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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Heat pipe solar receiver with thermal energy storage

An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

Zimmerman, W. F.↗
NASA NTRS1986

Development of an Advanced Trapezoidal Axially Grooved (ATAG) heat pipe

This paper discusses the breadboard development of an Advanced Trapezoidal Axially Grooved (ATAG) heat pipe, which will satisfy space constructible radiator heat rejection requirements for large space power systems. The ATAG heat pipe development program includes a technology demonstration of Space Station heat load and temperature requirements through the design, fabrication, and testing of breadboard and preprototype units. A parametric analysis was conducted to determine trapezoidal groove geometries that could meet the transport performance goal and could be fabricated by available extrusion technology for a diameter chosen to be compatible with an existing development test unit of a cylindrical, pressure-actuated contact heat exchanger. Performance test results for the breadboard heat pipes are presented.

Richter, R. F. G.↗
NASA NTRS1994

Carbon-Carbon Heat Pipe Testing and Evaluation

This report discusses development and proof-of-concept testing of a new lightweight carbon-carbon (C-C) space radiator heat pipe developed under the NASA Civil Space Technology Initiative (CSTI) High Capacity Power Program. The heat pipe was filled with potassium working fluid and tested for 11 hours including startup from ambient temperature with the working fluid initially in the frozen state to near 700 K condenser temperature. Steady-state heat pipe input power during testing was facility limited to about 300 watts, representing about 50 percent of the design input power. Post test inspection showed the heat pipe to be in excellent condition after eight thermal cycles from ambient to steady-state operating temperature. Potential applications, ranging from small spacecraft heat rejection to aircraft and terrestrial uses, are discussed.

Juhasz, Albert J.↗
NASA NTRS1979

Improved heat-pipe wick

Fabrication techniques in application with conventional heat pipe-wick technology produces high quality annular wicks with smaller pores, higher density, and greater rigidity.

Arcella, F. G.↗
NASA NTRS1981

Non-heat pipe receiver/p-40 Stirling engine

The technology for a full-up hybrid dish-Stirling Solar Thermal Power system is discussed. Overall solar-to-electric efficiency for the dish-Stirling system demonstration is approximately 30%. Hybrid operation is provided by fossil fuel combustion augmentation, which enables the Stirling engine to operate continuously at constant speed and power, regardless of insolation level, thus providing the capability to operate on cloudy days and at night.

Haglund, R. A.↗
NASA NTRS1972

An out-of-core version of a six cell heat-pipe heated thermionic converter array

A thermionic system concept is described which incorporates a heat-pipe cooled fast spectrum reactor and six-cell thermionic converter modules located in the space radiator. Much of the technology being developed for the in-core thermionic reactor concept is directly applicable to this out-of-core concept, particularly the fuel and converter development activity. The major technology extension required is in the area of heat-pipes for cooling the reactor and carrying thermal energy from the reactor station to the converters. The performance characteristics of an out-of-core thermionic system at power levels between 40 and 70 kWe are summarized, the adaptation of in-core technology to the out-of-core concept is described and applicable heat-pipe technology programs now underway are discussed.

Kroeger, E. W.↗
DOE OSTI2022

A Critical Review of Heat Pipe Experiments in Nuclear Energy Applications

This critical review provides heat pipe (HP) experimental data sets that contain pertinent information regarding nuclear technology that may be beneficial to researchers. Heat pipes have been shown to have a tremendously positive impact on nuclear technologies and will continue to become a more prevalent technology as more nuclear reactor concepts embrace this robust technology. Most previous reviews may focus on only a specific HP design or application, and some are backdated. Herein, this critical review extends previous efforts; integrates and summarizes previously reported HP experimental efforts; and provides updates with recently reported results in the literature for HPs in all nuclear-related applications, including space power (thermal radiators, core cooling, and electricity production), microreactors (emergency core cooling, hybrid control rods, and reactor core cooling), and HP involvement in other nuclear-related technologies (spent fuel pool cooling). The two main objectives of this critical review are (1) to facilitate the development of HP codes by outlining some of the existing experimental data sets to validate their codes and directing developers to these efforts and (2) to provide comprehensive information regarding the vast applicability of HPs used in the nuclear industry, including the theory of operation and limitations to supplement researchers in the development of new ideas for potential applications in nuclear-related technologies. The review clearly shows extensive and diverse experimental data sets for HPs developed under diverse testing conditions depending on the available nuclear application for validation purposes. Thus, this critical review is oriented to providing attention to the existing efforts rather than determining gaps in HP research.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1995

