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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1968

Advances in solid-fuel propulsion systems for tactical rockets

The objective of this paper is to present a brief survey of three areas in which advances of solid propulsion have enabled improved design of tactical rockets. The three areas are microwave attenuation, acceleration-combustion interactions, and performance optimization. In each of the three areas, improved understanding has significantly contributed to rocket technology. The problems remaining are far from solved, however, and the three subjects are fruitful areas for fundamental investigations.

Charles B Henderson↗
NASA NTRS1972

Advanced spacecraft fuel cell systems.

The specific goals of the system selected for development are 10,000 hours of operation with refurbishment, 20 lb/kW at a sustained power of 7 kW, and 21 kW peaking capability for durations of two hours. The system is designed to operate on low pressure, propulsion grade hydrogen and oxygen. Product water is removed by a passive water removal method that employs a porous hydrophobic membrane as a part of the water transport plate. Aspects of system component testing are discussed together with advanced materials to be used. It was found that the initial performance of a cell with a gold catalyzed cathode is superior to a cell with platinum catalyst. The problem of a certain inability to maintain the desired gas-electrolyte-catalyst interface is the main source of difficulty with the gold-based catalysts.

Thaller, L. H.↗
NASA NTRS1978

Hydrogen Embrittlement and Its Control in Hydrogen-Fueled Engine Systems

The nature of hydrogen embrittlement by high pressure gaseous hydrogen is described and methods of designing SSME gaseous hydrogen systems, including techniques of hydrogen embrittlement prevention, are discussed. The effects of gaseous hydrogen environments are emphasized. Results of extensive investigations of gaseous hydrogen environments on metals conducted under the SSME program are presented.

Chandler, W. T.↗
NASA NTRS1983

Gas cooled fuel cell systems technology development

The first phase of a planned multiphase program to develop a Phosphoric is addressed. This report describes the efforts performed that culminated in the: (1) Establishment of the preliminary design requirements and system conceptual design for the nominally rated 375 kW PAFC module and is interfacing power plant systems; (2) Establishment of PAFC component and stack performance, endurance, and design parameter data needed for design verification for power plant application; (3) Improvement of the existing PAFC materials data base and establishment of materials specifications and process procedes for the cell components; and (4) Testing of 122 subscale cell atmospheric test for 110,000 cumulative test hours, 12 subscale cell pressurized tests for 15,000 cumulative test hours, and 12 pressurized stack test for 10,000 cumulative test hours.

Feret, J. M.↗
NASA NTRS1989

Advanced space power PEM fuel cell systems

A model showing mass and heat transfer in proton exchange membrane (PEM) single cells is presented. For space applications, stack operation requiring combined water and thermal management is needed. Advanced hardware designs able to combine these two techniques are available. Test results are shown for membrane materials which can operate with sufficiently fast diffusive water transport to sustain current densities of 300 ma per square centimeter. Higher power density levels are predicted to require active water removal.

Vanderborgh, N. E.↗
NASA NTRS2008

Intelligent Engine Systems: Alternate Fuels Evaluation

The performance and gaseous emissions were measured for a well-stirred reactor operating under lean conditions for two fuels: JP8 and a synthetic Fisher-Tropsch fuel over a range of equivalence ratios from 0.6 down to the lean blowout. The lean blowout characteristics were determined in LBO experiments at loading parameter values from 0.7 to 1.4. The lean blowout characteristics were then explored under higher loading conditions by simulating higher altitude operation with the use of nitrogen as a dilution gas for the air stream. The experiments showed that: (1) The lean blowout characteristics for the two fuels were close under both low loading and high loading conditions. (2) The combustion temperatures and observed combustion efficiencies were similar for the two fuels. (3) The gaseous emissions were similar for the two fuels and the differences in the H2O and CO2 emissions appear to be directly relatable to the C/H ratio for the fuels.

