摘要:

The formation of iron fluoride (FeF3) through the interaction of perfluoropolyalkylether (PEPE) oil with steel surfaces was investigated under boundary lubrication conditions. Ball-bearing rolling action was simulated by a specially designed wear-test apparatus that incorporated noncoaxial wear members to give a skid/roll ratio of ∼0.16. The contact stress was 8.3 × 108N·m−2(∼120 000 psi), and the speed was 1750 rpm. Under these conditions, FeF3formation on the wear surfaces was inferred using x-ray photoelectron spectroscopic (XPS), Auger electron spectroscopic (AES), and secondary ion mass spectrometric (SIMS) surface analysis techniques. These findings support the hypothesis that, under the low oxygen environment of spacecraft earth orbit, formation of FeF3and subsequent FeF3catalyzed degradation of PEPE can constitute an important PFPE degradation pathway under boundary lubrication conditions.Presented at the 40th Annual Metting in Las Vegas, May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981668

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Hydrostatic journal bearings have been employed in several applications where the lubricant is a working fluid with low viscosity. The resulting turbulent flow can be analyzed by considering three major pressure drops: pressure drop across the orifice restrictor, pressure drop over the pocket edges, and pressure drop across the bearing lands. This paper presents a finite element analysis of bearings in the above category. The bearings here have axial grooves between the pockets and either one or two pockets per pad. Both static and dynamic bearing properties are calculated for example bearings.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981669

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Reactions of zinc dialkyldithiophosphates (ZDTP) in the presence of hydroperoxides have been further investigated using a model n-hexadecane oxidation system at 160°C. Results obtained with selected primary and secondary alkyl ZDTP added alone and in combination with 2,6-di-tert butyl-4-methylphenol suggest that substantial differences exist between the reactions of these two types of ZDTP with regard to both hydroperoxide decomposition and radical trapping. The best overall oxidation control in the presence of excess hydroperoxides has been provided by i-C3ZDTP in combination with a radical trapping inhibitor.Presented at the 40th Annual Meeting in las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981670

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Thermohydrodynamic effects in journal bearings operating under steady-state loading are investigated. An analytical model for the finite journal bearings was formulated. The model includes correction factors for the cavitation effects and the mixing of the recirculating oil and supply oil at the inlet. A finite difference computer program was developed to numerically solve the Reynolds, energy, Laplace heat-conduction equations, and a viscosity-temperature relation simultaneously. The program includes a numerical solution technique for obtaining an isothermal shaft temperature and handles the mixing of the recirculating oil and supply oil. Good agreement with published experimental tests was obtained. It was also found that conservative solutions for the film temperature and load-carrying capacity can be obtained by imposing an adiabatic boundary condition on the bush inner surface. Such simple boundary conditions result in significant computational savings and, therefore, may be attractive to the practicing designer.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981671

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Distortions of mechanical face seal components have a significant effect on the seal performance. The finite element method is often employed to analyze complex seal sections; however, experimental verification is needed.

ISSN:0569-8197    

DOI:10.1080/05698198608981672

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The stability and unsteady behavior of journal bearings is much influenced by bearing geometry, and various designs have been used by engineers to promote stable bearing performance.

ISSN:0569-8197    

DOI:10.1080/05698198608981673

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A comparative study is made of various finite difference and finite element solutions of the Reynolds equation for the steady, isoviscous, incompressible hydrodynamic lubrication problem. Numerical solutions are obtained for both one- and two-dimensional slider bearings, and the predicted load capacity is evaluated against that of the corresponding exact analytical solution. Two finite difference schemes of nominal second-and fourth-order accuracy are employed. Linear, quadratic, and cubic elements are used in the finite element solutions. The different solution methods are evaluated in terms of accuracy, computational complexities and cost.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981674

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An analysis of tilting-pad thrust bearing operating temperatures is described. The analysis includes an evaluation of various temperature locations based on their ability to reflect bearing operating conditions. Experimental results for a 267-mm (10.5-in) 8-pad thrust bearing indicates that while a babbitt location on the trailing edge of a pad is often the hottest, the 75/75 percent location provides temperature data on the high-pressure region of the pad. Babbitt temperatures also provide a convenient indicator of the transition from laminar to turbulent flow in the oil film.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981675

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Some aerospace rocket engine applications require that bearings operate at high speeds with cryogenic rocket fuel as the only liquid lubricant. Analyses and field data on these bearings indicate that life would be limited to a few minutes if they operated unlubricated. The extent to which cryogenic fluids are capable of generating elastohydrodynamic films is, therefore, an area of concern and is investigated in this paper. Results from experimental and analytical work at the authors' laboratories indicate sufficient films are not generated to lubricate the bearing reliably. This conclusion is supported by experimental data and analysis which show liquid nitrogen, the cryogenic fluid tested, to be isoviscous.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981676

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Modern instrumental methods of analysis have been applied to the study of neopentyl-polyol-based synthetic ester lubricants. These provide information on the nature of the polyol(s), the component acyl groups and the composition in term of concentration and distribution of acyl groups. In most cases, the analyses are performed directly on the base oil or the lubricant without chemical modification. Infrared spectroscopy can play a major role in the analysis and, with suitable standards, it provides all of the important information for the chemical and structural characterization.Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

ISSN:0569-8197    

DOI:10.1080/05698198608981677

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor