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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 325 records · Page 18
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NASA NTRS1992

Ion Thruster Development at NASA Lewis Research Center

Recent ion propulsion technology efforts at NASA's Lewis Research Center including development of kW-class xenon ion thrusters, high power xenon and krypton ion thrusters, and power processors are reviewed. Thruster physical characteristics, performance data, life projections, and power processor component technology are summarized. The ion propulsion technology program is structured to address a broad set of mission applications from satellite stationkeeping and repositioning to primary propulsion using solar or nuclear power systems.

Sovey, James S.↗
NASA NTRS1992

Lewis Online Travel System: Preparer's/Traveler's Manual, Release 1.0

The Lewis Online Travel System (LOTS) is a menu-driven interactive application that automates nearly all of the functions associated with government travel. The purpose of this manual is to provide LOTS users with concise instructions for using the computerized application. As such, it will not go into the details of travel regulations.

Seese, Michael↗
NASA NTRS1993

NASA Lewis 8- by 6-foot supersonic wind tunnel user manual

The 8- by 6-Foot Supersonic Wind Tunnel (SWT) at Lewis Research Center is available for use by qualified researchers. This manual contains tunnel performance maps which show the range of total temperature, total pressure, static pressure, dynamic pressure, altitude, Reynolds number, and mass flow as a function of test section Mach number. These maps are applicable for both the aerodynamic and propulsion cycle. The 8- by 6-Foot Supersonic Wind Tunnel is an atmospheric facility with a test section Mach number range from 0.36 to 2.0. General support systems (air systems, hydraulic system, hydrogen system, infrared system, laser system, laser sheet system, and schlieren system are also described as are instrumentation and data processing and acquisition systems. Pretest meeting formats are outlined. Tunnel user responsibility and personal safety requirements are also stated.

Soeder, Ronald H.↗
NASA NTRS1993

The development of hydrogen sensor technology at NASA Lewis Research Center

The detection of hydrogen leaks in aerospace applications, especially those involving hydrogen fuel propulsion systems, is of extreme importance for reasons of reliability, safety, and economy. Motivated by leaks occurring in liquid hydrogen lines supplying the main engine of the Space Shuttle, NASA Lewis has initiated a program to develop point-contact hydrogen sensors which address the needs of aerospace applications. Several different approaches are being explored. They include the fabrication of PdAg Schottky diode structures, the characterization of PdCr as a hydrogen sensitive alloy, and the use of SiC as a semiconductor for hydrogen sensors. This paper discusses the motivation behind and present status of each of the major components of the NASA LeRC hydrogen sensor program.

Hunter, Gary W.↗
NASA NTRS1992

Lewis number effect on the propagation of premixed flames in closed tubes

The evolution of a premixed flame under conditions of confinement is studied theoretically. The analysis is based on a hydrodynamic model in which the flame is treated as a surface of discontinuity. The flame structure is assumed to be quasi-steady with a high activation energy and a large heat release. Its resolution in the postignition period yields a coupled system of equations for the determination of the pressure and the burning rate. The analysis also resolves the thermal and flow fields on either side of the flame and determines the instantaneous location of the flame front together with the overall time required for the flame to reach the end of the tube. The results indicate that qualitatively distinct behaviors are possible for mixtures depending on whether their Lewis numbers Le are less or greater than one.

Mcgreevy, J. L.↗
NASA NTRS1993

Results of Low Power Deicer tests on a swept inlet component in the NASA Lewis Icing Research Tunnel

Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection system were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.

