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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen battery cells

An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, low earth-orbit (LEO) spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte, (2) use of a patented catalyzed wall wick, (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management, and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion. Six 125-Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they don't have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test. The cells have accumulated about 4700 LEO cycles (60 percent DOD 10 C). There have been no cell failures; the catalyzed wall wick cells, however, are performing better.

Smithrick, John J.↗
NASA NTRS1993

Validation test of 125 Ah advanced design IPV nickel-hydrogen flight cells

An update of validation test results confirming the advanced design nickel-hydrogen cell is presented. An advanced 125 Ah individual pressure vessel Ni-H cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term LEO spacecraft missions. The new features of this design are: (1) use of 26 percent rather than 31 percent KOH electrolyte; (2) use of a patented catalyzed wall wick; (3) use of serrated-edge separators to facilitate gaseous O and H flow within the cell, while maintaining physical contact with the wall wick for electrolyte management; and (4) use of a floating rather than a fixed stack to accommodate Ni electrode expansion due to charge/discharge cycling. The significant improvements resulting from these innovations are extended cycle life; enhanced thermal, electrolyte, and oxygen management; and accommodation of Ni electrode expansion. Six 125 Ah flight cells based on this design were fabricated; the catalyzed wall wick cells have been cycled for over 19,000 cycles with no cell failures in the continuing test. Two of the noncatalyzed wall wick cells failed (cycles 9588 and 13,900).

Smithrick, John J.↗
NASA NTRS1999

A Novel Silicon Micromachined Integrated MCM Thermal Management System

This research concerned the development of a novel porous wick, fabricated totally out of silicon, using state-of-the-art MEMS technology. A comprehensive summary of results, as well as additional fabrication details, can be found in the following three documents located in the attached Appendices: A) Selected pages and excerpts from Year 2 progress report of the principal NASA Grant awarded from NASA Lewis Research Center, Grant Number NAG3-1706 entitled "A Novel Silicon Nficromachined Integrated MCM Thermal Management System" submitted to NASA LRC on 4/4/98. B) Selected viewgraphs from the joint NASA, TEES, and UC meeting held at the University of Cincinnati on April 24, 1998. C) Pre-print of the paper entitled "Coherent Macro Porous Silicon as a Wick Structure in an Integrated Nficrofluidic Two-Phase Cooling System" to be presented September 20-25, 1998 at the SPIE conference held in Santa Clara, Ca. To summarize,. nearly all of the proposed work was successfully accomplished (albeit a 3-month time extension was required), proving that micromachining can indeed be used to fabricate porous silicon wick structures with precise hole sizes and patterning control, thus permitting a substantial improvement in future wick designs. In addition, the appropriate range of thermal conductivities of the porous samples were theoretically predicted (see Appendix A). Although not part of the scope of work, the permeability of the test samples were measured (see results sections of Appendices B and C).

Kazmierczak, M. J.↗
NASA NTRS1998

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

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.

Baker, David↗
NASA NTRS1989

Hanging drop crystal growth apparatus and method

An apparatus (10) is constructed having a cylindrical enclosure (16) within which a disc-shaped wicking element (18) is positioned. A well or recess (22) is cut into an upper side (24) of this wicking element, and a glass cover plate or slip (28) having a protein drop disposed thereon is sealably positioned on the wicking element (18), with drop (12) being positioned over well or recess (22). A flow of control fluid is generated by a programmable gradient former (16), with this control fluid having a vapor pressure that is selectively variable. This flow of control fluid is coupled to the wicking element (18) where control fluid vapor diffusing from walls (26) of the recess (22) is exposed to the drop (12), forming a vapor pressure gradient between the drop (12) and the control fluid vapor. Initially, this gradient is adjusted to draw solvent from the drop (12) at a relatively high rate, and as the critical supersaturation point is approached (the point at which crystal nucleation occurs), the gradient is reduced to more slowly draw solvent from the drop (12). This allows discrete protein molecules more time to orient themselves into an ordered crystalline lattice, producing protein crystals which, when processed by X-ray crystallography, possess a high degree of resolution.

Carter, Daniel C.↗
NASA NTRS2004

An Overview of Long Duration Sodium Heat Pipe Tests

High temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, and Stirling cycle heat sources; with the resurgence of space nuclear power, additional applications include reactor heat removal elements and radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly long-term materials compatibility is being evaluated through the use of high temperature life test heat pipes. Thermacore International, Inc., has carried out several sodium heat pipe life tests to establish long term operating reliability. Four sodium heat pipes have recently demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A 3l6L stainless steel heat pipe with a sintered porous nickel wick structure and an integral brazed cartridge heater has successfully operated at 650 to 700 C for over 115,000 hours without signs of failure. A second 3l6L stainless steel heat pipe with a specially-designed Inconel 60 I rupture disk and a sintered nickel powder wick has demonstrated over 83,000 hours at 600 to 650 C with similar success. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 41 ,000 hours at nearly 700 0c. A hybrid (i.e. gas-fired and solar) heat pipe with a Haynes 230 envelope and a sintered porous nickel wick structure was operated for about 20,000 hours at nearly 700 C without signs of degradation. These life test results collectively have demonstrated the potential for high temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability, Detailed design specifications, operating hi story, and test results are described for each of these sodium heat pipes. Lessons learned and future life test plans are also discussed.

