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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 1,387 records · Page 77
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Oxidizer heat exchanger component test

The RL10-IIB engine, is capable of multimode thrust operation. The engine operates at two low-thrust levels: tank head idle (THI), approximately 1 to 2 percent of full thrust; and pumped idle, 10 percent of full thrust. Operation at THI provides vehicle propellant settling thrust and efficient thermal conditioning; PI operation provides vehicle tank prepressurization and maneuver thrust for low-g deployment. Stable combustion of the RL10-IIB engine during the low-thrust operating modes can be accomplished by using a heat exchanger to supply gaseous oxygen to the propellant injector. The oxidized heat exchanger (OHE) vaporizes the liquid oxygen using hydrogen as the energy source. This report summarizes the test activity and post-test data analysis for two possible heat exchangers, each of which employs a completely different design philosophy. One design makes use of a low-heat transfer (PHT) approach in combination with a volume to attenuate pressure and flow oscillations. The test data showed that the LHT unit satisfied the oxygen exit quality of 0.95 or greater in both the THI and PI modes while maintaining stability. The HHT unit fulfilled all PI requirements; data for THI satisfactory operation is implied from experimental data that straddle the exact THI operating point.

Kanic, P. G.↗
NASA NTRS2016

Thermal Vacuum Test Correlation of a Zero Propellant Load Case Thermal Capacitance Propellant Gauging Analytical Model

This thesis describes the development and correlation of a thermal model that forms the foundation of a thermal capacitance spacecraft propellant load estimator. Specific details of creating the thermal model for the diaphragm propellant tank used on NASA's Magnetospheric Multiscale spacecraft using ANSYS and the correlation process implemented are presented. The thermal model was correlated to within plus or minus 3 degrees Celsius of the thermal vacuum test data, and was determined sufficient to make future propellant predictions on MMS. The model was also found to be relatively sensitive to uncertainties in applied heat flux and mass knowledge of the tank. More work is needed to improve temperature predictions in the upper hemisphere of the propellant tank where predictions were found to be 2 to 2.5 C lower than the test data. A road map for applying the model to predict propellant loads on the actual MMS spacecraft toward its end of life in 2017-2018 is also presented.

Gauging↗
NASA NTRS1972

Centaur space vehicle pressurized propellant feed system tests

Engine firing tests, using a full-scale flight-weight vehicle, were performed to evaluate a pressurized propellant feed system for the Centaur. The pressurant gases used were helium and hydrogen. The system was designed to replace the boost pumps currently used on Centaur. Two liquid oxygen tank pressurization modes were studied: (1) directly into the ullage and (2) below the propellant surface. Test results showed the two Centaur RL10 engines could be started and run over the range of expected flight variables. No system instabilities were encountered. Measured pressurization gas quantities agreed well with analytically predicted values.

Source record↗
NASA NTRS2014

Testing of a Neon Loop Heat Pipe for Large Area Cryocooling

Cryocooling of large areas such as optics, detector arrays, and cryogenic propellant tanks is required for future NASA missions. A cryogenic loop heat pipe (CLHP) can provide a closed-loop cooling system for this purpose and has many advantages over other devices in terms of reduced mass, reduced vibration, high reliability, and long life. A neon CLHP was tested extensively in a thermal vacuum chamber using a cryopump as the heat sink to characterize its transient and steady performance and verify its ability to cool large areas or components. Tests conducted included loop cool-down from the ambient temperature, startup, power cycle, heat removal capability, loop capillary limit and recovery from a dry-out, low power operation, and long duration steady state operation. The neon CLHP demonstrated robust operation. The loop could be cooled from the ambient temperature to subcritical temperatures very effectively, and could start successfully by applying power to both the pump and evaporator without any pre-conditioning. It could adapt to changes in the pump power andor evaporator power, and reach a new steady state very quickly. The evaporator could remove heat loads between 0.25W and 4W. When the pump capillary limit was exceeded, the loop could resume its normal function by reducing the pump power. Steady state operations were demonstrated for up to 6 hours. The ability of the neon loop to cool large areas was therefore successfully verified.

Cryogenics↗
DOE OSTI2022

Effective thermal conductivity of insulation materials for cryogenic LH 2 storage tanks: A review

An accurate estimation of the effective thermal conductivity of various insulation materials is essential in the evaluation of heat leak and boil-off rate from liquid hydrogen storage tanks. In this work, we review the existing experimental data and various proposed correlations for predicting the effective conductivity of insulation systems consisting of powders, foams, fibrous materials, and multilayer systems. We also propose a first principles-based correlation that may be used to estimate the dependence of the effective conductivity as a function of temperature, interstitial gas composition, pressure, and structural properties of the material. We validate the proposed correlation using available experimental data for some common insulation materials. Further improvements and testing of the proposed correlation using laboratory scale data obtained using potential LH 2 tank insulation materials are also discussed.

