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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Studies of cryogenic propellant storage and handling for the lunar landing and launch facility (complex 39L)

A brief description of Complex 39L as it is currently conceived is presented. A brief discussion of lunar thermal history is then presented. From this follows a discussion of the current lunar thermal environment which will impact the design of cryogenic storage and handling facilities on the moon. Some previous studies are discussed. A conceptual design of liquid oxygen and hydrogen storage facilities is presented. The essential feature of this facility is that cryogens are to be stored in a number of small tanks which can serve as lander propellant tanks rather than as one large storage vessel. These tanks will be placed under a Fuel Inventory Tent (FIT) for shadow shielding. Methods of dealing with propellant boil-off are discussed. A base case cascade refrigeration system for requirements are such that it seems very feasible to construct a prototype boil-off recovery system in a laboratory environment.

Linsley, Jerald N.↗
NASA NTRS1988

An analysis for high speed propeller-nacelle aerodynamic performance prediction. Volume 2: User's manual

A user's manual for the computer program developed for the prediction of propeller-nacelle aerodynamic performance reported in, An Analysis for High Speed Propeller-Nacelle Aerodynamic Performance Prediction: Volume 1 -- Theory and Application, is presented. The manual describes the computer program mode of operation requirements, input structure, input data requirements and the program output. In addition, it provides the user with documentation of the internal program structure and the software used in the computer program as it relates to the theory presented in Volume 1. Sample input data setups are provided along with selected printout of the program output for one of the sample setups.

Egolf, T. Alan↗
NASA NTRS1989

A review of the supply of liquid propellants and other fluids in support of the Space Shuttle Program

In this study, over twenty significant liquid propellants and other fluids were reviewed as to their supply in support of the Space Shuttle Program (SSP), primarily at KSC. The uniqueness of most of the products, either by their application or production characteristics, present a variety of supply issues to contend with. Each, however, is critical to the success of the SSP. It becomes necessary to formulate, and maintain, a logistic approach to assure a continued availability of each product. For convenience, two categories were established. One, labeled limited-availability, represents those products wherein they are single sourced, have production restrictions and/or there has been a history of supply problems. The other, labeled universally-available, is characteristic of those having several sources and/or having little, if any, historical supply problems. This last category was not examined in depth. Through concepts of establishing stockpile inventories, multiple supply contracts, or other arrangements, the supply of liquid propellants and other fluids can be assured.

Churchwell, Stacy E.↗
NASA NTRS1989

Aircraft propeller induced structure-borne noise

A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages. The test apparatus was employed to evaluate several aircraft installation effects (power plant placement, engine/nacelle mass loading, and wing/fuselage attachment methods) and several structural response modifications for structure-borne noise control (the use of wing blocking mass/fuel, wing damping treaments, and tuned mechanical dampers). Most important was the development of in-flight structure-borne noise transmission detection techniques using a combination of ground-based frequency response function testing and in-flight structural response measurement. Propeller wake/vortex excitation simulation techniques for improved ground-based testing were also developed to support the in-flight structure-borne noise transmission detection development.

Unruh, James F.↗
NASA NTRS1989

Modeling of impulsive propellant reorientation

The impulsive propellant reorientation process is modeled using the Energy Calculations for Liquid Propellants in a Space Environment (ECLIPSE) code. A brief description of the process and the computational model is presented. Code validation is documented via comparison to experimentally derived data for small scale tanks. Predictions of reorientation performance are presented for two tanks designed for use in flight experiments and for a proposed full scale OTV tank. A new dimensionless parameter is developed to correlate reorientation performance in geometrically similar tanks. Its success is demonstrated.

Hochstein, John I.↗
NASA NTRS1989

The effect of the wind tunnel wall boundary layer on the acoustic testing of propellers

An approximation based on the representation of the boundary layer by lamina of uniform flow with suitable interlayer boundary conditions is shown to be accurate, efficient, and compatible with finite element formulations. The approximation has been implemented using existing codes to produce a model for assessing the suitability of the acoustic environment in a wind tunnel for the acoustic testing of propellers. It is found that, with suitable acoustic treatment and with measurements made near the propeller and well removed from the walls, the free field directivity and level can be reproduced with good fidelity.

Eversman, Walter↗
NASA NTRS1989

Rocket propellants from Martian resources

In order for extensive round trip travel to become feasible in terms of mass required in low Earth orbit, propellant manufacturing at Mars becomes essential. Martian resources lend themselves to relatively easy generation of several promising propellant combinations. Not only manned missions but also smaller unmanned missions such as sample return may benefit from this technology.

