fired atmospheric fluidized bed heated closed cycle gas turbine and steam turbine cogeneration system designs were developed for each industrial plant. Preliminary cost and return-on-equity values were calculated and the results compared. The best of the three sites was selected for more detailed design and evaluation of both closed cycle gas turbine and steam turbine cogeneration systems during Task II. Task III involved characterizing the industrial sector electrical and thermal loads for the 48 contiguous states, applying a family of closed cycle gas turbine and steam turbine cogeneration systems to these loads, and conducting a market penetration analysis of the closed cycle gas turbine cogeneration system.

Ground Source Heat Pump Computational Results

DOE Data Explorer

James Menart

2013-07-31

This data submission includes simulation results for ground loop heat pump systems located in 6 different cities across the United States. The cities are Boston, MA, Dayton, OH, Omaha, NE, Orlando, FL, Sacramento, CA, and St. Paul, MN. These results were obtained from the two-dimensional geothermal computer code called GEO2D. GEO2D was written as part of this DOE funded grant. The results included in this submission for each of the 6 cities listed above are: 1) specific information on the building being heated or cooled by the ground loop geothermal system, 2) some extreme values for the building heating and cooling loads during the year, 3) the inputs required to carry out the simulation, 4) a plot of the hourly building heating and cooling loads throughout the year, 5) a plot of the fluid temperature exiting the ground loop for a 20 year period, 6) a plot of the heat exchange between the ground loop and the ground for a 20 year period, and 7) ground and ground loop temperature contour plots at different times of the year for the 20 year period.

Numerical Analysis of Combined Well and Open-Closed Loops Geothermal (CWG) Systems

NASA Astrophysics Data System (ADS)

Park, Yu-Chul

2016-04-01

Open-loop geothermal heat pump (GHP) system and closed-loop heat pump systems have been used in Korea to reduce emission of greenhouse gases such as carbon dioxide (CO2). The GHP systems have the pros and cons, for example, the open-loop GHP system is good energy-efficient and the closed-loop GHP system requires minimum maintenance costs. The open-loop GHP system can be used practically only with large amount of groundwater supply. The closed-loop GHP system can be used with high costs of initial installation. The performance and efficiency of the GHP system depend on the characteristics of the GHP system itself in addition to the geologic conditions. To overcome the cons of open-loop or closed-loop GHP system, the combined well and open-closed loops geothermal (CWG) system was designed. The open-loop GHP system is surrounded with closed-loop GHP systems in the CWG system. The geothermal energy in closed-loop GHP systems is supplied by the groundwater pumped by the open-loop GHP system. In this study, 2 different types of the CWG systems (small aperture hybrid CWG system and large aperture CWG system) are estimated using numerical simulation models in the aspect of energy efficiency. This work was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No.20153030111120).

From Steaming Mad to Staying Cool: A Constructive Approach to Anger Control

ERIC Educational Resources Information Center

Feindler, Eva L.; Starr, Karen E.

2003-01-01

Teaching children and adolescents to recognize how they feel when they are angry and what pushes their buttons enables them to make better choices about how they express their anger. They learn that staying cool gives them the power to create more positive outcomes for potentially negative encounters. Through self-assessment and role-plays, they…

Combined Steady-State and Dynamic Heat Exchanger Experiment

ERIC Educational Resources Information Center

Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

2009-01-01

This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

Sheet Membrane Spacesuit Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

2013-01-01

A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

Gasification of carbonaceous solids

DOEpatents

Coates, Ralph L.

1976-10-26

A process and apparatus for converting coal and other carbonaceous solids to an intermediate heating value fuel gas or to a synthesis gas. A stream of entrained pulverized coal is fed into the combustion stage of a three-stage gasifier along with a mixture of oxygen and steam at selected pressure and temperature. The products of the combustion stage pass into the second or quench stage where they are partially cooled and further reacted with water and/or steam. Ash is solidified into small particles and the formation of soot is suppressed by water/steam injections in the quench stage. The design of the quench stage prevents slag from solidifying on the walls. The products from the quench stage pass directly into a heat recovery stage where the products pass through the tube, or tubes, of a single-pass, shell and tube heat exchanger and steam is generated on the shell side and utilized for steam feed requirements of the process.

Condensation induced water hammer driven sterilization

DOEpatents

Kullberg, Craig M.

2004-05-11

A method and apparatus (10) for treating a fluid or materials therein with acoustic energy has a vessel (14) for receiving the fluid with inner walls shaped to focus acoustic energy to a target zone within the vessel. One or more nozzles (26) are directed into the vessel (14) for injecting a condensable vapor, such as steam, into the vessel (14). The system may include a steam source (18) for providing steam as the condensable vapor from an industrial waste heat source. Steam drums (88) are disposed between the steam source (18) and nozzles (26) to equalize and distribute the vapor pressure. A cooling source (30) provides a secondary fluid for maintaining the liquid in the vessel (14) in subcooled conditions. A heating jacket (32) surrounds the vessel (14) to heat the walls of the vessel (14) and prevent biological growth thereon. A pressurizer (33) may operate the system at elevated pressures.

Open cycle ocean thermal energy conversion system structure

DOEpatents

Wittig, J. Michael

1980-01-01

A generally mushroom-shaped, open cycle OTEC system and distilled water producer which has a skirt-conduit structure extending from the enlarged portion of the mushroom to the ocean. The enlarged part of the mushroom houses a toroidal casing flash evaporator which produces steam which expands through a vertical rotor turbine, partially situated in the center of the blossom portion and partially situated in the mushroom's stem portion. Upon expansion through the turbine, the motive steam enters a shell and tube condenser annularly disposed about the rotor axis and axially situated beneath the turbine in the stem portion. Relatively warm ocean water is circulated up through the radially outer skirt-conduit structure entering the evaporator through a radially outer portion thereof, flashing a portion thereof into motive steam, and draining the unflashed portion from the evaporator through a radially inner skirt-conduit structure. Relatively cold cooling water enters the annular condenser through the radially inner edge and travels radially outwardly into a channel situated along the radially outer edge of the condenser. The channel is also included in the radially inner skirt-conduit structure. The cooling water is segregated from the potable, motive steam condensate which can be used for human consumption or other processes requiring high purity water. The expansion energy of the motive steam is partially converted into rotational mechanical energy of the turbine rotor when the steam is expanded through the shaft attached blades. Such mechanical energy drives a generator also included in the enlarged mushroom portion for producing electrical energy. Such power generation equipment arrangement provides a compact power system from which additional benefits may be obtained by fabricating the enclosing equipment, housings and component casings from low density materials, such as prestressed concrete, to permit those casings and housings to also function as a floating support vessel.

Mechanical-thermal noise in drive-mode of a silicon micro-gyroscope.

PubMed

Yang, Bo; Wang, Shourong; Li, Hongsheng; Zhou, Bailing

2009-01-01

A new closed-loop drive scheme which decouples the phase and the gain of the closed-loop driving system was designed in a Silicon Micro-Gyroscope (SMG). We deduce the system model of closed-loop driving and use stochastic averaging to obtain an approximate "slow" system that clarifies the effect of thermal noise. The effects of mechanical-thermal noise on the driving performance of the SMG, including the noise spectral density of the driving amplitude and frequency, are derived. By calculating and comparing the noise amplitude due to thermal noise both in the opened-loop driving and in the closed-loop driving, we find that the closed-loop driving does not reduce the RMS noise amplitude. We observe that the RMS noise frequency can be reduced by increasing the quality factor and the drive amplitude in the closed-loop driving system. The experiment and simulation validate the feasibility of closed-loop driving and confirm the validity of the averaged equation and its stablility criterion. The experiment and simulation results indicate the electrical noise of closed-loop driving circuitry is bigger than the mechanical-thermal noise and as the driving mass decreases, the mechanical-thermal noise may get bigger than the electrical noise of the closed-loop driving circuitry.

Evidence for Widespread Cooling in an Active Region Observed with the SDO Atmospheric Imaging Assembly

NASA Technical Reports Server (NTRS)

Viall, Nicholeen M.; Klimchuk, James A.

2012-01-01

A well known behavior of EUV light curves of discrete coronal loops is that the peak intensities of cooler channels or spectral lines are reached at progressively later times. This time lag is understood to be the result of hot coronal loop plasma cooling through these lower respective temperatures. However, loops typically comprise only a minority of the total emission in active regions. Is this cooling pattern a common property of active region coronal plasma, or does it only occur in unique circumstances, locations, and times? The new SDO/AIA data provide a wonderful opportunity to answer this question systematically for an entire active region. We measure the time lag between pairs of SDO/AIA EUV channels using 24 hours of images of AR 11082 observed on 19 June 2010. We find that there is a time-lag signal consistent with cooling plasma, just as is usually found for loops, throughout the active region including the diffuse emission between loops for the entire 24 hour duration. The pattern persists consistently for all channel pairs and choice of window length within the 24 hour time period, giving us confidence that the plasma is cooling from temperatures of greater than 3 MK, and sometimes exceeding 7 MK, down to temperatures lower than approx. 0.8 MK. This suggests that the bulk of the emitting coronal plasma in this active region is not steady; rather, it is dynamic and constantly evolving. These measurements provide crucial constraints on any model which seeks to describe coronal heating.

Morphological changes in the cellulose and lignin components of biomass occur at different stages of steam pretreatment

DOE PAGES

Pingali, Sai Venkatesh; O'Neill, Hugh Michael; Nishiyama, Yoshiharu; ...

2014-01-09

Morphological changes to the different components of lignocellulosic biomass were observed as they occurred during steam pretreatment by placing a pressure reaction cell in a neutron beam and collecting time-resolved neutron scattering data. Changes to cellulose morphology occurred mainly in the heating phase, whereas changes in lignin morphology occurred mainly in the holding and cooling phases. During the heating stage, water is irreversibly expelled from cellulose microfibrils as the elementary fibrils coalesce. During the holding phase lignin aggregates begin to appear and they increase in size most noticeably during the cooling phase. This experiment demonstrates the unique information that inmore » situ small angle neutron scattering studies of pretreatment can provide. This approach is potentially useful in optimizing the heating, holding and cooling stages of pretreatments to allow the exact size and nature of lignin aggregates to be controlled in order to enhance enzyme accessibility to cellulose and therefore the efficiency of biomass conversion.« less

Thermal insulating barrier and neutron shield providing integrated protection for a nuclear reactor vessel

DOEpatents

Schreiber, R.B.; Fero, A.H.; Sejvar, J.

1997-12-16

The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor. 8 figs.

Thermal insulating barrier and neutron shield providing integrated protection for a nuclear reactor vessel

DOEpatents

Schreiber, Roger B.; Fero, Arnold H.; Sejvar, James

1997-01-01

The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel to form a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive valving also includes bistable vents at the upper end of the thermal insulating barrier for releasing steam. A removable, modular neutron shield extending around the upper end of the reactor cavity below the nozzles forms with the upwardly and outwardly tapered transition on the outer surface of the reactor vessel, a labyrinthine channel which reduces neutron streaming while providing a passage for the escape of steam during a severe accident, and for the cooling air which is circulated along the reactor cavity walls outside the thermal insulating barrier during normal operation of the reactor.

An experimental study on the performance of closed loop pulsating heat pipe (CLPHP) with methanol as a working fluid

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

Rahman, Md. Lutfor; Nourin, Farah Nazifa, E-mail: farahnazifanourin@gmail.com; Salsabil, Zaimaa

Thermal control is an important topic for thermal management of small electrical and electronic devices. Closed loop pulsating heat pipe (CLPHP) arises as the best solution for thermal control. The aim of this experimental study is to search a CLPHP of better thermal performance for cooling different electrical and electronic devices. In this experiment, methanol is used as working fluid. The effect of using methanol as a working fluid is studied on thermal performance in different filling ratios and angles of inclination. A copper capillary tube is used where the inner diameter is 2 mm,outer diameter is 2.5 mm andmore » 250 mm long. The CLPHP has 8 loops where the evaporation section is 50 mm, adiabatic section is 120 mm and condensation section is 80 mm. The experiment is done using FR of 40%-70% with 10% of interval and angles of inclination 0° (vertical), 30°, 45°, 60° varying heat input. The results are compared on the basis of evaporator temperature, condenser temperature and their differences, thermal resistance, heat transfer co-efficient, power input and pulsating time. The results demonstrate the effect of methanol in different filling ratios and angles of inclination. M ethanol shows better performance at 30° inclination with 40% FR.« less

158. ARAIII Reactor building (ARA608) Secondary cooling loop and piping ...

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

158. ARA-III Reactor building (ARA-608) Secondary cooling loop and piping plan. This drawing was selected as a typical example of piping arrangements within reactor building. Aerojet/general 880-area/GCRE-608-P-16. Date: February 1958. INeel index code no. 063-0608-50-013-102641. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

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

Jarrell, Mark

Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

TRAC-PF1 code verification with data from the OTIS test facility. [Once-Through Intergral System

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

Childerson, M.T.; Fujita, R.K.

1985-01-01

A computer code (TRAC-PF1/MOD1) developed for predicting transient thermal and hydraulic integral nuclear steam supply system (NSSS) response was benchmarked. Post-small break loss-of-coolant accident (LOCA) data from a scaled, experimental facility, designated the One-Through Integral System (OTIS), were obtained for the Babcock and Wilcox NSSS and compared to TRAC predictions. The OTIS tests provided a challenging small break LOCA data set for TRAC verification. The major phases of a small break LOCA observed in the OTIS tests included pressurizer draining and loop saturation, intermittent reactor coolant system circulation, boiler-condenser mode, and the initial stages of refill. The TRAC code wasmore » successful in predicting OTIS loop conditions (system pressures and temperatures) after modification of the steam generator model. In particular, the code predicted both pool and auxiliary-feedwater initiated boiler-condenser mode heat transfer.« less

SCW Pressure-Channel Nuclear Reactor Some Design Features

NASA Astrophysics Data System (ADS)

Pioro, Igor L.; Khan, Mosin; Hopps, Victory; Jacobs, Chris; Patkunam, Ruban; Gopaul, Sandeep; Bakan, Kurtulus

Concepts of nuclear reactors cooled with water at supercritical pressures were studied as early as the 1950s and 1960s in the USA and Russia. After a 30-year break, the idea of developing nuclear reactors cooled with SuperCritical Water (SCW) became attractive again as the ultimate development path for water cooling. The main objectives of using SCW in nuclear reactors are: 1) to increase the thermal efficiency of modern Nuclear Power Plants (NPPs) from 30-35% to about 45-48%, and 2) to decrease capital and operational costs and hence decrease electrical energy costs (˜1000 US/kW or even less). SCW NPPs will have much higher operating parameters compared to modern NPPs (pressure about 25 MPa and outlet temperature up to 625°C), and a simplified flow circuit, in which steam generators, steam dryers, steam separators, etc., can be eliminated. Also, higher SCW temperatures allow direct thermo-chemical production of hydrogen at low cost, due to increased reaction rates. Pressure-tube or pressure-channel SCW nuclear reactor concepts are being developed in Canada and Russia for some time. Some design features of the Canadian concept related to fuel channels are discussed in this paper. The main conclusion is that the development of SCW pressure-tube nuclear reactors is feasible and significant benefits can be expected over other thermal-energy systems.

Development of High-Powered Steam Turbines by OAO NPO Central Research and Design Institute for Boilers and Turbines

NASA Astrophysics Data System (ADS)

Mikhailov, V. E.; Khomenok, L. A.; Kovalev, I. A.

2018-01-01

The article provides an overview of the developments by OAO NPO TsKTI aimed at improvement of components and assemblies of new-generation turbine plants for ultra-supercritical steam parameters to be installed at the power-generating facilities in service. The list of the assemblies under development includes cylinder shells, the cylinder's flow paths and rotors, seals, bearings, and rotor cooling systems. The authors consider variants of the shafting-cylinder configurations for which advanced high-pressure and intermediate-pressure cylinders with reactive blading and low-pressure cylinders of conventional design and with counter-current steam flows are proposed and high-pressure rotors, which can increase the economic efficiency and reduce the overall turbine plant dimensions. Materials intended for the equipment components that operate at high temperatures and a steam cooling technique that allows the use of cheaper steel grades owing to the reduction in the metal's working temperature are proposed. A new promising material for the bearing surfaces is described that enables the operation at higher unit pressures. The material was tested on a full-scale test bench at OAO NPO TsKTI and a turbine in operation. Ways of controlling the erosion of the blades in the moisture-steam turbine compartments by the steam heating of the hollow guide blades are considered. To ensure the dynamic stability of the shafting, shroud and diaphragm seals that prevent the development of the destabilizing circulatory forces of the steam flow were devised and trialed. Advanced instrumentation and software are proposed to monitor the condition of the blading and thermal stresses under transient conditions, to diagnose the vibration processes, and to archive the obtained data. Attention is paid to the normalization of the electromagnetic state of the plant in order to prevent the electrolytic erosion of the plant components. The instrumentation intended for monitoring the relevant electric parameters is described.

Parameter analysis for feasibility evaluation of shallow groundwater cooling of power plants

NASA Astrophysics Data System (ADS)

Dirix, Katrijn; Harcouët-Menou, Virginie; Van Bael, Johan; Laenen, Ben

2017-04-01

This paper presents the first results of a finite difference-based numerical model, aiming to evaluate the potential of a new cooling concept that is based on the use of closed loop groundwater cooling integrated in a binary cycle. The new concept includes the seasonal combination of air cooling and shallow groundwater cooling and is part of the H2020 MATChING project. The proposed cooling system under investigation will be compared with dry type cooler condenser (e.g. air cooled condenser systems) and aims to reduce overall water withdrawal without compromising the energy efficiency of the system. The pilot site for this evaluation is the geothermal Balmatt site in Mol-Dessel, Belgium. When operating at its full potential, this site could produce up to 27 MW of heat. To (partly) cool this heat, water from the permeable Miocene 'Diest formation' could be used in a closed loop, i.e. without consuming water. This aquifer is located at a depth of 35 to 151 m bgl, consists of glauconitic coarse sands and has an average permeability of 10 m/day. The water has a temperature of ca. 12°C. In the design under evaluation, this water will be heated up to a maximum of 22°C after passing through the condenser. During summer months, the water will be injected directly back into the aquifer, while in winter, additional cooling will be realised using an air cooler before injecting the water (at ca. 6 °C). By adding this extra cooling step, the lifetime of the system will increase significantly. To cool the large amount of rejected heat, over 2000 m3/h of water needs to be extracted from the aquifer, requiring the installation of several doublet systems. The feasibility of such an installation depends on several interdependent factors, such as temperature, pressure, well distance, distance between the doublets, permeability and natural flow conditions. Since no exact values of most of these factors are available, a large uncertainty exists for feasibility predictions. To assess the sensitivity of the system to variations of these key parameters and the interaction between them, possible combinations of these parameters are modelled and subsequently optimized. To simulate the coupled subsurface fluid- and heat flow, the TOUGH2 numerical simulator was used. However, changing the parameter values by manually adapting the TOUGH input files and successfully running each file is time-consuming, tedious and likely to create errors. Therefore, we made use of the PyTOUGH library, which allows running TOUGH2 trough scripting. Using PyTOUGH, multiple parameters can be varied using a single script and post-processing, result-analysis and data visualisation can be automatized. This approach of batch simulation hence has significant advantages in all studies aiming to better understand the effects of parameter uncertainty on geothermal potential. The preliminary results of this project show that the proposed concept is technically feasible and that the most influent parameters are the distance between the wells and the doublets as well as the permeability of the shallow aquifer.

