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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Emergency cooling analysis for the loss of coolant malfunction

This report examines the dynamic response of a conceptual space power fast-spectrum lithium cooled reactor to the loss of coolant malfunction and several emergency cooling concepts. The results show that, following the loss of primary coolant, the peak temperatures of the center most 73 fuel elements can range from 2556 K to the region of the fuel melting point of 3122 K within 3600 seconds after the start of the accident. Two types of emergency aftercooling concepts were examined: (1) full core open loop cooling and (2) partial core closed loop cooling. The full core open loop concept is a one pass method of supplying lithium to the 247 fuel pins. This method can maintain fuel temperature below the 1611 K transient damage limit but requires a sizable 22,680-kilogram auxiliary lithium supply. The second concept utilizes a redundant internal closed loop to supply lithium to only the central area of each hexagonal fuel array. By using this method and supplying lithium to only the triflute region, fuel temperatures can be held well below the transient damage limit.

Peoples, J. A.↗
NASA NTRS2007

Initial Testing of the Stainless Steel NaK-Cooled Circuit (SNaKC)

An actively pumped alkali metal flow circuit, designed and fabricated at the NASA Marshall Space Flight Center, is currently undergoing testing in the Early Flight Fission Test Facility (EFF-TF). Sodium potassium (NaK) was selected as the primary coolant. Basic circuit components include: simulated reactor core, NaK to gas heat exchanger, electromagnetic liquid metal pump, liquid metal flowmeter, load/drain reservoir, expansion reservoir, test section, and instrumentation. Operation of the circuit is based around the 37-pin partial-array core (pin and flow path dimensions are the same as those in a full core), designed to operate at 33 kWt. This presentation addresses the construction, fill and initial testing of the Stainless Steel NaK-Cooled Circuit (SNaKC).

Garber, Anne↗
NASA NTRS2007

Capabilities and Testing of the Fission Surface Power Primary Test Circuit (FSP-PTC)

An actively pumped alkali metal flow circuit, designed and fabricated at the NASA Marshall Space Flight Center, is currently undergoing testing in the Early Flight Fission Test Facility (EFF-TF). Sodium potassium (NaK), which was used in the SNAP-10A fission reactor, was selected as the primary coolant. Basic circuit components include: simulated reactor core, NaK to gas heat exchanger, electromagnetic (EM) liquid metal pump, liquid metal flowmeter, load/drain reservoir, expansion reservoir, test section, and instrumentation. Operation of the circuit is based around a 37-pin partial-array core (pin and flow path dimensions are the same as those in a full core), designed to operate at 33 kWt. NaK flow rates of greater than 1 kg/sec may be achieved, depending upon the power applied to the EM pump. The heat exchanger provides for the removal of thermal energy from the circuit, simulating the presence of an energy conversion system. The presence of the test section increases the versatility of the circuit. A second liquid metal pump, an energy conversion system, and highly instrumented thermal simulators are all being considered for inclusion within the test section. This paper summarizes the capabilities and ongoing testing of the Fission Surface Power Primary Test Circuit (FSP-PTC).

Garber, Anne E.↗
NASA NTRS1973

Feasibility study of full-reactor gas core demonstration test

Separate studies of nuclear criticality, flow patterns, and thermodynamics for the gas core reactor concept have all given positive indications of its feasibility. However, before serious design for a full scale gas core application can be made, feasibility must be shown for operation with full interaction of the nuclear, thermal, and hydraulic effects. A minimum sized, and hence minimum expense, test arrangement is considered for a full gas core configuration. It is shown that the hydrogen coolant scattering effects dominate the nuclear considerations at elevated temperatures. A cavity diameter of somewhat larger than 4 ft (122 cm) will be needed if temperatures high enough to vaporize uranium are to be achieved.

Kunze, J. F.↗
NASA NTRS1994

Probing the galactic disk and halo. 1: The NGC 3783 sight line

We report a study of Galactic disk and halo absorption toward the Seyfert galaxy NGC 3783 which has Galactic coordinates l = 287.46 and b = +22.95. The data were obtained with the Goddard High Resolution Spectrograph operating at medium resolution with the Large Science Aperture, which produces a line spread function having a sharp core (full width at half maximum (FWHM) approximately 20 km/s) and broad wings extending to +/- 70 km/s. Ion species detected in absorption near zero LSR velocity include C IV and N V for high ions, and C I, Mg II, Si II, and S II for low ions. Absorption from a high-velocity cloud (HVC) at a velocity of +240 km/s along the sight line is also detected in the ion species of S II, Si II, and probably C I. This is the first reported case where S II and C I absorption has been detected in a HVC. The S II lines are especially useful since metal abundance estimates based on S are largely unaffected by dust grains. The study is aided by the availability of 21 cm emission data.

