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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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Differential-maximum-bubble-pressure apparatus used for surface tension measurements in air of liquid lubricants to 200 C
Dynamic response of gas lubricated thrust bearing with shrouded Raleigh-step pads
Performance tests of water-lubricated, Rayleigh step, hydrodynamic journal bearings under no load conditions to determine stability
Solid metal lubricant films bonding by ion plating using diode method, noting interface type and structure examination by electron microscopy
Rolling ball fatigue and lubrication with fluorinated polyethers at cryogenic temperatures compared to superfined mineral oil
Glow discharge cleaning for surface contaminants removal from hydrodynamic gas bearing components, discussing equipment application to thin film lubricant vapor deposition
Lubrication considerations concerning mechanical and service variables for obtaining optimum gear performance under severe operating conditions
Herringbone grooved gas lubricated journal bearing load capacity, attitude angle and power loss measurements
Quasi-static pressure characteristics of gas lubricated thrust bearing with shrouded Rayleigh step pads, solving nonlinear equation of motion
Nimbus B-2 satellite-borne IR spectrometer lubrication using solid film technique, discussing real time and accelerated vacuum environmental tests
Guide for gear designers, consisting of theory, calculations, charts, curves and references, explains lubrication requirements for gears to insure maximum performance. Mechanical and service variables are considered in order to obtain optimum gear performance under severe operating conditions.
Undersized spacer balls rub against oil impregnated wiper, pick up lubricant, and transmit it to load carrying balls and raceways.
Lubrication and cooling of turbopump rotor bearings by liquid Freon 21 is reported. Freon expands in rotor bearing and acts as heat sink by removing heat during warming and evaporation. Gaseous Freon is removed by vacuum pump controlling rotor chamber operation.
A high speed rotor, supported by gas-lubricated foil bearings, is free from self-excited whirl and displays no loss of load capacity when vibrated at frequency equal to the rotational speed. It is demonstrated that in addition to tolerance of geometrical imperfections, misalignment and foreign particles, the foil bearing performs well at elevated temperatures and accommodates appreciable temperature gradients. The foil bearing is endowed with superior wipe-wear characteristics and the flexibility of the foil accounts not only for the stability of the foil bearing, but also for its accommodation of, and compensation for, distortion, contamination, and contact.
A variational formulation of the transient lubrication problem is presented and the corresponding finite element equations derived for three and six point triangles, and, four and eight point quadrilaterals. Test solutions for a one dimensional slider bearing used in validating the computer program are given. Utility of the method is demonstrated by a solution of the shrouded step bearing.
Groups of 120-mm-bore angular-contact ball bearings made from AISI M-50 steel were fatigue tested with a tetraester and a synthetic paraffinic oil at a bearing temperature of 492 K (425 F) in an air environment. Bearing life exceeded AFBMA-predicted (catalog) life by factors in excess of 4 and 10 for the tetraester and synthetic paraffinic fluids, respectively. The final viscosities after 500 hours of operation were 14 and 6 times the initial values, respectively. During the same time period, when the test oil is replaced at a rate approximating the replenishment rate in actual commerical engine usage, no significant increase in lubricant viscosity with time was observed.
The wettabilities and heat transfer rates of microfog jets (oil-mist nozzle flows) impinging on a heated rotating disc were determined under an inert atmosphere of nitrogen at temperatures ranging from 600 to 800 F. The results are discussed in relation to the various factors involved in the microfog lubricant application systems. Two novel reclassifying nozzles and a vortex mist generator were also studied.
An analytical method is presented for determining elastohydrodynamic film thickness in gears from theory and how the film affects gear failure and life. The practical aspects of gear lubrication are presented, including mechanical and service variables which must be considered to obtain optimum gear performance under severe operating conditions.