Design of a low parasitic inductance SiC power module with double-sided cooling

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

Yang, Fei; Liang, Zhenxian; Wang, Fei

In this paper, a low-parasitic inductance SiC power module with double-sided cooling is designed and compared with a baseline double-sided cooled module. With the unique 3D layout utilizing vertical interconnection, the power loop inductance is effectively reduced without sacrificing the thermal performance. Both simulations and experiments are carried out to validate the design. Q3D simulation results show a power loop inductance of 1.63 nH, verified by the experiment, indicating more than 60% reduction of power loop inductance compared with the baseline module. With 0Ω external gate resistance turn-off at 600V, the voltage overshoot is less than 9% of the busmore » voltage at a load of 44.6A.« less

Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

2016-02-01

A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

ASME code considerations for the compact heat exchanger

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

Nestell, James; Sham, Sam

2015-08-31

The mission of the U.S. Department of Energy (DOE), Office of Nuclear Energy is to advance nuclear power in order to meet the nation's energy, environmental, and energy security needs. Advanced high temperature reactor systems such as sodium fast reactors and high and very high temperature gas-cooled reactors are being considered for the next generation of nuclear reactor plant designs. The coolants for these high temperature reactor systems include liquid sodium and helium gas. Supercritical carbon dioxide (sCO₂), a fluid at a temperature and pressure above the supercritical point of CO₂, is currently being investigated by DOE as a workingmore » fluid for a nuclear or fossil-heated recompression closed Brayton cycle energy conversion system that operates at 550°C (1022°F) at 200 bar (2900 psi). Higher operating temperatures are envisioned in future developments. All of these design concepts require a highly effective heat exchanger that transfers heat from the nuclear or chemical reactor to the chemical process fluid or the to the power cycle. In the nuclear designs described above, heat is transferred from the primary to the secondary loop via an intermediate heat exchanger (IHX) and then from the intermediate loop to either a working process or a power cycle via a secondary heat exchanger (SHX). The IHX is a component in the primary coolant loop which will be classified as "safety related." The intermediate loop will likely be classified as "not safety related but important to safety." These safety classifications have a direct bearing on heat exchanger design approaches for the IHX and SHX. The very high temperatures being considered for the VHTR will require the use of very high temperature alloys for the IHX and SHX. Material cost considerations alone will dictate that the IHX and SHX be highly effective; that is, provide high heat transfer area in a small volume. This feature must be accompanied by low pressure drop and mechanical reliability and robustness. Classic shell and tube designs will be large and costly, and may only be appropriate in steam generator service in the SHX where boiling inside the tubes occurs. For other energy conversion systems, all of these features can be met in a compact heat exchanger design. This report will examine some of the ASME Code issues that will need to be addressed to allow use of a Code-qualified compact heat exchanger in IHX or SHX nuclear service. Most effort will focus on the IHX, since the safety-related (Class A) design rules are more extensive than those for important-to-safety (Class B) or commercial rules that are relevant to the SHX.« less

Ground source heat pumps (GSHP) for heating and cooling in Greece

NASA Astrophysics Data System (ADS)

Dimera, Nikoletta

This report presents the results of a theoretical study about the feasibility of closed loop Ground Source Heat Pumps (GSHP) for heating and cooling in Greece in terms of their impact on the capital and running costs of the building services systems of the buildings. The main aim of carrying out this study was to investigate if the heating and cooling potential of the ground could be utilized cost efficiently to serve the buildings energy demand in the Greek region. At first, an existing implementation of a closed loop GSHP system in Greece is presented and its efficiency is discussed. The aim of doing so was to understand the way of sizing such systems and the efficiency of this technology in Greek climatic and ground conditions. In a separate part of this report, the impact of different user behaviour and of various ways of sizing a GSHP system is investigated in terms of the cost impact of the examined different options as well as of their effect on the internal health and comfort conditions. After the building simulation under different scenarios, it was concluded that the user behavior - the operation of windows mostly - can result in great savings on the annual energy bills. The conclusions of this first part of the report about the user behaviour and the way of sizing GSHP systems were utilized in the next part of it, where a GSHP system is proposed for a building currently under construction in central Greece. A simple 30-year cost analysis was used in order to estimate the performance of the proposed GSHP system in economic terms and to compare it with the conventional HVAC system commonly used in Greece. According to the results of the analysis, the capital cost of installing a GSHP system for heating and cooling in buildings in Greece appears higher than the cost of conventional HVAC systems. More specifically, the capital cost of an installation for heating including gas boilers and a cooling system based on air conditioning split units is about the half of installing a GSHP system for heating and cooling designed to serve the same loads. On the other hand, if the conventional HVAC system included cooling towers instead of A/C split units, the capital cost of such the installation raises up to double the price of the GSHP system for the same needs. However, after a 30-years period of continuous use of the systems, the money spent for installing and running the GSHP system are about the half of those that should be paid once a conventional HVAC system was preferred for the same energy demand.

Concentrating Solar Power Projects - La Africana | Concentrating Solar

Science.gov Websites

: Posadas (Córdoba) Owner(s): Ortiz/TSK/Magtel (100%) Technology: Parabolic trough Turbine Capacity: Net -Field Outlet Temp: 393°C Solar-Field Temp Difference: 100°C Power Block Turbine Capacity (Gross): 50.0 MW Turbine Capacity (Net): 50.0 MW Output Type: Steam Rankine Cooling Method: Wet cooling Thermal

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

NASA Astrophysics Data System (ADS)

Yata, Vishnu Vardhan Reddy

This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable flow and intermittent flow spray cooling cases in comparison with the reference, steady flow spray cooling case with constant flowrate, continuous spray cooling. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. HFE-7100 dielectric liquid is selected as the working fluid. Two types of test samples are prepared on 10 mm x 10 mm x 2 mm copper substrates with matching size thick film resistors attached onto the opposite side, to generate heat and simulate high heat flux electronic devices. The test samples include: (i) plain, smooth surface, and (ii) microporous surface featuring 100 ?m thick copper-based coating prepared by dual stage electroplating technique. Experimental conditions involve HFE-7100 at atmospheric pressure and 30°C and 10°C subcooling. Steady flow spray cooling tests are conducted at flow rates of 2-5 ml/cm2.s, by controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. Variable flow and intermittent flow spray cooling tests are done at selected flowrate and subcooling conditions to investigate the effects of dynamic flow conditions on maintaining the target surface temperatures defined based on reference steady flow spray cooling performance.

Design Construction and Operation of a Supercritical Carbon Dioxide (sCO 2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO 2 Power Conversion Cycles.

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

Middleton, Bobby D.; Rodriguez, Salvador B.; Carlson, Matthew David

This report outlines the work completed for a Laboratory Directed Research and Development project at Sandia National Laboratories from October 2012 through September 2015. An experimental supercritical carbon dioxide (sCO 2 ) loop was designed, built, and o perated. The experimental work demonstrated that sCO 2 can be uti lized as the working fluid in an air - cooled, natural circulation configuration to transfer heat from a source to the ultimate heat sink, which is the surrounding ambient environment in most ca ses. The loop was also operated in an induction - heated, water - cooled configuration that allows formore » measurements of physical parameters that are difficult to isolate in the air - cooled configuration. Analysis included the development of two computational flu id dynamics models. Future work is anticipated to answer questions that were not covered in this project.« less

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

NASA Technical Reports Server (NTRS)

1981-01-01

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

DOEpatents

Berry, G.F.; Minkov, V.; Petrick, M.

1981-11-02

A magnetohydrodynamic (MHD) power generating system is described in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

DOEpatents

Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael

1988-01-05

A magnetohydrodynamic (MHD) power generating system in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

Open-cycle magnetohydrodynamic power plant based upon direct-contact closed-loop high-temperature heat exchanger

DOEpatents

Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael

1988-01-01

A magnetohydrodynamic (MHD) power generating system in which ionized combustion gases with slag and seed are discharged from an MHD combustor and pressurized high temperature inlet air is introduced into the combustor for supporting fuel combustion at high temperatures necessary to ionize the combustion gases, and including a heat exchanger in the form of a continuous loop with a circulating heat transfer liquid such as copper oxide. The heat exchanger has an upper horizontal channel for providing direct contact between the heat transfer liquid and the combustion gases to cool the gases and condense the slag which thereupon floats on the heat transfer liquid and can be removed from the channel, and a lower horizontal channel for providing direct contact between the heat transfer liquid and pressurized air for preheating the inlet air. The system further includes a seed separator downstream of the heat exchanger.

Credit WCT. Photographic copy of photograph, view looking northeast down ...

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

Credit WCT. Photographic copy of photograph, view looking northeast down onto new Dd test station from Test Stand "D" tower. Hatch of Dd test cell is open, and a test engine sits on a dolly nearby awaiting mounting. Note the water-cooled diffuser on the east end of the test chamber; this was soon replaced with a new diffuser and a steam-driven ejector for simulated high-altitude tests. A closed circuit television camera is mounted on the west end of the test cell. At the lower left of the view are fuel and oxidizer run tanks which supply propellants for test runs. (JPL negative no. 384-2650-A, 8 February 1961) - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Description and cost analysis of a deluge dry/wet cooling system.

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

Wiles, L.E.; Bamberger, J.A.; Braun, D.J.

1978-06-01

The use of combined dry/wet cooling systems for large base-load power plants offers the potential for significant water savings as compared to evaporatively cooled power plants and significant cost savings in comparison to dry cooled power plants. The results of a detailed engineering and cost study of one type of dry/wet cooling system are described. In the ''deluge'' dry/wet cooling method, a finned-tube heat exchanger is designed to operate in the dry mode up to a given ambient temperature. To avoid the degradation of performance for higher ambient temperatures, water (the delugeate) is distributed over a portion of the heatmore » exchanger surface to enhance the cooling process by evaporation. The deluge system used in this study is termed the HOETERV system. The HOETERV deluge system uses a horizontal-tube, vertical-plate-finned heat exchanger. The delugeate is distributed at the top of the heat exchanger and is allowed to fall by gravity in a thin film on the face of the plate fin. Ammonia is used as the indirect heat transfer medium between the turbine exhaust steam and the ambient air. Steam is condensed by boiling ammonia in a condenser/reboiler. The ammonia is condensed in the heat exchanger by inducing airflow over the plate fins. Various design parameters of the cooling system have been studied to evaluate their impact on the optimum cooling system design and the power-plant/utility-system interface. Annual water availability was the most significant design parameter. Others included site meteorology, heat exchanger configuration and air flow, number and size of towers, fan system design, and turbine operation. It was concluded from this study that the HOETERV deluge system of dry/wet cooling, using ammonia as an intermediate heat transfer medium, offers the potential for significant cost savings compared with all-dry cooling, while achieving substantially reduced water consumption as compared to an evaporatively cooled power plant. (LCL)« less

Condensation heat transfer and flow friction in silicon microchannels

NASA Astrophysics Data System (ADS)

Wu, Huiying; Wu, Xinyu; Qu, Jian; Yu, Mengmeng

2008-11-01

An experimental investigation was performed on heat transfer and flow friction characteristics during steam condensation flow in silicon microchannels. Three sets of trapezoidal silicon microchannels, with hydraulic diameters of 77.5 µm, 93.0 µm and 128.5 µm respectively, were tested under different flow and cooling conditions. It was found that both the condensation heat transfer Nusselt number (Nu) and the condensation two-phase frictional multiplier (phi2Lo) were dependent on the steam Reynolds number (Rev), condensation number (Co) and dimensionless hydraulic diameter (Dh/L). With the increase in the steam Reynolds number, condensation number and dimensionless hydraulic diameter, the condensation Nusselt number increased. However, different variations were observed for the condensation two-phase frictional multiplier. With the increase in the steam Reynolds number and dimensionless hydraulic diameter, the condensation two-phase frictional multiplier decreased, while with the increase in the condensation number, the condensation two-phase frictional multiplier increased. Based on the experimental results, dimensionless correlations for condensation heat transfer and flow friction in silicon microchannels were proposed for the first time. These correlations can be used to determine the condensation heat transfer coefficient and pressure drop in silicon microchannels if the steam mass flow rate, cooling rate and geometric parameters are fixed. It was also found that the condensation heat transfer and flow friction have relations to the injection flow (a transition flow pattern from the annular flow to the slug/bubbly flow), and with injection flow moving toward the outlet, both the condensation heat transfer coefficient and the condensation two-phase frictional multiplier increased.

Qualification of Sub-Atmospheric Pressure Sensors for the Cryomagnet Bayonet Heat Exchangers of the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Bager, T.; Casas-Cubillos, J.; Jeanmonod, N.

2006-04-01

The superconducting magnets of the Large Hadron Collider (LHC) will be cooled at 1.9 K by distributed cooling loops working with saturated two-phase superfluid helium flowing in 107 m long bayonet heat exchangers located in each magnet cold-mass cell. The temperature of the magnets could be difficult to control because of the large dynamic heat load variations. Therefore, it is foreseen to measure the heat exchangers pressure to feed the regulation loops with the corresponding saturation temperature. The required uncertainty of the sub-atmospheric saturation pressure measurement shall be of the same order of the one associated to the magnet thermometers, in pressure it translates as ±5 Pa at 1.6 kPa. The transducers shall be radiation hard as they will endure, in the worst case, doses up to 10 kGy and 1015 neutronsṡcm-2 over 10 years. The sensors under evaluation were installed underground in the dump section of the SPS accelerator with a radiation environment close to the one expected for the LHC. The monitoring equipment was installed in a remote radiation protected area. This paper presents the results of the radiation qualification campaign with emphasis on the reliability and accuracy of the pressure sensors under the test conditions.

CoolLoop® First: A First In Man Study To Test A Novel Circular Cryoablation System In Paroxysmal Atrial Fibrillation.

PubMed

Stuehlinger, Markus; Hoenig, Simon; Spuller, Karin; Koman, Christian; Stoeger, Markus; Poelzl, Gerhard; Ulmer, Hanno; Pachinger, Otmar; Steinwender, Clemens

2015-01-01

Pulmonary vein (PV) isolation is the mainstay of catheter treatment of paroxysmal atrial fibrillation (AF). The CoolLoop® cryoablation catheter (AFreeze® GmbH; Innsbruck, Austria) was developed to create wide and complete circular lesions around the PVs. In this study we evaluated feasibility and safety of this novel ablation system in humans. 10 patients (6M/4F; 57.6±7.6y) with paroxysmal AF were included in 2 referral centers. The CoolLoop® catheter was positioned at each PV antrum using a steerable transseptal sheath. Subsequently, 2-6 double-freezes over 5min were performed at each vein and PV-isolation was assessed thereafter using a circular mapping catheter. During cryoablation of the right PVs, pacing was used to monitor phrenic nerve function. The CoolLoop® catheter could be successfully positioned at each PV. A mean of 5.6±1.8 cryoablations were performed in the LSPV, 5.2±1.6 in the LIPV, 6.3±2.5 in the RSPV and 5.4±1.6 in the RIPV, respectively. Mean procedure time was 251±60min and mean fluoroscopy time was 44.0±13.2min. 6 / 10 LSPV, 6 / 10 LIPV, 5 / 10 RSPV and 6 / 10 RIPV could be isolated exclusively using the novel cryoablation system. One patient developed groin hematoma and a brief episode of ST-elevation due to air embolism was observed in another subject. No other clinical complications occurred during 3 months of follow up. PV-isolation for paroxysmal atrial fibrillation using the CoolLoop® catheter is feasible and appears safe. Clinical long term efficacy still needs to be evaluated and will be compared with established catheters used for AF ablation.

Case Study for the ARRA-Funded Ground Source Heat Pump Demonstration at Ball State University

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

Im, Piljae; Liu, Xiaobing; Henderson, Jr., Hugh

With funding provided by the American Recovery and Reinvestment Act (ARRA), 26 ground-source heat pump (GSHP) projects were competitively selected in 2009 to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. One of the selected demonstration projects is a district central GSHP system installed at Ball State University (BSU) in Muncie, IN. Prior to implementing the district GSHP system, 47 major buildings in BSU were served by a central steam plant with four coal-fired and three natural-gas-fired steam boilers. Cooling was provided by five water-cooled centrifugal chillers at the District Energy Station Southmore » (DESS). The new district GSHP system replaced the existing coal-fired steam boilers and conventional water-cooled chillers. It uses ground-coupled heat recovery (HR) chillers to meet the simultaneous heating and cooling demands of the campus. The actual performance of the GSHP system was analyzed based on available measured data from August 2015 through July 2016, construction drawings, maintenance records, personal communications, and construction costs. Since Phase 1 was funded in part by the ARRA grant, it is the focus of this case study. The annual energy consumption of the GSHP system was calculated based on the available measured data and other related information. It was compared with the performance of a baseline scenario— a conventional water-cooled chiller and natural-gas-fired boiler system, both of which meet the minimum energy efficiencies allowed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 90.1-2013). The comparison was made to determine source energy savings, energy cost savings, and CO2 emission reductions achieved by the GSHP system. A cost analysis was performed to evaluate the simple payback of the GSHP system. The following sections summarize the results of the analysis, the lessons learned, and recommendations for improvement in the operation of this district GSHP system.« less

Closing loop base pairs in RNA loop-loop complexes: structural behavior, interaction energy and solvation analysis through molecular dynamics simulations.

PubMed

Golebiowski, Jérôme; Antonczak, Serge; Fernandez-Carmona, Juan; Condom, Roger; Cabrol-Bass, Daniel

2004-12-01

Nanosecond molecular dynamics using the Ewald summation method have been performed to elucidate the structural and energetic role of the closing base pair in loop-loop RNA duplexes neutralized by Mg2+ counterions in aqueous phases. Mismatches GA, CU and Watson-Crick GC base pairs have been considered for closing the loop of an RNA in complementary interaction with HIV-1 TAR. The simulations reveal that the mismatch GA base, mediated by a water molecule, leads to a complex that presents the best compromise between flexibility and energetic contributions. The mismatch CU base pair, in spite of the presence of an inserted water molecule, is too short to achieve a tight interaction at the closing-loop junction and seems to force TAR to reorganize upon binding. An energetic analysis has allowed us to quantify the strength of the interactions of the closing and the loop-loop pairs throughout the simulations. Although the water-mediated GA closing base pair presents an interaction energy similar to that found on fully geometry-optimized structure, the water-mediated CU closing base pair energy interaction reaches less than half the optimal value.

Small Modular Reactors: The Army’s Secure Source of Energy?

DTIC Science & Technology

2012-03-21

significant advantages of SMRs is the minimal amount of carbon dioxide (greenhouse gases) that is released in conjunction with the lifecycle operations...moderator in these reactors as well as the cooling agent and the means by which heat is removed to produce steam for turning the turbines of the...separate water system to generate steam to turn a turbine which then produces electricity. In the second type of light water reactors, the boiling water

Legionnaires' disease bacteria in power plant cooling systems: downtime report. Final report

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

Tyndall, R.L.; Solomon, J.A.; Christensen, S.W.

1985-11-01

Legionnaires' disease bacteria (Legionella) are a normal part of the aquatic community that, when aerosolized, can be pathogenic to man. The downtime study was designed to determine the degree to which Legionella populations are aerosolized during cleaning and maintenance operations in a closed-cycle steam-electric power plant. Both high-volume and impinger air samples were collected prior to and during downtime operations. Emphasis was placed on sampling inside or adjacent to water boxes, condensers, and cooling towers. Control air samples were taken upwind from the plant site. Water and sludge samples were also collected at various locations. In the laboratory, the concentrationsmore » of Legionella were determined using the direct fluorescent antibody method. All positive air samples, and other selected air samples, were injected into guinea pigs to detect infectious Legionella. Legionella could be detected in only 12 of the 127 air samples collected. These were predominantly L. pneumophila, serogroups 1-6. In contrast to the air samples, most of the water and sludge samples were positive for Legionella, again predominantly L. pneumophila, serogroups 1-6. The highest Legionella concentrations were found in sludge samples associated with condenser tube cleaning. Among the water samples, the highest Legionella concentrations were found in cooling towers, immediately after the tower basins were cleaned and refilled, and in condenser tubes. Two of the three cooling tower water samples collected prior to downtime operations were infectious for guinea pigs. 16 refs., 4 figs., 11 tabs.« less

Study on steam pressure characteristics in various types of nozzles

NASA Astrophysics Data System (ADS)

Firman; Anshar, Muhammad

2018-03-01

Steam Jet Refrigeration (SJR) is one of the most widely applied technologies in the industry. The SJR system was utilizes residual steam from the steam generator and then flowed through the nozzle to a tank that was containing liquid. The nozzle converts the pressure energy into kinetic energy. Thus, it can evaporate the liquid briefly and release it to the condenser. The chilled water, was produced from the condenser, can be used to cool the product through a heat transfer process. This research aims to study the characteristics of vapor pressure in different types of nozzles using a simulation. The Simulation was performed using ANSYS FLUENT software for nozzle types such as convergent, convrgent-parallel, and convergent-divergent. The results of this study was presented the visualization of pressure in nozzles and was been validated with experiment data.