08 HYDROGEN↗
DOE OSTI2024

Long-Term Performance of Reference Electrodes in Alkaline Radioactive Waste Storage Environments

Accurate measurements of corrosion potential are important for assessing the likelihood of internal localized corrosion and stress corrosion cracking of carbon steel tanks used for storing radioactive wastes. Reference electrodes in underground radioactive waste storage tanks are challenging to deploy, and more difficult to extract and replace frequently due to radiological exposure and disposal constraints. Hence, electrodes that exhibit stable performance over long periods of immersion in these waste environments are desirable. The present study evaluates the stability of reference electrodes used in radioactive waste storage tanks over a much longer period than previously studied. Long-term tests on Ag/AgCl and Hg/HgO reference electrodes were performed in nonradioactive simulants formulated from wastes stored at the Hanford site. Electrode degradation, which was studied by various in situ and ex situ evaluation techniques, was correlated to changes in electrode fill chemistry from waste intrusion via the porous frit junction. An intentional contamination study was performed to better understand and predict contamination effects on electrode potential drift.

Materials Science↗
NASA NTRS1973

Apparatus and method for generating large mass flow of high temperature air at hypersonic speeds

High temperature, high mass air flow and a high Reynolds number test air flow in the Mach number 8-10 regime of adequate test flow duration is attained by pressurizing a ceramic-lined storage tank with air to a pressure of about 100 to 200 atmospheres. The air is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the air over an electric arc heater means. The air cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized air in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized air effects an exothermic reaction which maintains the pressure and temperature of the pressurized air during the rapid release.

Sabol, A. P.↗
NASA NTRS1980

Advanced fuel system technology for utilizing broadened property aircraft fuels

Factors which will determine the future supply and cost of aviation turbine fuels are discussed. The most significant fuel properties of volatility, fluidity, composition, and thermal stability are discussed along with the boiling ranges of gasoline, naphtha jet fuels, kerosene, and diesel oil. Tests were made to simulate the low temperature of an aircraft fuel tank to determine fuel tank temperatures for a 9100-km flight with and without fuel heating; the effect of N content in oil-shale derived fuels on the Jet Fuel Thermal Oxidation Tester breakpoint temperature was measured. Finally, compatibility of non-metallic gaskets, sealants, and coatings with increased aromatic content jet fuels was examined.

Reck, G. M.↗
NASA NTRS1984

Development of acceptance criteria for batches of silane primer for external tank thermal protection system bonding applications

Silane primers for use as thermal protection on external tanks were subjected to various analytic techniques to determine the most effective testing method for silane lot evaluation. The analytic methods included high performance liquid chromatography, gas chromatography, thermogravimetry (TGA), and fourier transform infrared spectroscopy (FTIR). It is suggested that FTIR be used as the method for silane lot evaluation. Chromatograms, TGA profiles, bar graphs showing IR absorbances, and FTIR spectra are presented.

Mikes, F.↗
NASA NTRS1986

Low-Flammability PTFE for High-Oxygen Environments

Modified forming process removes volatile combustible materials. Flammability of cable-wrapping tape reduced by altering tape-manufacturing process. In new manufacturing process, tape formed by proprietary process of screw extrusion, followed by washing in solvent and drying. Tape then wrapped as before. Spectrogram taken after extrusion, washing, and drying shows lower hydrocarbon content. PTFE formed by new process suited to oxygen-rich environments. Safe in liquid oxygen of Space Shuttle tank and in medical uses; thin-wall shrinkable tubing in hospital test equipment, surgical instruments, and implants.

Walle, E.↗
NASA NTRS1988

Pathfinder: Shuttle Exhibit

This video introduces the Pathfinder Shuttle Exhibit, a joint project between the Marshall Space Flight Center and the State of Alabama's Space and Rocket Center in Huntsville. The exhibit features a never flown Shuttle vehicle, Pathfinder, that was used in early ground tests in the Shuttle Program, as well as an actual external fuel tank and set of booster rockets. The video includes footage of actual launches, the Pathfinder Shuttle Exhibit, and shots of the Space Camp at Alabama's Space and Rocket Center.

Source record↗
NASA NTRS1994

Flight investigation of the use of a nose gear jump strut to reduce takeoff ground roll distance of STOL aircraft

A series of flight tests was conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short takeoff and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high pressure pneumatic system and a control system provided the extendible nose gear, or 'jump strut,' capability. The limited flight test program explored the effects of thrust-to-weight ratio, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that the predicted reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

Eppel, Joseph C.↗
NASA NTRS1964

Spin Tunnel Investigation of a 1/30 Scale Model of the North American A-5A Airplane

An investigation has been made in the Langley spin tunnel to determine the erect and inverted spin and recovery characteristics of a 1/30-scale dynamic model of the North American A-5A airplane. Tests were made for the basic flight design loading with the center of gravity at 30-percent mean aerodynamic chord and also for a forward position and a rearward position with the center of gravity at 26-percent and 40-percent mean aerodynamic chord, respectively. Tests were also made to determine the effect of full external wing tanks on both wings, and of an asymmetrical condition when only one full tank is carried.