Rosenfeld, John H.↗
NASA NTRS2015

Cryogenic Autogenous Pressurization Testing for Robotic Refueling Mission 3

A wick-heater system has been selected for use to pressurize the Source Dewar of the Robotic Refueling Mission Phase 3 on-orbit cryogen transfer experiment payload for the International Space Station. Experimental results of autogenous pressurization of liquid argon and liquid nitrogen using a prototype wick-heater system are presented. The wick-heater generates gas to increase the pressure in the tank while maintaining a low bulk fluid temperature. Pressurization experiments were performed in 2013 to characterize the performance of the wick heater. This paper describes the experimental setup, pressurization results, and analytical model correlations.

cryogenics↗
NASA NTRS2016

Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

Ababneh, Mohammed T.↗
NASA NTRSDate not supplied

Ceramic Heat Pipe for Thermal Management of a High Frequency Inductor

As the power density of electric machines and power electronics continues to increase to meet the demands of more electric aircraft, the thermal management of these devices becomes increasingly important. Ideally, the thermal management solution of the device should have high thermal conductivity and be electrically insulating so that it can be directly integrated with the device in question. Technical ceramics are a class of materials that meet these two requirements. Direct liquid cooling by submerging electric components in a dielectric fluid is an alternate option, but adds system complexity and may incur pumping loss. In this work, the thermal management solution for a high frequency inductor is presented. A conventional wicked heat pipe is designed that is made from a solid ceramic case with a sintered ceramic wick. This heat pipe can provide structural support for the core and windings and is electrically insulating, so it does not incur any additional eddy current losses from the high frequency magnetic fields. It does not require additional pumping power, because conventional wicked heat pipes are passive devices. In this paper, the manufacturing process of the ceramic heat pipe is also presented. It is shown that the sintering of large diameter spherical ceramic particles is difficult due to their high specific surface area and low surface free energy. To overcome this difficulty, a flux material was used to initiate liquid phase sintering. The results of the sintering trials show that for the 120 μm diameter α-Al2O3powder selected for the wick, the combination of 1650°C sintering temperature and the addition of 5 wt% talc sintered the porous matrix together sufficiently for use as a heat pipe wic

High-frequency Inductor↗
DOE OSTI2025

Phenomena Identification and Ranking Table (PIRT) for Heat Pipes

This Phenomena Identification and Ranking Table (PIRT) report provides an evaluation of key phenomena affecting the performance and operational regimes of heat pipes, particularly in the context of heat pipe microreactors (HPMRs). Heat pipes are advanced passive thermal management devices that utilize phase change and capillary action to achieve efficient heat transfer. However, due to the complexity of the phenomena coupled in the heat pipe, including phase change, turbulent transition, and compressibility effects, among others, there is high uncertainty in identifying and ranking the important phenomena affecting the operation of heat pipes and the current knowledge for their modeling and simulation and experimental measurements and instrumentation. This PIRT exercise, conducted as a collaborative effort involving the Department of Energy (DOE) Microreactor Program (MRP), the Nuclear Regulatory Commission (NRC), and university partners systematically identifies, reviews, and prioritizes critical phenomena affecting the operation of heat pipes based on their importance and knowledge levels. The report analyzes phenomena with high importance and low knowledge, such as wick de-wetting, critical heat flux, contact angles, and pressure dynamics, discussing challenges and future research directions for improving their modeling and simulation and experimental measurements. Additionally, the report addresses phenomena with low knowledge that could impact heat pipe operation during non-normal or transient operation, including frozen startup, laminar to turbulent transition, geysering, wick priming, underfilling conditions, surface roughness of the wick, NCGs trapped in the wick, and the timescales of startup and shutdown. This comprehensive evaluation serves as a valuable resource for guiding future research and development efforts, supporting the successful integration of heat pipes into critical applications such as nuclear reactors, and contributing to the advancement of heat pipe technologies in safety-critical industries.

21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
DOE OSTI2023

Development of Laboratory Testbeds Simulating Real-World Greenhouse Gas Emissions [Slides]

In this presentation, I discussed the development of laboratory test beds that simulate field greenhouse gas emissions. Field experiments are used to test new landscape management practices that could reduce greenhouse gas emissions. However, field experiments are very expensive and time consuming. Laboratory experiments are generally more cost efficient and timesaving. There are methods that can be used to make these laboratory tests more closely replicate natural systems for the improvement of agricultural lands used in biofuel and food production. The goal of this project is to develop a laboratory testbed that will mimic field greenhouse gas emissions. To achieve this goal, we used soil cores taken from agricultural and marginal lands, then attached fiberglass wicks to improve the drainage system in the core to simulate a more natural hydraulic system. The combination of using native soils and fiberglass wicks should demonstrate similar greenhouse gas emissions between the lab and the field. Our preliminary results suggest that the carbon dioxide and nitrous oxide flux from the agricultural land site were comparable to the greenhouse soil cores equipped with the drainage wicks. The data suggests that laboratory testbeds can be used to mimic field greenhouse gas emissions if parameters, such as soil water content are in a set range.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Development of Laboratory Testbeds Simulating Real-World Greenhouse Gas Emissions

