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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 NTRS1928

The Effects of Fuel and Cylinder Gas Densities on the Characteristics of Fuel Sprays for Oil Engines

This investigation was conducted as a part of a general research on fuel-injection engines for aircraft. The purpose of the investigation was to determine the effects of fuel and cylinder gas densities with several characteristics of fuel sprays for oil engines. The start, growth, and cut-off of single fuel sprays produced by automatic injection valves were recorded on photographic film by means of special high-speed motion-picture apparatus. This equipment, which has been described in previous reports, is capable of taking twenty-five consecutive pictures of the moving spray at the rate of 4,000 per second. The penetrations of the fuel sprays increased and the cone angles and relative distributions decreased with increase in the specific gravity of the fuel. The density of the gas into which the fuel sprays were injected controlled their penetration. This was the only characteristic of the chamber gas that had a measurable effect upon the fuel sprays. Application of fuel-spray penetration data to the case of an engine, in which the pressure is rising during injection, indicated that fuel sprays may penetrate considerably farther than when injected into a gas at a density equal to that of the gas in an engine cylinder at top center.

Joachim, W F↗
NASA NTRS1979

Topping pressure for gas-storage cylinders

With charts derived from gas-storage system model, required topping pressure can be determined from initial cylinder pressure and temperature of gas entering cylinder. Charts are available for hydrogen and oxygen and can be developed for other important industrial gases as well.

Haben, R. L.↗
NASA NTRS2012

Cascade Storage and Delivery System for a Multi Mission Space Exploration Vehicle (MMSEV)

NASA is developing a Multi Mission Space Exploration Vehicle (MMSEV) for missions beyond Low Earth Orbit (LEO). The MMSEV is a pressurized vehicle used to extend the human exploration envelope for Lunar, Near Earth Object (NEO), and Deep Space missions. The Johnson Space Center is developing the Environmental Control and Life Support System (ECLSS) for the MMSEV. The MMSEV s intended use is to support longer sortie lengths with multiple Extra Vehicular Activities (EVAs) on a higher magnitude than any previous vehicle. This paper presents an analysis of a high pressure oxygen cascade storage and delivery system that will accommodate the crew during long duration Intra Vehicular Activity (IVA) and capable of multiple high pressure oxygen fills to the Portable Life Support System (PLSS) worn by the crew during EVAs. A cascade is a high pressure gas cylinder system used for the refilling of smaller compressed gas cylinders. Each of the large cylinders are filled by a compressor, but the cascade system allows small cylinders to be filled without the need of a compressor. In addition, the cascade system is useful as a "reservoir" to accommodate low pressure needs. A regression model was developed to provide the mechanism to size the cascade systems subject to constraints such as number of crew, extravehicular activity duration and frequency, and ullage gas requirements under contingency scenarios. The sizing routine employed a numerical integration scheme to determine gas compressibility changes during depressurization and compressibility effects were captured using the Soave-Redlich-Kwong (SRK) equation of state. A multi-dimensional nonlinear optimization routine was used to find the minimum cascade tank system mass that meets the mission requirements. The sizing algorithms developed in this analysis provide a powerful framework to assess cascade filling, compressor, and hybrid systems to design long duration vehicle ECLSS architecture. 1

Yagoda, Evan↗
NASA NTRS1984

Investigation of the effects of pressure gradient, temperature and wall temperature ratio on the stagnation point heat transfer for circular cylinders and gas turbine vanes

Low and high pressure shock tubes were designed and constructed for the purpose of obtaining heat transfer data over a temperature range of 390 to 2500 K, pressures of 0.3 to 42 atm, and Mach numbers of 0.15 to 1.5 with and without pressure gradient. A square test section with adjustable top and bottom walls was constructed to produce the favorable and adverse pressure gradient over the flat plate with heat gages. A water cooled gas turbine nozzle cascade which is attached to the high pressure shock tube was obtained to measuse the heat flux over pressure and suction surfaces. Thin-film platinum heat gages with a response time of a few microseconds were developed and used to measure the heat flux for laminar, transition, and turbulent boundary layers. The laminar boundary heat flux on the shock tube wall agreed with Mirel's flat plate theory. Stagnation point heat transfer for circular cylinders at low temperature compared with the theoretical prediction, but for a gas temperature of 922 K the heat fluxes were higher than the predicted values. Preliminary flat plate heat transfer data were measured for laminar, transition, and turbulent boundary layers with and without pressure gradients for free-stream temperatures of 350 to 2575 K and flow Mach numbers of 0.11 to 1.9. The experimental heat flux data were correlated with the laminar and turbulent theories and the agreement was good at low temperatures which was not the case for higher temperatures.