Heating mechanisms for intermittent loops in active region cores from AIA/SDO EUV observations

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

Cadavid, A. C.; Lawrence, J. K.; Christian, D. J.

2014-11-01

We investigate intensity variations and energy deposition in five coronal loops in active region cores. These were selected for their strong variability in the AIA/SDO 94 Å intensity channel. We isolate the hot Fe XVIII and Fe XXI components of the 94 Å and 131 Å by modeling and subtracting the 'warm' contributions to the emission. HMI/SDO data allow us to focus on 'inter-moss' regions in the loops. The detailed evolution of the inter-moss intensity time series reveals loops that are impulsively heated in a mode compatible with a nanoflare storm, with a spike in the hot 131 Å signalsmore » leading and the other five EUV emission channels following in progressive cooling order. A sharp increase in electron temperature tends to follow closely after the hot 131 Å signal confirming the impulsive nature of the process. A cooler process of growing emission measure follows more slowly. The Fourier power spectra of the hot 131 Å signals, when averaged over the five loops, present three scaling regimes with break frequencies near 0.1 min{sup –1} and 0.7 min{sup –1}. The low frequency regime corresponds to 1/f noise; the intermediate indicates a persistent scaling process and the high frequencies show white noise. Very similar results are found for the energy dissipation in a 2D 'hybrid' shell model of loop magneto-turbulence, based on reduced magnetohydrodynamics, that is compatible with nanoflare statistics. We suggest that such turbulent dissipation is the energy source for our loops.« less

Apparatus and method of direct water cooling several parallel circuit cards each containing several chip packages

DOEpatents

Cipolla, Thomas M [Katonah, NY; Colgan, Evan George [Chestnut Ridge, NY; Coteus, Paul W [Yorktown Heights, NY; Hall, Shawn Anthony [Pleasantville, NY; Tian, Shurong [Mount Kisco, NY

2011-12-20

A cooling apparatus, system and like method for an electronic device includes a plurality of heat producing electronic devices affixed to a wiring substrate. A plurality of heat transfer assemblies each include heat spreaders and thermally communicate with the heat producing electronic devices for transferring heat from the heat producing electronic devices to the heat transfer assemblies. The plurality of heat producing electronic devices and respective heat transfer assemblies are positioned on the wiring substrate having the regions overlapping. A heat conduit thermally communicates with the heat transfer assemblies. The heat conduit circulates thermally conductive fluid therethrough in a closed loop for transferring heat to the fluid from the heat transfer assemblies via the heat spreader. A thermally conductive support structure supports the heat conduit and thermally communicates with the heat transfer assemblies via the heat spreader transferring heat to the fluid of the heat conduit from the support structure.

Human life support during interplanetary travel and domicile. III - Mars expedition system trade study

NASA Technical Reports Server (NTRS)

Seshan, P. K.; Ferrall, Joseph F.; Rohatgi, Naresh K.

1991-01-01

Several alternative configurations of life-support systems (LSSs) for a Mars missions are compared analytically on a quantitative basis in terms of weight, volume, and power. A baseline technology set is utilized for the illustrations of systems including totally open loop, carbon dioxide removal only, partially closed loop, and totally closed loop. The analytical model takes advantage of a modular, top-down hierarchical breakdown of LSS subsystems into functional elements that represent individual processing technologies. The open-loop systems are not competitive in terms of weight for both long-duration orbiters and short-duration lander vehicles, and power demands are lowest with the open loop and highest with the closed loop. The closed-loop system can reduce vehicle weight by over 70,000 lbs and thereby overcome the power penalty of 1600 W; the closed-loop variety is championed as the preferred system for a Mars expedition.

Thermal discharges and their role in pending power plant regulatory decisions

NASA Technical Reports Server (NTRS)

Miller, M. H.

1978-01-01

Federal and state laws require the imminent retrofit of offstream condenser cooling to the newer steam electric stations. Waiver can be granted based on sound experimental data, demonstrating that existing once-through cooling will not adversely affect aquatic ecosystems. Conventional methods for monitoring thermal plumes, and some remote sensing alternatives, are reviewed, using on going work at one Maryland power plant for illustration.

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

Not Available

The Boston Christian Science Center recently purchased its own packaged boiler system to provide heating and cooling steam for its building complex. The system is expected to reduce the center's energy costs by $450,000 in the first year.

Posttest analysis of MIST Test 320201 using TRAC-PF1/MOD1

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

Siebe, D.A.; Steiner, J.L.; Boyack, B.E.

A posttest calculation and analysis of Multi-Loop Integral System Test 320201, a small-break loss-of-coolant accident (SBLOCA) test with a scaled 50-cm{sup 2} cold-leg pump discharge leak, has been completed and is reported herein. It was one in a series of tests, with leak size varied parametrically. Scaled leak sizes included 5, 10, (the nominal, Test 3109AA), and 50 cm{sub 2}. The test exhibited the major post-SBLOCA phenomena, as expected, including depressurization to saturation, interruption of loop flow, boiler-condenser mode cooling, refill, and postrefill cooldown. Full high-pressure injection and auxiliary feedwater were available, reactor coolant pumps were not available, and reactor-vesselmore » vent valves and guard heaters were automatically controlled. Constant level control in the steam-generator (SG) secondaries was used after SG-secondary refill; and symmetric SG pressure control was also used. The sequence of events seen in this test was similar to the sequence of events for much of the nominal test except that events occurred in a shorter time frame as the system inventory was reduced and the system depressurized at a faster rate. The calculation was performed using TRAC-PFL/MOD 1. Agreement between test data and the calculation was generally reasonable. All major trends and phenomena were correctly predicted. We believe that the correct conclusions about trends and phenomena will be reached if the code is used in similar applications.« less

Posttest analysis of MIST Test 320201 using TRAC-PF1/MOD1

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

Siebe, D.A.; Steiner, J.L.; Boyack, B.E.

A posttest calculation and analysis of Multi-Loop Integral System Test 320201, a small-break loss-of-coolant accident (SBLOCA) test with a scaled 50-cm[sup 2] cold-leg pump discharge leak, has been completed and is reported herein. It was one in a series of tests, with leak size varied parametrically. Scaled leak sizes included 5, 10, (the nominal, Test 3109AA), and 50 cm[sub 2]. The test exhibited the major post-SBLOCA phenomena, as expected, including depressurization to saturation, interruption of loop flow, boiler-condenser mode cooling, refill, and postrefill cooldown. Full high-pressure injection and auxiliary feedwater were available, reactor coolant pumps were not available, and reactor-vesselmore » vent valves and guard heaters were automatically controlled. Constant level control in the steam-generator (SG) secondaries was used after SG-secondary refill; and symmetric SG pressure control was also used. The sequence of events seen in this test was similar to the sequence of events for much of the nominal test except that events occurred in a shorter time frame as the system inventory was reduced and the system depressurized at a faster rate. The calculation was performed using TRAC-PFL/MOD 1. Agreement between test data and the calculation was generally reasonable. All major trends and phenomena were correctly predicted. We believe that the correct conclusions about trends and phenomena will be reached if the code is used in similar applications.« less

Measurements and calculations of water velocity, momentum flux, and related flow parameters obtaned from single-phase water integral acceptance tests of the PKL instrumented spool pieces

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

Stein, W.

The operation of the emergency core cooling system and its related steam-binding problems in pressurized water reactors is the subject of a cooperative study by the United States, Germany, and Japan. Lawrence Livermore Laboratory and EG and G, Inc., San Ramon Operations, are responsible for the design, hardware, and software of the 80.8-mm and 113-mm spool piece measurement systems for the German Primarkreislauf (PKL) Test Facility at Kraftwerk Union in Erlangen, West Germany. This work was done for the US Nuclear Regulatory Commission, Division of Reactor Safety Research, under its 3-D Technical Support and Instrumentation Program. Four instrumented spools capablemore » of measuring individual phase parameters in two-phase flows were constructed. Each spool contains a flow turbine, drag screen, three-beam densitometer, and pressure and temperature probes. A computerized data acquisition system is also provided to store and analyze data from the four spools. The four spools were shipped to the PKL Test Facility in West Germany for acceptance testing in a water-flow loop. Spool measurements of velocity and momentum flux were compared to the values obtained from an orifice meter installed in the loop piping system. The turbine flowmeter velocity data for all tests were within allowable tolerances. Drag screen momentum flux measurements were also within tolerance with the exception of a few points.« less

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, W.D.; Ramirez, A.L.; Newmark, R.L.; Udell, K.; Buetnner, H.M.; Aines, R.D.

1995-09-12

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process. 4 figs.

Dynamic underground stripping: steam and electric heating for in situ decontamination of soils and groundwater

DOEpatents

Daily, William D.; Ramirez, Abelardo L.; Newmark, Robin L.; Udell, Kent; Buetnner, Harley M.; Aines, Roger D.

1995-01-01

A dynamic underground stripping process removes localized underground volatile organic compounds from heterogeneous soils and rock in a relatively short time. This method uses steam injection and electrical resistance heating to heat the contaminated underground area to increase the vapor pressure of the contaminants, thus speeding the process of contaminant removal and making the removal more complete. The injected steam passes through the more permeable sediments, distilling the organic contaminants, which are pumped to the surface. Large electrical currents are also applied to the contaminated area, which heat the impermeable subsurface layers that the steam has not penetrated. The condensed and vaporized contaminants are withdrawn by liquid pumping and vacuum extraction. The steam injection and electrical heating steps are repeated as necessary. Geophysical imaging methods can be used to map the boundary between the hot, dry, contamination-free underground zone and the cool, damp surrounding areas to help monitor the dynamic stripping process.

Process for gasifying carbonaceous material from a recycled condensate slurry

DOEpatents

Forney, Albert J.; Haynes, William P.

1981-01-01

Coal or other carbonaceous material is gasified by reaction with steam and oxygen in a manner to minimize the problems of effluent water stream disposal. The condensate water from the product gas is recycled to slurry the coal feed and the amount of additional water or steam added for cooling or heating is minimized and preferably kept to a level of about that required to react with the carbonaceous material in the gasification reaction. The gasification is performed in a pressurized fluidized bed with the coal fed in a water slurry and preheated or vaporized by indirect heat exchange contact with product gas and recycled steam. The carbonaceous material is conveyed in a gas-solid mixture from bottom to top of the pressurized fluidized bed gasifier with the solids removed from the product gas and recycled steam in a supported moving bed filter of the resulting carbonaceous char. Steam is condensed from the product gas and the condensate recycled to form a slurry with the feed coal carbonaceous particles.

Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development

DTIC Science & Technology

2016-09-01

ARL-TN-0779 ● SEP 2016 US Army Research Laboratory Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and...Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development by Neal Tesny Sensors and Electron Devices Directorate...TITLE AND SUBTITLE Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development 5a. CONTRACT NUMBER 5b

Closed-loop spontaneous baroreflex transfer function is inappropriate for system identification of neural arc but partly accurate for peripheral arc: predictability analysis

PubMed Central

Kamiya, Atsunori; Kawada, Toru; Shimizu, Shuji; Sugimachi, Masaru

2011-01-01

Abstract Although the dynamic characteristics of the baroreflex system have been described by baroreflex transfer functions obtained from open-loop analysis, the predictability of time-series output dynamics from input signals, which should confirm the accuracy of system identification, remains to be elucidated. Moreover, despite theoretical concerns over closed-loop system identification, the accuracy and the predictability of the closed-loop spontaneous baroreflex transfer function have not been evaluated compared with the open-loop transfer function. Using urethane and α-chloralose anaesthetized, vagotomized and aortic-denervated rabbits (n = 10), we identified open-loop baroreflex transfer functions by recording renal sympathetic nerve activity (SNA) while varying the vascularly isolated intracarotid sinus pressure (CSP) according to a binary random (white-noise) sequence (operating pressure ± 20 mmHg), and using a simplified equation to calculate closed-loop-spontaneous baroreflex transfer function while matching CSP with systemic arterial pressure (AP). Our results showed that the open-loop baroreflex transfer functions for the neural and peripheral arcs predicted the time-series SNA and AP outputs from measured CSP and SNA inputs, with r2 of 0.8 ± 0.1 and 0.8 ± 0.1, respectively. In contrast, the closed-loop-spontaneous baroreflex transfer function for the neural arc was markedly different from the open-loop transfer function (enhanced gain increase and a phase lead), and did not predict the time-series SNA dynamics (r2; 0.1 ± 0.1). However, the closed-loop-spontaneous baroreflex transfer function of the peripheral arc partially matched the open-loop transfer function in gain and phase functions, and had limited but reasonable predictability of the time-series AP dynamics (r2, 0.7 ± 0.1). A numerical simulation suggested that a noise predominantly in the neural arc under resting conditions might be a possible mechanism responsible for our findings. Furthermore, the predictabilities of the neural arc transfer functions obtained in open-loop and closed-loop conditions were validated by closed-loop pharmacological (phenylephrine and nitroprusside infusions) pressure interventions. Time-series SNA responses to drug-induced AP changes predicted by the open-loop transfer function matched closely the measured responses (r2, 0.9 ± 0.1), whereas SNA responses predicted by closed-loop-spontaneous transfer function deviated greatly and were the inverse of measured responses (r, −0.8 ± 0.2). These results indicate that although the spontaneous baroreflex transfer function obtained by closed-loop analysis has been believed to represent the neural arc function, it is inappropriate for system identification of the neural arc but is essentially appropriate for the peripheral arc under resting conditions, when compared with open-loop analysis. PMID:21486839

Biocides: Capturing bugs and bigger markets

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

Hairston, D.W.

1995-10-01

Deep in the dark interior of cooling water towers, intake streams and purifiers, there is a jungle. Hundreds of thousands of microorganisms dwell in algae and biofilm, breeding mutant and increasingly resistant strains of bacteria. For biocide manufacturers, the imperative is to find better ways to control the proliferation of the microscopic bugs. Some of the most robust demand for biocides is in the cooling water market, particularly as industrial water treatment continues to switch from gaseous chlorine to bromine compounds. The trend toward closed-loop and faster cycles for process water treatment will require more biological control. Biocides are expectedmore » to benefit from that trend, but in pulp and paper operations, chlorine dioxide may reap the biggest gains. Also making inroads is an electrolytic system that uses ClO{sub 2} to control microorganisms in cooling towers. Despite growing demand for safe and more-effective biocides in Europe and the US, new product development is stymied by the rigorous and costly process of getting regulatory approval. In the US, EPA registration can cost $5--10 million and take 5 to 10 years.« less

Techniques for enhancing durability and equivalence ratio control in a rich-lean, three-stage ground power gas turbine combustor

NASA Technical Reports Server (NTRS)

Schultz, D. F.

1982-01-01

Rig tests of a can-type combustor were performed to demonstrate two advanced ground power engine combustor concepts: steam cooled rich-burn combustor primary zones for enhanced durability; and variable combustor geometry for three stage combustion equivalence ratio control. Both concepts proved to be highly successful in achieving their desired objectives. The steam cooling reduced peak liner temperatures to less than 800 K. This offers the potential of both long life and reduced use of strategic materials for liner fabrication. Three degrees of variable geometry were successfully implemented to control airflow distribution within the combustor. One was a variable blade angle axial flow air swirler to control primary airflow while the other two consisted of rotating bands to control secondary and tertiary or dilution air flow.

Performance of the supercritical helium cooling loop for the JET divertor cryopump

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

Obert, W.; Mayaux, C.; Barth, K.

1996-12-31

A supercritical helium cooling loop for the two JET divertor cryopumps has been tested, commissioned and is operational practically uninterrupted for over one year. Operation experience under a number of different boundary and transient conditions have been obtained. The flow of the supercritical helium (6 g/s, 2.7 bar) is driven by the main compressor of the JET helium refrigerator passing a heat exchanger where it is subcooled to 4.1 K before entering the two cryopumps which are an assembly of two 60 m long and 20 mm diameter corrugated stainless steel tubes. By using a dedicated cold ejector which ismore » driven by the main flow and where the expansion from 12 bar to 2.7 bar takes place increases the flow of supercritical helium up to {approximately}17 g/s. The steady state thermal load to the cooling loop of the cryopump is < 80 W but during transient conditions in particular due to nuclear heating in the active phase of JET considerably higher transient heat loads can be accepted by the loop. Details about the steady state and transient thermal conditions as well as the cooldown and warm up behavior of the loop and the interaction of the supercritical loop with the operation of other plant equipment will be discussed in the paper.« less

Conditions for Stabilizability of Linear Switched Systems

NASA Astrophysics Data System (ADS)

Minh, Vu Trieu

2011-06-01

This paper investigates some conditions that can provide stabilizability for linear switched systems with polytopic uncertainties via their closed loop linear quadratic state feedback regulator. The closed loop switched systems can stabilize unstable open loop systems or stable open loop systems but in which there is no solution for a common Lyapunov matrix. For continuous time switched linear systems, we show that if there exists solution in an associated Riccati equation for the closed loop systems sharing one common Lyapunov matrix, the switched linear systems are stable. For the discrete time switched systems, we derive a Linear Matrix Inequality (LMI) to calculate a common Lyapunov matrix and solution for the stable closed loop feedback systems. These closed loop linear quadratic state feedback regulators guarantee the global asymptotical stability for any switched linear systems with any switching signal sequence.

STEAM STIRRED HOMOGENEOUS NUCLEAR REACTOR

DOEpatents

Busey, H.M.

1958-06-01

A homogeneous nuclear reactor utilizing a selfcirculating liquid fuel is described. The reactor vessel is in the form of a vertically disposed tubular member having the lower end closed by the tube walls and the upper end closed by a removal fianged assembly. A spherical reaction shell is located in the lower end of the vessel and spaced from the inside walls. The reaction shell is perforated on its lower surface and is provided with a bundle of small-diameter tubes extending vertically upward from its top central portion. The reactor vessel is surrounded in the region of the reaction shell by a neutron reflector. The liquid fuel, which may be a solution of enriched uranyl sulfate in ordinary or heavy water, is mainiained at a level within the reactor vessel of approximately the top of the tubes. The heat of the reaction which is created in the critical region within the spherical reaction shell forms steam bubbles which more upwardly through the tubes. The upward movement of these bubbles results in the forcing of the liquid fuel out of the top of these tubes, from where the fuel passes downwardly in the space between the tubes and the vessel wall where it is cooled by heat exchangers. The fuel then re-enters the critical region in the reaction shell through the perforations in the bottom. The upper portion of the reactor vessel is provided with baffles to prevent the liquid fuel from splashing into this region which is also provided with a recombiner apparatus for recombining the radiolytically dissociated moderator vapor and a control means.