Climate change leads to drastic variations in the environment that can threaten food security. To protect the security and prosperity of the environment, new agricultural practices that mitigate greenhouse gas emissions need to be developed. Agriculture plays a large role in the emissions of greenhouse gases, thus a need for new practices. At present, testing landscape management practices for carbon sequestration and reduction of greenhouse gas emissions are expensive because such tests often require intricate field experiments. Laboratory tests on landscape management practices often fail to simulate and accurately represent the natural systems researchers intend to study. There are methods that can be used to make these laboratory tests more closely replicate natural systems for the improvement of agricultural lands used in biofuel and food production. The goal of this project is to develop a laboratory testbed replicating field conditions that will mimic field greenhouse gas emissions. To achieve this goal, we used soil cores taken from agricultural and marginal lands, then attached fiberglass wicks to improve the drainage system in the soil core to simulate a more natural hydraulic system. The soil cores with the wicks were used to compared to greenhouse gas emissions observed in the field. Our preliminary results suggest that the soil carbon dioxide and nitrous oxide flux from the agricultural land site were comparable to the soil cores equipped with the drainage wicks. The data suggests that laboratory testbeds can be used to mimic field greenhouse gas emissions if parameters, such as soil water content were in a set range. The laboratory testbed produces similar greenhouse gas emissions to the agricultural site when the soil water content was between 15-25%.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1974

Electrohydrodynamic heat pipe experiments

Experiments with two electrohydrodynamic heat pipes are reported. Both devices employ an electromechanical flow structure for axial liquid flow and a capillary wicking structure for (1) collection of condensed liquid at the cooled end and (2) distribution of this liquid at the heated end. One device has circumferential grooving for the capillary structure and the other has feltmetal wicking. The experiments successfully demonstrate the electrohydrodynamic heat pipe concept. Compatibility of the two circumferential wick structures with an axial electromechanical flow structure is also demonstrated. A significant mismatch of the capillary groove and electrohydrodynamic pumping capabilities results in severe hydrodynamic burn-out limiting in the first heat pipe. Both devices have very poor over-all thermal conductances of the order of 1-2 W/deg C, reflecting the generally poor heat-transfer properties of the dielectric working fluids required in electrohydrodynamic heat pipes.

Jones, T. B.↗
NASA NTRS1978

Performance investigations of liquid-metal heat pipes for space and terrestrial applications

The high heat transfer capacity of liquid-metal heat pipes is demonstrated in performance tests with mercury, potassium, sodium, and lithium working fluids and wick structures which serve to minimize liquid pressure losses and vapor/liquid interactions. Appropriate wicks for horizontal and vertical operation are described. It is shown that heat-transfer with these wicks is limited by vapor flow effects. Examples are given of particular effects associated with a long adiabatic section between evaporator and condenser and with a heat source of uniform temperature as opposed to a source of uniform power.

Kemme, J. E.↗
NASA NTRS1982

Heat Pipe Blocks Return Flow

Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

Eninger, J. E.↗
NASA NTRS1982

Absorbent product to absorb fluids

A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

Dawn, F. S.↗
NASA NTRS1983

Heat pipe thermal switch

A thermal switch for controlling the dissipation of heat between a body is described. The thermal switch is comprised of a flexible bellows defining an expansible vapor chamber for a working fluid located between an evaporation and condensation chamber. Inside the bellows is located a coiled retaining spring and four axial metal mesh wicks, two of which have their central portions located inside of the spring while the other two have their central portions located between the spring and the side wall of the bellows. The wicks are terminated and are attached to the inner surfaces of the outer end walls of evaporation and condensation chambers respectively located adjacent to the heat source and heat sink. The inner surfaces of the end walls furthermore include grooves to provide flow channels of the working fluid to and from the wick ends. The evaporation and condensation chambers are connected by turnbuckles and tension springs to provide a set point adjustment for setting the gap between an interface plate on the condensation chamber and the heat sink.

Wolf, D. A.↗
NASA NTRS1986

Hydraulic-Leak Detector for Hidden Joints

Slow leakage of fluid made obvious. Indicator consists of wick wrapped at one end around joint to be monitored. Wick absorbs hydraulic fluid leaking from joint and transmits to opposite end, located outside cover plate and visible to inspector. Leakage manifested as discoloration of outside end of wick. Indicator reveals leaks in hidden fittings on hydraulic lines. Fast inspection of joints without disassembly. Used in aerospace, petroleum, chemical, nuclear, and other industries where removing covers for inspection impossible, difficult, or time-consuming.

Anderson, G. E.↗