French, J. R.↗
NASA NTRS1989

Pressure-time history of pylon wake signature on a pusher propeller in flight

Miniature, high-frequency, pressure transducers were mounted on a pusher propeller at 3/4 and 90-percent radii. Time-history of fluctuating surface pressure over 700 revolutions and 26 flight conditions reveal intriguing phenomena. The anticipated pylon wake signature manifests itself as a negative pressure pulse over extended portions of the suction surface. The phenomenon further develops into a primarily random turbulence signature at 80-percent chord and interestingly may reevolve as a coherent wake signature further downstream. A new type of periodic disturbance of long time-scale, compared to propeller period-of-revolution, is discovered at positions beyond 0.6 chord on the suction surface in the transonic regime.

Farokhi, Saeed↗
NASA NTRS1990

Effect of Pylon Wake with and Without Pylon Blowing on Propeller Thrust

Pylon trailing edge blowing was investigated as a means of alleviating the effects of the pylon wake on a pusher arrangement of an advanced single-rotation turboprop. Measurements were made of steady-state propeller thrust and pylon wake pressures and turbulence levels with and without blowing. Results show that the pylon trailing edge blowing practically eliminated the pylon wake, significantly reduced the pylon wake turbulence, and had a relatively small effect on the steady-state propeller thrust. The data are presented with a minimum of analysis.

Gentry, Garl L., Jr.↗
NASA NTRS1990

Predicted and measured boundary layer refraction for advanced turboprop propeller noise

Currently, boundary layer refraction presents a limitation to the measurement of forward arc propeller noise measured on an acoustic plate in the NASA Lewis 8- by 6-Foot Supersonic Wind Tunnel. The use of a validated boundary layer refraction model to adjust the data could remove this limitation. An existing boundary layer refraction model is used to predict the refraction for cases where boundary layer refraction was measured. In general, the model exhibits the same qualitative behavior as the measured refraction. However, the prediction method does not show quantitative agreement with the data. In general, it overpredicts the amount of refraction for the far forward angles at axial Mach number of 0.85 and 0.80 and underpredicts the refraction at axial Mach numbers of 0.75 and 0.70. A more complete propeller source description is suggested as a way to improve the prediction method.

Dittmar, James H.↗
NASA NTRS1989

Effect of Propellant Flowrate and Purity on Carbon Deposition in LO2/Methane Gas Generators

The generation and deposition of carbon was studied in the Carbon Deposition Program using subscale hardware with LO2/Liquid Natural Gas (LNG) and LO2/Methane propellants at low mixture ratios. The purpose of the testing was to evaluate the effect of methane purity and full scale injection density on carbon deposition. The LO2/LNG gas generator/preburner testing was performed at mixture ratios between 0.24 and 0.58 and chamber pressures from 5.8 to 9.4 MPa (840 to 1370 psia). A total of seven 200 second duration tests were performed. The LNG testing occurred at low injection densities, similar to the previous LO2/RP-1, LO2/propane, and LO2/methane testing performed on the carbon deposition program. The current LO2/methane test series occurred at an injection density factor of approximately 10 times higher than the previous testing. The high injection density LO2/methane testing was performed at mixture ratios between from 0.23 to 0.81 and chamber pressures from 6.4 to 15.2 MPa (925 to 2210 psia). A total of nine high injection density tests were performed. The testing performed demonstrated that low purity methane (LNG) did not produce any detectable change in carbon deposition when compared to pure methane. In addition, the C* performance and the combustion gas temperatures measured were similar to those obtained for pure methane. Similar results were obtained testing pure methane at higher propellant injection densities with coarse injector elements.

Bossard, J. A.↗
NASA NTRS1989

A Perspective on the Use of Storable Propellants for Future Space Vehicle Propulsion

Propulsion system configurations for future NASA and DOD space initiatives are driven by the continually emerging new mission requirements. These initiatives cover an extremely wide range of mission scenarios, from unmanned planetary programs, to manned lunar and planetary programs, to earth-oriented (Mission to Planet Earth) programs, and they are in addition to existing and future requirements for near-earth missions such as to geosynchronous earth orbit (GEO). Increasing space transportation costs, and anticipated high costs associated with space-basing of future vehicles, necessitate consideration of cost-effective and easily maintainable configurations which maximize the use of existing technologies and assets, and use budgetary resources effectively. System design considerations associated with the use of storable propellants to fill these needs are presented. Comparisons in areas such as complexity, performance, flexibility, maintainability, and technology status are made for earth and space storable propellants, including nitrogen tetroxide/monomethylhydrazine and LOX/monomethylhydrazine.

