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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 1,351 records · Page 75

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NASA NTRS1981

Anomalous C-12H4:C-13H4 strengths in 3 ny sub 3

The C-12:C-13 ratios in the atmospheres of the outer planets are important parameters with which to test models for isotope formation and fractionation during the early history of the solar system, yielding insight into processes occurring in the primitive solar nebula. The 3 ny sub 3 spectra of methane were obtained using the Kitt Peak Solar Fourier Transform Spectrometer and a 6 m White cell. The experimental results are summarized in a table. The strength ratios for the R-branch of 3 ny sub 3 exhibit strong anomalies, with C-13H4 lines consistently weaker than their C-12H4 counterparts. The C-12:C-13 abundance ratios for the atmospheres of Jupiter and Saturn have been redetermined using the 3 ny sub 3 line-strength ratios measured.

Brault, J. W.↗

NASA NTRS1983

Rod-Wall Sound Shield for Wind Tunnels

Test model is shielded from turbulence radiated from wind tunnel walls. Shield overcomes problems caused by leading-edge configuration and leading edge angle of inclination of previous designs. Has successfully maintained a laminar rather than turbulent boundary layer.

Creel, T. R. J.↗

NASA NTRS1981

Wind tunnel supplementary Mach number minimum section insert

A device is described which changes the Mach number capability of a wind tunnel without permanently altering the existing nozzle of the tunnel. An insert is removably attached to the wall of the existing nozzle expansion area thereby creating a second minimum section upstream of the model test section. The added insert may be removed without complicated and expensive changes to the basic wind tunnel. In one embodiment, a removable insert is disposed within wind tunnel nozzle walls with a portion of the flow boundary layer being bled off from the tunnel via passageway and tunnel exit to reduce the extent of separated flow normally occuring upstream of the insert contraction section.

Couch, L. M.↗

NASA NTRS1982

Transit Thermal Control Design for Galileo Entry Probe for Planet Jupiter

A totally passive design was completed for the thermal control of the Galileo entry probe during its transit to the planet Jupiter. The design utilizes radio isotope heater units, multilayer insulation blankets and a thermal radiator in conjunction with a design conductance support structure to achieve both the required storage and critical initial planet atmosphere entry temperatures. The probe transit thermal design was completed and verified based on thermal vacuum testing of a prototype probe thermal test model.

Haverly, George C.↗

NASA NTRS1982

Experimental study of turbulence in blade end wall corner region

Corner flows and wall pressure fluctuations, design and fabrication of the test model, preliminary resuls on boundary layer, flow visualization, turbulence intensity and spectra measurements are presented. The design consideration and fabrication report on the newly built wind tunnel to be used for subsequent continuation of the research effort is also presented.

Raj, R.↗

NASA NTRS1982

Experimental investigation of two nonaxisymmetric wedge nozzles at free stream Mach numbers up to 1.20

Forces and pressures on two nonaxisymmetric wedge nozzles were measured in a 16 foot transonic tunnel. Tests were conducted at static conditions and at free stream Mach numbers of 0.60, 0.80, 0.90, 0.94, and 1.20. The range of nozzle pressure ratios varied with configuration and Mach number. The internal and external geometry of the nozzles and the test model are defined in detail. Nozzle performance data are presented as discharge coefficients, internal thrust ratios, thrust minus nozzle drag ratios, and ideal thrust coefficients. Extensive internal and external pressure measurements are presented.

Mason, M. L.↗

NASA NTRS1982

Measurement of Three-dimensional Density Distributions by Holographic Interferometry and Computer Tomography

The use of holographic interferometry to measure two and threedimensional flows and the interpretation of multiple-view interferograms with computer tomography are discussed. Computational techniques developed for tomography are reviewed. Current research topics are outlined including the development of an automated fringe readout system, optimum reconstruction procedures for when an opaque test model is present in the field, and interferometry and tomography with strongly refracting fields and shocks.

Vest, C. M.↗

NASA NTRS1982

Propeller tip vortex - A possible contributor to aircraft cabin noise

Wind tunnel model tests support the hypothesis that a propeller tip vortex may subject a downstream wing surface to greater excitation than would be experienced by the aircraft fuselage side wall exposed to propeller-generated noise, ultimately transmitting this structural response to incident dynamic pressure to the cabin interior. Even if structure-borne excitations are less efficient than airborne excitations in the creation of cabin noise, the higher level of the former could still govern cabin noise levels.

Miller, B. A.↗

NASA NTRS1982

Higher-order flow angle corrections for three-dimensional wind tunnel wall interference

A second-order theory including camber effects in wind tunnel wall interference corrections is described. Changes in the geometrical configuration of the model tested are avoided by introducing the camber correction as an equivalent angle-of-attack correction. Tabular and graphic data are presented which indicate improved accuracy for second-order over first-order theory.

Rizk, M. H.↗

NASA NTRS1982

Conceptual design, evaluation and research identification for Remote Augmented Propulsive Lift Systems (RALS) with ejectors for VTOL aircraft

Ejector concepts for use with a remote augmented lift system (RALS) exhaust nozzle were studied. A number of concepts were considered and three were selected as having the greatest promise of providing the desired aircraft and exhaust gas cooling and lift enhancement. A scale model test program is recommended to explore the effects of the more important parameters on ejector performance.

Willis, W. S.↗

NASA NTRS1982

The phototron: A light to RF energy conversion device

The phototron, a photoelectric device that converts light to radio frequency energy, is described. It is a vacuum tube, free electron, device that is mechanically similar to a reflex klystron with the hot filament cathode replaced by a large area photocathode. The device can operate either with an external voltage source used to accelerate the photoelectrons or with zero bias voltage; in which case the photokinetic energy of the electrons sustains the R.F. oscillations in the tuned R.F. circuit. One basic design of the phototron was tested. Frequencies as high as about 1 GHz and an overall efficiency of about 1% in the biased mode were obtained. In the unbiased mode, the frequencies of operation and efficiences are considerably lower. Success with test model suggests that considerable improvements are possible through design refinements. One such design refinement is the reduction of the length of the electron flight path.

