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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Testing the Effects of Helium Pressurant on Thermodynamic Vent System Performance with Liquid Hydrogen

In support of the development of a zero gravity pressure control capability for liquid hydrogen, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the effects of helium pressurant on the performance of a spray bar thermodynamic vent system (TVS). Fourteen days of testing was performed in August - September 2005, with an ambient heat leak of about 70-80 watts and tank fill levels of 90%, 50%, and 25%. The TVS successfully controlled the tank pressure within a +/- 3.45 kPa (+/- 0.5 psi) band with various helium concentration levels in the ullage. Relative to pressure control with an "all hydrogen" ullage, the helium presence resulted in 10 to 30 per cent longer pressure reduction durations, depending on the fill level, during the mixing/venting phase of the control cycle. Additionally, the automated control cycle was based on mixing alone for pressure reduction until the pressure versus time slope became positive, at which time the Joule-Thomson vent was opened. Testing was also conducted to evaluate thermodynamic venting without the mixer operating, first with liquid then with vapor at the recirculation line inlet. Although ullage stratification was present, the ullage pressure was successfully controlled without the mixer operating. Thus, if vapor surrounded the pump inlet in a reduced gravity situation, the ullage pressure can still be controlled by venting through the TVS Joule Thomson valve and heat exchanger. It was evident that the spray bar configuration, which extends almost the entire length of the tank, enabled significant thermal energy removal from the ullage even without the mixer operating. Details regarding the test setup and procedures are presented in the paper. 1

Flachbart, R. H.↗
NASA NTRS1990

A figure-of-merit approach to extraterrestrial resource utilization

A concept is developed for interrelated optimizations in space missions that utilize extraterrestrial resources. It is shown that isolated (component) optimizations may not result in the best mission. It is shown that substantial benefits can be had through less than the best propellants, propellant combinations, propulsion hardware, and actually, some waste in the traditional sense. One ready example is the possibility of discarding hydrogen produced extraterrestrially by water splitting and using only the oxygen to burn storable fuels. The gains in refrigeration and leak-proof equipment mass (elimination) outweigh the loss in specific impulse. After a brief discussion of this concept, the synthesis of the four major components of any future space mission is developed. The four components are: orbital mechanics of the transportation; performance of the rocket motor; support systems that include power; thermal and process controls, and instruments; and in situ resource utilization plant equipment. This paper's main aim is to develop the concept of a figure-of-merit for the mission. The Mars Sample Return Mission is used to illustrate the new concept. At this time, a popular spreadsheet is used to quantitatively indicate the interdependent nature of the mission optimization. Future prospects are outlined that promise great economy through extraterrestrial resource utilization and a technique for quickly evaluating the same.

Ramohalli, K.↗
NASA NTRS2009

Optimization of Layer Densities for Spacecraft Multilayered Insulation Systems

Numerous tests of various multilayer insulation systems have indicated that there are optimal densities for these systems. However, the only method of calculating this optimal density was by a complex physics based algorithm developed by McIntosh. In the 1970's much data were collected on the performance of these insulation systems with many different variables analyzed. All formulas generated included number of layers and layer density as geometric variables in solving for the heat flux, none of them was in a differentiable form for a single geometric variable. It was recently discovered that by converting the equations from heat flux to thermal conductivity using Fourier's Law, the equations became functions of layer density, temperatures, and material properties only. The thickness and number of layers of the blanket were merged into a layer density. These equations were then differentiated with respect to layer density. By setting the first derivative equal to zero, and solving for the layer density, the critical layer density was determined. Taking a second derivative showed that the critical layer density is a minimum in the function and thus the optimum density for minimal heat leak, this is confirmed by plotting the original function. This method was checked and validated using test data from the Multipurpose Hydrogen Testbed which was designed using McIntosh's algorithm.

Johnson, W. L.↗
NASA NTRS1966

Mixer conditions temperature of liquified gas streams

Room temperature gaseous hydrogen mixed with liquified hydrogen in a venturi produces a two- phased liquid hydrogen stream at a stable temperature. This technique is useful in laboratory testing where presently, temperature control is maintained by a calibrated heat leak that results in considerable expenditure of cryogenic refrigerants.