Boyd, William C.↗
NASA NTRS1990

Unsteady potential flow past a propeller blade section

An analytical study was conducted to predict the effect of an oscillating stream on the time dependent sectional pressure and lift coefficients of a model propeller blade. The assumption is that as the blade sections encounter a wake, the actual angles of attack vary in a sinusoidal manner through the wake, thus each blade is exposed to an unsteady stream oscillating about a mean value at a certain reduced frequency. On the other hand, an isolated propeller at some angle of attack can experience periodic changes in the value of the flow angle causing unsteady loads on the blades. Such a flow condition requires the inclusion of new expressions in the formulation of the unsteady potential flow around the blade sections. These expressions account for time variation of angle of attack and total shed vortices in the wake of each airfoil section. It was found that the final expressions for the unsteady pressure distribution on each blade section are periodic and that the unsteady circulation and lift coefficients exhibit a hysteresis loop.

Takallu, M. A.↗
NASA NTRS1989

Optics and materials considerations for a laser-propelled lightsail

The principles of a laser-propelled lightsail for an interstellar probe are discussed. The feasibility of a laser-propelled-lightsail round-trip interstellar mission proposed by Forward (1984) is examined, with special attention given to the issues of optics and materials. It is shown that the large lens and a high lens/target distance required by such a mission result in optical difficulties, requiring positioning tolerance for the 1000-km-diam lens of only 3 m, which is unlikely to be achievable. Techniques and sail materials that would reduce this problem are suggested, including the use of LiF and CaF2 quarter-wave dielectric films and the use of many intermediate lenses spaced between the probe and the source. It is pointed out that, as sail materials, the quarter-wavelength dielectric films have significant advantages over metals.

Landis, Geoffrey A.↗
NASA NTRS1989

Blade surface pressure measurement on a pusher propeller in flight

Unsteady aerodynamics of a pusher propeller operating in the wake of a pylon is investigated through analysis of flight test data. Twenty-two surface-mounted miniature pressure transducers were installed at the 75 and 90 percent radius locations on a propeller blade on a test-bed aircraft. Twenty-six different flight conditions were flown to cover the range of speeds, rpm, altitudes, and flap positions encountered by an advanced turboprop general aviation aircraft. Preliminary analysis of the flight test data indicate a strong three-dimensionality to the perturbed flow at the 75 and 90 percent radii due to pylon wake encounter. Time-history of the pressure transducer waveforms recorded for 700 revolutions exhibit a one-per-cycle wave oscillation on the wake signature. No explanation is found for this behavior yet.

Farokhi, S.↗
NASA NTRS1990

Prediction of self-pressurization rate of cryogenic propellant tankage

The SOLA-ECLIPSE code is being developed to enable prediction of the behavior of cryogenic propellants in spacecraft tankage. A brief description of the formulations used for modeling heat transfer and for determining the thermodynamic state is presented. Code performance is verified through comparison to experimental data for the self-pressurization of scale-model liquid hydrogen tanks. SOLA-ECLIPSE is used to examine the effect of initial subcooling of the liquid phase on the self-pressurization rate of an on-orbit full-scale liquid hydrogen tank typical for a chemical-propulsion orbit transfer vehicle. The computational predictions show that even small amounts of subcooling will significantly decrease the self-pressurization rate. Further, if the cooling is provided by a thermodynamic vent system, it is concluded that small levels of subcooling will maximize propellant conservation.

Hochstein, John I.↗
NASA NTRS1990

The engineering of a nuclear thermal landing and ascent vehicle utilizing indigenous Martian propellant

A design study of a novel space transportation concept called NIMF (Nuclear rocket using Indigenous Martian Fuel) is reported. In this concept, Martian CO2 gas, which constitutes 95 percent of the atmosphere, is liquified by simple compression to about 100 psi and remains stable without refrigeration. When heated and exhausted out of a rocket nozzle, a specific impulse of about 264 s can be achieved, sufficient for flights from the surface to highly energetic orbits or from one point on the surface to any other point. The propellant acquisition system can travel with the vehicle, allowing it to refuel itself each time it lands. The concept offers unequalled potential to achieve planetwide mobility, allowing complete global access for the exploration of Mars. By eliminating the necessity of transporting ascent propellant to Mars, the NIMF can also significantly reduce the initial mass in LEO and of a manned Mars mission.

Zubrin, Robert M.↗
NASA NTRS1990

Counter-rotating propellant analysis using a frequency domain panel method

The unsteady aerodynamic coupling between the front and rear rotors in a counter-rotating propeller system is analyzed using a frequency-domain panel method based on linear compressible aerodynamic theory. The periodic loads are decomposed into harmonics, and the harmonic amplitudes are found iteratively. Each stage of the interation involves the solution of an isolated propeller problem, the interaction being done through the Fourier transform of the induced velocity field. The method was validated by comparing mean performance parameters with measured data and by comparing the predicted velocity field with detailed laser Doppler velocimeter measurements. Comparisons have also been made between the fluctuating loads predicted by the present method and a time-domain panel method.

Williams, Marc H.↗