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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 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Flowing gas, non-nuclear experiments on the gas core reactor

Variations in cavity wall and injection configurations of the gas core reactor were aimed at establishing flow patterns that give a maximum of the nuclear criticality eigenvalue. Correlation with the nuclear effect was made using multigroup diffusion theory normalized by previous benchmark critical experiments. Air was used to simulate the hydrogen propellant in the flow tests, and smoked air, argon, or Freon to simulate the central nuclear fuel gas. Tests were run both in the down-firing and upfiring directions. Results showed that acceptable flow patterns with volume fraction for the simulated nuclear fuel gas and high flow rate ratios of propellant to fuel can be obtained. Using a point injector for the fuel, good flow patterns are obtained by directing the outer gas at high velocity long the cavity wall, using louvered injection schemes. Recirculation patterns were needed to stabilize the heavy central gas when different gases are used.

Kunze, J. F.↗
NASA NTRS1973

Dynamic analysis of gas-core reactor system

A heat transfer analysis was incorporated into a previously developed model CODYN to obtain a model of open-cycle gaseous core reactor dynamics which can predict the heat flux at the cavity wall. The resulting model was used to study the sensitivity of the model to the value of the reactivity coefficients and to determine the system response for twenty specified perturbations. In addition, the model was used to study the effectiveness of several control systems in controlling the reactor. It was concluded that control drums located in the moderator region capable of inserting reactivity quickly provided the best control.

Turner, K. H., Jr.↗
NASA NTRS1972

Effects of sudden mixing in the solar core on solar neutrinos and ice ages.

Some numerical experiments with a solar model have been conducted in connection with the hypothesis regarding the effects of mixing in the solar core. Questions concerning a plausible mechanism by which such a mixing could be produced are explored. The variation of solar luminosity throughout the numerical experiments is shown. In connection with a great change in luminosity after a second mixing, it is suggested that the earth is presently undergoing an ice age.

Ezer, D.↗
NASA NTRS1972

Post impact behavior of mobile reactor core containment systems.

In the future, nuclear assemblies containing fission products will be transported at high speeds. An example is a reactor supplying power to a large subsonic airplane. In this case an accident can occur resulting in a ground impact at speeds up to 1000 ft/sec. This paper analyzes the containment vessel temperatures after impact and attempts to understand the design variables that affect the post impact survival of the system. The heat transfer analysis includes conduction, radiation, and convection in addition to the core material heats of fusion and vaporization under partial-burial conditions. Also, included is the fact that fission products vaporize and transport radially outward and condense on cooler surfaces, resulting in a moving heat source.

Puthoff, R. L.↗
NASA NTRS1972

Partitioning of potassium between silicates and sulphide melts - Experiments relevant to the earth's core.

The partitioning of potassium between roedderite, K2Mg5Si12O30 and an Fe-FeS melt was investigated at temperatures about 40 C above the Fe-FeS eutectic. Roedderite was considered a prime candidate for one of the potassium-bearing phases in the primitive earth because roedderite and merrihueite are the only two silicates containing essential potassium which have been identified in stony meteorites. Application of the results to a primitive chondritic earth is discussed, and it is concluded that extraction of most of the earth's potassium into the Fe-FeS core would occur under the conditions in the early earth.-

Goettel, K. A.↗
NASA NTRS1973

Particle track record in Apollo 15 deep core from 54 to 80 cm depths.

Particle track measurements have been made in nearly 500 individual grains from 13 levels in the 54-80 cm depth range of the Apollo 15 deep core. They reveal a wide range of track densities at all depths and some systematic variations within layers, indicating that both predepositional mixing and subsequent layering are present and that separate sublayers exist within larger regions where no sublayers are visible. Minimum track densities are inferred to be useful measures of maximum residence times for undisturbed layers. Using the observed minimum track densities, we conclude that the average deposition rate in this section of soil column was greater than 0.4 cm/million years.

Fleischer, R. L.↗
NASA NTRS1973

Solid core in neutron stars.

Consideration of the question of the solidification of neutron matter under a sufficiently high pressure. Calculations are presented which show that under conditions of pressure and density that typically prevail in the interior of a neutron star a system of strongly interacting baryons minimizes the energy by arranging the constituents in a lattice structure. In addition, observational evidence (regarding pulsar spinups or glitches) is cited which supports the idea of a solid neutron core for heavy neutron stars.

Canuto, V.↗
NASA NTRS1974

Laminating cored, stressed-face, sandwich structures

Structure assemblies of fragile and flexible components are rigidly supported from aggregate exterior during bonding operation. Support assures conformance to desired profiles and duplication of assembly results. It minimizes exterior surface identification with core character, improving structure rigidity while adding desirable aerodynamic qualities and finished appearance.

Heier, W. C.↗
NASA NTRS1974

Research turbine for high temperature core engine application. 1: Cold-airoverall performance of solid scaled turbine

A solid, half-scale model of a 50.8-cm (20-in) research turbine designed for a high temperature core engine application was investigated over a range of speeds and pressure ratios. The results of this test are presented. The effect of rotor blade twist was also investigated. At the design equivalent speed and specific work output, the total efficiency of the turbine with untwisted rotor blades was 87.1 percent; at the same pressure ratio the efficiency of the turbine with twisted rotor blades was 88.0 percent.