Modeling Chilled-Water Storage System Components for Coupling to a Small Modular Reactor in a Nuclear Hybrid Energy System

NASA Astrophysics Data System (ADS)

Misenheimer, Corey Thomas

The intermittency of wind and solar power puts strain on electric grids, often forcing carbonbased and nuclear sources of energy to operate in a load-follow mode. Operating nuclear reactors in a load-follow fashion is undesirable due to the associated thermal and mechanical stresses placed on the fuel and other reactor components. Various Thermal Energy Storage (TES) elements and ancillary energy applications can be coupled to nuclear (or renewable) power sources to help absorb grid instabilities caused by daily electric demand changes and renewable intermittency, thereby forming the basis of a candidate Nuclear Hybrid Energy System (NHES). During the warmer months of the year in many parts of the country, facility air-conditioning loads are significant contributors to the increase in the daily peak electric demand. Previous research demonstrated that a stratified chilled-water storage tank can displace peak cooling loads to off-peak hours. Based on these findings, the objective of this work is to evaluate the prospect of using a stratified chilled-water storage tank as a potential TES reservoir for a nuclear reactor in a NHES. This is accomplished by developing time-dependent models of chilled-water system components, including absorption chillers, cooling towers, a storage tank, and facility cooling loads appropriate for a large office space or college campus, as a callable FORTRAN subroutine. The resulting TES model is coupled to a high-fidelity mPower-sized Small Modular Reactor (SMR) Simulator, with the goal of utilizing excess reactor capacity to operate several sizable chillers in order to keep reactor power constant. Chilled-water production via single effect, lithium bromide (LiBr) absorption chillers is primarily examined in this study, although the use of electric chillers is briefly explored. Absorption chillers use hot water or low-pressure steam to drive an absorption-refrigeration cycle. The mathematical framework for a high-fidelity dynamic absorption chiller model is presented. The transient FORTRAN model is grounded on time-dependent mass, species, and energy conservation equations. Due to the vast computational costs of the high-fidelity model, a low-fidelity absorption chiller model is formulated and calibrated to mimic the behavior of the high-fidelity model. Stratified chilled-water storage tank performance is characterized using Computational Fluid Dynamics (CFD). The geometry employed in the CFD model represents a 5-million-gallon storage tank currently in use at a North Carolina college campus. Simulation results reveal the laminar numerical model most closely aligns with actual tank charging and discharging data. A subsequent parametric study corroborates storage tank behavior documented throughout literature and industry. Two absorption chiller configurations are considered. The first involves bypassing lowpressure steam from the low-pressure turbine to absorption chillers during periods of excess reactor capacity in order to keep reactor power constant. Simulation results show steam conditions downstream of the turbine control valves are a strong function of turbine load, and absorption chiller performance is hindered by reduced turbine impulse pressures at reduced turbine demands. A more suitable configuration entails integrating the absorption chillers into a flash vessel system that is thermally coupled to a sensible heat storage system. The sensible heat storage system is able to maintain reactor thermal output constant at 100% and match turbine output with several different electric demand profiles. High-pressure condensate in the sensible heat storage system is dropped across a let-down orifice and flashed in an ideal separator. Generated steam is sent to a bank of absorption chillers. Simulation results show enough steam is available during periods of reduced turbine demand to power four large absorption chillers to charge a 5-million-gallon stratified chilled-water storage tank, which is used to offset cooling loads in an adjacent facility. The coupled TES systems operating in conjunction with an SMR comprise the foundation of a tightly coupled NHES.

Using OPC technology to support the study of advanced process control.

PubMed

Mahmoud, Magdi S; Sabih, Muhammad; Elshafei, Moustafa

2015-03-01

OPC, originally the Object Linking and Embedding (OLE) for Process Control, brings a broad communication opportunity between different kinds of control systems. This paper investigates the use of OPC technology for the study of distributed control systems (DCS) as a cost effective and flexible research tool for the development and testing of advanced process control (APC) techniques in university research centers. Co-Simulation environment based on Matlab, LabVIEW and TCP/IP network is presented here. Several implementation issues and OPC based client/server control application have been addressed for TCP/IP network. A nonlinear boiler model is simulated as OPC server and OPC client is used for closed loop model identification, and to design a Model Predictive Controller. The MPC is able to control the NOx emissions in addition to drum water level and steam pressure. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Review article: closed-loop systems in anesthesia: is there a potential for closed-loop fluid management and hemodynamic optimization?

PubMed

Rinehart, Joseph; Liu, Ngai; Alexander, Brenton; Cannesson, Maxime

2012-01-01

Closed-loop (automated) controllers are encountered in all aspects of modern life in applications ranging from air-conditioning to spaceflight. Although these systems are virtually ubiquitous, they are infrequently used in anesthesiology because of the complexity of physiologic systems and the difficulty in obtaining reliable and valid feedback data from the patient. Despite these challenges, closed-loop systems are being increasingly studied and improved for medical use. Two recent developments have made fluid administration a candidate for closed-loop control. First, the further description and development of dynamic predictors of fluid responsiveness provides a strong parameter for use as a control variable to guide fluid administration. Second, rapid advances in noninvasive monitoring of cardiac output and other hemodynamic variables make goal-directed therapy applicable for a wide range of patients in a variety of clinical care settings. In this article, we review the history of closed-loop controllers in clinical care, discuss the current understanding and limitations of the dynamic predictors of fluid responsiveness, and examine how these variables might be incorporated into a closed-loop fluid administration system.

Transient boiling in two-phase helium natural circulation loops

NASA Astrophysics Data System (ADS)

Furci, H.; Baudouy, B.; Four, A.; Meuris, C.

2014-01-01

Two-phase helium natural circulation loops are used for cooling large superconducting magnets, as CMS for LHC. During normal operation or in the case of incidents, transients are exerted on the cooling system. Here a cooling system of this type is studied experimentally. Sudden power changes are operated on a vertical-heated-section natural convection loop, simulating a fast increase of heat deposition on magnet cooling pipes. Mass flow rate, heated section wall temperature and pressure drop variations are measured as a function of time, to assess the time behavior concerning the boiling regime according to the values of power injected on the heated section. The boiling curves and critical heat flux (CHF) values have been obtained in steady state. Temperature evolution has been observed in order to explore the operating ranges where heat transfer is deteriorated. Premature film boiling has been observed during transients on the heated section in some power ranges, even at appreciably lower values than the CHF. A way of attenuating these undesired temperature excursions has been identified through the application of high enough initial heating power.

STEAM GENERATOR FOR GAS COOLED NUCLEAR REACTORS

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

None

1960-03-14

A steam generator for a gas-cooled nuclear reactor is disposed inside the same pressure vessel as the reactor and has a tube system heated by the gas circulating through the reactor; the pressure vessel is double-walled, and the interspace between these two walls is filled with concrete serving as radiation shielding. The steam generator has a cylindricaIly shaped vertical casing, through which the heating gas circulates, while the tubes are arranged in a plurality of parallel horizontal planes and each of them have the shape of an involute of a circle. The tubes are uniformly distributed over the available surfacemore » in the plane, all the tubes of the same plane being connected in parallel. The exterior extremities of these involute-shaped tubes are each connected with similar tubes disposed in the adjacent lower situated plane, while the interior extremities are connected with tubes in the adjacent higher situated plane. The alimentation of the tubes is performed over annular headers. The tube system is self-supporting, the tubes being joined together by welded spacers. The fluid flow in the tubes is performed by forced circulation. (NPO)« less

District heating and cooling systems for communities through power plant retrofit distribution network. Volume 3. Final report, September 1, 1978-May 31, 1979

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

None

This final report of Phase I of the study presents Task 4, Technical Review and Assessment. The most-promising district-heating concept identified in the Phase I study for the Public Service Electric and Gas Company, Newark, New Jersey, is a hot-water system in which steam is extracted from an existing turbine and used to drive a new, small backpressure turbine-generator. The backpressure turbine provides heat for district heating and simultaneously provides additional electric-generating capacity to partially offset the capacity lost due to the steam extraction. This approach is the most-economical way to retrofit the stations studied for district heating while minimizingmore » electric-capacity loss. Nine fossil-fuel-fired stations within the PSE and G system were evaluated for possibly supplying heat for district heating and cooling in cogeneration operations, but only three were selected to supply the district-heating steam. They are Essex, Hudson, and Bergen. Plant retrofit, thermal distribution schemes, consumer-conversion scheme, and consumer-metering system are discussed. Extensive technical information is provided in 16 appendices, additional tables, figures, and drawings. (MCW)« less

Comparative assessment of the efficacy of closed helical loop and T-loop for space closure in lingual orthodontics-a finite element study.

PubMed

Chacko, Ajay; Tikku, Tripti; Khanna, Rohit; Maurya, Rana Pratap; Srivastava, Kamna

2018-05-28

Retraction in lingual orthodontics has biomechanical differences when compared to labial orthodontics, which is not yet established. Thus, we have intended to compare the biomechanical characteristics of closed helical loop and T-loop on 1 mm activation with 30° of compensatory curvatures during retraction in lingual orthodontics. STb lingual brackets were indirectly bonded to maxillary typhodont model that was scanned to obtain FEM model. Closed helical loop (2 × 7 mm) and T-loop (6 × 2 × 7 mm) of 0.016″ × 0.016″ TMA wire were modeled without preactivation bends. Preactivation bends at 30° were given in the software. Boundary conditions were set. The force (F) and moment (M) of both the loops were determined on 1 mm activation, using ANSYS software. M/F ratio was also calculated for both the loops. T-loop exerted less force, thus increased M/F ratio as compared to closed helical loop on 1 mm activation. When torque has to be preserved in the anterior segment during retraction in lingual orthodontics, T-loop can be preferred over closed helical loop.

Start-up circuit upgrading to reduce the erosion of the rotor blades of the last stages of steam turbines and prevent the mass strips of stellite plates

NASA Astrophysics Data System (ADS)

Bozhko, V. V.; Gorin, A. V.; Zaitsev, I. V.; Kovalev, I. A.; Nosovitskii, I. A.; Orlik, V. G.; Lomagin, S. N.; Chernov, V. P.

2017-03-01

At turbine starts with low steam flow rates in idle mode, the low-pressure rotor blades consume energy, causing the ventilation heating of the stages and creating higher depression in them than in the condenser. This leads to the return steam flows in the exhaust of the low-pressure cylinder (LPC), reducing the heat due to the moisture of starting steam damps and cooling injections. It is shown that, as a result of upgrading with the transition to fully milled shroud platforms of rotor blades, the depression in the stages decreases and their cooling efficiency is reduced due to the removal of an elastic turn of the rotor blades under the action of centrifugal forces and seal of them by periphery. Heating the rotor blades of the last stages exceeds the temperature threshold of soldering resistance of stellite plates (150°C), and their mass strips begin. The start-up circuit providing both the temperature retention of the last stages lower the soldering resistance threshold due to overwetting the steam damps up to saturation condition and the high degree of removal from the dump steam of excessive erosive-dangerous condensed moisture was proposed, applied, and tested at the operating power unit. The investment in the development and application of the new start-up circuit are compensated in the course of a year owing to guaranteed prevention of the strips of stellite plates that lengthens the service life of the rotor blades of the last stages as well as increase of the rotor blade efficiency due to the sharp decrease of erosive wear of the profiles and reduction of their surface roughness. This reduces the annual consumption of equivalent fuel by approximately 1000 t for every 100 MW of installed capacity.

Power generating system and method utilizing hydropyrolysis

DOEpatents

Tolman, R.

1986-12-30

A vapor transmission cycle is described which burns a slurry of coal and water with some of the air from the gas turbine compressor, cools and cleans the resulting low-Btu fuel gas, burns the clean fuel gas with the remaining air from the compressor, and extracts the available energy in the gas turbine. The cycle lends itself to combined-cycle cogeneration for the production of steam, absorption cooling, and electric power.

Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

NASA Technical Reports Server (NTRS)

Steele, John; Elms, Theresa; Peyton, Barbara; Rector, Tony; Jennings, Mallory A.

2016-01-01

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR (Airlock Cooling Loop Recovery) Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation is being investigation. A simplified means to acquire on-orbit EMU cooling water samples have been designed. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin are undergoing evaluation. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit.

Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

NASA Technical Reports Server (NTRS)

Steele, John; Elms, Theresa; Peyton, Barbara; Rector, Tony; Jennings, Mallory

2016-01-01

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR (Airlock Cooling Loop Recovery) Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation is being investigated. A simplified means to acquire on-orbit EMU cooling water samples has been designed. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin are undergoing evaluation. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit.

Coronal Loops: Observations and Modeling of Confined Plasma.

PubMed

Reale, Fabio

Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops) are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC) and impulsive (DC) heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.

Ground Source Heat Pumps vs. Conventional HVAC: A Comparison of Economic and Environmental Costs

DTIC Science & Technology

2009-03-26

of systems are surface water heat pumps (SWHPs), ground water heat pumps (GWHPs), and ground coupled heat pumps ( GCHPs ) (Kavanaugh & Rafferty, 1997...Kavanaugh & Rafferty, 1997). Ground Coupled Heat Pumps (Closed-Loop Ground Source Heat Pumps) GCHPs , otherwise known as closed-loop GSHPs, are the...Significant confusion has arisen through the use of GCHP and closed-loop GSHP terminology. Closed-loop GSHP is the preferred nomenclature for this

1. Credit BG. View looking southeast down onto roof and ...

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

1. Credit BG. View looking southeast down onto roof and the north and west facades of Steam Generator Plant, Building 4280/E-81. Vents on roof were from gas-fired steam generators. Pipes emerging from north facade are for steam. Elevated narrow tray is for electrical cables. To lower left of image (immediate north of 4280/E-81) is concrete-lined pond originally built to neutralize rocket engine exhaust compounds; it was only used as a cooling pond. To the lower right of this image are concrete pads which held two 7,500 gallon feedwater tanks for the boilers in 4280/E-81; these tanks were transferred to another federal space science organization and removed from the JPL compound in 1994. Beyond 4280/E-81 to the upper left is a reclamation pond. ... - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Steam Generator Plant, Edwards Air Force Base, Boron, Kern County, CA

Passive cooling system for top entry liquid metal cooled nuclear reactors

DOEpatents

Boardman, Charles E.; Hunsbedt, Anstein; Hui, Marvin M.

1992-01-01

A liquid metal cooled nuclear fission reactor plant having a top entry loop joined satellite assembly with a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during shutdown, or heat produced during a mishap. This satellite type reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary cooling system when rendered inoperative.

Evaluation of on-line chelant addition to PWR steam generators. Steam generator cleaning project

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

Tvedt, T.J.; Wallace, S.L.; Griffin, F. Jr.

1983-09-01

The investigation of chelating agents for continuous water treatment of secondary loops of PWR steam generators were conducted in two general areas: the study of the chemistry of chelating agents and the study of materials compatability with chelating agents. The thermostability of both EDTA and HEDTA metal chelates in All Volatile Treatment (AVT) water chemistry were shown to be greater than or equal to the thermostability of EDTA metal chelates in phosphate-sulfite water chemistry. HEDTA metal chelates were shown to have a much greater stability than EDTA metal chelates. Using samples taken from the EDTA metal chelate thermostability study andmore » from the Commonwealth Research Corporation (CRC) model steam generators (MSG), EDTA decomposition products were determined. Active metal surfaces were shown to become passivated when exposed to EDTA and HEDTA concentrations as high as 0.1% w/w in AVT. Trace amounts of iron in the water were found to increase the rate of passivation. Material balance and visual inspection data from CRC model steam generators showed that metal was transported through and cleaned from the MSG's. The Inconel 600 tubes of the salt water fouled model steam generators experienced pitting corrosion. Results of this study demonstrates the feasibility of EDTA as an on-line water treatment additive to maintain nuclear steam generators in a clean condition.« less

Solid oxide fuel cell power plant having a bootstrap start-up system

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

Lines, Michael T

The bootstrap start-up system (42) achieves an efficient start-up of the power plant (10) that minimizes formation of soot within a reformed hydrogen rich fuel. A burner (48) receives un-reformed fuel directly from the fuel supply (30) and combusts the fuel to heat cathode air which then heats an electrolyte (24) within the fuel cell (12). A dilute hydrogen forming gas (68) cycles through a sealed heat-cycling loop (66) to transfer heat and generated steam from an anode side (32) of the electrolyte (24) through fuel processing system (36) components (38, 40) and back to an anode flow field (26)more » until fuel processing system components (38, 40) achieve predetermined optimal temperatures and steam content. Then, the heat-cycling loop (66) is unsealed and the un-reformed fuel is admitted into the fuel processing system (36) and anode flow (26) field to commence ordinary operation of the power plant (10).« less

Closed-loop fiber optic gyroscope with homodyne detection

NASA Astrophysics Data System (ADS)

Zhu, Yong; Qin, BingKun; Chen, Shufen

1996-09-01

Interferometric fiber optic gyroscope (IFOG) has been analyzed with autocontrol theory in this paper. An open-loop IFOG system is not able to restrain the bias drift, but a closed-loop IFOG system can do it very well using negative feedback in order to suppress zero drift. The result of our theoretic analysis and computer simulation indicate that the bias drift of a closed-loop system is smaller than an open- loop one.

Probing the Production of Extreme-ultraviolet Late-phase Solar Flares Using the Model Enthalpy-based Thermal Evolution of Loops

NASA Astrophysics Data System (ADS)

Dai, Yu; Ding, Mingde

2018-04-01

Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares that is characterized by a second peak in warm coronal emissions (∼3 MK) several tens of minutes to a few hours after the soft X-ray (SXR) peak. Using the model enthalpy-based thermal evolution of loops (EBTEL), we numerically probe the production of EUV late-phase solar flares. Starting from two main mechanisms of producing the EUV late phase, i.e., long-lasting cooling and secondary heating, we carry out two groups of numerical experiments to study the effects of these two processes on the emission characteristics in late-phase loops. In either of the two processes an EUV late-phase solar flare that conforms to the observational criteria can be numerically synthesized. However, the underlying hydrodynamic and thermodynamic evolutions in late-phase loops are different between the two synthetic flare cases. The late-phase peak due to a long-lasting cooling process always occurs during the radiative cooling phase, while that powered by a secondary heating is more likely to take place in the conductive cooling phase. We then propose a new method for diagnosing the two mechanisms based on the shape of EUV late-phase light curves. Moreover, from the partition of energy input, we discuss why most solar flares are not EUV late flares. Finally, by addressing some other factors that may potentially affect the loop emissions, we also discuss why the EUV late phase is mainly observed in warm coronal emissions.

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi B. R.

2010-01-01

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

Steam trap monitor

DOEpatents

Ryan, M.J.

1987-05-04

A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (a hot finger) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellow in providing an indication of total energy (steam + condensate) of the system. Processing means coupled to and responsive to outputs from the hot and cold fingers subtracts the former from the latter to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning. 2 figs.

A Model for Developing Clinical Analytics Capacity: Closing the Loops on Outcomes to Optimize Quality.

PubMed

Eggert, Corinne; Moselle, Kenneth; Protti, Denis; Sanders, Dale

2017-01-01

Closed Loop Analytics© is receiving growing interest in healthcare as a term referring to information technology, local data and clinical analytics working together to generate evidence for improvement. The Closed Loop Analytics model consists of three loops corresponding to the decision-making levels of an organization and the associated data within each loop - Patients, Protocols, and Populations. The authors propose that each of these levels should utilize the same ecosystem of electronic health record (EHR) and enterprise data warehouse (EDW) enabled data, in a closed-loop fashion, with that data being repackaged and delivered to suit the analytic and decision support needs of each level, in support of better outcomes.

Design and experimental investigation of a cryogenic system for environmental test applications

NASA Astrophysics Data System (ADS)

Yan, Lutao; Li, Hong; Liu, Yue; Han, Che; Lu, Tian; Su, Yulei

2015-04-01

This paper is concerned with the design, development and performance testing of a cryogenic system for use in high cooling power instruments for ground-based environmental testing. The system provides a powerful tool for a combined environmental test that consists of high pressure and cryogenic temperatures. Typical cryogenic conditions are liquid hydrogen (LH2) and liquid oxygen (LO2), which are used in many fields. The cooling energy of liquid nitrogen (LN2) and liquid helium (LHe) is transferred to the specimen by a closed loop of helium cycle. In order to minimize the consumption of the LHe, the optimal design of heat recovery exchangers has been used in the system. The behavior of the system is discussed based on experimental data of temperature and pressure. The results show that the temperature range from room temperature to LN2 temperature can be achieved by using LN2, the pressurization process is stable and the high test pressure is maintained. Lower temperatures, below 77 K, can also be obtained with LHe cooling, the typical cooling time is 40 min from 90 K to 22 K. Stable temperatures of 22 K at the inlet of the specimen have been observed, and the system in this work can deliver to the load a cooling power of several hundred watts at a pressure of 0.58 MPa.