Talmor, E.↗
NASA NTRS1978

Development of flightweight static face seals for 75.84 MPa /11 000 psi/ pressure and cryogenic temperatures

The development of a static seal configuration to meet the lightweight low-leakage requirements of the Space Shuttle Main Engine (pressure carrying capability of up to 75.84 MPa) is discussed. The design features, fabrication methods, lab testing, and performance of seal are examined. Flange and bolt details of the joint assembly are considered with attention to an ultrasonic technique for measuring preload in the bolts. Methods used for leak testing in the laboratory and in the field are described; the practicality of the procedures is considered. Attention is directed to hydrogen-environment embrittlement and its influence on seal and joint design.

Daniels, C. M.↗
NASA NTRS2011

A CFD Analysis of Hydrogen Leakage During On-Pad Purge in the ORION/ARES I Shared Volume

A common open volume is created by the stacking of the Orion vehicle onto the Ares I Upper Stage. Called the Shared Volume, both vehicles contribute to its gas, fluid, and thermal environment. One of these environments is related to hazardous hydrogen gas. While both vehicles use inert purge gas to mitigate any hazardous gas buildup, there are concerns that hydrogen gas may still accumulate and that the Ares I Hazardous Gas Detection System will not be sufficient for monitoring the integrated volume. This Computational Fluid Dynamics (CFD) analysis has been performed to examine these topics. Results of the analysis conclude that the Ares I Hazardous Gas Detection System will be able to sample the vent effluent containing the highest hydrogen concentrations. A second conclusion is that hydrogen does not accumulate under the Orion Service Module (SM) avionics ring as diffusion and purge flow mixing sufficiently dilute the hydrogen to safe concentrations. Finally the hydrogen concentrations within the Orion SM engine nozzle may slightly exceed the 1 percent volume fraction when the entire worse case maximum full leak is directed vertically into the engine nozzle.

Ajmani, Kumud↗
NASA NTRS1995

Impact damage resistance of carbon/epoxy composite tubes for the DC-XA liquid hydrogen feedline

Low-velocity impacts were inflicted upon two elbow sections of carbon/epoxy feedline that are to be a part of the Delta Clipper-XA flight vehicle. A soap-based liquid leak detector solution was used to inspect the impact sites for leaks of pressurized gas that was pumped into the tube. Visual surface damage was noted and recorded for each impact site. After impact testing of each of the two sections of tubes was completed, the damage zones were disected from the tube and cross sectioned through the impact site. These specimens were polished after potting them in epoxy and were examined for microcracking using a fluorescent dye penetrant technique. The results showed that nonvisible damage could cause microcracking, thereby resulting in leaks through the tube wall.

Nettles, A. T.↗
NASA NTRS2007

Polymer-Layered Silicate Nanocomposites for Cryotank Applications

Previous composite cryotank designs have relied on the use of conventional composite materials to reduce microcracking and permeability. However, revolutionary advances in nanotechnology derived materials may enable the production of ultra-lightweight cryotanks with significantly enhanced durability and damage tolerance, as well as reduced propellant permeability. Layered silicate nanocomposites are especially attractive in cryogenic storage tanks based on results that have been reported for epoxy nanocomposite systems. These materials often exhibit an order of magnitude reduction in gas permeability when compared to the base resin. In addition, polymer-silicate nanocomposites have been shown to yield improved dimensional stability, strength, and toughness. The enhancement in material performance of these systems occurs without property trade-offs which are often observed in conventionally filled polymer composites. Research efforts at NASA Glenn Research Center have led to the development of epoxy-clay nanocomposites with 70% lower hydrogen permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. The pronounced reduction observed with the tank may be due to flow induced alignment of the clay layers during processing. Additionally, the nanocomposites showed CTE reductions of up to 30%, as well as a 100% increase in toughness.