Composite heat pipe development status: Development of lightweight prototype carbon-carbon heat pipe with integral fins and metal foil liner

This report discusses development and proof-of-concept testing of a new lightweight carbon-carbon (C-C) space radiator heat pipe, carried out under the NASA Civil Space Technology Initiative (CSTI) High Capacity Power Program. The prototype heat pipe, equipped with a niobium-zirconium foil liner, was filled with potassium working fluid and tested for 11 hours, including startup from ambient temperature with the working fluid initially in the frozen state to near 700 K condenser temperature. Steady-state heat pipe input power during testing was facility limited to about 300 watts. Post test inspection showed the heat pipe to be in excellent condition after eight thermal cycles from ambient to steady-state operating temperature. Utilization of other liner materials and working fluids would greatly extend the spectrum of service temperatures for this technology, with potential applications ranging from small spacecraft heat rejection to aircraft and terrestrial uses.

Juhasz, Albert J.↗
DOE OSTI2022

Multiphysics Analysis of Load Following and Safety Transients for MicroReactors

The tools developed within the U.S. Department of Energy (DOE) Office of Nuclear Energy’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program aim at providing high fidelity multiphysics modeling capabilities to support design and licensing of various types of advanced nuclear reactors, including the technologies being developed by U.S. microreactor vendors relying on heat pipe and gas-cooled technologies. In FY-2022, the NEAMS Multiphysics Applications team made significant progress both in demonstrating capabilities applied to microreactor problems, and in supporting NEAMS developers.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2005

Thermo-Physical Properties of Intermediate Temperature Heat Pipe Fluids

Heat pipes are among the most promising technologies for space radiator systems. The paper reports further evaluation of potential heat pipe fluids in the intermediate temperature range of 400 to 700 K in continuation of two recent reports. More thermo-physical property data are examined. Organic, inorganic, and elemental substances are considered. The evaluation of surface tension and other fluid properties are examined. Halides are evaluated as potential heat pipe fluids. Reliable data are not available for all fluids and further database development is necessary. Many of the fluids considered are promising candidates as heat pipe fluids. Water is promising as a heat pipe fluid up to 500 to 550 K. Life test data for thermo-chemical compatibility are almost non-existent.

Beach, Duane E.↗
NASA NTRS2004

Thermo-Physical Properties of Intermediate Temperature Heat Pipe Fluids

Heat pipes are among the most promising technologies for space radiator systems. The paper reports further evaluation of potential heat pipe fluids in the intermediate temperature range of 400 to 700 K in continuation of two recent reports. More thermo-physical property data are examined. Organic, inorganic and elemental substances are considered. The evaluation of surface tension and other fluid properties are examined. Halides are evaluated as potential heat pipe fluids. Reliable data are not available for all fluids and further database development in necessary. Many of the fluids considered are promising candidates as heat pipe fluids. Water is promising as a heat pipe fluid up to 500-550 K. Life test data for thermo-chemical compatibility are almost non-existent.

Devarakonda, Angirasa↗
NASA NTRSDate not supplied

Intermediate Temperature Ceramic Heat Pipe Modeling and Optimization

The intermediate temperature regime of heat pipes, 450-700 K, has not been well characterized due in part to the corrosive nature of many of the working fluids, as well as the poor performance in many conventional metal envelope systems. Spacecraft nuclear electric propulsion, as well as other emerging technologies, can benefit from heat pipes with optimal performance in this intermediate regime. In this work, we have explored halide working fluids coupled with aluminum nitride shells to operate at 500-600 K and interface with a nuclear electric propulsion system. The shells have been additively manufactured and tested to ensure compatibility with the halides. Specifically, AlBr 3 , AlCl 3 , FeCl 3 , and SbBr 3 were selected owing to their higher performance and comparatively safe handling characteristics compared to other intermediate temperature working fluids. The additive manufacturing process enables highly customizable designs that integrate the heat pipe and radiator fin together, optimized for each fluid. We have evaluated the performance limits of such a heat pipe design in order to establish the feasibility of AlBr 3 in particular, and present design that achieves an areal density of 5.2 kg/m 2 and mass per unit heat performance of 0.71 kg/kW. Analysis is ongoing for all working fluids.