Nagamatsu, H. T.↗
NASA NTRS2011

Hardware Design Improvements to the Major Constituent Analyzer

The Major Constituent Analyzer (MCA) onboard the International Space Station (ISS) is designed to monitor the major constituents of the ISS's internal atmosphere. This mass spectrometer based system is an integral part of the Environmental Control and Life Support System (ECLSS) and is a primary tool for the management of ISS atmosphere composition. As a part of NASA Change Request CR10773A, several alterations to the hardware have been made to accommodate improved MCA logistics. First, the ORU 08 verification gas assembly has been modified to allow the verification gas cylinder to be installed on orbit. The verification gas is an essential MCA consumable that requires periodic replenishment. Designing the cylinder for subassembly transport reduces the size and weight of the maintained item for launch. The redesign of the ORU 08 assembly includes a redesigned housing, cylinder mounting apparatus, and pneumatic connection. The second hardware change is a redesigned wiring harness for the ORU 02 analyzer. The ORU 02 electrical connector interface was damaged in a previous on-orbit installation, and this necessitated the development of a temporary fix while a more permanent solution was developed. The new wiring harness design includes flexible cable as well as indexing fasteners and guide-pins, and provides better accessibility during the on-orbit maintenance operation. This presentation will describe the hardware improvements being implemented for MCA as well as the expected improvement to logistics and maintenance.

Combs, Scott↗
NASA NTRS1981

An experimental investigation of 235 sub UF sub 6 fission produced plasmas

A gas handling system capable of use with uranium fluoride was designed and constructed for use with nuclear pumped laser experiments using the TRIGA research reactor. By employing careful design and temperature controls, the UF6 can be first transported into the irradiation chamber, and then, at the conclusion of the experiment, returned to gas cylinders. The design of the system is described. Operating procedures for the UF6 and gas handling systems are included.

Miley, G. H.↗
NASA NTRS1981

Reciprocating engines

An intake valve arrangement for positively controlling the opening and closing of the poppet valve in a hot gas cylinder in a hydrazine powered engine is described. The poppet valve is operated by the piston and gas pressure only. The poppet valve uses a pneumatic spring which holds the poppet valve against the piston while the valve is opened and closed. To accomplish this, a poppet valve is slidably mounted in a pneumatic spring chamber which reaches a pressure approaching the gas supply pressure and, during the opening of the valve, the spring chamber retains enough pressure to hold the poppet valve onto the piston. In addition, the bottom of the poppet valve can have a suction cup type configuration to hold the poppet valve on the piston during the down stroke.

Akkerman, J. W.↗
NASA NTRS2009

Design and Testing of Trace Contaminant Injection and Monitoring Systems

In support of the Carbon dioxide And Moisture Removal Amine Swing-bed (CAMRAS) testing, a contaminant injection system as well as a contaminant monitoring system has been developed by the Johnson Space Center Air Revitalization Systems (JSC-ARS) team. The contaminant injection system has been designed to provide trace level concentrations of contaminants generated by humans in a closed environment during space flight missions. The contaminant injection system continuously injects contaminants from three gas cylinders, two liquid reservoirs and three permeation ovens. The contaminant monitoring system has been designed to provide real time gas analysis with accurate flow, humidity and gas concentration measurements for collection during test. The contaminant monitoring system consists of an analytical real time gas analyzer, a carbon monoxide sensor, and an analyzer for ammonia and water vapor.

Broerman, Craig D.↗
NASA NTRS1997

In-situ generation of carrier gases for scientific analyses on Mars

The search for useful raw materials on planetary surfaces will involve various scientific analyses of soil and rock samples. The devices performing these measurements often require inert carrier gases for moving analytes and purging instrumentation. At present, the carrier or sweep gas must be carried from Earth in a compressed gas cylinder, and so the supply of this depletable resource sets a hard limit on the (flexible) life span of the experiment. If a suitable carrier gas could be produced in-situ, then the scientific return of exploration missions could be extended and enhanced greatly. Many more samples could be analyzed, long-ranging rovers could have independent gas supplies, and designs could have added flexibility with respect to gas consumption.