Freeman, J. W.↗

NASA NTRS1983

Aerodynamic characteristics of a series of single-inlet air-breathing missile configurations

A series of air-breathing missile configurations was investigated to provide a data base for the design of such missiles. The model could be configured with either a single axisymmetric or a two dimensional inlet located at the bottom of the body. Two tail configurations were investigated: a tri-tail and an X-tail. The tail surfaces could be deflected to provide pitch control. A wing could be located above the inlet on the center line of the model. Tests were made at supersonic Mach numbers with the inlet open and internal flow, and at subsonic-transonic Mach numbers with the internal duct closed and no internal flow.

Hayes, C.↗

NASA NTRS1983

Development of a simplified optical technique for the simultaneous measurement of particle size distribution and velocity

Existing techniques were surveyed, an experimental procedure was developed, a laboratory test model was fabricated, limited data were recovered for proof of principle, and the relationship between particle size distribution and amplitude measurements was illustrated in an effort to develop a low cost, simplified optical technique for measuring particle size distributions and velocities in fluidized bed combustors and gasifiers. A He-Ne laser illuminated Rochi Rulings (range 10 to 500 lines per inch). Various samples of known particle size distributions were passed through the fringe pattern produced by the rulings. A photomultiplier tube converted light from the fringe volume to an electrical signal which was recorded using an oscilloscope and camera. The signal amplitudes were correlated against the known particle size distributions. The correlation holds true for various samples.

Smith, J. L.↗

NASA NTRS1982

Space shuttle solid rocket booster water entry cavity collapse loads

Solid rocket booster cavity collapse flight measurements included external pressures on the motor case and aft skirt, internal motor case pressures, accelerometers located in the forward skirt, mid-body area, and aft skirt, as well as strain gages located on the skin of the motor case. This flight data yielded applied pressure longitudinal and circumferential distributions which compare well with model test predictions. The internal motor case ullage pressure, which is below atmospheric due to the rapid cooling of the hot internal gas, was more severe (lower) than anticipated due to the ullage gas being hotter than predicted. The structural dynamic response characteristics were as expected. Structural ring and wall damage are detailed and are considered to be attributable to the direct application of cavity collapse pressure combined with the structurally destabilizing, low internal motor case pressure.

Keefe, R. T.↗

NASA NTRS1981

A new electronic scanner of pressure designed for installation in wind-tunnel models

A new electronic scanner of pressure (ESOP) has been developed by NASA Ames Research Center for installation in wind-tunnel models. An ESOP system includes up to 20 pressure modules, each with 48 pressure transducers, an A/D converter, a microprocessor, a data controller, a monitor unit, and a heater controller. The system is sized so that the pressure modules and A/D converter module can be installed within an average-size model tested in the Ames Aerodynamics Division wind tunnels. This paper describes the ESOP system, emphasizing the main element of the system - the pressure module. The measured performance of the overall system is also presented.

Coe, C. T.↗

NASA NTRS1983

Progress toward the analysis of complex propulsion installation flow phenomenon

A trend toward replacement of parametric model testing with parametric analysis for the design of aircraft is driven by the rapidly escalating cost of wind tunnel testing, the increasing availability of large fast computers, and powerful numerical flow algorithms. In connection with the complex flow phenomena characteristic of propulsion installations, it is now necessary to employ both parametric analysis and testing for design procedures. Powerful flow analysis techniques are available to predict local flow phenomena. However, the employment of these techniques is very expensive. It is, therefore, necessary to link these analyses with less powerful and less expensive procedures for an accurate analysis of propulsion installation flowfields. However, the interfacing and coupling processes needed are not available. The present investigation is concerned with progress made regarding the development of suitable linking methods. Attention is given to methods of analysis for predicting the flow around a nacelle coupled to a highly swept wing.

Kern, P. R. A.↗

NASA NTRS1983

Advanced technology exhaust nozzle development

The requirement for greater tactical aircraft operational capabilities has led to increasing research emphasis on the refinement of engine/airframe integration methods and exhaust nozzle flexibility. A major prospective advancement in the development of these capabilities takes the form of multifunctional exhaust nozzle systems with thrust reversal and thrust vectoring features, whose operation will be shared by both airframe and powerplant control systems. Attention is presently given to the two-dimensional convergent-divergent and single expansion ramp nozzle designs, with emphasis on the variable geometry mechanical systems by which they assume cruising flight, vectoring, and thrust reversal operations. The nozzles have been wind tunnel model-tested for the cases of the F-18 fighter and a supersonic cruise configuration concept.

Dusa, D. J.↗

NASA NTRS1983

The Integrated Technology and Flight Research Rotor Technology demonstrators for the 1985-1995 timeframe

The purposes and progress in the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) Project, a joint effort by the U.S. Army and NASA, are outlined. The project goal is to integrate the disciplines of rotor design, aerodynamics, structures, materials, dynamics, and acoustics, to remove the risks in applying the technology, and to develop an advanced flight research rotor which permits significant variation in the rotor properties. Composite rotors are believed to be capable of displaying infinite fatigue lifetimes with fail-safe characteristics, and bearingless hubs simplify hub designs. The programs will also consider the flight control, propulsion, and structures. Concept definition contracts are presently distributed among five companies, and preliminary designs will lead to model tests in 1984.

Bousman, W.↗