Miller, Sandi G.↗
NASA NTRS2001

Solid Hydrogen Particles Analyzed for Atomic Fuels

Solid hydrogen particles have been selected as a means of storing atomic propellants in future launch vehicles (refs. 1 to 2). In preparation for this, hydrogen particle formation in liquid helium was tested experimentally. These experiments were conducted to visually characterize the particles and to observe their formation and molecular transformations (aging) while in liquid helium. The particle sizes, molecular transformations, and agglomeration times were estimated from video image analyses. The experiments were conducted at the NASA Glenn Research Center in the Supplemental Multilayer Insulation Research Facility (SMIRF, ref. 3). The facility has a vacuum tank, into which the experimental setup was placed. The vacuum tank prevented heat leaks and subsequent boiloff of the liquid helium, and the supporting systems maintained the temperature and pressure of the liquid helium bath where the solid particles were created. As the operation of the apparatus was developed, the hydrogen particles were easily visualized. The figures (ref. 1) show images from the experimental runs. The first image shows the initial particle freezing, and the second image shows the particles after the small particles have agglomerated. The particles finally all clump, but stick together loosely. The solid particles tended to agglomerate within a maximum of 11 min, and the agglomerate was very weak. Because the hydrogen particles are buoyant in the helium, the agglomerate tends to compact itself into a flat pancake on the surface of the helium. This pancake agglomerate is easily broken apart by reducing the pressure above the liquid. The weak agglomerate implies that the particles can be used as a gelling agent for the liquid helium, as well as a storage medium for atomic boron, carbon, or hydrogen. The smallest particle sizes that resulted from the initial freezing experiments were about 1.8 mm. About 50 percent of the particles formed were between 1.8 to 4.6 mm in diameter. These very small particle sizes are encouraging for future formation experiments, where simpler operations will reduce the costs of production.

Palaszewski, Bryan A.↗
NASA NTRS2012

NASA Tech Briefs, October 2012

Topics discussed include: Detection of Chemical Precursors of Explosives; Detecting Methane From Leaking Pipelines and as Greenhouse Gas in the Atmosphere; Onboard Sensor Data Qualification in Human-Rated Launch Vehicles; Rugged, Portable, Real-Time Optical Gaseous Analyzer for Hydrogen Fluoride; A Probabilistic Mass Estimation Algorithm for a Novel 7-Channel Capacitive Sample Verification Sensor; Low-Power Architecture for an Optical Life Gas Analyzer; Online Cable Tester and Rerouter; A Three-Frequency Feed for Millimeter-Wave Radiometry; Capacitance Probe Resonator for Multichannel Electrometer; Inverted Three-Junction Tandem Thermophotovoltaic Modules; Fabrication of Single Crystal MgO Capsules; Inflatable Hangar for Assembly of Large Structures in Space; Mars Aqueous Processing System; Hybrid Filter Membrane; Design for the Structure and the Mechanics of Moballs; Pressure Dome for High-Pressure Electrolyzer; Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings; Compact, Low-Force, Low-Noise Linear Actuator; Ultra-Compact Motor Controller; Extreme Ionizing-Radiation-Resistant Bacterium; Wideband Single-Crystal Transducer for Bone Characterization; Fluorescence-Activated Cell Sorting of Live Versus Dead Bacterial Cells and Spores; Nonhazardous Urine Pretreatment Method; Laser-Ranging Transponders for Science Investigations of the Moon and Mars; Ka-Band Waveguide Three-Way Serial Combiner for MMIC Amplifiers; Structural Health Monitoring with Fiber Bragg Grating and Piezo Arrays; Low-Gain Circularly Polarized Antenna with Torus-Shaped Pattern; Stereo and IMU- Assisted Visual Odometry for Small Robots; Global Swath and Gridded Data Tiling; GOES-R: Satellite Insight; Aquarius iPhone Application; Monitoring of International Space Station Telemetry Using Shewhart Control Charts; Theory of a Traveling Wave Feed for a Planar Slot Array Antenna; Time Manager Software for a Flight Processor; Simulation of Oxygen Disintegration and Mixing With Hydrogen or Helium at Supercritical Pressure; A Superfluid Pulse Tube Refrigerator Without Moving Parts for Sub-Kelvin Cooling; Sapphire Viewports for a Venus Probe; The Mobile Chamber; Electric Propulsion Induced Secondary Mass Spectroscopy; and Radiation-Tolerant DC-DC Converters.

