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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

The calibration of photographic and spectroscopic films. Part 1: Film batch variations of reciprocity failure in IIaO film. Part 2: Thermal and aging effects in relationship to reciprocity failure. P art 3: Shifting of reciprocity failure points as a function of thermal and aging effects

Reciprocity failure was examined for IIaO spectroscopic film. Three separate experiments were performed in order to study film batch variations, thermal and aging effects in relationship to reciprocity failure, and shifting of reciprocity failure points as a function of thermal and aging effects. The failure was examined over ranges of time between 5 and 60 seconds. The variation to illuminance was obtained by using thirty neutral density filters. A standard sensitometer device imprinted the wedge pattern on the film as exposure time was subjected to variation. Results indicate that film batch differences, temperature, and aging play an important role in reciprocity failure of IIaO spectroscopic film. A shifting of the failure points was also observed in various batches of film.

Peters, Kevin A.↗
NASA NTRS1976

Earth-based radio observations of Jupiter - Millimeter to meter wavelengths

The historical development of the study of Jupiter radio emission is considered and a description of the observational data is presented, taking into account the spectrum of the continuous microwave radiation, the polarization of the microwave radiation, the brightness distribution, the rotation-related variability, variations related to the zenocentric declination of the earth, and other time variations. The separation of radio emission into thermal and nonthermal components is discussed and interpretations of the two components are provided. A comparison of earth-based radio measurements with Pioneer 10 and 11 data is conducted and the future of earth-based radio observations is evaluated.

Berge, G. L.↗
NASA NTRS1979

Concepts for solar production of hydrogen

Some basic technical approaches to producing hydrogen from solar energy are surveyed. Solar energy forms are divided into: (1) direct solar radiation and (2) indirect forms such as wind and ocean thermal gradient. Technical approaches are separated into: (1) direct hydrogen production from the action of sunlight on some substrate, (2) hydrogen production from sunlight via an intermediate form of energy such as heat and electricity, and (3) hydrogen production from indirect solar energy via an intermediate energy form. It is concluded that while hydrogen from solar energy will be expensive by present standards, the depletion of fossil fuels will cause solar hydrogen to emerge as one of the few alternatives to a nuclear-electric or nuclear-electric-hydrogen energy system.

Hanson, J. A.↗
NASA NTRS1980

Remote sensing data of SP mountain and SP lava flow in north-central Arizona

Multifrequency airborne radar image data of SP Mountain and SP flow in north-central Arizona were obtained in diverse viewing directions and direct and cross-polarization and compared with surface and aerial photography, Landsat multispectral scanner data, airborne thermal infrared imagery, surface geology, and surface roughness statistics. The extremely blocky, basaltic andesite of SP flow is brighter on direct-polarization K-band images than on cross-polarized images taken simultaneously. This effect is explained by multiple scattering and the strong wavelength dependence of polarization effects caused by the rectilinear basaltic andesite scatters. Two distinct types of surface relief on SP flow, one extremely blocky, the other subdued, are clearly discriminated on the visible and thermal wavelength images but are separable only on the longer wavelength L-band radar image data.

Schaber, G. G.↗
NASA NTRS1983

Energetic closed-cycle gas core reactors for orbit raising

Closed-cycle gas core reactor power plants can be of two types. In the 'mixed flow' type, the gaseous nuclear fuel is intimately mixed with the working gas in the cavity. In the 'light bulb' type the fissioning plasma is enclosed in a transparent tube, and energy transfer to the separate working gas occurs by thermal radiation. The potentials of high temperature gas core reactors in terrestrial electric power generator applications have been considered, and a number of civilian power-beaming applications for gaseous fuel nuclear-MHD power plants in space have been suggested. Major conclusions of investigations related to the design of space power systems are discussed. Attention is given to options for conversion cycles, the power system specific mass, and research and technology issues.

Rosa, R. J.↗
NASA NTRS1985

Local heat-transfer measurements on a large, scale-model turbine blade airfoil using a composite of a heater element and liquid crystals

Local heat transfer coefficients were experimentally mapped along the midchord of a five-time-size turbine blade airfoil in a static cascade operated at room temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a mylar sheet with a layer of cholesteric liquid crystals, that change color with temperature, and a heater sheet made of a carbon-impregnated paper, that produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. The local heat transfer coefficients are presented for Reynolds numbers from 2.8 x 10 to the 5th power to 7.6 x 10 to the 5th power. Comparisons are made with analytical values of heat transfer coefficients obtained from the STAN5 boundary layer code. Also, a leading edge separation bubble was revealed by thermal and flow visualization.