Bond, Thomas H.↗
NASA NTRS1993

An overview of shed ice impact studies in the NASA Lewis Icing Research Tunnel

One of the areas of active research in commercial and military rotorcraft is directed toward developing the capability of sustained flight in icing conditions. The emphasis to date has been on the accretion and subsequent shedding of ice in an icing environment, where the shedding may be natural or induced. Historically, shed-ice particles have been a problem for aircraft, particularly rotorcraft. Because of the high particle velocities involved, damage to a fuselage or other airframe component from a shed-ice impact can be significant. Design rules for damage tolerance from shed-ice impact are not well developed because of a lack of experimental data. Thus, NASA Lewis (LeRC) has begun an effort to develop a database of impact force and energy resulting from shed ice. This effort consisted of a test of NASA LeRC's Model Rotor Test Rig (MRTR) in the Icing Research Tunnel (IRT). Both natural shedding and forced shedding were investigated. Forced shedding was achieved by fitting the rotor blades with Small Tube Pneumatic (STP) deicer boots manufactured by BF Goodrich. A detailed description of the test is given as well as the design of a new impact sensor which measures the force-time history of an impacting ice fragment. A brief discussion of the procedure to infer impact energy from a force-time trace are required for the impact-energy calculations. Recommendations and future plans for this research area are also provided.

Britton, Randall K.↗
NASA NTRS1993

Liquid water content measurements using the Phase Doppler Particle Analyzer in the NASA Lewis Icing Research Tunnel

The performance of a Phase Doppler Particle Analyzer (PDPA) based icing probe suitable for use in icing tunnels and airborne applications is assessed. The instrument is shown to accurately and repeatably measure liquid water content (LWC) to within better than 20 percent of the nominal expected value in the NASA Lewis IRT. This was seen to be true over a wide range of tunnel operating conditions. The principles used by the PDPA for MVD and LWC determination are discussed. Calibration curves for the IRT median volume diameter are also determined and compared to the existing calibration determined via the PMS instruments. As has been shown in previous work, the PDPA is quite repeatable. The results are typically 3 to 5 microns smaller than the existing calibrations for a given run condition. Reasons for these differences are also discussed.

Rudoff, R. C.↗
NASA NTRS1990

Summary of NASA. Lewis Research Center validation efforts

NASA Lewis Research Center personnel presented a summary of LeRC validation experiments. The subjects discussed included: iced wing, linear transonic cascade, transition duct aerodynamics, transition duct heat transfer, low speed centrifugal compressor, turbomachinery blade row interactions, and three dimensional fluid mechanics.

Gaugler, Raymond E.↗
NASA NTRS1990

NASA. Lewis Research Center/IFMD inlet duct and nozzle high speed validation experiments

Personnel from NASA Lewis Research Center spoke on the subject of inlet duct and nozzle high speed validation experiments to include crossing shocks and boundary layer interaction, unsteady shock/boundary layer interactions, and vortex generators. Attention was also paid to the subjects of high speed mixing and transition ducts. Specific application was made to the NASP hypermixing concepts.

Hingst, Warren↗
NASA NTRS1993

The NASA Lewis Research Center SBIR program: An assessment

An assessment was made of the NASA Lewis Small Business Innovation Research (SBIR) Program for the years 1983 to 1989. The assessment was based on the study of 99 Phase 1 contracts and 39 Phase 2 contracts. The overall impact of SBIR was found to be very positive, contributing strongly to many NASA programs. In addition, many successful efforts were commercialized benefiting the small business, federal agencies, and the aerospace industry. The program was evaluated in terms of contract quality, innovativeness, comparison to the state-of-the-art, achievement of goals, difficulty, and impact. Program difficulties were also identified, which could suggest possible program improvements. Much of the information gained in this assessment provided a basis for a SBIR data base which will be updated every year. This data base is computerized and will provide an excellent source of information about past SBIR efforts and company capabilities.

Grimes, Hubert H.↗
NASA NTRS1993

NASA Lewis 9- by 15-foot low-speed wind tunnel user manual

This manual describes the 9- by 15-Foot Low-Speed Wind Tunnel at the Lewis Research Center and provides information for users who wish to conduct experiments in this atmospheric facility. Tunnel variables such as pressures, temperatures, available tests section area, and Mach number ranges (0.05 to 0.20) are discussed. In addition, general support systems such as air systems, hydraulic system, hydrogen system, laser system, flow visualization system, and model support systems are described. Instrumentation and data processing and acquisition systems are also discussed.