Szanca, E. M.↗
NASA NTRS1974

Research turbine for high-temperature core engine application. 2: Effect of rotor tip clearance on overall performance

A 25.4-cm (10-in) tip diameter turbine was tested to determine the effect of rotor radial tip clearance on turbine overall performance. The test turbine was a half-scale model of a 50.8-cm-(20-in.-) diameter research turbine designed for high-temperature core engine application. The test turbine was fabricated with solid vanes and blades with no provision for cooling air and tested at much reduced inlet conditions. The tests were run at design speed over a range of pressure ratios for three different rotor clearances ranging from 2.3 to 6.7 percent of the annular blade passage height. The results obtained are compared to the results obtained with three other turbines of varying amounts of reaction.

Szanca, E. M.↗
NASA NTRS1974

Incidence loss for a core turbine rotor blade in a two-dimensional cascade

The effect of incidence angle on the aerodynamic performance of an uncooled core turbine rotor blade was investigated experimentally in a two-dimensional cascade. The cascade test covered a range of incidence angles from minus 15 deg to 15 deg in 5-degree increments and a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95. The principal measurements were blade-surface static pressures and cross-channel surveys of exit total pressure, static pressure, and flow angle. The results of the investigation include blade-surface velocity distribution and overall performance in terms of weight flow and loss for the range of incidence angles and exit velocity ratios investigated. The measured losses are also compared with two common methods of predicting incidence loss.

Stabe, R. G.↗
NASA NTRS1974

Temperatures inside Mars - Is the core liquid or solid

If internal heating in the mantle of Mars is similar to that in the earth, solid-state convection is the mechanism preventing large scale melting of the Martian mantle. Convection is efficient enough in transporting heat to preclude the existence of a liquid core and hence a dynamo-driven intrinsic magnetic field, if the viscosity of mantle material is lower than 10 to the 22nd to 10 to the 23rd sq cm/sec at temperatures in excess of about 1500 C. The Martian lithosphere is probably several hundred kilometers thick, intermediate in size between that of the earth and Moon.

Young, R. E.↗
NASA NTRS1975

Minimization of jet and core noise by rotation of flow

Jet and core noise can be reduced and flame lengths may be significantly decreased when exhaust gases are caused to rotate or swirl about longitudinal axis of exhaust. Combustion in rotating flows is steady and quiet, and is not accompanied by pulsations or violent fluctuations.

Schwartz, I. R.↗
NASA NTRS1975

Aerodynamic performance of a fully film cooled core turbine vane tested with cold air in a two-dimensional cascade

The aerodynamic performance of a fully film cooled core turbine vane was investigated experimentally in a two-dimensional cascade of 10 vanes. Three of the 10 vanes were cooled; the others were solid (uncooled) vanes. Cold air was used for both the primary and coolant flows. The cascade test covered a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95 and a range of coolant flow rates to 7.5 percent of the primary flow. The coolant flow was varied by changing the coolant supply pressure. The principal measurements were cross-channel surveys of exit total pressure, static pressure, and flow angle. The results presented include exit survey data and overall performance in terms of loss, flow angle, and weight flow for the range of exit velocity ratios and coolant flows investigated. The performance of the cooled vane is compared with the performance of an uncooled vane of the same profile and also with the performance obtained with a single cooled vane in the 10-vane cascade.

Stabe, R. G.↗
NASA NTRS1975

Aerodynamic performance of a ceramic-coated core turbine vane tested with cold air in a two-dimensional cascade

The aerodynamic performance of a core turbine vane with a ceramic coating was investigated experimentally in a two-dimensional cascade of 10 vanes. The vane was first tested with a rough coating and then retested after the coating had been smoothed. The test fluid was atmospheric air. The cascade tests covered a range of pressure ratios corresponding to ideal exit critical velocity ratios of 0.6 to 0.95. The principal measurements were cross-channel surveys of exit total pressure, static pressure, and flow angle. The results presented include exit survey results and overall performance in terms of flow angle, weight flow, and kinetic energy loss. The performance of the ceramic-coated vanes is compared with the performance of an uncoated vane having a similar profile.

Stabe, R. G.↗
NASA NTRS1975

Cold-air annular-cascade investigation of aerodynamic performance of core-engine-cooled turbine vanes. 1: Solid-vane performance and facility description

The aerodynamic performance of a solid (uncooled) version of a core engine cooled stator vane was experimentally determined in a full-annular cascade, where three-dimensional effects could be obtained. The solid vane, which serves as a basis for comparison with subsequent cooled tests, was tested over a range of aftermixed critical velocity ratios of 0.57 to 0.90. Overall vane aftermixed efficiencies were obtained over this critical velocity ratio range and compared with results from a two-dimensional cascade. The variation in vane efficiency and aftermixed flow conditions with circumferential and radial position were obtained and compared with design values. Vane surface static-pressure distributions were also measured and compared with theoretical results.

Goldman, L. J.↗
NASA NTRS1975

Some aspects of core formation in Mercury

An evaluation of existing theories on the existence of the planet's metallic core is presented. Topics considered are: (1) magnetic fields; (2) surface geology; (3) cosmochemical models.

Solomon, S. C.↗
NASA NTRS1975

Preliminary core-engine noise abatement experimental results of a fluid injection nozzle on a JT-15D turbofan engine

Jet noise, as induced by shear stress, in an jet exhaust is investigated. Experiments were performed on a JT-15D fan jet to verify the inward momentum stress reduction concept. The experiments involved making fan air flow convergently around the high velocity core jet with a small angle. Ring airfoils were used as flow separators for the minimization of the thrust loss. Jet exhaust noise reduction of ll db at 30 deg from the jet axis was recorded and 8 db integrated overall noise reduction over a hemisphere was measured with only 4.6% thrust loss, or 152 db/percent thrust loss.

Cheng, D. Y.↗