Comparison of a RELAP5/MOD2 posttest calculation to the data during the recovery portion of a semiscale single-tube steam generator tube rupture experiment

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

Chapman, J.C.

This report discusses the comparisons of a RELAP5 posttest calculation of the recovery portion of the Semiscale Mod-2B test S-SG-1 to the test data. The posttest calculation was performed with the RELAP5/MOD2 cycle 36.02 code without updates. The recovery procedure that was calculated mainly consisted of secondary feed and steam using auxiliary feedwater injection and the atmospheric dump valve of the unaffected steam generator (the steam generator without the tube rupture). A second procedure was initiated after the trends of the secondary feed and steam procedure had been established, and this was to stop the safety injection that had beenmore » provided by two trains of both the charging and high pressure injection systems. The Semiscale Mod-2B configuration is a small scale (1/1705), nonnuclear, instrumented, model of a Westinghouse four-loop pressurized water reactor power plant. S-SG-1 was a single-tube, cold-side, steam generator tube rupture experiment. The comparison of the posttest calculation and data included comparing the general trends and the driving mechanisms of the responses, the phenomena, and the individual responses of the main parameters.« less

Strain actuated aeroelastic control

NASA Technical Reports Server (NTRS)

Lazarus, Kenneth B.

1992-01-01

Viewgraphs on strain actuated aeroelastic control are presented. Topics covered include: structural and aerodynamic modeling; control law design methodology; system block diagram; adaptive wing test article; bench-top experiments; bench-top disturbance rejection: open and closed loop response; bench-top disturbance rejection: state cost versus control cost; wind tunnel experiments; wind tunnel gust alleviation: open and closed loop response at 60 mph; wind tunnel gust alleviation: state cost versus control cost at 60 mph; wind tunnel command following: open and closed loop error at 60 mph; wind tunnel flutter suppression: open loop flutter speed; and wind tunnel flutter suppression: closed loop state cost curves.

Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory Radio Frequency (RF) Propagation Section

DTIC Science & Technology

2016-10-01

ARL-TR-7860 ● OCT 2016 US Army Research Laboratory Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop ...ARL-TR-7860 ● OCT 2016 US Army Research Laboratory Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory...Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory Radio Frequency (RF) Propagation Section 5a. CONTRACT NUMBER

Hypoglycaemia incidence and recovery during home use of hybrid closed-loop insulin delivery in adults with type 1 diabetes.

PubMed

Ruan, Yue; Bally, Lia; Thabit, Hood; Leelarathna, Lalantha; Hartnell, Sara; Tauschmann, Martin; Wilinska, Malgorzata E; Evans, Mark L; Mader, Julia K; Kojzar, Harald; Dellweg, Sibylle; Benesch, Carsten; Arnolds, Sabine; Pieber, Thomas R; Hovorka, Roman

2018-03-25

Glucose excursion was assessed prior to and post hypoglycaemia to increase understanding of hypoglycaemia incidence and recovery during hybrid closed-loop insulin delivery. We retrospectively analysed data from 60 adults with type 1 diabetes who received, in a crossover randomized design, day-and-night hybrid closed-loop insulin delivery and insulin pump therapy, the latter with or without real-time continuous glucose monitoring. Over 4-week study periods, we identified hypoglycaemic episodes, defined as sensor glucose <3.0 mmol/L, and analysed sensor glucose relative to the onset of hypoglycaemia. We identified 377 hypoglycaemic episodes during hybrid closed-loop intervention vs 662 during control intervention (P < .001), with a predominant reduction of nocturnal hypoglycaemia. The slope of sensor glucose prior to hypoglycaemia was steeper during closed-loop intervention than during control intervention (P < .01), while insulin delivery was reduced (P < .01). During both day and night, participants recovered from hypoglycaemia faster when treated by closed-loop intervention. At 120 minutes post hypoglycaemia, sensor glucose levels were higher during closed-loop intervention compared to the control period (P < .05). In conclusion, closed-loop intervention reduces the risk of hypoglycaemia, particularly overnight, with swift recovery from hypoglycaemia leading to higher 2-hour post-hypoglycaemia glucose levels. © 2018 John Wiley & Sons Ltd.

Pairing transition, coherence transition, and the irreversibility line in granular GdBa2Cu3O7-δ

NASA Astrophysics Data System (ADS)

Roa-Rojas, J.; Menegotto Costa, R.; Pureur, P.; Prieto, P.

2000-05-01

We report on electrical magnetoconductivity experiments near the superconducting transition of a granular sample of GdBa2Cu3O7-δ. The measurements were performed in magnetic fields ranging from 0 to 500 Oe applied parallel to the current orientation. The results show that the transition proceeds in two steps. When the temperature is decreased we first observe the pairing transition, which stabilizes superconductivity within the grains at a temperature practically coincident with the bulk critical temperature Tc. Analysis of the fluctuation contributions to the conductivity shows that the universality class for this transition is that of the three dimensional (3D)-XY model in the ordered case, with dynamic critical exponent z=3/2. Close to the zero-resistance state, the measurements reveal the occurrence of a coherence transition, where the phases of the order parameter in individual grains become long-range ordered. The critical temperature Tco for this transition is close to the point where the resistivity vanishes. A strong enlargement of the fluctuation interval preceding the coherence transition is caused by the applied magnetic field. In this region, a 3D-Gaussian regime and an asymptotic critical regime were clearly identified. The critical conductivity behavior for the coherence transition is interpreted within a 3D-XY model where disorder and frustration are relevant. The irreversibility line is determined from magnetoconductivity measurements performed according to the zero-field-cooled (ZFC) and field-cooled data collected on cooling (FCC) recipes. The locus of this line coincides with the upper temperature limit for the fluctuation region above the coherence transition. The irreversibility line is interpreted as an effect of the formation of small clusters with closed loops of Josephson-coupled grains.

The Multidisk Diode-Pumped High Power Yb:YAG Laser Amplifier of High-Intensity Laser System with 1 kHz Repetition Rate

NASA Astrophysics Data System (ADS)

Kuptsov, G. V.; Petrov, V. V.; Petrov, V. A.; Laptev, A. V.; Kirpichnikov, A. V.; Pestryakov, E. V.

2018-04-01

The source of instabilities in the multidisk diode-pumped high power Yb:YAG laser amplifier with cryogenic closed-loop cooling in the laser amplification channel of the high-intensity laser system with 1 kHz repetition rate was determined. Dissected copper mounts were designed and used to suppress instabilities and to achieve repeatability of the system. The equilibrium temperature dependency of the active elements on average power was measured. The seed laser for the multidisk amplifier was numerically simulated and designed to allow one to increase pulses output energy after the amplifier up to 500 mJ.

Combining Charge Couple Devices and Rate Sensors for the Feedforward Control System of a Charge Coupled Device Tracking Loop.

PubMed

Tang, Tao; Tian, Jing; Zhong, Daijun; Fu, Chengyu

2016-06-25

A rate feed forward control-based sensor fusion is proposed to improve the closed-loop performance for a charge couple device (CCD) tracking loop. The target trajectory is recovered by combining line of sight (LOS) errors from the CCD and the angular rate from a fiber-optic gyroscope (FOG). A Kalman filter based on the Singer acceleration model utilizes the reconstructive target trajectory to estimate the target velocity. Different from classical feed forward control, additive feedback loops are inevitably added to the original control loops due to the fact some closed-loop information is used. The transfer function of the Kalman filter in the frequency domain is built for analyzing the closed loop stability. The bandwidth of the Kalman filter is the major factor affecting the control stability and close-loop performance. Both simulations and experiments are provided to demonstrate the benefits of the proposed algorithm.

STEAM PLANT, TRA609. SECTION A SHOWS FEATURES OF NORTH/SOUTH AXIS: ...

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

STEAM PLANT, TRA-609. SECTION A SHOWS FEATURES OF NORTH/SOUTH AXIS: STEAM GENERATOR AND CATWALK, STACK, DEGREASER FEED WATER HEATER IN PENTHOUSE, MEZZANINE, SURGE TANK PIT (BELOW GROUND LEVEL). UTILITY ROOM SHOWS DIESEL ENGINE GENERATORS, AIR TANKS, STARTING AIR COMPRESSORS. OUTSIDE SOUTH END ARE EXHAUST MUFFLER, AIR INTAKE OIL FILTER, RADIATOR COOLING UNIT, AIR SURGE TANK. SECTION B CROSSES WEST TO EAST NEAR SOUTH END OF BUILDING TO SHOW ARRANGEMENT OF DIESEL ENGINE GENERATOR, AIR DRIER, AFTER COOLER, AIR COMPRESSOR, AND BLOWDOWN TANK. BLAW-KNOX 3150-9-2, 6/1950. INL INDEX NO. 431-0609-00-098-100018, REV. 3. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Combined Heat and Power

EPA Pesticide Factsheets

CHP is on-site electricity generation that captures the heat that would otherwise be wasted to provide useful thermal energy such as steam or hot water than can be used for space heating, cooling, domestic hot water and industrial processes.

The hydrogen sulfide emissions abatement program at the Geysers Geothermal Power Plant

NASA Technical Reports Server (NTRS)

Allen, G. W.; Mccluer, H. K.

1974-01-01

The scope of the hydrogen sulfide (H2S) abatement program at The Geysers Geothermal Power Plant and the measures currently under way to reduce these emissions are discussed. The Geysers steam averages 223 ppm H2S by weight and after passing through the turbines leaves the plant both through the gas ejector system and by air-stripping in the cooling towers. The sulfide dissolved in the cooling water is controlled by the use of an oxidation catalyst such as an iron salt. The H2S in the low Btu ejector off gases may be burned to sulfur dioxide and scrubbed directly into the circulating water and reinjected into the steam field with the excess condensate. Details are included concerning the disposal of the impure sulfur, design requirements for retrofitting existing plants and modified plant operating procedures. Discussion of future research aimed at improving the H2S abatement system is also included.

Pressure suppression containment system

DOEpatents

Gluntz, Douglas M.; Townsend, Harold E.

1994-03-15

A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto.

Pressure suppression containment system

DOEpatents

Gluntz, D.M.; Townsend, H.E.

1994-03-15

A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of-coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto. 6 figures.

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.

Minor loop dependence of the magnetic forces and stiffness in a PM-HTS levitation system

NASA Astrophysics Data System (ADS)

Yang, Yong; Li, Chengshan

2017-12-01

Based upon the method of current vector potential and the critical state model of Bean, the vertical and lateral forces with different sizes of minor loop are simulated in two typical cooling conditions when a rectangular permanent magnet (PM) above a cylindrical high temperature superconductor (HTS) moves vertically and horizontally. The different values of average magnetic stiffness are calculated by various sizes of minor loop changing from 0.1 to 2 mm. The magnetic stiffness with zero traverse is obtained by using the method of linear extrapolation. The simulation results show that the extreme values of forces decrease with increasing size of minor loop. The magnetic hysteresis of the force curves also becomes small as the size of minor loop increases. This means that the vertical and lateral forces are significantly influenced by the size of minor loop because the forces intensely depend on the moving history of the PM. The vertical stiffness at every vertical position when the PM vertically descends to 1 mm is larger than that as the PM vertically ascents to 30 mm. When the PM moves laterally, the lateral stiffness during the PM passing through any horizontal position in the first time almost equal to the value during the PM passing through the same position in the second time in zero-field cooling (ZFC), however, the lateral stiffness in field cooling (FC) and the cross stiffness in ZFC and FC are significantly affected by the moving history of the PM.

A 1 kW-class multi-stage heat-driven thermoacoustic cryocooler system operating at liquefied natural gas temperature range

NASA Astrophysics Data System (ADS)

Zhang, L. M.; Hu, J. Y.; Wu, Z. H.; Luo, E. C.; Xu, J. Y.; Bi, T. J.

2015-07-01

This article introduces a multi-stage heat-driven thermoacoustic cryocooler capable of reaching cooling capacity about 1 kW at liquefied natural gas temperature range without any moving mechanical parts. The cooling system consists of an acoustically resonant double-acing traveling wave thermoacoustic heat engine and three identical pulse tube coolers. Unlike other traditional traveling wave thermoacoustic heat engines, the acoustically resonant double-acting thermoacoustic heat engine is a closed-loop configuration consists of three identical thermoacoustic conversion units. Each pulse tube cooler is bypass driven by one thermoacoustic heat engine unit. The device is acoustically completely symmetric and therefore "self-matching" for efficient traveling-wave thermoacoustic conversion. In the experiments, with 7 MPa helium gas as working gas, when the heating temperature reaches 918 K, total cooling capacity of 0.88 kW at 110 K is obtained with a resonant frequency of about 55 Hz. When the heating temperature is 903 K, a maximum total cooling capacity at 130 K of 1.20 kW is achieved, with a thermal-to-cold exergy efficiency of 8%. Compared to previously developed heat-driven thermoacoustic cryocoolers, this device has higher thermal efficiency and higher power density. It shows a good prospect of application in the field of natural gas liquefaction and recondensation.

A Closed-loop Brain Computer Interface to a Virtual Reality Avatar: Gait Adaptation to Visual Kinematic Perturbations

PubMed Central

Luu, Trieu Phat; He, Yongtian; Brown, Samuel; Nakagome, Sho; Contreras-Vidal, Jose L.

2016-01-01

The control of human bipedal locomotion is of great interest to the field of lower-body brain computer interfaces (BCIs) for rehabilitation of gait. While the feasibility of a closed-loop BCI system for the control of a lower body exoskeleton has been recently shown, multi-day closed-loop neural decoding of human gait in a virtual reality (BCI-VR) environment has yet to be demonstrated. In this study, we propose a real-time closed-loop BCI that decodes lower limb joint angles from scalp electroencephalography (EEG) during treadmill walking to control the walking movements of a virtual avatar. Moreover, virtual kinematic perturbations resulting in asymmetric walking gait patterns of the avatar were also introduced to investigate gait adaptation using the closed-loop BCI-VR system over a period of eight days. Our results demonstrate the feasibility of using a closed-loop BCI to learn to control a walking avatar under normal and altered visuomotor perturbations, which involved cortical adaptations. These findings have implications for the development of BCI-VR systems for gait rehabilitation after stroke and for understanding cortical plasticity induced by a closed-loop BCI system. PMID:27713915

Virtual grasping: closed-loop force control using electrotactile feedback.

PubMed

Jorgovanovic, Nikola; Dosen, Strahinja; Djozic, Damir J; Krajoski, Goran; Farina, Dario

2014-01-01

Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously "unseen" objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

High frequency noise measurements during CNEN/NIRA steam generator testing at Les Renardieres

NASA Astrophysics Data System (ADS)

Clapis, A.; Scandolo, D.; Regis, V.; Rappini, R.

The most significant results of the acoustic measurements carried out on the PGV-1 sodium-steam generator during the test of the 50 MW prototype on the CGVS loop facility are described. The prototype test was done in the isothermal condition, i.e., without steam production and in the power condition. During the first phase tests were made with low pressure hydrogen injection in sodium. The main purpose of the acoustic measurements, limited to the 100 to 1000 kHz frequency range, was to evaluate the noise characteristics (level and power spectrum) in all working states of the plant. A small leak of gas found in the isothermal condition enabled the sensitivity of the acoustic leak detection technique to be evaluated qualitatively. The results in form of spectral analysis charts are included.

Bandwidth controller for phase-locked-loop

NASA Technical Reports Server (NTRS)

Brockman, Milton H. (Inventor)

1992-01-01

A phase locked loop utilizing digital techniques to control the closed loop bandwidth of the RF carrier phase locked loop in a receiver provides high sensitivity and a wide dynamic range for signal reception. After analog to digital conversion, a digital phase locked loop bandwidth controller provides phase error detection with automatic RF carrier closed loop tracking bandwidth control to accommodate several modes of transmission.

Experimentally Determined Overall Heat Transfer Coefficients for Spacesuit Liquid Cooled Garments

NASA Technical Reports Server (NTRS)

Bue, Grant; Rhodes, Richard; Anchondo, Ian; Westheimer, David; Campbell, Colin; Vogel, Matt; Vonaue, Walt; Conger, Bruce; Stein, James

2015-01-01

A Human-In-The-Loop (HITL) Portable Life Support System 2.0 (PLSS 2.0) test has been conducted at NASA Johnson Space Center in the PLSS Development Laboratory from October 27, 2014 to December 19, 2014. These closed-loop tests of the PLSS 2.0 system integrated with human subjects in the Mark III Suit at 3.7 psi to 4.3 psi above ambient pressure performing treadmill exercise at various metabolic rates from standing rest to 3000 BTU/hr (880 W). The bulk of the PLSS 2.0 was at ambient pressure but effluent water vapor from the Spacesuit Water Membrane Evaporator (SWME) and the Auxiliary Membrane Evaporator (Mini-ME), and effluent carbon dioxide from the Rapid Cycle Amine (RCA) were ported to vacuum to test performance of these components in flight-like conditions. One of the objectives of this test was to determine the overall heat transfer coefficient (UA) of the Liquid Cooling Garment (LCG). The UA, an important factor for modeling the heat rejection of an LCG, was determined in a variety of conditions by varying inlet water temperature, flow rate, and metabolic rate. Three LCG configurations were tested: the Extravehicular Mobility Unit (EMU) LCG, the Oceaneering Space Systems (OSS) LCG, and the OSS auxiliary LCG. Other factors influencing accurate UA determination, such as overall heat balance, LCG fit, and the skin temperature measurement, will also be discussed.

Experimentally Determined Heat Transfer Coefficients for Spacesuit Liquid Cooled Garments

NASA Technical Reports Server (NTRS)

Bue, Grant; Watts, Carly; Rhodes, Richard; Anchondo, Ian; Westheimer, David; Campbell, Colin; Vonau, Walt; Vogel, Matt; Conger, Bruce

2015-01-01

A Human-In-The-Loop (HITL) Portable Life Support System 2.0 (PLSS 2.0) test has been conducted at NASA Johnson Space Center in the PLSS Development Laboratory from October 27, 2014 to December 19, 2014. These closed-loop tests of the PLSS 2.0 system integrated with human subjects in the Mark III Suit at 3.7 psi to 4.3 psi above ambient pressure performing treadmill exercise at various metabolic rates from standing rest to 3000 BTU/hr (880 W). The bulk of the PLSS 2.0 was at ambient pressure but effluent water vapor from the Spacesuit Water Membrane Evaporator (SWME) and the Auxiliary Membrane Evaporator (Mini-ME), and effluent carbon dioxide from the Rapid Cycle Amine (RCA) were ported to vacuum to test performance of these components in flight-like conditions. One of the objectives of this test was to determine the heat transfer coefficient (UA) of the Liquid Cooling Garment (LCG). The UA, an important factor for modeling the heat rejection of an LCG, was determined in a variety of conditions by varying inlet water temperature, flowrate, and metabolic rate. Three LCG configurations were tested: the Extravehicular Mobility Unit (EMU) LCG, the Oceaneering Space Systems (OSS) LCG, and the OSS auxiliary LCG. Other factors influencing accurate UA determination, such as overall heat balance, LCG fit, and the skin temperature measurement, will also be discussed.

Flakeboard thickness swelling. Part I, Stress relaxation in a flakeboard mat

Treesearch

R. L. Geimer; J. H. Kwon; J. Bolton

1998-01-01

The steam injection schedule best suited for dimensionally stabilizing a flake mat is one in which steam treatment is initiated before the press is closed and is continued at least until the mat attains target thickness. Experiments showed that resinless mats treated with 20 sec of steam at 600 kPa had maximum thickness swelling of 205% compared to 350% for resinless...