Lu, Limin↗
NASA NTRS1978

Aerodynamic and acoustic effects of eliminating core swirl from a full scale 1.6 stage pressure ratio fan (QF-5A)

Fan QF-5A was a modification of fan QF-5 which had an additional core stator and adjusted support struts to turn the core exit flow from a 30 deg swirl to the axial direction. This modification was necessary to eliminate the impingement of the swirling core flow on the axial support pylon of the NASA-Lewis Quiet Fan Facility that caused aerodynamic, acoustic and structural problems with the original fan stage at fan speeds greater than 85 percent of design. The redesigned fan QF-5A did obtain the design bypass ratio with an increased core airflow suggesting that the flow problem was resolved. Acoustically, the redesigned stage showed a low frequency broadband noise reduction compared to the results for fan QF-5 at similar operating conditions.

Woodward, R. P.↗
NASA NTRS1993

Two-dimensional thermal-hydraulics analyses of the Pellet Bed Reactor for Nuclear Thermal Propulsion

Thermal-hydraulics design and analyses of the Pellet Bed Reactor for nuclear thermal propulsion are performed using the nuclear propulsion thermal-hydraulic analysis model to determine the 2D steady-state temperature, pressure, and flow fields in the core and optimize the orificing in the hot-frit to avoid hot spots in the core at full power operation. Results show that by properly adjusting the axial porosity profile in the hot frit, hot spots in the core can be essentially eliminated during full power operation. This important accomplishment is achieved at the expense of slightly larger pressure losses in the core because of flow restriction at the hot frit. However, the overall pressure losses is only about 11 percent of the propellant inlet pressure.

Morley, Nicholas J.↗
NASA NTRS1988

The dynamical regime of fluid flow at the core surface

An alternative method for determining the fluid motion immediately beneath the core-mantle boundary is presented which is based on solving the full nonlinear core motions problem. This method is used to examine three dynamical hypotheses about the flow: (1) the steady motions hypothesis; (2) the geostrophic hypothesis; and (3) the toroidal flow hypothesis. Better fits to the field are obtained with the toroidal flows than with geostrophic flows, casting considerable doubt on the validity of the geostrophic hypothesis. Additionally, some indication is found that failure of the frozen-flux approximation, a concomitant assumption, may be a serious obstacle to obtaining reliable maps of the core fluid flow.

Bloxham, Jeremy↗
NASA NTRS2009

Comparison of the Effects of RAS vs. Kain-Fritsch Convective Schemes on Katrina Forecasts with GEOS-5

Global forecasts were made with the 0.25-degree latitude version of GEOS-5, with the RAS scheme and with the Kain-Fritsch scheme. Examination was made of the Katrina (2005) hurricane simulation. Replacement of the RAS convective scheme with the K-F scheme results in a much more vigorous Katrina, closer to reality. Still, the result is not as vigorous as reality. In terms of wind maximum, the gap was closed by ~50%. The result seems to be due to the RAS scheme drying out the boundary layer, thus hampering the grid-scale secondary circulation and attending cyclone development. The RAS case never developed a full warm core, whereas the K-F case did. Not shown here: The K-F scheme also resulted in a more vigorous storm than when GEOS-5 is run with no convective parameterization. Also not shown: An experiment in which the RAS firing level was moved up by 3 model levels resulted in a stronger, warm-core storm, though not as strong as the K-F case. Effects on storm track were noticed, but not studied.

Miller, Timothy L.↗
NASA NTRS2012

Initial SEE Testing of Maestro

We have reported on initial SEE sensitivity of the full 49-core Maestro device. Supporting the low-level structures and qualitative system observation goals of phase 1 of testing. Observed sensitivities found to be consistent with Boeing predictions. Highlighted by the L1 data cache sensitivity which drives the rates on the current Maestro device. Presented details to the hardware and software setups that show where the limitations - highlighting future work. Key future work includes testing with memory and IO ports.

cache sensitivity↗
NASA NTRS1969

Comments on the feasibility of developing gas core nuclear reactors

Recent developments in the fields of gas core hydrodynamics, heat transfer, and neutronics indicate that gas core nuclear rockets may be feasible from the point of view of basic principles. Based on performance predictions using these results, mission analyses indicate that gas core nuclear rockets may have the potential for reducing the initial weight in orbit of manned interplanetary vehicles by a factor of 5 when compared to the best chemical rocket systems. In addition, there is a potential for reducing total trip times from 450 to 500 days for chemical systems to 250 to 300 days for gas core systems. The possibility of demonstrating the feasibility of gas core nuclear rocket engines by means of a logical series of experiments of increasing difficulty that ends with ground tests of full scale gas core reactors is considered.

Rom, F. E.↗
NASA NTRS2015

Optimization of Selected Remote Sensing Algorithms for Embedded NVIDIA Kepler GPU Architecture

This paper evaluates the potential of embedded Graphic Processing Units in the Nvidias Tegra K1 for onboard processing. The performance is compared to a general purpose multi-core CPU and full fledge GPU accelerator. This study uses two algorithms: Wavelet Spectral Dimension Reduction of Hyperspectral Imagery and Automated Cloud-Cover Assessment (ACCA) Algorithm. Tegra K1 achieved 51 for ACCA algorithm and 20 for the dimension reduction algorithm, as compared to the performance of the high-end 8-core server Intel Xeon CPU with 13.5 times higher power consumption.