Source record↗
NASA NTRS1981

Conceptual design and analysis of orbital cryogenic liquid storage and supply systems

A wide variety of orbital cryogenic liquid storage and supply systems are defined in NASA and DOD long-range plans. These systems include small cooling applications, large chemical and electrical orbit transfer vehicles and supply tankers. All have the common requirements of low-g fluid management to accomplish gas-free liquid expulsion and efficient thermal control to manage heat leak and tank pressure. A preliminary design study was performed to evaluate tanks ranging from 0.6 to 37.4 cu m (22 to 1320 cu ft). Liquids of interest were hydrogen, oxygen, methane, argon and helium. Conceptual designs were generated for each tank system and fluid dynamic, thermal and structural analyses were performed for Shuttle compatible operations. Design trades considered the paradox of conservative support structure and minimum thermal input. Orbital performance and weight data were developed, and a technology evaluation was completed.

Eberhardt, R. N.↗
NASA NTRS2017

Zero Boil-Off Methods for Large Scale Liquid Hydrogen Tanks Using Integrated Refrigeration and Storage

NASA has completed a series of tests at the Kennedy Space Center to demonstrate the capability of using integrated refrigeration and storage (IRAS) to remove energy from a liquid hydrogen (LH2) tank and control the state of the propellant. A primary test objective was the keeping and storing of the liquid in a zero boil-off state, so that the total heat leak entering the tank is removed by a cryogenic refrigerator with an internal heat exchanger. The LH2 is therefore stored and kept with zero losses for an indefinite period of time. The LH2 tank is a horizontal cylindrical geometry with a vacuum-jacketed, multi-layer insulation system and a capacity of 125,000 liters. The closed-loop helium refrigeration system was a Linde LR1620 capable of 390W cooling at 20K (without any liquid nitrogen pre-cooling). Three different control methods were used to obtain zero boil-off: temperature control of the helium refrigerant, refrigerator control using the tank pressure sensor, and duty cycling (on/off) of the refrigerator as needed. Summarized are the IRAS design approach, zero boil-off control methods, and results of the series of zero boil-off tests.

ZBO↗
NASA NTRS2018

Large Scale Cryogenic Storage with Active Refrigeration

Storage and transfer of cryogenic liquefied gases on volume scales from under 10 liters for lab use, up to hundreds of millions of liters for industrial applications is of paramount importance across a vast range of industries. Traditionally, these commodities have been stored at or near the normal boiling point due to relative ease of operation and safety-related considerations; however, this also means that some percentage will always be lost due to environmental heat leaking into the vessel and causing boil-off. These losses become more concerning as scales increase, and are of particular importance for high-cost commodities such helium and hydrogen. Additionally, the normal boiling point marks the highest liquid density achievable; which becomes a strong driver of end-use system designs such as space launch vehicles. Recent development and testing of an Integrated Refrigeration and Storage (IRAS) system for liquid hydrogen has proven that next generation cryogenic storage operations such as zero boil-off and densification are feasible on a large scale. This IRAS system married an 850 Watt at 20 Kelvin reverse-Brayton cycle commercial cryogenic refrigerator with a 125,000 liter LH2 storage tank via and internal tubular heat exchanger. This allowed heat to be removed directly from the hydrogen, and by extension, provided a means to control the bulk thermodynamic state. Zero boil-off, in-situ liquefaction, and densification down to the triple point was performed during testing, and data such as fluid temperature profiles and tank pressure were gathered. Details regarding the design, setup, and testing of the IRAS system are discussed herein, and the data used to anchor various physics models created to predict the behavior of the system during transient and steady state operation. It is hoped that these efforts will provide a useful basis for the design and implementation of future large scale IRAS systems across numerous industries.

Swanger, Adam M.↗
NASA NTRS1980

Cooling of high pressure rocket thrust chambers with liquid oxygen

An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/sq m chamber pressure. It was aimed to demonstrate the effect of LOX leaking into the combustion region through small cracks in the chamber wall, and to verify the supercritical oxygen heat transfer correlation developed from heated tube experiments. Four thrust chambers with throat diameters of 0.066 m were tested; three of these were cyclically tested to 4.14 MM/sq m chamber pressure until a crack developed; the fourth chamber was operated at 8.274 MM/sq m pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation.