Finn, J. E.↗
NASA NTRS1968

Compact monitoring and control console for pressurized gas bottles

Compact monitoring and control console dispenses gas over a range of pressures from conventional compressed-gas cylinders. It incorporates in a single assembly the necessary equipment for a portable pressurization system that can be used in welding and other operations requiring a controlled gas supply.

Freeman, B.↗
NASA NTRS1977

Yield-pressure determination

Stress/strain relationship of complex-shape vessel is recorded under hydrostatic pressure. Technique is used to test pressurized gas cylinders and tubular transition joints made of dissimilar metals and to determine burst or system-failure pressures.

Wakefield, M. E.↗
NASA NTRS1978

A surface flow visualisation technique for use in cryogenic wind tunnels

A method of surface flow visualization for use in cryogenic wind tunnels is described which requires injection of a cryogenic liquid onto the model while the tunnel is running. This necessitates the use of a substance that remains liquid over a large range of cryogenic wind tunnel operating temperatures. It is found that propane (C3H8) is a suitable substance. Experiments are conducted in a subsonic cryogenic wind tunnel to assess the practical application of liquid propane flow visualization. The propane is stored in a chamber cooled by liquid nitrogen and when required is pumped through pipes to a gallery inside the model and then out onto the surface through small holes. To color the liquid a suspension of pigment particles is used. Propane is supplied to the cooled chamber in gaseous form from a standard liquefied gas cylinder. The sequence of events is illustrated on a propane temperature-entropy diagram. The use of liquefied propane for flow visualization in a cryogenic tunnel operating at pressures up to 40 atm appears to be feasible. Illustrative examples are provided.

Kell, D. M.↗
NASA NTRS1990

Shock enhancement and control of hypersonic mixing and combustion

Experimental and computational analyses of the possibility that shock-enhanced mixing can substantially increase the rate of mixing between coflowing streams of hydrogen and air are discussed. Numerical computations indicate that the steady interaction between a weak shock in air with a coflowing hydrogen jet can be approximated by the two-dimensional time-dependent interaction between a weak shock and an initially circular region filled with hydrogen imbedded in air. Experimental results obtained in a shock tube and contoured wall injector are presented. It is shown that the shock impinging process causes the light gas cylinder to split into two parts; one of these mixes rapidly with air and the other forms a stably stratified vortex pair which mixes more slowly. The geometry of the flow field and the mixing process and scaling parameters are assessed.

Marble, Frank E.↗
NASA NTRS1990

Propulsion simulation for magnetically suspended wind tunnel models

The feasibility of simulating propulsion-induced aerodynamic effects on scaled aircraft models in wind tunnels employing Magnetic Suspension and Balance Systems. The investigation concerned itself with techniques of generating exhaust jets of appropriate characteristics. The objectives were to: (1) define thrust and mass flow requirements of jets; (2) evaluate techniques for generating propulsive gas within volume limitations imposed by magnetically-suspended models; (3) conduct simple diagnostic experiments for techniques involving new concepts; and (4) recommend experiments for demonstration of propulsion simulation techniques. Various techniques of generating exhaust jets of appropriate characteristics were evaluated on scaled aircraft models in wind tunnels with MSBS. Four concepts of remotely-operated propulsion simulators were examined. Three conceptual designs involving innovative adaptation of convenient technologies (compressed gas cylinders, liquid, and solid propellants) were developed. The fourth innovative concept, namely, the laser-assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels for small thrust levels.

Joshi, Prakash B.↗
NASA NTRS1992

Propulsion simulator for magnetically suspended wind tunnel models

Simulation of propulsion induced aerodynamic forces and moments, which arise as a result of interactions between propulsive jets and the free stream, is one of the most desired capabilities in magnetic suspension wind tunnels. The feasibility of generating exhaust jets of appropriate characteristics onboard magnetically suspended models was examined. Four concepts of remotely operated propulsion simulators was considered. Three conceptual designs involving conventional technologies such as compressed gas cylinders, liquid monopropellants, and solid propellants were developed. The fourth concept, a laser assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels. The measurement of aerodynamic forces and/or moments were demonstrated, including the effects of exhaust jets, in MSBS wind tunnels. Two propulsion simulator models were developed, a small scale and a large scale unit, both using compressed, liquified CO2 as propellant. Results of the wind tunnel tests with the small scale simulator are discussed.

Joshi, P. B.↗