thermal management↗
DOE OSTI2022

SPHERE Gas Composition Test and SOCKEYE Validation

The single primary heat extraction and removal emulator (SPHERE) gas composition test was performed to obtain data on the temperature distribution of a 2-m, 0.625-in.-diameter sodium-filled heat pipe from Advanced Cooling Technologies (ACT) in a horizontal orientation filled with varying gas compositions to support NEAMS tool development.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1989

Initial characterization of a modular heat exchanger with an integral heat pipe

As part of the Civil Space Technology Initiative (CSTI) Advanced Technology program, a conceptual design of the Stirling space engibe (SSE) was generated to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The free-piston Stirling engine (FPSE) was chosen as the growth option in the CSTI program. An existing FPSE was modified as a test bed for a modular heat exchanger evaluation. Evaluation of the individual heat pipes before installation in the engine is described.

Schreiber, Jeffrey G.↗
DOE OSTI2025

Evaporator Temperature Transient Testing of a High-Performance Sodium Filled Heat Pipe

Heat pipes are two-phase heat transfer devices that enable passive removal of heat from the reactor core to the power conversion system in heat pipe-cooled microreactor designs. Experimental investigations of heat pipe transients are needed for technology demonstration, verification and validation of numerical codes, and the establishment of regulatory requirements. The Single Primary Heat Extraction and Removal Emulator (SPHERE) facility at Idaho National Laboratory (INL) serves as a platform for evaluating the dynamic response of high-temperature heat pipes under a variety of operating conditions. The present work details the experimental investigation of a high-performance, defined as over 2 kW sodium heat pipe subjected to rapid input power fluctuations induced by sudden changes in the evaporator temperature setpoint. In addition, the heat pipe was subjected to an asymmetrical heat load where a subset of heaters operated at 30% and 70% below their nominal power. These experimental conditions were chosen to simulate thermal and operational stresses expected to be encountered in microreactors to provide data on heat pipe behavior during such important transient events. Key data and performance metrics, including time series of temperatures and strains, axial temperature profiles, thermal response times, and heat transfer capabilities, the thermal output over thermal input, were reported and discussed. The results highlight the resilience of heat pipes, revealing their potential to maintain thermal stability and efficiency under varying power loads. Lastly, the paper concludes with a discussion on the significance of the results and their implications for future research.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

A two-phase three-field modeling framework for heat pipe application in nuclear reactors

Heat pipes and two-phase thermosyphons are highly efficient heat transfer devices utilizing continuous evaporation and condensation of working fluid for two-phase heat transport in closed systems. Because of the nearly isothermal and fully passive phase-change heat transfer mechanism, heat pipes and thermosyphons have found many applications in nuclear engineering, space technologies, and other energy systems. High-temperature heat pipes are used in nuclear microreactors to remove fission power from the primary system and are coupled with power conversion systems or process heat applications. Modeling of the two-phase flow phenomena inside a heat pipe is essential to its design and safety analysis. In this study, a comprehensive one-dimensional two-phase three-field flow model has been developed for the analysis of heat pipes in normal operation conditions and transients. The conservation or field equations of mass, momentum, and energy were developed for the liquid film, vapor, and droplet. In addition, constitutive models or correlations were reviewed thoroughly and provided for the closure of the three-field equations. Specific constitutive equations regarding interfacial mass and heat transfer at two interfaces, namely film-gas interface and gas-droplet interface, were reviewed for droplet entrainment and deposition rates as well as film and droplet evaporation rates. Furthermore, mechanistic correlations of annular flow film thickness were recommended for the modeling of the thermosyphons without a wick as a critical constitutive correlation. Furthermore, experimental data needs from new experiments using a prototype working fluid or surrogate fluids for the model validation of high-temperature heat pipes in microreactors were recommended for future research.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