Hippensteele, S. A.↗
NASA NTRS1985

Local heat-transfer measurements on a large scale-model turbine blade airfoil using a composite of a heater element and liquid crystals

Local heat transfer coefficients were experimentally mapped along the midchord of a five-time-size turbine blade airfoil in a static cascade operated at room temperature over a range of Reynolds numbers. The test surface consisted of a composite of commercially available materials: a mylar sheet with a layer of cholesteric liquid crystals, that change color with temperature, and a heater sheet made of a carbon-impregnated paper, that produces uniform heat flux. After the initial selection and calibration of the composite sheet, accurate, quantitative, and continuous heat transfer coefficients were mapped over the airfoil surface. The local heat transfer coefficients are presented for Reynolds numbers from 2.8 x 10 to the 5th power to 7.6 x 10 to the 5th power. Comparisons are made with analytical values of heat transfer coefficients obtained from the STANS boundary layer code. Also, a leading edge separation bubble was revealed by thermal and flow visualization.

Hippensteele, S. A.↗
NASA NTRS1989

High-Performance Power-Semiconductor Packages

A 600-V, 50-A transistor and 1,200-V, 50-A diode in rugged, compact, lightweight packages intended for use in inverter-type power supplies having switching frequencies up to 20 kHz. Packages provide low-inductance connections, low loss, electrical isolation, and long-life hermetic seal. Low inductance achieved by making all electrical connections to each package on same plane. Also reduces high-frequency losses by reducing coupling into inherent shorted turns in packaging material around conductor axes. Stranded internal power conductors aid conduction at high frequencies, where skin effect predominates. Design of packages solves historical problem of separation of electrical interface from thermal interface of high-power semiconductor device.

Renz, David↗
NASA NTRS1989

Performance testing of a two-phase interface heat exchanger

This paper describes the design and performance testing of a heat exchanger which interfaces separate two-phase ammonia thermal loops. The basic design involves a tube-in-tube concept, with boiling occurring in the inner tube and condensation in the outer tube. Eight such tubes are arranged in parallel. Testing has demonstrated that up to 8.2 kW of heat may be transferred across the heat exchanger when the saturation temperature difference between the systems is 5 C. Performance of the heat exchanger is affected primarily by the mass flow rate of ammonia in the liquid supply loop.

Mccabe, M. E., Jr.↗
NASA NTRS2004

A Summary of the Space Shuttle Columbia Tragedy and the Use of LS Dyna in the Accident Investigation and Return to Flight Efforts

On February 1, 2003, the Space Shuttle Columbia broke apart during reentry resulting in loss of 7 crewmembers and craft. For the next several months an extensive investigation of the accident ensued involving a nationwide team of experts from NASA, industry, and academia, spanning dozens of technical disciplines. The Columbia Accident Investigation Board (CAIB), a group of experts assembled to conduct an investigation independent of NASA concluded in August, 2003 that the cause of the loss of Columbia and its crew was a breach in the left wing leading edge Reinforced Carbon-Carbon (RCC) thermal protection system initiated by the impact of thermal insulating foam that had separated from the orbiters external fuel tank 81 seconds into the missions launch. During reentry, this breach allowed superheated air to penetrate behind the leading edge and erode the aluminum structure of left wing which ultimately led to the breakup of the orbiter. In order to gain a better understanding the foam impact on the orbiters RCC wing leading edge, a multi-center team of NASA and Boeing impact experts was formed to characterize the foam and RCC materials for impact analysis using LS Dyna. Dyna predictions were validated with sub-component and full scale tests. LS Dyna proved to be a valuable asset in supporting both the Columbia Accident Investigation and NASA s return to flight efforts. This paper summarizes Columbia Accident and the nearly seven month long investigation that followed. The use of LS-DYNA in this effort is highlighted. Contributions to the investigation and return to flight efforts of the multicenter team consisting of members from NASA Glenn, NASA Langley, and Boeing Philadelphia are introduced and covered in detail in papers to follow in these proceedings.