Iterative LQG Controller Design Through Closed-Loop Identification

NASA Technical Reports Server (NTRS)

Hsiao, Min-Hung; Huang, Jen-Kuang; Cox, David E.

1996-01-01

This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from the previous cycle. Then the identified open-loop model is used to redesign the state feedback. The state feedback and the identified Kalman filter gain are used to form an updated LQC controller for the next cycle. This iterative process continues until the updated controller converges. The proposed controller design is demonstrated by numerical simulations and experiments on a highly unstable large-gap magnetic suspension system.

Closed-loop carrier phase synchronization techniques motivated by likelihood functions

NASA Technical Reports Server (NTRS)

Tsou, H.; Hinedi, S.; Simon, M.

1994-01-01

This article reexamines the notion of closed-loop carrier phase synchronization motivated by the theory of maximum a posteriori phase estimation with emphasis on the development of new structures based on both maximum-likelihood and average-likelihood functions. The criterion of performance used for comparison of all the closed-loop structures discussed is the mean-squared phase error for a fixed-loop bandwidth.

Explaining Warm Coronal Loops

NASA Technical Reports Server (NTRS)

Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros

2008-01-01

One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.

Mercury Thermal Hydraulic Loop (MTHL) Summary Report

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

Felde, David K.; Crye, Jason Michael; Wendel, Mark W.

2017-03-01

The Spallation Neutron Source (SNS) is a high-power linear accelerator built at Oak Ridge National Laboratory (ORNL) which incorporates the use of a flowing liquid mercury target. The Mercury Thermal Hydraulic Loop (MTHL) was constructed to investigate and verify the heat transfer characteristics of liquid mercury in a rectangular channel. This report provides a compilation of previously reported results from the water-cooled and electrically heated straight and curved test sections that simulate the geometry of the window cooling channel in the target nose region.

STEAM FORMING NEUTRONIC REACTOR AND METHOD OF OPERATING IT

DOEpatents

Untermyer, S.

1960-05-10

The heterogeneous reactor is liquid moderated and cooled by a steam forming coolant and is designed to produce steam from the coolant directly within the active portion of the reactor while avoiding the formation of bubbles in the liquid moderator. This reactor achieves inherent stability as a result of increased neutron leakage and increased neutron resonance absorption in the U/sup 238/ fuel with the formation of bubbles. The invention produces certain conditions under which the formation of vapor bubbles as a result of a neutron flux excursion from the injection of a reactivity increment into the reactor will operate to nullify the reactivity increment within a sufficiently short period of time to prevent unsafe reactor operating conditions from developing. This is obtained by disposing a plurality of fuel elements within a mass of steam forming coolant in the core with the ratio of the volume of steam forming coolant to the volume of fissionable isotopes being within the range yielding a multiplication factor greater than unity and a negative reactivity to core void coefficient at the boiling temperature of the coolant.

Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

2009-01-01

Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

A comparative approach to closed-loop computation.

PubMed

Roth, E; Sponberg, S; Cowan, N J

2014-04-01

Neural computation is inescapably closed-loop: the nervous system processes sensory signals to shape motor output, and motor output consequently shapes sensory input. Technological advances have enabled neuroscientists to close, open, and alter feedback loops in a wide range of experimental preparations. The experimental capability of manipulating the topology-that is, how information can flow between subsystems-provides new opportunities to understand the mechanisms and computations underlying behavior. These experiments encompass a spectrum of approaches from fully open-loop, restrained preparations to the fully closed-loop character of free behavior. Control theory and system identification provide a clear computational framework for relating these experimental approaches. We describe recent progress and new directions for translating experiments at one level in this spectrum to predictions at another level. Operating across this spectrum can reveal new understanding of how low-level neural mechanisms relate to high-level function during closed-loop behavior. Copyright © 2013 Elsevier Ltd. All rights reserved.

Near term application of water cooling

NASA Astrophysics Data System (ADS)

Horner, M. W.; Caruvana, A.; Cohn, A.; Smith, D. P.

1980-03-01

The paper presents studies of combined gas and steam-turbine cycles related to the near term application of water cooling technology to the commercial gas turbine operating on heavy residual oil or coal derived liquid fuels. Water cooling promises significant reduction of hot corrosion and ash deposition at the turbine first-stage nozzle. It was found that: (1) corrosion of some alloys in the presence of alkali contaminant was less as metal temperatures were lowered to the 800-1000 F range, (2) the rate of ash deposition is increased for air-cooled and water-cooled nozzles at the 2060 F turbine firing temperature compared to 1850 F, (3) the ash deposit for the water cooled nozzle was lighter and more easily removed at both 1850 and 2050 F, (4) on-line nutshelling was effective on the water-cooled nozzles even at 2050 F, and (5) the data indicates that the rate of ash deposition may be sensitive to surface wall temperatures.

Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

DOEpatents

Aines, Roger D.; Bourcier, William L.; Viani, Brian

2013-01-29

A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

46. VIEW LOOKING NORTHEAST OF CONDENSER NUMBER 2 (LEFT BACKGROUND) ...

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

46. VIEW LOOKING NORTHEAST OF CONDENSER NUMBER 2 (LEFT BACKGROUND) AND MOTOR FOR PUMPING CONDENSER HOT WELL (LOWER CENTER OF PHOTOGRAPH). SPENT STEAM EXHAUSTED FROM THE TURBINE WAS CONDENSED BY A SPRAY OF BRACKISH WATER. THIS CREATED A PARTIAL VACUUM WHICH IMPROVED TURBINE EFFICIENCY. THE MIXTURE OF CONDENSED STEAM AND COOL BRACKISH WATER FELL TO THE BOTTOM OF THE CONDENSER INTO A HOT WELL. FROM THE WELL IT WAS PUMPED TO THE MAIN DISCHARGE FLUME. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

K-65-12.8 condensing steam turbine

NASA Astrophysics Data System (ADS)

Valamin, A. E.; Kultyshev, A. Yu.; Gol'dberg, A. A.; Sakhnin, Yu. A.; Bilan, V. N.; Stepanov, M. Yu.; Polyaeva, E. N.; Shekhter, M. V.; Shibaev, T. L.

2016-11-01

A new condensing steam turbine K-65-12.8 is considered, which is the continuation of the development of the steam turbine family of 50-70 MW and the fresh steam pressure of 12.8 MPa, such as twocylinder T-50-12.8 and T-60/65-12.8 turbines. The turbine was developed using the modular design. The design and the main distinctive features of the turbine are described, such as a single two-housing cylinder with the steam flow loop; the extraction from the blading section for the regeneration, the inner needs, and heating; and the unification of some assemblies of serial turbines with shorter time of manufacture. The turbine uses the throttling steam distribution; steam from a boiler is supplied to a turbine through a separate valve block consisting of a central shut-off valve and two side control valves. The blading section of a turbine consists of 23 stages: the left flow contains ten stages installed in the inner housing and the right flow contains 13 stages with diaphragm placed in holders installed in the outer housing. The disks of the first 16 stages are forged together with a rotor, and the disks of the rest stages are mounted. Before the two last stages, the uncontrolled steam extraction is performed for the heating of a plant with the heat output of 38-75 GJ/h. Also, a turbine has five regenerative extraction points for feed water heating and the additional steam extraction to a collector for the inner needs with the consumption of up to 10 t/h. The feasibility parameters of a turbine plant are given. The main solutions for the heat flow diagram and the layout of a turbine plant are presented. The main principles and features of the microprocessor electro hydraulic control and protection system are formulated.

Influence of high-temperature steam on the reactivity of CaO sorbent for CO₂ capture.

PubMed

Donat, Felix; Florin, Nicholas H; Anthony, Edward J; Fennell, Paul S

2012-01-17

Calcium looping is a high-temperature CO(2) capture technology applicable to the postcombustion capture of CO(2) from power station flue gas, or integrated with fuel conversion in precombustion CO(2) capture schemes. The capture technology uses solid CaO sorbent derived from natural limestone and takes advantage of the reversible reaction between CaO and CO(2) to form CaCO(3); that is, to achieve the separation of CO(2) from flue or fuel gas, and produce a pure stream of CO(2) suitable for geological storage. An important characteristic of the sorbent, affecting the cost-efficiency of this technology, is the decay in reactivity of the sorbent over multiple CO(2) capture-and-release cycles. This work reports on the influence of high-temperature steam, which will be present in flue (about 5-10%) and fuel (∼20%) gases, on the reactivity of CaO sorbent derived from four natural limestones. A significant increase in the reactivity of these sorbents was found for 30 cycles in the presence of steam (from 1-20%). Steam influences the sorbent reactivity in two ways. Steam present during calcination promotes sintering that produces a sorbent morphology with most of the pore volume associated with larger pores of ∼50 nm in diameter, and which appears to be relatively more stable than the pore structure that evolves when no steam is present. The presence of steam during carbonation reduces the diffusion resistance during carbonation. We observed a synergistic effect, i.e., the highest reactivity was observed when steam was present for both calcination and carbonation.

Multiday Fully Closed Loop Insulin Delivery in Monitored Outpatient Conditions

ClinicalTrials.gov

2014-04-29

To Demonstrate That the Closed Loop System Can be Used Safely Over a Few Consecutive Days.; To Assess Effectiveness in Maintaining Patients' Glucose Levels in the Target Range of 70 to 180 mg/dl, Measured by Blood Glucose Sensor.; To Evaluate the User Experience With a Closed Loop System

Closed Loop Vibrational Control: Theory and Applications

DTIC Science & Technology

1993-10-01

the open loop system dynamics will be close to that of Bit. However, in general, in a closed loop system with a specified feedback co-’ - oller , for...Juang, and G. Rodriguez , "Formulations and Applications of Large Structure Actuator and Sensor Placements," Second VPI & SU/AIAA Symposium on Dynamics

High-temperature electrolysis of CO2-enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells

NASA Astrophysics Data System (ADS)

Kim, Si-Won; Bae, Yonggyun; Yoon, Kyung Joong; Lee, Jong-Ho; Lee, Jong-Heun; Hong, Jongsup

2018-02-01

To mitigate CO2 emissions, its reduction by high-temperature electrolysis using solid oxide cells is extensively investigated, for which excessive steam supply is assumed. However, such condition may degrade its feasibility due to massive energy required for generating hot steam, implying the needs for lowering steam demand. In this study, high-temperature electrolysis of CO2-enriched mixtures by using fuel-electrode supported La0.6Sr0.4CoO3/YSZ/Ni-YSZ solid oxide cells is considered to satisfy such needs. The effect of internal and external steam supply on its electrochemical performance and gas productivity is elucidated. It is shown that the steam produced in-situ inside the fuel-electrode by a reverse water gas shift reaction may decrease significantly the electrochemical resistance of dry CO2-fed operations, attributed to self-sustaining positive thermo-electrochemical reaction loop. This mechanism is conspicuous at low current density, whereas it is no longer effective at high current density in which total reactant concentrations for electrolysis is critical. To overcome such limitations, a small amount of external steam supply to the CO2-enriched feed stream may be needed, but this lowers the CO2 conversion and CO/H2 selectivity. Based on these results, it is discussed that there can be minimum steam supply sufficient for guaranteeing both low electrochemical resistance and high gas productivity.

Degradation of different elastomeric polymers in simulated geothermal environments at 300°C

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

Sugama, Toshifumi; Pyatina, Tatiana; Redline, Erica Marie

This study evaluates the degradation of six different elastomeric polymers used for O-rings: EPDM, FEPM, type I- and II-FKM, FFKM, and FSR, in five different simulated geothermal environments at 300 °C: 1) non-aerated steam/cooling cycles, 2) aerated steam/cooling cycles, 3) water-based drilling fluid, 4) CO 2-rich geo-brine fluid, and, 5) heat–cool water quenching cycles. The factors assessed included the extent of oxidation, changes in thermal behavior, micro-defects, permeation of ionic species from the test environments into the O-rings, silicate-related scale-deposition, and changes in the O-rings' elastic modulus. The reliability of the O-rings to maintain their integrity depended on the elastomericmore » polymer composition and the exposure environment. FSR disintegrated while EPDM was oxidized only to some degree in all the environments, FKM withstood heat-water quenching but underwent chemical degradation, FEPM survived in all the environments with the exception of heat-water quenching where it underwent severe oxidation-induced degradation, and FFKM displayed outstanding compatibility with all the tested environments. This study discusses the degradation mechanisms of the polymers under the aforementioned conditions.« less

Degradation of different elastomeric polymers in simulated geothermal environments at 300°C

DOE PAGES

Sugama, Toshifumi; Pyatina, Tatiana; Redline, Erica Marie; ...

2015-07-17

This study evaluates the degradation of six different elastomeric polymers used for O-rings: EPDM, FEPM, type I- and II-FKM, FFKM, and FSR, in five different simulated geothermal environments at 300 °C: 1) non-aerated steam/cooling cycles, 2) aerated steam/cooling cycles, 3) water-based drilling fluid, 4) CO 2-rich geo-brine fluid, and, 5) heat–cool water quenching cycles. The factors assessed included the extent of oxidation, changes in thermal behavior, micro-defects, permeation of ionic species from the test environments into the O-rings, silicate-related scale-deposition, and changes in the O-rings' elastic modulus. The reliability of the O-rings to maintain their integrity depended on the elastomericmore » polymer composition and the exposure environment. FSR disintegrated while EPDM was oxidized only to some degree in all the environments, FKM withstood heat-water quenching but underwent chemical degradation, FEPM survived in all the environments with the exception of heat-water quenching where it underwent severe oxidation-induced degradation, and FFKM displayed outstanding compatibility with all the tested environments. This study discusses the degradation mechanisms of the polymers under the aforementioned conditions.« less

Credit BG. View looking northeast down from the tower onto ...

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

Credit BG. View looking northeast down from the tower onto the two horizontal test stations at Test Stand "D." Station Dy is at the far left (Dy vacuum cell out of view), with in-line exhaust gas cooling sections and steam-driven "air ejector" (or evacuator) discharging engine exhausts to the east. The Dd cell is visible at the lower left, and the Dd exhaust train has the same functions as at Dy. The spherical tank is an electrically heated "accumulator" which supplies steam to the ejectors at Dv, Dd, and Dy stations. Other large piping delivered cooling water to the horizontal train cooling sections. The horizontal duct at the "Y" branch in the Dd train connects the Dd ejector to the Dv and Cv vacuum duct system (a blank can be bolted into this duct to isolate the Dd system). The shed roof for the Dpond test station appears at bottom center of this image. The open steel frame to the lower left of the image supports a hoist and crane for installing or removing test engines from the Dd test cell - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Use of mock-up training to reduce personnel exposure at the North Anna Unit 1 Steam Generator Replacement Project

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

Henry, H.G.; Reilly, B.P.

1995-03-01

The North Anna Power Station is located on the southern shore of Lake Anna in Louisa County, approximately forty miles northwest of Richmond, Virginia. The two 910 Mw nuclear units located on this site are owned by Virginia Electric and Power Company (Virginia Power) and Old Dominion Electric Cooperative and operated by Virginia Power. Fuel was loaded into Unit 1 in December 1977, and it began commercial operation in June 1978. Fuel was loaded into Unit 2 in April 1980 and began commercial operation in December 1980. Each nuclear unit includes a three-coolant-loop pressurized light water reactor nuclear steam supplymore » system that was furnished by Westinghouse Electric Corporation. Included within each system were three Westinghouse Model 51 steam generators with alloy 600, mill-annealed tubing material. Over the years of operation of Unit 1, various corrosion-related phenomena had occurred that affected the steam generators tubing and degraded their ability to fulfill their heat transfer function. Advanced inspection and repair techniques helped extend the useful life of the steam generators, but projections based on the results of the inspections indicated that the existing steam generators tubing and degraded their ability to fullfill their heat transfer function. Advanced inspection and repair techniques helped extend the useful life of the steam generators, but projections based on the results of the inspections indicated that the existing steam generators would not last their design life and must be repaired. To this end Virginia Power determined that a steam generator replacement (SGR) program was necessary to remove the old steam generator tube bundles and lower shell sections, including the channel heads (collectively called the lower assemblies), and replace them with new lower assemblies incorporating design features that will prevent the degradation problems that the old steam generators had experienced.« less

Update on Production Chemistry of the Roosevelt Hot Springs Reservoir

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

Simmons, Stuart; Kirby, Stefan; Allis, Rick

Analyses of production fluids from the Roosevelt Hot Springs reservoir were acquired from well sampling campaigns in 2015 and 2016. The resulting data have been recalculated to reservoir conditions by correcting for effects of steam loss, and the values are compared to legacy data from earlier reports to quantify changes with time in response to fluid production. The reservoir composition is similar to that at the start of reservoir exploitation, having near neutral pH, total dissolved solids of 7000-10,000 mg/kg, and ionic ratios of Cl/HCO3 ~50-100, Cl/SO4 ~50-100, and Na/K ~4-5. Cation, gas and silica geothermometers indicate a range ofmore » equilibration temperatures between 240 and 300 °C, but quartz-silica values are most closely consistent with measured reservoir temperatures and well enthalpies. The largest change in fluid composition is observed in well 54-3. The fluid has evolved from being fed by a single phase liquid to a twophase mixture of steam and liquid due to pressure draw down. The fluid also shows a 25% increase in reservoir chloride and a ~20° C decrement of cooling related to mixing with injected brine. The other production wells also show increase in chloride and decrease in temperature, but these changes diminish in magnitude with distance from injection well 14-2. Stable isotope compositions indicate that the reservoir water is largely meteoric in origin, having been modified by hydrothermal waterrock interaction. The water has also become progressively enriched in isotopic values in response to steam loss and mixing of injectate. N2-Ar-He and helium isotope ratios indicate a deep magmatic source region that probably supplies the heat for the hydrothermal system, consistent with recent Quaternary volcanism in the Mineral Mountains.« less

Closed-loop thrust and pressure profile throttling of a nitrous oxide/hydroxyl-terminated polybutadiene hybrid rocket motor

NASA Astrophysics Data System (ADS)

Peterson, Zachary W.

Hybrid motors that employ non-toxic, non-explosive components with a liquid oxidizer and a solid hydrocarbon fuel grain have inherently safe operating characteristics. The inherent safety of hybrid rocket motors offers the potential to greatly reduce overall operating costs. Another key advantage of hybrid rocket motors is the potential for in-flight shutdown, restart, and throttle by controlling the pressure drop between the oxidizer tank and the injector. This research designed, developed, and ground tested a closed-loop throttle controller for a hybrid rocket motor using nitrous oxide and hydroxyl-terminated polybutadiene as propellants. The research simultaneously developed closed-loop throttle algorithms and lab scale motor hardware to evaluate the fidelity of the throttle simulations and algorithms. Initial open-loop motor tests were performed to better classify system parameters and to validate motor performance values. Deep-throttle open-loop tests evaluated limits of stable thrust that can be achieved on the test hardware. Open-loop tests demonstrated the ability to throttle the motor to less than 10% of maximum thrust with little reduction in effective specific impulse and acoustical stability. Following the open-loop development, closed-loop, hardware-in-the-loop tests were performed. The closed-loop controller successfully tracked prescribed step and ramp command profiles with a high degree of fidelity. Steady-state accuracy was greatly improved over uncontrolled thrust.

Integrated Vehicle Thermal Management - Combining Fluid Loops in Electric Drive Vehicles (Presentation)

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

Rugh, J. P.

2013-07-01

Plug-in hybrid electric vehicles and electric vehicles have increased vehicle thermal management complexity, using separate coolant loop for advanced power electronics and electric motors. Additional thermal components result in higher costs. Multiple cooling loops lead to reduced range due to increased weight. Energy is required to meet thermal requirements. This presentation for the 2013 Annual Merit Review discusses integrated vehicle thermal management by combining fluid loops in electric drive vehicles.