Price, H. G.↗
NASA NTRS1992

Nickel hydrogen multicell common pressure vessel battery development update

The technology background and design qualification of the multicell common pressure vessel nickel hydrogen battery are described. The results of full flight qualification, including random vibration at 19.5 g for two minutes in each axis, electrical characterization in a thermal vacuum chamber, and mass spectroscopy vessel leak detection are reviewed and 12.7 cm qualification and 25.4 cm design adaptation are discussed.

Zagrodnik, Jeffrey P.↗
NASA NTRSDate not supplied

Alternative MMOD Shielding Concepts

A core objective of the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) group is to improve spacecraft meteoroid and orbital debris (MMOD) shielding by evaluating new materials and shielding concepts by test and analysis. This paper describes hypervelocity impact tests that were performed over several years to evaluate alternative MMOD shielding concepts. Specific objectives of the work were to incorporate improved MMOD and radiation protection within Stuffed Whipple shields, and to evaluate various self-sealing MMOD shielding concepts. The tests were performed under similar impact conditions and with fixed shield standoff and comparable overall shield mass. Damage to the rear wall was quantified and compared to determine the best performing shield concepts. Generally, the best shielding for both MMOD and radiation protection included polymer materials rich in hydrogen introduced into the intermediate and final layers of the shielding. In the self-sealing material evaluations, the test objective was to gauge the ability of different materials and techniques to stop leaks in a rear wall with a delta-pressure across the wall typical of spacecraft crew cabins (i.e., up to 1 atmosphere pressure). Shielding containing ionomer films and elastomer materials satisfied this objective for pressure shell holes up to 6mm diameter. This paper provides results of the investigations.

Orbital Debris↗
NASA NTRS1984

Evaluation of propellant tank insulation concepts for low-thrust chemical propulsion systems

An analytical evaluation of cryogenic propellant tank insulations for liquid oxygen/liquid hydrogen low-thrust 2224N (500 lbf) propulsion systems (LTPS) was conducted. The insulation studied consisted of combinations of N2-purged foam and multilayer insulation (MLI) as well as He-purged MLI-only. Heat leak and payload performance predictions were made for three Shuttle-launched LTPS designed for Shuttle bay packaged payload densities of 56 kg/cu m, 40 kg/cu m and 24 kg/cu m. Foam/MLI insulations were found to increase LTPS payload delivery capability when compared with He-purged MLI-only. An additional benefit of foam/MLI was reduced operational complexity because Orbiter cargo bay N2 purge gas could be used for MLI purging. Maximum payload mass benefit occurred when an enhanced convection, rather than natural convection, heat transfer was specified for the insulation purge enclosure. The enhanced convection environment allowed minimum insulation thickness to be used for the foam/MLI interface temperature selected to correspond to the moisture dew point in the N2 purge gas. Experimental verification of foam/MLI benefits was recommended. A conservative program cost estimate for testing a MLI-foam insulated tank was 2.1 million dollars. It was noted this cost could be reduced significantly without increasing program risk.

Kramer, T.↗
NASA NTRS1984

Evaluation of propellent tank insulation concepts for low-thrust chemical propulsion systems: Executive summary

Cryogenic propellant tank insulations or liquid oxygen/liquid hydrogen low-thrust 2224N (500 lbf) propulsion systems (LTPS) were assessed. The insulation studied consisted of combinations of N2-purged foam and multilayer insulation (MLI) as well as He-purged MLI-only. Heat leak and payload performance predictions were made for three shuttle-launched LTPS designed for shuttle bay packaged payload densities of 56 kg cu/m (3.5 lbm/cu ft), 40 kg/cu m (2.5 lbm/cu ft) and 24 kg/cu m (1.5 lbm/cu ft). Foam/MLI insulations were found to increase LTPS payload delivery capability when compared with He-purged MLI-only. An additional benefit of foam/MLI was reduced operational complexity because orbiter cargo bay N2 purge gas could be used for MLI purging. Maximum payload mass benefit occurred when an enhanced convection, rather than natural convection, heat transfer was specified for the insulation purge enclosure. The enhanced convection environment allowed minimum insulation thickness to be used for the foam/MLI interface temperature selected to correspond to the moisture dew point in the N2 purge gas. Experimental verification of foam/MLI benefits was recommended. A conservative program cost estimate for testing a MLI-foam insulated tank was 2.1 million dollars. This cost could be reduced significantly without increasing program risk.

Kramer, T.↗