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  • 1
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    Numerical solution of boundary-layer flows with massive blowing (1971)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Boundary layer flow with large mass injection rate, presenting numerical method with rapid convergence for increasing blowing parameter
    Keywords: FLUID MECHANICS
    Type: ; YAL SOCIETY (
    Format: text
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  • 2
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    Thermal shielding by subliming volume reflectors in convective and intense radiative environments. (1973)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The behavior of dielectric materials having densely packed internal scattering centers subject to extreme convective and radiative environments is analyzed. Experiments have shown that these materials act as volume reflectors of incident radiation even when the exposed surface is being eroded by thermochemical ablation. The analysis was applied to interpret experiments of subliming Teflon models exposed to combined radiative and convective fluxes up to 1.7 kW/sq cm for several seconds. Results show that, although the exposed surface receded at an apparently steady rate, the internal temperature climbed continually, due to internal absorption of radiation and would have caused failure internally if the test duration were extended a few seconds. Thus, performance is time-limited by the internal absorption coefficient. Results were obtained for larger configurations and other materials. Typically, Teflon shells may withstand radiant fluxes up to 20 kW/sq cm for about 5 sec and fritted quartz up to 50 kW/sq cm for about 8 sec (corresponding to the Jupiter entry).
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA Journal; 11; July 197
    Format: text
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  • 3
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    Analysis of sublimation-cooled coated mirrors in convective and radiative environments. (1973)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Analytical solutions were obtained for the thermal response of a transpiration- or sublimation-cooled spherical mirror coating exposed to convective and radiative heating. The solutions allow unlimited spectral detail to be accounted for. Results indicate that transpiration-cooled thick coatings (1 cm) may withstand up to 10 kW/sq cm on a steady basis without excessive temperature rise for quartzlike materials with an internal absorption coefficient of 0.01 per cm. On a transient basis, fluxes up to 20 kW/sq cm can be accommodated for a second (cW laser exposure time), 4 kW/sq cm for 5 sec (planetary entry heating time), and of the order of MW/sq cm for millisecond times (short-duration laser bursts) without transpiration cooling for a material with an absorption coefficient of 0.1 per cm. Proportionately higher fluxes can be accommodated with lower absorption coefficients. Thermal stresses produced by the heat pulse are found to be high but within the strength of the materials. The regime in which meaningful solutions may be obtained is mapped in detail.
    Keywords: THERMODYNAMICS AND COMBUSTION
    Type: AIAA Journal; 11; Jan. 197
    Format: text
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  • 4
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    Ablation of carbonaceous materials in a hydrogen-helium arcjet flow (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: NONMETALLIC MATERIALS
    Type: AIAA Journal (ISSN 0001-1452); 22; 1491-149
    Format: text
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  • 5
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    Numerical simulation of hypersonic, axisymmetric flowfields (1986)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Flow conditions corresponding to those of three previously conducted hypersonic axisymmetric flow experiments are presently treated by numerical solutions of the axisymmetric, thin layer Navier-Stokes equations with the Chemistry and Gasdynamic Implicit computer code's Version 2. While simulation and experimental results agree for ideal gas flows, the simulation for the case of a real gas flow reveals that the particular coupling of the gasdynamics and the chemistry used in the code degrades the convergence level obtainable, by comparison with ideal gas cases. The computed stagnation point heating is 60 percent lower than for the experiment.
