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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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Recirculation zone in fluid mechanics experiments on cylindrical cavity simulating gas-core nuclear rocket as heavy gas reservoir, discussing flow patterns
High-speed recirculating water tunnel measurements of pressure to show its effect on the onset and cessation of cavitation flow along a wall
As thrust levels increase and as rocket engines fire for longer periods of time, the difficulties encountered in the protection of critical components from the effects of excessively high temperatures greatly increase. To protect these components a series of filled elastomeric composites have been evaluated. A brief discussion is presented of the problems of hot gas recirculation, radiation, and base plane heating with particular reference to large, clustered, liquid propellant rocket engines. The effect on components is discussed and an evaluation of a series of insulators based on filled elastomeric composites is presented. The evaluations are based on specialized thermal tests which were designed to simulate as far as possible, conditions during flight. The most promising of these elastomeric composites are compared to three alternative insulative systems, a filled, castable ceramic, a metal foil-silica fiber batting, and an asbestos-inconel wire mesh composite, in terms of weight, cost, and ease of fabrication and repair.
Failure mode and operation life of ball bearings using fluid lubricants at high temperatures in recirculating system
The wake skew angle used in applying the theory of NASA TR R-124 to data correction should be such that the angular deflection of the wake vorticity from the horizontal is one-half that calculated from momentum theory at the lifting element. This usage is in contrast to that of the original paper which used the angle of the mass flow. Because of large-scale recirculation effects, there is a finite lower limit to the test speed at which reliable and correctable data can be obtained in closed wind tunnels. Although a zero-correction wind tunnel for V/STOL testing has not yet been achieved, it is shown that the use of suitably mixed wind-tunnel boundaries can alleviate boundary effects on V/STOL data.
Recirculating gas cooled test loop facility for Plum Brook reactor
Flow equations for convective heating associated with recirculating flow in clustered engine boosters for free viscous shear layer along exhaust jet boundary
Design criteria for water vapor electrolysis cell modules with integral ducting and fan for operation in recirculated spacecraft cabin air
Lubricants for recirculating inerted lubrication systems in Mach 3 aircraft engines
Liquid lubricants for recirculating inerted lubrication systems of Mach 3 aircraft gas turbine engines tested at high temperatures
Atmospheric exposure chamber design for small animals, discussing dynamic and recirculating operations and gas scrubbing system
Resonant piston compressor for recirculation system of hermetically sealed platform
Turbulent viscoseal with gas-liquid interface, using recirculation loop for gas ingestion reduction
Analysis of recirculating type external pressurization systems for use in pressure control of cryogenic hydrogen, oxygen, and nitrogen storage systems
Recirculating cells and entrance conditions influence on confined heterogeneous jets laminar mixing, measuring velocity and concentration profiles
Portable prebreathing system was developed which recirculates and reconditions respiratorily exhaled oxygen. Apparatus reduces fire hazards, simplifies prebreathing procedures, and does not require extensive enclosure venting system usage.
Centrifugal compressor performance was examined analytically to determine optimum geometry for various applications as characterized by specific speed. Seven specific losses were calculated for various combinations of inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, blade exit backsweep, and inlet-tip absolute tangential velocity for solid body prewhirl. The losses considered were inlet guide vane loss, blade loading loss, skin friction loss, recirculation loss, disk friction loss, vaneless diffuser loss, and vaned diffuser loss. Maximum total efficiencies ranged from 0.497 to 0.868 for a specific speed range of 0.257 to 1.346. Curves of rotor exit absolute flow angle, inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, head coefficient and blade exit backsweep are presented over a range of specific speeds for various inducer tip speeds to permit rapid selection of optimum compressor size and shape for a variety of applications.
A flight investigation was performed with the Dornier DO-31 VTOL to evaluate the performance, handling qualities, and operating characteristics that are considered to be important in the operation of a commerical VTOL transport in the terminal area. The DO-31, a 20,000 kilogram transport, has a mixed jet propulsion system; main engines with nozzles deflect from a cruise to a hover position, and vertical lift engines operated below 170 knots. This VTOL mode incorporates pitch and roll attitude and yaw rate stabilization. The tests concentrated on the transition, approach, and vertical landing. The mixed jet propulsion system provided a large usable performance envelope that enabled simulated IFR approaches to be made on 7 deg and 12 deg glide slopes. In these approaches management of thrust magnitude and direction was a primary problem, and some form of integrating the controls will be necessary. The handling qualities evaluation pointed out the need for additional research of define flight path criteria. The aircraft had satisfactory control and stability in hover out of ground effect. The recirculation effects in vertical landing were large below 15 meters.