Ballal, Dilip↗
NASA NTRS2015

Gas Conversion Systems Reclaim Fuel for Industry

A human trip to Mars will require astronauts to utilize resources on the Red Planet to generate oxygen and fuel for the ride home, among other things. Lakewood, Colorado-based Pioneer Energy has worked under SBIR agreements with Johnson Space Center to develop technology for those purposes, and now uses a commercialized version of the technology to recover oil and gas that would otherwise be wasted at drilling sites.

Source record↗
NASA NTRSDate not supplied

Cryogenic Fuel Aviation – Challenges and Opportunities

NASA aeronautics goals include pioneering new technology to increase efficiency and reduce emissions from air travel. The feasibility of using of on-board cryogenic fuels systems in combination with fuel cells, high efficiency engines, and electric motors for high efficiency commercial transport aircraft is being examined at NASA in collaborations with external partners. Growing emphasis on next generation air transportation resulted in the development of strategic investigations into cryogenic fuels aviation, including roadmaps for maturing new technologies, needs to improve testing and manufacturing capabilities, and the requirements for establishing regulatory and certification standards. A NASA cross-organizational multidisciplinary project team is exploring new aircraft architectures, enabling materials, and the engineering challenges associated with cryogenic fuels for aircraft. The engineering challenges include high performance cryogenic, thermal management, and power/propulsion components and subsystems to tackle the challenging problem of development of commercially viable aircraft that would radically transform air transportation.

liquid natural gas↗
NASA NTRS1979

High-freezing-point fuels used for aviation turbine engines

Broadened-specification aviation fuels could be produced from a greater fraction of crude source material with improvements in fuel supply and price. These fuels, particularly those with increased final boiling temperatures, would have higher freezing temperatures than current aviation turbine fuels. The higher-freezing-point fuels can be substituted in the majority of present commercial flights, since temperature data indicate that in-flight fuel temperatures are relatively mild. For the small but significant fraction of commercial flights where low fuel temperatures make higher freezing-point fuel use unacceptable, adaptations to the fuel or fuel system may be made to accommodate this fuel. Several techniques are discussed. Fuel heating is the most promising concept. One simple system design uses existing heat rejection from the fuel-lubricating oil cooler, another uses an engine-driven generator for electrical heating. Both systems offer advantages that outweigh the obvious penalties.

Friedman, R.↗
NASA NTRS1986

NASA Lewis Evaluation of Regenerative Fuel Cell (RFC) Systems

Evaluation of two regenerative fuel cell (RFC) systems was begun in-house, and under contracts and grants. The passive hydrogen-oxygen RFC offers the possibility of a high-energy density, long-life storage system for geosynchronous Earth orbit missions. The hydrogen-bromine RFC offers the combination of high efficiency and moderate energy density that could ideally suit low Earth orbit missions if successfully developed. Either or both of these systems would be attractive additions to the storage options available to designers of future missions.

Hagedorn, N. H.↗
NASA NTRS1964

Photographic Study of Liquid-Oxygen Boiling and Gas Injection in the Injector of a Chugging Rocket Engine

High-speed motion pictures were taken of conditions in the injector liquid-oxygen cavity of an RL-10 rocket engine during throttled engine operation. Photographs were taken during operation of the engine in the chugging region as the helium gas was injected to stabilize combustion, during operation at rated thrust, and during transition into chugging conditions as the gas injection was discontinued. Results of the investigation indicate that, during chugging rocket operation of the RL-10 engine, a high population of fairly large bubbles formed and collapsed within the liquid-oxygen cavity at the same frequency as the chamber pressure oscillations. When gaseous helium was injected into the liquid-oxygen cavity, a fog rapidly spread over the entire field of view, and the system immediately became stable. The injection of gaseous helium at rated conditions produced a very slight increase in engine performance but not enough to produce a net gain in a typical mission payload with the extra equipment needed. The inherent low-frequency system instability associated with the fuel system at low thrust levels was reduced by injecting either gaseous helium or hydrogen. Complete stabilization was achieved in some cases, and a reduction in the severity of the oscillations in others. This was apparently due to the ·anchoring of the phase change front to the location of the gas injection.

Conrad, E. William↗