Heterogeneous Ignition of Metals - Model and Experiment
Spontaneous ignition temperature, ignition temperature, and transition temperature for metal-oxidizing gas system models of solid propellant rocket engine combustion processes
Mellor, A. M.↗
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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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Effect of cover gas pressures on accelerated cavitation damage
Gas pressure effects on cavitation resistance of structural materials in liquid metal space power systems
Johnston, J. R.↗
The effect of periodic pressure and temperature fluctuations on unsteady heat transfer in a closed system
Unsteady heat transfer from closed gas system to plane metal surface with periodic pressure and temperature oscillations on gas
Wendland, D. W.↗
Thermal control characteristics of a diffuse bladed, specular base louver system.
Spacecraft temperature control louver system using diffuse metallic blades and specular base reflection
Parmer, J. F.↗
Photometry of cepheid variables
Qualitative photometric analysis system for metal-rich and metal-poor cepheid variable stars
Kelsall, T. N.↗
Arc jet tests of metallic TPS materials
Arc jets tests of thoria dispersed nickel base alloys and cobalt base alloys for space shuttle metallic thermal protection system
Centolanzi, F. J.↗
Arc jet tests of metallic TPS materials.
Seven thoria dispersed nickel base alloys and one cobalt base alloy, candidates for the Metallic Thermal Protection System for the Space Shuttle Vehicle, were tested simultaneously in an arc jet at a nominal test temperature of 1366 deg K (2000 deg F) and pressure of 0.01 atmospheres. The degradation of the materials after 50 one half-hour cycles in the arc jet simulating Space Shuttle entry conditions was determined utilizing techniques including X-ray diffraction, metallography, and electron beam microprobe.
Centolanzi, F. J.↗
Metallic materials for the space shuttle.
The need for further development and reevaluation of current space-vehicle materials (intended for a single mission) to meet the long-time requirements of a space shuttle is demonstrated. Leading metallic material candidates and their properties are tabulated for a delta-wing space shuttle configuration with a metallic thermal protection system.
Tavassoli, A. A.↗
Liquid-metal binary cycles for stationary power
The use of topping cycles to increase electric power plant efficiency is discussed, with particular attention to mercury and alkali metal Rankine cycle systems that could be considered for topping cycle applications. An overview of this technology, possible system applications, the required development, and possible problem areas is presented.
Gutstein, M.↗
Solidification under zero gravity: A Long Duration Exposure Facility (LDEF) experiment for an early space shuttle mission
The preliminary design of two series of simple experiments the objectives of which are to determine the effect of an absence of gravity on (1) the general morphology of the structure, (2) location of ullage space, and (3) magnitude of surface tension driven convection, during the solidification of several metallic and nonmetallic systems is described. Details of the investigative approach, experimental procedure, experimental hardware, data reduction and analysis, and anticipated results are given.
Bailey, J. A.↗
Conference on In Situ Composites, 2nd, Bolton Landing, N.Y., September 2-5, 1975, Proceedings
The present collection of papers deals with advances in several areas of interest in in-situ composites. Major areas discussed include solidification and structural control, physical properties, mechanical behavior, stability, environmental response, and development of new metallic and ceramic systems. New evidence about directional solidification in terms of temperature gradients is presented along with solidification rates for successful formation of in-situ composite structures. Much is learned about the factors that control structure in directionally solidified eutectic alloys and the relationship of properties to structure, especially the change in properties as a function of operating environment. Less progress is achieved in the area of physical properties than in the area of mechanical properties. Individual items are announced in this issue.
Jackson, M. R.↗
Tensile and compressive test results for metal matrix composites
Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression specimens is presented.
Shuart, M. J.↗
Incoherent scatter radar observations of irregular structure in mid-latitude sporadic E layers
The basic experiments used phase-coded pulses to record electron density profiles with a resolution of 600 m in range and 300 m in horizontal extent, while scanning in azimuth. Data from incoherent scatter radar were compared with simultaneous ionosonde observations. Observations of sporadic E layers by incoherent scatter radar were discussed in terms of the effects of the neutral wind system acting on metallic ions. Several features were noted in the data, which support the wind shear mechanism of layer formation. The sporadic E layers often contained a pronounced small-scale structure, especially at times when partially transparent echoes were observed by the ionosonde. Under specific conditions, the ions in a meteor trail can be converged by a shear in the neutral wind into a relatively small irregularity at the center of a sporadic E layer.
Miller, K. L.↗
Technology and operational considerations for low-heat-rate trajectories
A broad parametric study which examines several critical aspects of low-heat-rate entry trajectories is performed. Low planform loadings associated with future winged earth-entry vehicles coupled with the potential application of metallic thermal protection systems (TPS) suggest that such trajectories are of particular interest. Studied are three heating conditions - reference, stagnation, and windward centerline, for both laminar and turbulent flow; configuration-related factors including planform loading and hypersonic angle of attack; and mission-related factors such as cross-range and orbit inclination. Results indicate benefits in the design of TPS to be gained by utilizing moderate angles of attack as opposed to high-lift coefficient, high angles of attack, during entry. An assessment of design and technology implications is made.
Wurster, K. E.↗
The 1979 Goddard Space Flight Center Battery Workshop
Papers discussing the latest results of testing, analysis, and development of the sealed nickel cadmium cell system are presented. Metal hydrogen and lithium cell technology and applications are also discussed. The purpose of the workshop was to share flight and test experience, stimulate discussion on problem areas, and to review the latest technology improvements.
Halpert, G.↗
Electric propulsion technology
The advanced electric propulsion program is directed towards lowering the specific impulse and increasing the thrust per unit of ion thruster systems. In addition, electrothermal and electromagnetic propulsion technologies are being developed to attempt to fill the gap between the conventional ion thruster and chemical rocket systems. Most of these new concepts are exagenous and are represented by rail accelerators, ablative Teflon thrusters, MPD arcs, Free Radicals, etc. Endogenous systems such as metallic hydrogen offer great promise and are also being pursued.
Finke, R. C.↗
Solidification phenomena of binary organic mixtures
The coalescence rates and motion of liquid bubbles in binary organic mixtures were studied. Several factors such as temperature gradient, composition gradient, interfacial tension, and densities of the two phases play important roles in separation of phases of immiscible liquids. An attempt was made to study the effect of initial compositions on separation rates of well-dispersed organic mixtures at different temperatures and, ultimately, on the homogeneity of solidification of the immiscible binary organic liquids. These organic mixtures serve as models for metallic pseudo binary systems under study. Two specific systems were investigated: ethyl salicylate - diethyl glycol and succinonitrile - water.
Chang, K.↗
The solidification of monotectic alloys - Microstructures and phase spacings
The microstructures of directionally grown monotectic alloys in metallic and organic systems fall into two categories those which can form aligned fibrous composite structures with even phase spacings and fiber sections, and those in which the phase distribution is coarser and less regular. This division appears to relate to the form of the phase diagram and has been rationalized by Cahn (1977, 1979) in terms of the relative surface energies between solid and two liquids to give steady state or nonsteady state profiles. The transition in growth behavior occurs when the ratio of the monotectic temperature to that of the upper consolute temperature is approximately 0.9. Differences in phase spacings between a range of monotectic and eutectic systems are discussed in terms of the expected growth interface shapes and the factors which will influence them.
Grugel, R. N.↗