Melis, Matthew↗
NASA NTRS1997

Field Thermal Infrared Imaging Experiments

Day/night radiant temperature differences acquired from thermal imaging techniques proved effective in separating four seral stage and one deciduous forest class.

temperature↗
NASA NTRS2007

The Columbia Accident Investigation and The NASA Glenn Ballistic Impact Laboratory Contributions Supporting NASA's Return to Flight

On February 1, 2003, the Space Shuttle Columbia broke apart during reentry, resulting in loss of the vehicle and its seven crewmembers. For the next several months, an extensive investigation of the accident ensued involving a nationwide team of experts from NASA, industry, and academia, spanning dozens of technical disciplines. The Columbia Accident Investigation Board (CAIB), a group of experts assembled to conduct an investigation independent of NASA, concluded in August, 2003 that the most likely cause of the loss of Columbia and its crew was a breach in the left wing leading edge Reinforced Carbon-Carbon (RCC) thermal protection system initiated by the impact of thermal insulating foam that had separated from the orbiters external fuel tank 81 seconds into the mission's launch. During reentry, this breach allowed superheated air to penetrate behind the leading edge and erode the aluminum structure of left wing, which ultimately led to the breakup of the orbiter. The findings of the CAIB were supported by ballistic impact tests, which simulated the physics of External Tank Foam impact on the RCC wing leading edge material. These tests ranged from fundamental material characterization tests to full-scale Orbiter Wing Leading Edge tests. Following the accident investigation, NASA spent the next 18 months focused on returning the shuttle safely to flight. In order to fully evaluate all potential impact threats from the many debris sources on the Space Shuttle during ascent, NASA instituted a significant impact testing program. The results from these tests led to the validation of high-fidelity computer models, capable of predicting actual or potential Shuttle impact events, were used in the certification of STS-114, NASA s Return to Flight Mission, as safe to fly. This presentation will provide a look into the inner workings of the Space Shuttle and a behind the scenes perspective on the impact analysis and testing done for the Columbia Accident Investigation and NASA's Return to Flight programs. In addition, highlights from recent Shuttle missions are presented.

Melis, Matthew E.↗
NASA NTRS2007

Spherical Cryogenic Hydrogen Tank Preliminary Design Trade Studies

A structural analysis, sizing optimization, and weight prediction study was performed by Collier Research Corporation and NASA Glenn on a spherical cryogenic hydrogen tank. The tank consisted of an inner and outer wall separated by a vacuum for thermal insulation purposes. HyperSizer (Collier Research and Development Corporation), a commercial automated structural analysis and sizing software package was used to design the lightest feasible tank for a given overall size and thermomechanical loading environment. Weight trade studies were completed for different panel concepts and metallic and composite material systems. Extensive failure analyses were performed for each combination of dimensional variables, materials, and layups to establish the structural integrity of tank designs. Detailed stress and strain fields were computed from operational temperature changes and pressure loads. The inner tank wall is sized by the resulting biaxial tensile stresses which cause it to be strength driven, and leads to an optimum panel concept that need not be stiffened. Conversely, the outer tank wall is sized by a biaxial compressive stress field, induced by the pressure differential between atmospheric pressure and the vacuum between the tanks, thereby causing the design to be stability driven and thus stiffened to prevent buckling. Induced thermal stresses become a major sizing driver when a composite or hybrid composite/metallic material systems are used for the inner tank wall for purposes such as liners to contain the fuel and reduce hydrogen permeation.

Arnold, Steven M.↗
NASA NTRS1988

Shock structure in classical magnetohydrodynamics

How the structure of coplanar MHD fast and slow shocks depends upon the relative magnitudes of the dissipation coefficients contained in classical magnetohydrodynamics is examined. An asymptotic method is used in which the scale lengths for resistivity, thermal conduction, and viscosity are widely separated, and the qualitative dependence of the shock solutions upon the ordering of the scales is studied. Upper limit Mach numbers for both fast and slow shocks are defined at which resistivity and thermal conduction taken together can provide all the shock dissipation and at which viscosity is not needed.

Kennel, Charles F.↗
NASA NTRS1980

Pyrotechnic shock at the orbiter/external tank forward attachment

During the initial certification test of the forward structural attachment of the space shuttle orbiter to the external tank, pyrotechnic shock from actuation of the separation device resulted in structural failure of the thermal protection tiles surrounding the attachment. Because of the high shock associated with the separation bolt, the development of alternative low shock separation designs was initiated. Two concepts that incorporate a 5.08 centimeter frangible nut as the release device were developed and tested.

Rogers, W. F.↗
NASA NTRS1988

Thermal instability of a radiative and resistive coronal plasma

Thermal instability is believed to determine the evolution and formation of cool structures in the solar atmosphere such as the transition region and prominences (or filaments). The linear modes that arise in a sheared, force-free, magnetic field due to thermal instability are studied numerically. Previous studies have considered separately modes that arise due to the effects of radiation, compression, anisotropic thermal conduction, and ohmic heating. Here the results of such studies are integrated, first by presenting simple arguments that illustrate the essential physics of ideal, sheared-field, condensation modes, and second by showing numerically how finite resistivity affects the condensational instability in parameter regimes applicable to the solar corona.

Sparks, L.↗