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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1964

Experimental Data on Stagnation-Point Gas Injection Cooling on a Hemisphere-Cone in a Hypersonic Arc Tunnel

Exploratory tests were made to determine the reduction of heat transfer resulting from ejection of gases at the stagnation point on a hemisphere-cone at a nominal Mach number of about 9 and at stagnation enthalpies up to 1600 BTU per pound. Helium, nitrogen, and argon gases were used as coolants. The ratio of mass flow of coolant to the mass flow of air swept out by the model projected area was less than 0.20 in all cases. The experimental heat-transfer data were normalized by the calculated stagnation-point values based on test conditions in the tunnel and are presented as a function of the surface distance from the stagnation point. The variation of shock standoff distances with mass flow and volumetric flow of the gaseous ejectants is presented along with photographs of the luminous flow field of the model during tests.

STAGNATION FLOW↗
NASA NTRS1965

Lunar geothermal power - Some problems and potentials

Power from geothermal deposits on earth is an established fact, with plant capacities ranging from a few kilowatts to several hundred megawatts. The increasing evidence for contemporary volcanic and fumarolic activity on the moon lends strong support to the validity of the concepts of utilizing geothermal fluids as a source of lunar power. Geothermal energy, whatever the size of installation desired, will probably not be an energy source during early exploratory operations, because of the inherent uncertainty in developing natural resources. On the other hand, the attractiveness of geothermal concepts with their abundant potential for byproduct fuel and life-support production, plus the potential for large continuous power outputs, suggests chat the location and testing of areas of geothermal potential should be an early goa] for lunar exploration efforts. This paper briefly describes the chemical and structural properties of geothermal deposits and outlines the differences expected between lunar and terrestrial deposits and their surface expressions. The problems of finding geothermal deposits, and of then deciding upon the probable subsurface exploitive testing for initial production are suggested and the problems inherent in large-scale geothermal development and utilization are indicated.

ENERGY SOURCE↗
NASA NTRS1969

Torsion system for creep testing with multiple stress reversals

Torsion system proves exploratory data on accelerated creep due to multiple stress reversals. Torsional testing of tubular specimens is best suited for reversed stress creep tests since large strains are obtainable while maintaining specimen geometry.

Lilienthal, P. A.↗
NASA NTRS1970

User oriented data processing at the University of Michigan

The multispectral techniques have shown themselves capable of solving problems in a large number of user areas. The results obtained are in some instances quite impressive. In many instances, the multispectral detection of various phenomena is an empirical fact for which there is little physical explanation today. To date, most of the user applications that have been addressed are exploratory in nature. The closest approximation to an operational situation encountered so far is that of the survey of wetlands in North Dakota reported in this paper.

Thomson, F. J.↗
NASA NTRS1972

Dynamic flow angle measurements at the diffuser exit of a Mach 2.5 mixed compression inlet

An exploratory investigation was made to determine the magnitude of the dynamic flow angle at a single point in the diffuser exit of a Mach 2.50 inlet. Results indicate that the maximum flow angle variation was + or - 3 degrees except when vortex generators were installed in the subsonic diffuser. The amplitude of these flow angle fluctuations was directly related to the amplitude of the total pressure fluctuations at the probe survey point. Flow angle fluctuations as high as + or - 11 degrees were recorded when vortex generators were installed near the probe survey point.

Prati, W. M.↗
NASA NTRS1969

Some aspects of remote atmospheric sensing by laser radar

An analysis has been made of some aspects of atmospheric sensing by laser radar spectroscopy. A discussion of the laser radar equation is presented which leads to methods for obtaining atmospheric information by spectroscopic means. Calculations are presented which investigate the potential of Doppler, Raman and differential absorption techniques. It is concluded that atmospheric measurements based upon Doppler and Raman approaches are restricted to qualitative studies at the present time primarily because of the limitations imposed by existing laser sources and detectors. It is probable that these limitations will be removed in the near future and it is recommended that exploratory experiments be continued. The differential absorption method for obtaining the spatial distribution of atmospheric gases is well developed for such gases as water vapor and oxygen where the basic laser frequency lies close to the center of the particular absorption line. Further investigation is recommended in the field of laser frequency shifting. Additional information is also required on the shape of the absorption line, particular in the region where the line reflects both pressure and Doppler broadening.

Schotland, R. M.↗
NASA NTRS1972

Minimum impulse tests of 0.45-N liquid hydrazine catalytic thrusters

An exploratory test series was conducted on three types of 0.45-N (0.1 lbf) liquid hydrazine thrusters to ascertain the minimum impulse bit capability for this class of engine. The test series is described and the results are presented. The testing was performed at 21 and 145 C (70 and 300 F) while maintaining nominal 0.45 N (0.1 lbf) upstream conditions. Valve on-times as low as 0.008 sec were applied. Impulse bits were observed for thruster temperatures of 21 and 145 C (70 and 300 F), respectively.

Moynihan, P. I.↗
NASA NTRS1971

Status and plans of NASA's Materials Science and Manufacturing in Space /MS-MS/ program.

Following two years of relatively low-level exploratory work, the Materials Science and Manufacturing in Space program is now in a phase of expansion toward higher levels of effort. The main thrust of this effort is toward initiation of a research and development program on the Space Shuttle missions that can prepare the way for possible commercial manufacturing operations on permanently orbiting space stations. Experiment capabilities currently being planned for the Space Shuttle will be based on an inventory of reusable general-purpose equipment that can be configured in many different ways to meet individual experiment requirements. It is expected that this approach can support very large numbers of experiments and make flight opportunities accessible to many potential experimenters who would not be prepared to involve themselves in the development of flight hardware.

Armstrong, W. O.↗
NASA NTRS1972

The NASA Advanced Transport Technology Program.

Review of an advanced technology program initiated by NASA to expedite the development and application of advanced technologies to the next generation of subsonic CTOL jet transports. The major technical elements of this program include airframe and engine system studies for identifying technology needs, technology development for providing the necessary base in those areas of the aeronautical disciplines offering significant payoffs, and exploratory flight vehicles for validating advanced concepts and demonstrating specific benefits associated with civil applications. The possible benefits and application of the NASA-developed supercritical aerodynamic technology are discussed in some detail. Early experimental aerodynamic results obtained from wind tunnel and flight investigations are included.

Ayers, T. G.↗
NASA NTRS1972

Friction welding.

Results of an exploratory study of the structure and properties of friction welds in Udimet 700 (U-700) and TD-nickel (TD-Ni) bar materials, as well as dissimilar U-700/TD-Ni friction welds. Butt welds were prepared by friction welding 12.7-mm-diam U-700 bars and TD-Ni bars. Specimens for elevated temperature tensile and stress rupture testing were machined after a postweld heat treatment. Friction welding of U-700 shows great potential because the welds were found to be as strong as the parent metal in stress rupture and tensile tests at 760 and 980 C. In addition, the weld line was not detectable by metallographic examination after postheating. Friction welds in TD-Ni or between U-700 and TD-Ni were extremely weak at elevated temperatures. The TD-Ni friction welds could support only 9% as much stress as the base metal for 10-hour stress rupture life at 1090 C. The U-700/TD-Ni weld could sustain only 15% as much stress as the TD-Ni parent metal for a 10-hour stress rupture life at 930 C. Thus friction welding is not a suitable joining method for obtaining high-strength TD-Ni or U-700/TD-Ni weldments.

Moore, T. J.↗