Soeder, Ronald H.↗
NASA NTRS1993

NASA Lewis Meshed VSAT Workshop meeting summary

NASA Lewis Research Center's Space Electronics Division (SED) hosted a workshop to address specific topics related to future meshed very small-aperture terminal (VSAT) satellite communications networks. The ideas generated by this workshop will help to identify potential markets and focus technology development within the commercial satellite communications industry and NASA. The workshop resulted in recommendations concerning these principal points of interest: the window of opportunity for a meshed VSAT system; system availability; ground terminal antenna sizes; recommended multifrequency for time division multiple access (TDMA) uplink; a packet switch design concept for narrowband; and fault tolerance design concepts. This report presents a summary of group presentations and discussion associated with the technological, economic, and operational issues of meshed VSAT architectures that utilize processing satellites.

Ivancic, William↗
NASA NTRS1993

Solid State Technology Branch of NASA Lewis Research Center: Fifth Annual Digest

The digest is a collection of papers written by the members of the Solid State Technology Branch of NASA Lewis Research Center from June 1992-June 1993. The papers cover a range of topics relating to superconductivity, monolithic microwave integrated circuits (MMIC's), coplanar waveguide, and material characterization.

Source record↗
NASA NTRS1993

Space applications of superconducting microwave electronics at NASA Lewis Research Center

Since the discovery of high temperature superconductivity in 1987, NASA Lewis Research Center has been involved in efforts to demonstrate its advantages for applications involving microwave electronics in space, especially space communications. The program included thin film fabrication by means of laser ablation. Specific circuitry which was investigated includes microstrip ring resonators at 32 GHz, phase shifters which utilize a superconducting, optically activated switch, an 8x8 32 GHz superconducting microstrip antenna array, and an HTS-ring-resonator stabilized oscillator at 8 GHz. The latter two components are candidates for use in space experiments which are described in other papers. Experimental data on most of the circuits are presented as well as, in some cases, a comparison of their performance with an identical circuit utilizing gold or copper metallization.

Leonard, R. F.↗
NASA NTRS1993

Users manual for the NASA Lewis three-dimensional ice accretion code (LEWICE 3D)

A description of the methodology, the algorithms, and the input and output data along with an example case for the NASA Lewis 3D ice accretion code (LEWICE3D) has been produced. The manual has been designed to help the user understand the capabilities, the methodologies, and the use of the code. The LEWICE3D code is a conglomeration of several codes for the purpose of calculating ice shapes on three-dimensional external surfaces. A three-dimensional external flow panel code is incorporated which has the capability of calculating flow about arbitrary 3D lifting and nonlifting bodies with external flow. A fourth order Runge-Kutta integration scheme is used to calculate arbitrary streamlines. An Adams type predictor-corrector trajectory integration scheme has been included to calculate arbitrary trajectories. Schemes for calculating tangent trajectories, collection efficiencies, and concentration factors for arbitrary regions of interest for single droplets or droplet distributions have been incorporated. A LEWICE 2D based heat transfer algorithm can be used to calculate ice accretions along surface streamlines. A geometry modification scheme is incorporated which calculates the new geometry based on the ice accretions generated at each section of interest. The three-dimensional ice accretion calculation is based on the LEWICE 2D calculation. Both codes calculate the flow, pressure distribution, and collection efficiency distribution along surface streamlines. For both codes the heat transfer calculation is divided into two regions, one above the stagnation point and one below the stagnation point, and solved for each region assuming a flat plate with pressure distribution. Water is assumed to follow the surface streamlines, hence starting at the stagnation zone any water that is not frozen out at a control volume is assumed to run back into the next control volume. After the amount of frozen water at each control volume has been calculated the geometry is modified by adding the ice at each control volume in the surface normal direction.

Bidwell, Colin S.↗
NASA NTRS1994

Flow quality studies of the NASA Lewis Research Center Icing Research Tunnel diffuser

The purpose was to document the airflow characteristics in the diffuser of the NASA Lewis Research Center Icing Research Tunnel and to determine the effects of vortex generators on the flow quality in the diffuser. The results were used to determine how to improve the flow in this portion of the tunnel so that it can be more effectively used as an icing test section and such that overall tunnel efficiency can be improved. The demand for tunnel test time and the desire to test models that are too large for the test section were two of the drivers behind this diffuser study. For all vortex generator configurations tested, the flow quality was improved.

Arrington, E. Allen↗