Exploratory study of several advanced nuclear-MHD power plant systems.

NASA Technical Reports Server (NTRS)

Williams, J. R.; Clement, J. D.; Rosa, R. J.; Yang, Y. Y.

1973-01-01

In order for efficient multimegawatt closed cycle nuclear-MHD systems to become practical, long-life gas cooled reactors with exit temperatures of about 2500 K or higher must be developed. Four types of nuclear reactors which have the potential of achieving this goal are the NERVA-type solid core reactor, the colloid core (rotating fluidized bed) reactor, the 'light bulb' gas core reactor, and the 'coaxial flow' gas core reactor. Research programs aimed at developing these reactors have progressed rapidly in recent years so that prototype power reactors could be operating by 1980. Three types of power plant systems which use these reactors have been analyzed to determine the operating characteristics, critical parameters and performance of these power plants. Overall thermal efficiencies as high as 80% are projected, using an MHD turbine-compressor cycle with steam bottoming, and slightly lower efficiencies are projected for an MHD motor-compressor cycle.

Diffuse CO2 degassing at Vesuvio, Italy

NASA Astrophysics Data System (ADS)

Frondini, Francesco; Chiodini, Giovanni; Caliro, Stefano; Cardellini, Carlo; Granieri, Domenico; Ventura, Guido

2004-10-01

At Vesuvio, a significant fraction of the rising hydrothermal-volcanic fluids is subjected to a condensation and separation process producing a CO2-rich gas phase, mainly expulsed through soil diffuse degassing from well defined areas called diffuse degassing structures (DDS), and a liquid phase that flows towards the outer part of the volcanic cone. A large amount of thermal energy is associated with the steam condensation process and subsequent cooling of the liquid phase. The total amount of volcanic-hydrothermal CO2 discharged through diffuse degassing has been computed through a sequential Gaussian simulation (sGs) approach based on several hundred accumulation chamber measurements and, at the time of the survey, amounted to 151 t d-1. The steam associated with the CO2 output, computed assuming that the original H2O/CO2 ratio of hydrothermal fluids is preserved in fumarolic effluents, is 553 t d-1, and the energy produced by the steam condensation and cooling of the liquid phase is 1.47×1012 J d-1 (17 MW). The location of the CO2 and temperature anomalies show that most of the gas is discharged from the inner part of the crater and suggests that crater morphology and local stratigraphy exert strong control on CO2 degassing and subsurface steam condensation. The amounts of gas and energy released by Vesuvio are comparable to those released by other volcanic degassing areas of the world and their estimates, through periodic surveys of soil CO2 flux, can constitute a useful tool to monitor volcanic activity.

INTESTINAL OBSTRUCTION

PubMed Central

Whipple, G. H.; Stone, H. B.; Bernheim, B. M.

1913-01-01

Closed duodenal loops may be made in dogs by ligatures placed just below the pancreatic duct and just beyond the duodenojejunal junction, together with a posterior gastro-enterostomy. These closed duodenal loop dogs die with symptoms like those of patients suffering from volvulus or high intestinal obstruction. This duodenal loop may simulate closely a volvulus in which there has been no vascular disturbance. Dogs with closed duodenal loops which have been washed out carefully survive a little longer on the average than animals with unwashed loops. The duration of life in the first instance is one to three days, with an average of about forty-eight hours. The dogs usually lose considerable fluid by vomiting and diarrhea. A weak pulse, low blood pressure and temperature are usually conspicuous in the last stages. Autopsy shows more or less splanchnic congestion which may be most marked in the mucosa of the upper small intestine. The peritoneum is usually clear and the closed loop may be distended with thin fluid, or collapsed, and contain only a small amount of pasty brown material. The mucosa of the loop may show ulceration and even perforation, but in the majority of cases it is intact and exhibits only a moderate congestion. Simple intestinal obstruction added to a closed duodenal loop does not modify the result in any manner, but it may hasten the fatal outcome. The liver plays no essential role as a protective agent against this poison, for a dog with an Eck fistula may live three days with a closed loop. A normal dog reacts to intraportal injection and to intravenous injection of the toxic substance in an identical manner. Drainage of this loop under certain conditions may not interfere with the general health over a period of weeks or months. Excision of the part of the duodenum included in this loop causes no disturbance. The material from the closed duodenal loops contains no bile, pancreatic juice, gastric juice, or split products from the food. It can be formed in no other way than by the activity of the intestinal mucosa and the growth of the intestinal bacteria. This material after dilution, autolysis, sterilization, and filtration produces a characteristic effect when introduced intravenously. When in toxic doses it causes a profound drop in blood pressure, general collapse, drop in temperature, salivation, vomiting, and profuse diarrhea, which is often blood-stained. Splanchnic congestion is the conspicuous feature at autopsy and shows especially in the villi of the duodenal and jejunal mucosæ. Adrenalin, during this period of low blood pressure and splanchnic congestion, will cause the usual reaction when given intravenously, but applied locally or given intravenously it causes no bleaching of the engorged intestinal mucosa. Secretin is not found in the duodenal loop fluid, and the loop material does not influence the pancreatic secretion. Intraportal injection of the toxic material gives a reaction similar to intravenous injection. Intraperitoneal and subcutaneous injections produce a relatively slow reaction which closely resembles the picture seen in the closed duodenal loop dog. In both cases there is a relatively slow absorption, but the splanchnic congestion and other findings, though less intense, are present in both groups. There seems, therefore, to be no escape from the conclusion that a poisonous substance is formed in this closed duodenal loop which is absorbed from it and causes intoxication and death. Injection of this toxic substance into a normal dog gives intoxication and a reaction more intense but similar to that developing in a closed-loop dog. PMID:19867644

2. Credit BG. Looking west at east facade of Steam ...

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

2. Credit BG. Looking west at east facade of Steam Generator Plant, Building 4280/E-81; steam generators have been removed as part of dismantling program for Test Stand 'D.' Metal cylindrical objects to left of door were roof vents. The steam-driven ejector system for Dv Cell is clearly visible on the east side of Test Stand 'D' tower. The X-stage ejector is vertically installed at the bottom left of the tower, Y-stage is horizontally positioned close to the tower top, and the Z- and Z-1 stages are attached to the top of the interstage condenser. Light-colored piping is thermally insulated steam line. - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Steam Generator Plant, Edwards Air Force Base, Boron, Kern County, CA

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.

Stochastic cooling of bunched beams from fluctuation and kinetic theory

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

Chattopadhyay, S.

1982-09-01

A theoretical formalism for stochastic phase-space cooling of bunched beams in storage rings is developed on the dual basis of classical fluctuation theory and kinetic theory of many-body systems in phase-space. The physics is that of a collection of three-dimensional oscillators coupled via retarded nonconservative interactions determined by an electronic feedback loop. At the heart of the formulation is the existence of several disparate time-scales characterizing the cooling process. Both theoretical approaches describe the cooling process in the form of a Fokker-Planck transport equation in phase-space valid up to second order in the strength and first order in the auto-correlationmore » of the cooling signal. With neglect of the collective correlations induced by the feedback loop, identical expressions are obtained in both cases for the coherent damping and Schottky noise diffusion coefficients. These are expressed in terms of Fourier coefficients in a harmonic decomposition in angle of the generalized nonconservative cooling force written in canonical action-angle variables of the particles in six-dimensional phase-space. Comparison of analytic results to a numerical simulation study with 90 pseudo-particles in a model cooling system is presented.« less

78 FR 58535 - Hydropower Regulatory Efficiency Act of 2013; Supplemental Notice of Workshop

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-24

... license for hydropower development at non-powered dams and closed-loop pumped storage projects in... for licensing hydropower development at non-powered dams and closed-loop pumped storage projects... closed- loop pumped storage) affect the steps included in a two-year process? 3.9 Should there be a...

The Effects of Closed-Loop Medical Devices on the Autonomy and Accountability of Persons and Systems.

PubMed

Kellmeyer, Philipp; Cochrane, Thomas; Müller, Oliver; Mitchell, Christine; Ball, Tonio; Fins, Joseph J; Biller-Andorno, Nikola

2016-10-01

Closed-loop medical devices such as brain-computer interfaces are an emerging and rapidly advancing neurotechnology. The target patients for brain-computer interfaces (BCIs) are often severely paralyzed, and thus particularly vulnerable in terms of personal autonomy, decisionmaking capacity, and agency. Here we analyze the effects of closed-loop medical devices on the autonomy and accountability of both persons (as patients or research participants) and neurotechnological closed-loop medical systems. We show that although BCIs can strengthen patient autonomy by preserving or restoring communicative abilities and/or motor control, closed-loop devices may also create challenges for moral and legal accountability. We advocate the development of a comprehensive ethical and legal framework to address the challenges of emerging closed-loop neurotechnologies like BCIs and stress the centrality of informed consent and refusal as a means to foster accountability. We propose the creation of an international neuroethics task force with members from medical neuroscience, neuroengineering, computer science, medical law, and medical ethics, as well as representatives of patient advocacy groups and the public.

75 FR 16576 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-01

..., open-loop biomass, geothermal energy, solar energy, small irrigation power, municipal solid waste... electricity produced from closed-loop biomass, open-loop biomass, geothermal energy, solar energy, small... electricity produced from the qualified energy resources of wind, closed-loop biomass, geothermal energy, and...

77 FR 21835 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

..., open-loop biomass, geothermal energy, solar energy, small irrigation power, municipal solid waste... electricity produced from closed-loop biomass, open-loop biomass, geothermal energy, solar energy, small... electricity produced from the qualified energy resources of wind, closed-loop biomass, geothermal energy, and...

76 FR 21947 - Credit for Renewable Electricity Production, Refined Coal Production, and Indian Coal Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-19

..., open-loop biomass, geothermal energy, solar energy, small irrigation power, municipal solid waste... electricity produced from closed-loop biomass, open-loop biomass, geothermal energy, solar energy, small... electricity produced from the qualified energy resources of wind, closed-loop biomass, geothermal energy, and...

Fiber Fabry-Perot Force Sensor with Small Volume and High Performance for Assessing Fretting Damage of Steam Generator Tubes

PubMed Central

Huang, Peijian; Wang, Ning; Li, Junying; Zhu, Yong; Zhang, Jie

2017-01-01

Measuring the radial collision force between the steam generator tube (SGT) and the tube support plate (TSP) is essential to assess the fretting damage of the SGT. In order to measure the radial collision force, a novel miniaturized force sensor based on fiber Fabry-Perot (F-P) was designed, and the principle and characteristics of the sensor were analyzed in detail. Then, the F-P force sensor was successfully fabricated and calibrated, and the overall dimensions of the encapsulated fiber F-P sensor were 17 mm × 5 mm × 3 mm (L × W × H). The sensor works well in humid, high pressure (10 MPa), high temperature (350 °C), and vibration (40 kHz) environments. Finally, the F-P force sensors were installed in a 1:1 steam generator test loop, and the radial collision force signals between the SGT and the TSP were obtained. The experiments indicated that the F-P sensor with small volume and high performance could help in assessing the fretting damage of the steam generator tubes. PMID:29236087

Loop-bed combustion apparatus

DOEpatents

Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.

1984-01-01

The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

Preliminary demonstration of a robust controller design method

NASA Technical Reports Server (NTRS)

Anderson, L. R.

1980-01-01

Alternative computational procedures for obtaining a feedback control law which yields a control signal based on measurable quantitites are evaluated. The three methods evaluated are: (1) the standard linear quadratic regulator design model; (2) minimization of the norm of the feedback matrix, k via nonlinear programming subject to the constraint that the closed loop eigenvalues be in a specified domain in the complex plane; and (3) maximize the angles between the closed loop eigenvectors in combination with minimizing the norm of K also via the constrained nonlinear programming. The third or robust design method was chosen to yield a closed loop system whose eigenvalues are insensitive to small changes in the A and B matrices. The relationship between orthogonality of closed loop eigenvectors and the sensitivity of closed loop eigenvalues is described. Computer programs are described.

Automated hybrid closed-loop control with a proportional-integral-derivative based system in adolescents and adults with type 1 diabetes: individualizing settings for optimal performance.

PubMed

Ly, Trang T; Weinzimer, Stuart A; Maahs, David M; Sherr, Jennifer L; Roy, Anirban; Grosman, Benyamin; Cantwell, Martin; Kurtz, Natalie; Carria, Lori; Messer, Laurel; von Eyben, Rie; Buckingham, Bruce A

2017-08-01

Automated insulin delivery systems, utilizing a control algorithm to dose insulin based upon subcutaneous continuous glucose sensor values and insulin pump therapy, will soon be available for commercial use. The objective of this study was to determine the preliminary safety and efficacy of initialization parameters with the Medtronic hybrid closed-loop controller by comparing percentage of time in range, 70-180 mg/dL (3.9-10 mmol/L), mean glucose values, as well as percentage of time above and below target range between sensor-augmented pump therapy and hybrid closed-loop, in adults and adolescents with type 1 diabetes. We studied an initial cohort of 9 adults followed by a second cohort of 15 adolescents, using the Medtronic hybrid closed-loop system with the proportional-integral-derivative with insulin feed-back (PID-IFB) algorithm. Hybrid closed-loop was tested in supervised hotel-based studies over 4-5 days. The overall mean percentage of time in range (70-180 mg/dL, 3.9-10 mmol/L) during hybrid closed-loop was 71.8% in the adult cohort and 69.8% in the adolescent cohort. The overall percentage of time spent under 70 mg/dL (3.9 mmol/L) was 2.0% in the adult cohort and 2.5% in the adolescent cohort. Mean glucose values were 152 mg/dL (8.4 mmol/L) in the adult cohort and 153 mg/dL (8.5 mmol/L) in the adolescent cohort. Closed-loop control using the Medtronic hybrid closed-loop system enables adaptive, real-time basal rate modulation. Initializing hybrid closed-loop in clinical practice will involve individualizing initiation parameters to optimize overall glucose control. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Direct-contact closed-loop heat exchanger

DOEpatents

Berry, Gregory F.; Minkov, Vladimir; Petrick, Michael

1984-01-01

A high temperature heat exchanger with a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.

40 CFR 455.21 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... stream and product washes, equipment and floor washes, water used as solvent for raw materials, water used as reaction medium, spent acids, spent bases, contact cooling water, water of reaction, air pollution control blowdown, steam jet blowdown, vacuum pump water, pump seal water, safety equipment...

78 FR 8195 - Biweekly Notice

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-05

... of the bases for the contention and a concise statement of the alleged facts or expert opinion which..., ``Allowable Value for Primary Containment and Drywell Isolation Instrumentation,'' Function 3.c, ``Reactor Core Isolation Cooling (RCIC) Steam Supply Line Pressure--Low.'' This TS allowable value will be...

Closed-Loop Control of Complex Networks: A Trade-Off between Time and Energy

NASA Astrophysics Data System (ADS)

Sun, Yong-Zheng; Leng, Si-Yang; Lai, Ying-Cheng; Grebogi, Celso; Lin, Wei

2017-11-01

Controlling complex nonlinear networks is largely an unsolved problem at the present. Existing works focus either on open-loop control strategies and their energy consumptions or on closed-loop control schemes with an infinite-time duration. We articulate a finite-time, closed-loop controller with an eye toward the physical and mathematical underpinnings of the trade-off between the control time and energy as well as their dependence on the network parameters and structure. The closed-loop controller is tested on a large number of real systems including stem cell differentiation, food webs, random ecosystems, and spiking neuronal networks. Our results represent a step forward in developing a rigorous and general framework to control nonlinear dynamical networks with a complex topology.

DC servomechanism parameter identification: a Closed Loop Input Error approach.

PubMed

Garrido, Ruben; Miranda, Roger

2012-01-01

This paper presents a Closed Loop Input Error (CLIE) approach for on-line parametric estimation of a continuous-time model of a DC servomechanism functioning in closed loop. A standard Proportional Derivative (PD) position controller stabilizes the loop without requiring knowledge on the servomechanism parameters. The analysis of the identification algorithm takes into account the control law employed for closing the loop. The model contains four parameters that depend on the servo inertia, viscous, and Coulomb friction as well as on a constant disturbance. Lyapunov stability theory permits assessing boundedness of the signals associated to the identification algorithm. Experiments on a laboratory prototype allows evaluating the performance of the approach. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Analysis of boron dilution in a four-loop PWR

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

Sun, J.G.; Sha, W.T.

1995-12-31

Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plantmore » is at hot standby and the reactor coolant system has been heated up to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated.« less

Steam trap monitor

DOEpatents

Ryan, Michael J.

1988-01-01

A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (the combination of a hot finger and thermocouple well) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellows in providing an indication of total energy (steam+condensate) of the system. Processing means coupled to and responsive to outputs from the thermocouple well hot and cold fingers subtracts the condensate energy as measured by the hot finger and thermocouple well from the total energy as measured by the cold finger to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning.

Fabrication and assembly of a superconducting undulator for the advanced photon source

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

Hasse, Quentin; Fuerst, J. D.; Ivanyushenkov, Y.

2014-01-29

A prototype superconducting undulator magnet (SCU0) has been built at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) and has successfully completed both cryogenic performance and magnetic measurement test programs. The SCU0 closed loop, zero-boil-off cryogenic system incorporates high temperature superconducting (HTS) current leads, cryocoolers, a LHe reservoir supplying dual magnetic cores, and an integrated cooled beam chamber. This system presented numerous challenges in the design, fabrication, and assembly of the device. Aspects of this R and D relating to both the cryogenic and overall assembly of the device are presented here. The SCU0 magnet has been installedmore » in the APS storage ring.« less

Multi-Purpose Thermal Hydraulic Loop: Advanced Reactor Technology Integral System Test (ARTIST) Facility for Support of Advanced Reactor Technologies

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

James E. O'Brien; Piyush Sabharwall; SuJong Yoon

2001-11-01

Effective and robust high temperature heat transfer systems are fundamental to the successful deployment of advanced reactors for both power generation and non-electric applications. Plant designs often include an intermediate heat transfer loop (IHTL) with heat exchangers at either end to deliver thermal energy to the application while providing isolation of the primary reactor system. In order to address technical feasibility concerns and challenges a new high-temperature multi-fluid, multi-loop test facility “Advanced Reactor Technology Integral System Test facility” (ARTIST) is under development at the Idaho National Laboratory. The facility will include three flow loops: high-temperature helium, molten salt, and steam/water.more » Details of some of the design aspects and challenges of this facility, which is currently in the conceptual design phase, are discussed« less

Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

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

Thangirala, Mani

The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynesmore » 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which demonstrated the importance of proper heat treat cycles for Homogenization, and Solutionizing parameters selection and implementation. 3) Step blocks casting of Nimonic 263: Carried out casting solidification simulation analysis, NDT inspection methods evaluation, detailed test matrix for Chemical, Tensile, LCF, stress rupture, CVN impact, hardness and J1C Fracture toughness section sensitivity data and were reported. 4) Centrifugal Casting of Haynes 282, weighing 1400 lbs. with hybrid mold (half Graphite and half Chromite sand) mold assembly was cast using compressor casing production tooling. This test provided Mold cooling rates influence on centrifugally cast microstructure and mechanical properties. Graphite mold section out performs sand mold across all temperatures for 0.2% YS; %Elongation, %RA, UTS at 1400°F. Both Stress-LMP and conditional Fracture toughness plots data were in the scatter band of the wrought alloy. 5) Fundamental Studies on Cooling rates and SDAS test program. Evaluated the influence of 6 mold materials Silica, Chromite, Alumina, Silica with Indirect Chills, Zircon and Graphite on casting solidification cooling rates. Actual Casting cooling rates through Liquidus to Solidus phase transition were measured with 3 different locations based thermocouples placed in each mold. Compared with solidification simulation cooling rates and measurement of SDAS, microstructure features were reported. The test results provided engineered casting potential methods, applicable for heavy section Haynes 282 castings for optimal properties, with foundry process methods and tools. 6) Large casting of Haynes 282 Drawings and Engineering FEM models and supplemental requirements with applicable specifications were provided to suppliers for the steam turbine proto type feature valve casing casting. Molding, melting and casting pouring completed per approved Manufacturing Process Plan during 2014 Q4. The partial valve casing was successfully cast after casting methods were validated with solidification simulation analysis and the casting met NDT inspection and acceptance criteria. Heat treated and sectioned to extract trepan samples at different locations comparing with cast on coupons test data. Material properties requisite for design, such as tensile, creep/rupture, LCF, Fracture Toughness, Charpy V-notch chemical analysis testing were carried out. The test results will be presented in the final report. The typical Haynes 282 large size Steam Turbine production casting from Order to Delivery foundry schedule with the activity break up is shown in Figures 107 and 108. • From Purchase Order placement to Casting pouring ~ 26 weeks. 1. Sales and commercial review 3 2. Engineering Drawings/models review 4 3. Pattern and core box manufacturing 6 4. Casting process engineering review 4 5. FEM and solidification simulation analysis 4 6. Gating & Feeder Attachments, Ceramic tiling 2 7. Molding and coremaking production scheduling 6 8. Melting planning and schedule 3 9. Pouring, cooling and shake out 2 • From Pouring to casting Delivery ~ 29 weeks 10. Shot blast and riser cutting, gates removal 3 11. Homogenizing , solutionizing HT furnace prep 4 12. Grinding, Fettling 2 13. Aging HT Cycle, cooling 2 14. VT and LPT NDT inspections 2 15. Radiographic inspection 4 16. Mechanical testing, Chemical analysis test certs 4 17. Casting weld repair upgrades and Aging PWHT 4 18. NDT after weld repairs and casting upgrades 3 19. Casting Final Inspection and test certifications 3 20. Package and delivery 2 Hence the Total Lead time from P.O to Casting delivery is approximately 55 weeks. The Task 4.2 and Task 4.3 activities and reporting completed.« less

Unresolved fine-scale structure in solar coronal loop-tops

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

Scullion, E.; Van der Voort, L. Rouppe; Wedemeyer, S.