    Keywords: AERODYNAMICS
    Type: AIAA PAPER 86-1285
    Format: text
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  • 6
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    Ablation of carbonaceous materials in a hydrogen-helium arc-jet flow (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The stagnation-point ablation rates of a graphite, a carbon-carbon composite, and four carbon-phenolic materials are measured in an arc-jet wind tunnel with a 50 percent hydrogen-50 percent helium mixture as the test gas. Flow environments are determined through measurements of static and impact pressures, heat-transfer rates to a calorimeter, and radiation spectra, and through numerical calculation of the flow through the wind tunnel, spectra, and heat-transfer rates. The environments so determined are: impact pressure approximately equal to 3 atm, Mach number approximately equal to 2.1, convective heat-transfer rate approximately equal to 14 kW/sq cm, and radiative heat-transfer rate approximately equal to 7 kW/sq cm in the absence of ablation. Ablation rates are determined from the measured rates of mass loss and recession of the ablation specimens. Compared with the predicted ablation rates obtained by running RASLE and CMA codes, the measured rates are higher by about 15 percent for all tested materials.
    Keywords: NONMETALLIC MATERIALS
    Type: AIAA PAPER 83-1561
    Format: text
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  • 7
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    Supporting flight data analysis for Space Shuttle Orbiter Experiments at NASA Ames Research Center (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.
    Keywords: SPACE TRANSPORTATION
    Type: AIAA PAPER 83-1532
    Format: text
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  • 8
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    Ablation of carbonaceous materials in a hydrogen-helium arc-jet flow (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The stagnation-point ablation rates of a graphite, a carbon-carbon composite, and four carbon-phenolic materials are measured in an arc-jet wind tunnel with a 50% hydrogen-50% helium mixture as the test gas. Flow environments are determined through measurements of static and impact pressures, heat-transfer rates to a calorimeter, and radiation spectra, and through numerical calculation of the flow through the wind tunnel, spectra, and heat-transfer rates. The environments so determined are: impact pressure approx. 3 atm, Mach number approx. 2.1, convective heat-transfer rate approx. 14 kw/sq cm, and radiative heat-transfer rate approx. 7 kw/sq cm in the absence of ablation. Ablation rates are determined from the measured rates of mass loss and recession of the ablation specimens. Compared with the predicted ablation rates obtained by running RASLE and CMA codes, the measured rates are higher by about 15% for all tested materials.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-TM-84346 , A-9286 , NAS 1.15:84346
    Format: application/pdf
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  • 9
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    Aerothermodynamic environment for a Titan probe with deployable decelerator (1985)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: It is pointed out that further exploration of Titan, Saturn's largest moon, is of current interest to the scientific community, particularly from the standpoint of the organic chemical evolution of its atmosphere. For a suitable study of this Saturnian satellite, a mission involving a Titan atmospheric entry probe is to be conducted. The probe is to employ a deployable decelerator with the aim to allow scientific measurements in the haze layer. The present investigation is concerned with an assessment of the aerothermodynamic environment for the considered probe during its hypervelocity, low-Reynolds-number entry. Attention is given to the employed computational method, the Titan probe configuration, the Titan probe trajectory, the viscous-layer regime of the aerothermodynamic environment, and the incipient merged-layer regime.
    Keywords: AERODYNAMICS
    Type: AIAA PAPER 85-1063
    Format: text
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  • 10
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    Radiative viscous-shock-layer analysis of Fire, Apollo, and PAET flight data (1985)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Equilibrium, radiating viscous-shock-layer solutions are obtained for a number of trajectory points of the Fire II, Apollo 4, and PAET experimental flight vehicles. Convective heating rates calculated by a benchmark code agree well, except at high altitudes corresponding to low densities, with two engineering correlations. Calculated radiation intensities are compared with the flight radiometer data and with inviscid flow results. Differences as great as 70 percent are observed between measured data and the viscous calculations. Viscous effects reduce the intensity toward the wall, because of boundary-layer absorption, by as much as 30 percent, compared with inviscid intensities. Preliminary chemical and thermal nonequilibrium flow calculations along a stagnation streamline for a PAET trajectory predict enhancement of radiation owing to chemical relaxation. Stagnation point solutions are also presented for future air-assisted orbital transfer vehicle geometries with nose radii ranging from 0.3 to 15 m.
    Keywords: AERODYNAMICS
    Type: AIAA PAPER 85-1064
    Format: text
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