Riha, Lubomir↗
NASA NTRS1976

Flight loads measurements obtained from calibrated strain-gage bridges mounted externally on the skin of a low-aspect-ratio wing

Flight-test measurements of wingloads (shear, bending moment, and torque) were obtained by means of strain-gage bridges mounted on the exterior surface of a low-aspect-ratio, thin, swept wing which had a structural skin, full-depth honeycomb core, sandwich construction. Details concerning the strain-gage bridges, the calibration procedures used, and the flight-test results are presented along with some pressure measurements and theoretical calculations for comparison purposes.

Eckstrom, C. V.↗
NASA NTRS1981

NASA VCE test bed engine aerodynamic performance characteristics and test results

The Core Driven Fan Stage (CDFS) Variable Cycle Engine (VCE) has been identified as a leading candidate for advanced supersonic cruise aircraft. A scale demonstrator version of this engine has been designed and tested. This testbed engine features a split fan with double bypass capability, variable forward and aft mixers, and a variable area low pressure turbine nozzle to permit exploration and optimization of the cycle in both single and double bypass modes. This paper presents the aerodynamic performance characteristics and experimental results obtained from both the core engine and full engine tests.

French, M. W.↗
NASA NTRS1984

Conceptual design of a noncontacting power transfer device for the ASPS Vernier system

The conceptual of electrical power transfer across a magnetically controlled gap as discussed for several years. The design represents the culmination of the first serious attempt to design a very low force, noncontracting power transfer mechanism. The electromagnetic device advanced herein is an ironless, translatable secondary transformer in which one of the two coils is fixed to the entire magnetic core. The second coil is free to move within the core over the full range of motions required. The specific application considered for this design was the Vernier subsystem of the Annular Suspension and Pointing System (ASPS). The development of and rationale for the electromagnetics design is presented. Similar documentation is provided for the Electronics Design. The Appendices detail the results of small scale model tests, disturbance force calculations, the baseline transformer fabrication drawings, the AVS Converter Parts List, and model schematic diagrams.

Kroeger, J.↗
NASA NTRS2010

Deep Galex Observations of the Coma Cluster: Source Catalog and Galaxy Counts

We present a source catalog from deep 26 ks GALEX observations of the Coma cluster in the far-UV (FUV; 1530 Angstroms) and near-UV (NUV; 2310 Angstroms) wavebands. The observed field is centered 0.9 deg. (1.6 Mpc) south-west of the Coma core, and has full optical photometric coverage by SDSS and spectroscopic coverage to r-21. The catalog consists of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically-confirmed Coma member galaxies that range from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is 80% complete to NUV=23 and FUV=23.5, and has a limiting depth at NUV=24.5 and FUV=25.0 which corresponds to a star formation rate of 10(exp -3) solar mass yr(sup -1) at the distance of Coma. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies. This required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as a position prior), and used the GALEX pipeline catalog for bright and/or extended objects. We performed simulations to assess the importance of systematic effects (e.g. object blends, source confusion, Eddington Bias) that influence source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is also free from source confusion over the UV magnitude range studied here: conversely, we estimate that the GALEX pipeline catalogs are confusion limited at NUV approximately 23 and FUV approximately 24. We have measured the total UV galaxy counts using our catalog and report a 50% excess of counts across FUV=22-23.5 and NUV=21.5-23 relative to previous GALEX measurements, which is not attributed to cluster member galaxies. Our galaxy counts are a better match to deeper UV counts measured with HST.

Hammer, D.↗
NASA NTRS2016

Venera-D: Technology Implications

The Venera-D concept mission being developed by the Joint Russian US Science Definition Team (JSDT) is an exciting concept for exploring Venus and is based largely successful approach of heritage Soviet Veneras and VEGA missions. The desired science of Venera-D seeks to build on the results on these missions and also missions by other nations such as the American Mariners, Pioneer Venus, and Magellan missions, ESAs Venus Express, and the current Japanese Akatsuki mission. A number of elements comprise the potential full mission concept. Core elements of the mission include a long lived orbiter (3 years) and a short duration ( 2 hour) but powerful lander. Several other mission elements are possible depending on mission constraints which include cost limitations. Other possible elements include some form of mobile aerial platform, such as a balloon, long lived dropsonde(s), and sub-satellite. One can image the diverse maturity of technologies that will be needed to support the various elements of the Venera-D mission concept. Given the long heritage and recent orbiting missions, little technology challenges are expected for the orbiter. However it has been several decades since humanity has placed a functioning lander on the Venus surface or spent time floating in the Venus atmosphere so the technology challenges will be of greater concern. This briefing presents some of the results of the Venera-D technology sub-group.

Venera-D↗