2014-12-10

New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal loop substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric Hα 656.28 nm spectral line core and wings can, under certainmore » circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal loops, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in Hα) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal loop-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from loop-top to footpoint. We discover that coronal loop fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal loop cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal loops, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal loops.« less

Gas-cooled reactor programs. High-temperature gas-cooled reactor technology development program. Annual progress report, December 31, 1983

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

Kasten, P.R.; Rittenhouse, P.L.; Bartine, D.E.

1984-06-01

ORNL continues to make significant contributions to the national program. In the HTR fuels area, we are providing detailed statistical information on the fission product retention performance of irradiated fuel. Our studies are also providing basic data on the mechanical, physical, and chemical behavior of HTR materials, including metals, ceramics, graphite, and concrete. The ORNL has an important role in the development of improved HTR graphites and in the specification of criteria that need to be met by commercial products. We are also developing improved reactor physics design methods. Our work in component development and testing centers in the Componentmore » Flow Test Loop (CFTL), which is being used to evaluate the performance of the HTR core support structure. Other work includes experimental evaluation of the shielding effectiveness of the lower portions of an HTR core. This evaluation is being performed at the ORNL Tower Shielding Facility. Researchers at ORNL are developing welding techniques for attaching steam generator tubing to the tubesheets and are testing ceramic pads on which the core posts rest. They are also performing extensive testing of aggregate materials obtained from potential HTR site areas for possible use in prestressed concrete reactor vessels. During the past year we continued to serve as a peer reviewer of small modular reactor designs being developed by GA and GE with balance-of-plant layouts being developed by Bechtel Group, Inc. We have also evaluated the national need for developing HTRs with emphasis on the longer term applications of the HTRs to fossil conversion processes.« less

Cooling tower plume - model and experiment

NASA Astrophysics Data System (ADS)

Cizek, Jan; Gemperle, Jiri; Strob, Miroslav; Nozicka, Jiri

The paper discusses the description of the simple model of the, so-called, steam plume, which in many cases forms during the operation of the evaporative cooling systems of the power plants, or large technological units. The model is based on semi-empirical equations that describe the behaviour of a mixture of two gases in case of the free jet stream. In the conclusion of the paper, a simple experiment is presented through which the results of the designed model shall be validated in the subsequent period.

Pre-test analysis of protected loss of primary pump transients in CIRCE-HERO facility

NASA Astrophysics Data System (ADS)

Narcisi, V.; Giannetti, F.; Del Nevo, A.; Tarantino, M.; Caruso, G.

2017-11-01

In the frame of LEADER project (Lead-cooled European Advanced Demonstration Reactor), a new configuration of the steam generator for ALFRED (Advanced Lead Fast Reactor European Demonstrator) was proposed. The new concept is a super-heated steam generator, double wall bayonet tube type with leakage monitoring [1]. In order to support the new steam generator concept, in the framework of Horizon 2020 SESAME project (thermal hydraulics Simulations and Experiments for the Safety Assessment of MEtal cooled reactors), the ENEA CIRCE pool facility will be refurbished to host the HERO (Heavy liquid mEtal pRessurized water cOoled tubes) test section to investigate a bundle of seven full scale bayonet tubes in ALFRED-like thermal hydraulics conditions. The aim of this work is to verify thermo-fluid dynamic performance of HERO during the transition from nominal to natural circulation condition. The simulations have been performed with RELAP5-3D© by using the validated geometrical model of the previous CIRCE-ICE test section [2], in which the preceding heat exchanger has been replaced by the new bayonet bundle model. Several calculations have been carried out to identify thermal hydraulics performance in different steady state conditions. The previous calculations represent the starting points of transient tests aimed at investigating the operation in natural circulation. The transient tests consist of the protected loss of primary pump, obtained by reducing feed-water mass flow to simulate the activation of DHR (Decay Heat Removal) system, and of the loss of DHR function in hot conditions, where feed-water mass flow rate is absent. According to simulations, in nominal conditions, HERO bayonet bundle offers excellent thermal hydraulic behavior and, moreover, it allows the operation in natural circulation.

Closing the Feedback Loop Is Not Enough: The Assessment Spiral

ERIC Educational Resources Information Center

Wehlburg, Catherine M.

2007-01-01

For quite some time, the call to close the feedback loop has been heard throughout higher education. Faculty and administrators have paid attention, and now they can more easily than ever point to the fact that at their institution, the feedback loop is almost always closed. As reviewers from accreditation teams visit campuses, they often hear…

78 FR 62322 - Hydropower Regulatory Efficiency Act of 2013; Notice of Rescheduled Two-Year Licensing Process...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-16

... at non-powered dams and closed-loop pumped storage projects in compliance with section 6 of the... process for licensing hydropower development at non-powered dams and closed-loop pumped storage projects...-powered dam versus closed- loop pumped storage) affect the steps included in a two-year process? 3.9...

Fluidized bed heat exchanger with water cooled air distributor and dust hopper

DOEpatents

Jukkola, Walfred W.; Leon, Albert M.; Van Dyk, Jr., Garritt C.; McCoy, Daniel E.; Fisher, Barry L.; Saiers, Timothy L.; Karstetter, Marlin E.

1981-11-24

A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat.

PubMed

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-04-21

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat

PubMed Central

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-01-01

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892

Performance constraints and compensation for teleoperation with delay

NASA Technical Reports Server (NTRS)

Mclaughlin, J. S.; Staunton, B. D.

1989-01-01

A classical control perspective is used to characterize performance constraints and evaluate compensation techniques for teleoperation with delay. Use of control concepts such as open and closed loop performance, stability, and bandwidth yield insight to the delay problem. Teleoperator performance constraints are viewed as an open loop time delay lag and as a delay-induced closed loop bandwidth constraint. These constraints are illustrated with a simple analytical tracking example which is corroborated by a real time, 'man-in-the-loop' tracking experiment. The experiment also provides insight to those controller characteristics which are unique to a human operator. Predictive displays and feedforward commands are shown to provide open loop compensation for delay lag. Low pass filtering of telemetry or feedback signals is interpreted as closed loop compensation used to maintain a sufficiently low bandwidth for stability. A new closed loop compensation approach is proposed that uses a reactive (or force feedback) hand controller to restrict system bandwidth by impeding operator inputs.

Evaluation of distributed gas cooling of pressurized PAFC for utility power generation

NASA Technical Reports Server (NTRS)

Farooque, M.; Hooper, M.; Maru, H.

1981-01-01

A proof-of-concept test for a gas-cooled pressurized phosphoric acid fuel cell is described. After initial feasibility studies in short stacks, two 10 kW stacks are tested. Progress includes: (1) completion of design of the test stations with a recirculating gas cooling loop; (2) atmospheric testing of the baseline stack.

Overnight closed-loop insulin delivery with model predictive control: assessment of hypoglycemia and hyperglycemia risk using simulation studies.

PubMed

Wilinska, Malgorzata E; Budiman, Erwin S; Taub, Marc B; Elleri, Daniela; Allen, Janet M; Acerini, Carlo L; Dunger, David B; Hovorka, Roman

2009-09-01

Hypoglycemia and hyperglycemia during closed-loop insulin delivery based on subcutaneous (SC) glucose sensing may arise due to (1) overdosing and underdosing of insulin by control algorithm and (2) difference between plasma glucose (PG) and sensor glucose, which may be transient (kinetics origin and sensor artifacts) or persistent (calibration error [CE]). Using in silico testing, we assessed hypoglycemia and hyperglycemia incidence during over-night closed loop. Additionally, a comparison was made against incidence observed experimentally during open-loop single-night in-clinic studies in young people with type 1 diabetes mellitus (T1DM) treated by continuous SC insulin infusion. Simulation environment comprising 18 virtual subjects with T1DM was used to simulate overnight closed-loop study with a model predictive control (MPC) algorithm. A 15 h experiment started at 17:00 and ended at 08:00 the next day. Closed loop commenced at 21:00 and continued for 11 h. At 18:00, protocol included meal (50 g carbohydrates) accompanied by prandial insulin. The MPC algorithm advised on insulin infusion every 15 min. Sensor glucose was obtained by combining model-calculated noise-free interstitial glucose with experimentally derived transient and persistent sensor artifacts associated with FreeStyle Navigator (FSN). Transient artifacts were obtained from FSN sensor pairs worn by 58 subjects with T1DM over 194 nighttime periods. Persistent difference due to FSN CE was quantified from 585 FSN sensor insertions, yielding 1421 calibration sessions from 248 subjects with diabetes. Episodes of severe (PG < or = 36 mg/dl) and significant (PG < or = 45 mg/dl) hypoglycemia and significant hyperglycemia (PG > or = 300 mg/dl) were extracted from 18,000 simulated closed-loop nights. Severe hypoglycemia was not observed when FSN CE was less than 45%. Hypoglycemia and hyperglycemia incidence during open loop was assessed from 21 overnight studies in 17 young subjects with T1DM (8 males; 13.5 +/- 3.6 years of age; body mass index 21.0 +/- 4.0 kg/m2; duration diabetes 6.4 +/- 4.1 years; hemoglobin A1c 8.5% +/- 1.8%; mean +/- standard deviation) participating in the Artificial Pancreas Project at Cambridge. Severe and significant hypoglycemia during simulated closed loop occurred 0.75 and 17.11 times per 100 person years compared to 1739 and 3479 times per 100 person years during experimental open loop, respectively. Significant hyperglycemia during closed loop and open loop occurred 75 and 15,654 times per 100 person years, respectively. The incidence of severe and significant hypoglycemia reduced 2300- and 200-fold, respectively, during stimulated overnight closed loop with MPC compared to that observed during open-loop overnight clinical studies in young subjects with T1DM. Hyperglycemia was 200 times less likely. Overnight closed loop with the FSN and the MPC algorithm is expected to reduce substantially the risk of hypoglycemia and hyperglycemia. 2009 Diabetes Technology Society.

Legionnaires' Disease Bacteria in power plant cooling systems: downtime report. Final report

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

Tyndall, R.L.; Solomon, J.A.; Christensen, S.W.

1985-04-01

Legionnaires' Disease Bacteria (Legionella) are a normal part of the aquatic community that, when aerosolized, can be pathogenic to man. The downtime study was designed to determine the degree to which Legionella populations are aerosolized during cleaning and maintenance operations in a closed-cycle steam-electric power plant. Both high-volume and impinger air samples were collected prior to and during downtime operations. Emphasis was placed on sampling inside or adjacent to water boxes, condensers, and cooling towers. Control air samples were taken upwind from the plant site. Water and sludge samples were also collected at various locations. In the laboratory, the concentrationsmore » of Groups A, B, and C Legionella were determined using the direct fluorescent antibody method. All positive air samples, and other selected air samples, were injected into guinea pigs to detect infectious Legionella. Legionella could be detected in only 12 of the 126 air samples collected. These were predominantly Group A Legionella (L. pneumophila, serogroups 1 to 6). All 12 positive samples had been collected in the vicinity of water boxes, condensers, detention ponds, and cooling towers during downtime operations where aerosolization of Legionella populations would be expected. None of the air samples yielded infectious Legionella when injected into guinea pigs. Detection of Legionella in air samples taken during downtime was significantly more likely than detection during normal operating conditions (p <0.01). 13 refs., 4 figs., 10 tabs.« less

Fundamental Physics and Practical Applications of Electromagnetic Local Flow Control in High Speed Flows (Rutgers)

DTIC Science & Technology

2010-02-16

field. Techniques utilizing this design use an open- loop control and no flow monitoring sensors are required. Conversely, reactive (or closed - loop ...and closed (dashed line) configuration. 38 closed configuration described above, the ambiguity in the critical limits of the transition...flow; a new vortex is then shed from the cavity leading edge, closing the feedback loop .[31] Open cavities with an L/D approximately greater than

Direct-contact closed-loop heat exchanger

DOEpatents

Berry, G.F.; Minkov, V.; Petrick, M.

1981-11-02

A high temperature heat exchanger is disclosed which has a closed loop and a heat transfer liquid within the loop, the closed loop having a first horizontal channel with inlet and outlet means for providing direct contact of a first fluid at a first temperature with the heat transfer liquid, a second horizontal channel with inlet and outlet means for providing direct contact of a second fluid at a second temperature with the heat transfer liquid, and means for circulating the heat transfer liquid.

Intraoperative stroke volume optimization using stroke volume, arterial pressure, and heart rate: closed-loop (learning intravenous resuscitator) versus anesthesiologists.

PubMed

Rinehart, Joseph; Chung, Elena; Canales, Cecilia; Cannesson, Maxime

2012-10-01

The authors compared the performance of a group of anesthesia providers to closed-loop (Learning Intravenous Resuscitator [LIR]) management in a simulated hemorrhage scenario using cardiac output monitoring. A prospective cohort study. In silico simulation. University hospital anesthesiologists and the LIR closed-loop fluid administration system. Using a patient simulator, a 90-minute simulated hemorrhage protocol was run, which included a 1,200-mL blood loss over 30 minutes. Twenty practicing anesthesiology providers were asked to manage this scenario by providing fluids and vasopressor medication at their discretion. The simulation program was also run 20 times with the LIR closed-loop algorithm managing fluids and an additional 20 times with no intervention. Simulated patient weight, height, heart rate, mean arterial pressure, and cardiac output (CO) were similar at baseline. The mean stroke volume, the mean arterial pressure, CO, and the final CO were higher in the closed-loop group than in the practitioners group, and the coefficient of variance was lower. The closed-loop group received slightly more fluid (2.1 v 1.9 L, p < 0.05) than the anesthesiologist group. Despite the roughly similar volumes of fluid given, the closed-loop maintained more stable hemodynamics than the practitioners primarily because the fluid was given earlier in the protocol and CO optimized before the hemorrhage began, whereas practitioners tended to resuscitate well but only after significant hemodynamic change indicated the need. Overall, these data support the potential usefulness of this closed-loop algorithm in clinical settings in which dynamic predictors are not available or applicable. Published by Elsevier Inc.

Assessing performance of closed-loop insulin delivery systems by continuous glucose monitoring: drawbacks and way forward.

PubMed

Hovorka, Roman; Nodale, Marianna; Haidar, Ahmad; Wilinska, Malgorzata E

2013-01-01

We investigated whether continuous glucose monitoring (CGM) levels can accurately assess glycemic control while directing closed-loop insulin delivery. Data were analyzed retrospectively from 33 subjects with type 1 diabetes who underwent closed-loop and conventional pump therapy on two separate nights. Glycemic control was evaluated by reference plasma glucose and contrasted against three methods based on Navigator (Abbott Diabetes Care, Alameda, CA) CGM levels. Glucose mean and variability were estimated by unmodified CGM levels with acceptable clinical accuracy. Time when glucose was in target range was overestimated by CGM during closed-loop nights (CGM vs. plasma glucose median [interquartile range], 86% [65-97%] vs. 75% [59-91%]; P=0.04) but not during conventional pump therapy (57% [32-72%] vs. 51% [29-68%]; P=0.82) providing comparable treatment effect (mean [SD], 28% [29%] vs. 23% [21%]; P=0.11). Using the CGM measurement error of 15% derived from plasma glucose-CGM pairs (n=4,254), stochastic interpretation of CGM gave unbiased estimate of time in target during both closed-loop (79% [62-86%] vs. 75% [59-91%]; P=0.24) and conventional pump therapy (54% [33-66%] vs. 51% [29-68%]; P=0.44). Treatment effect (23% [24%] vs. 23% [21%]; P=0.96) and time below target were accurately estimated by stochastic CGM. Recalibrating CGM using reference plasma glucose values taken at the start and end of overnight closed-loop was not superior to stochastic CGM. CGM is acceptable to estimate glucose mean and variability, but without adjustment it may overestimate benefit of closed-loop. Stochastic CGM provided unbiased estimate of time when glucose is in target and below target and may be acceptable for assessment of closed-loop in the outpatient setting.

Comparison of cardiac output optimization with an automated closed-loop goal-directed fluid therapy versus non standardized manual fluid administration during elective abdominal surgery: first prospective randomized controlled trial.

PubMed

Lilot, Marc; Bellon, Amandine; Gueugnon, Marine; Laplace, Marie-Christine; Baffeleuf, Bruno; Hacquard, Pauline; Barthomeuf, Felicie; Parent, Camille; Tran, Thomas; Soubirou, Jean-Luc; Robinson, Philip; Bouvet, Lionel; Vassal, Olivia; Lehot, Jean-Jacques; Piriou, Vincent

2018-01-27

An intraoperative automated closed-loop system for goal-directed fluid therapy has been successfully tested in silico, in vivo and in a clinical case-control matching. This trial compared intraoperative cardiac output (CO) in patients managed with this closed-loop system versus usual practice in an academic medical center. The closed-loop system was connected to a CO monitoring system and delivered automated colloid fluid boluses. Moderate to high-risk abdominal surgical patients were randomized either to the closed-loop or the manual group. Intraoperative final CO was the primary endpoint. Secondary endpoints were intraoperative overall mean cardiac index (CI), increase from initial to final CI, intraoperative fluid volume and postoperative outcomes. From January 2014 to November 2015, 46 patients were randomized. There was a lower initial CI (2.06 vs. 2.51 l min -1 m -2 , p = 0.042) in the closed-loop compared to the control group. No difference in final CO and in overall mean intraoperative CI was observed between groups. A significant relative increase from initial to final CI values was observed in the closed-loop but not the control group (+ 28.6%, p = 0.006 vs. + 1.2%, p = 0.843). No difference was found for intraoperative fluid management and postoperative outcomes between groups. There was no significant impact on the primary study endpoint, but this was found in a context of unexpected lower initial CI in the closed-loop group.Trial registry number ID-RCB/EudraCT: 2013-A00770-45. ClinicalTrials.gov Identifier NCT01950845, date of registration: 17 September 2013.