Lee, Henry A.↗
NASA NTRS2000

The Low Temperature Microgravity Physics Experiments Project

The Low Temperature Microgravity Physics Facility (LTMPF) is being developed by NASA to provide long duration low temperature and microgravity environment on the International Space Station (ISS) for performing fundamental physics investigations. Currently, six experiments have been selected for flight definition studies. More will be selected in a two-year cycle, through NASA Research Announcement. This program is managed under the Low Temperature Microgravity Physics Experiments Project Office at the Jet Propulsion Laboratory. The facility is being designed to launch and returned to earth on a variety of vehicles including the HII-A and the space shuttle. On orbit, the facility will be connected to the Exposed Facility on the Japanese Experiment Module, Kibo. Features of the facility include a cryostat capable of maintaining super-fluid helium at a temperature of 1.4 K for 5 months, resistance thermometer bridges, multi-stage thermal isolation system, thermometers capable of pico-Kelvin resolution, DC SQUID magnetometers, passive vibration isolation, and magnetic shields with a shielding factor of 80dB. The electronics and software architecture incorporates two VME buses run using the VxWorks operating system. Technically challenging areas in the design effort include the following: 1) A long cryogen life that survives several launch and test cycles without the need to replace support straps for the helium tank. 2) The minimization of heat generation in the sample stage caused by launch vibration 3) The design of compact and lightweight DC SQUID electronics. 4) The minimization of RF interference for the measurement of heat at pico-Watt level. 5) Light weighting of the magnetic shields. 6) Implementation of a modular and flexible electronics and software architecture. The first launch is scheduled for mid-2003, on an H-IIA Rocket Transfer Vehicle, out of the Tanegashima Space Center of Japan. Two identical facilities will be built. While one facility is onboard the ISS, the other is re-integrated on the ground with new experiments. When the cryogen of the facility in space are exhausted, it will be swapped with the other facility with the new experiment. A total of 20 science missions are envisioned over the next 20 years.

Holmes, Warren↗
NASA NTRS2004

Tensile Properties of Polymeric Matrix Composites Subjected to Cryogenic Environments

Polymer matrix composites (PMC s) have seen limited use as structural materials in cryogenic environments. One reason for the limited use of PMC s in cryogenic structures is a design philosophy that typically requires a large, validated database of material properties in order to ensure a reliable and defect free structure. It is the intent of this paper to provide an initial set of mechanical properties developed from experimental data of an advanced PMC (IM7/PETI-5) exposed to cryogenic temperatures and mechanical loading. The application of this data is to assist in the materials down-select and design of cryogenic fuel tanks for future reusable space vehicles. The details of the material system, test program, and experimental methods will be outlined. Tension modulus and strength were measured at room temperature, -196 C, and -269 C on five different laminates. These properties were also tested after aging at -186 C with and without loading applied. Microcracking was observed in one laminate.

Whitley, Karen S.↗
NASA NTRS1948

Ditching Tests of a 1/24-Scale Model of the Lockheed XR60-1 Airplane, TED No. NACA 235

The ditching characteristics of the Lockheed XR60-1 airplane were determined by tests of a 1/24-scale dynamic model in calm water at the Langley tank no. 2 monorail. Various landing attitudes, flap settings, speeds, and conditions of damager were investigated. The ditching behavior was evaluated from recordings of decelerations, length of runs, and motions of the model. Scale-strength bottoms and simulated crumpled bottoms were used to reproduce probable damage to the fuselage. It was concluded that the airplane should be ditched at a landing attitude of about 5 deg with flaps full down. At this attitude, the maximum longitudinal deceleration should not exceed 2g and the landing run will be bout three fuselage lengths. Damage to the fuselage will not be excessive and will be greatest near the point of initial contact with the water.

Fisher, Lloyd J.↗
NASA NTRS2004

Cryogenic Nitrogen Thermosyphon Developed and Characterized

A two-phase nitrogen thermosyphon was developed at the NASA Glenn Research Center to efficiently integrate a cryocooler into an insulated liquid-nitrogen-filled tank as part of an advanced development zero-boiloff (ZBO) ground test. NASA Marshall Space Flight Center's (MSFC) Advanced Space Transportation Program supported this test to improve the performance of in-space propulsion system concepts. Recent studies (ref. 1) have shown significant mass reductions and other advantages when incorporating active cooling in a ZBO configuration, enabling consideration of high-performing cryogenic propellants for long-duration applications in space. Active cooling was integrated via a thermosyphon, made of copper, 42 in. (1070 mm) long with an inner diameter of 0.436 in. (11 mm). It was charged with nitrogen to 225 psia at 300 K, which provided a fill ratio of 15 percent. The temperatures and heat flows through the thermosyphon were monitored during the startup phase of the ZBO test, and steady-state tests were conducted over a range of increasing and decreasing heat flows. The results also were compared with the initial design calculations and with results for a similar thermosyphon. They show that the thermal resistance of the thermosyphon was one-half of that expected--0.2 K/W at a heat flow of 8.0 W. The design calculations also showed that this resistance can be made relatively constant over a wider range of heat flows by making the ratio of evaporator area to condenser area 3:1. The better-than-expected results will translate into reduced integration loss for the ZBO concept.

Plachta, David W.↗