摘要:

The foil journal bearing is essentially a series of thin overlapping circular metal foils, one end of which is cantilevered to the bearing and the other end rests on an adjacent foil. Typically, the radial load at the high temperature end (turbine) of a gas turbine engine is supported by a roller bearing. The high temperatures encountered at the turbine end result in reduced roller bearing life and also necessitate elaborate cooling and lubricating systems to keep the bearing temperatures within reasonable limits. Foil-journal bearings are simple, lightweight and well suited for such high temperature applications, and since they are self-acting air bearings the need for a lubricant supply system is obviated.

ISSN:1040-2004    

DOI:10.1080/10402009208982082

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

An outside-pressurized, bi-directional, gas face seal is analyzed here. This seal face is made up of a hydrodynamic section, consisting of alternate regions of land and groove, and a hydrostatic dam. The groove region, based on its optimum width, can have either parallel or radial side boundaries, depending on the cost of machining and tooling.

ISSN:1040-2004    

DOI:10.1080/10402009208982083

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The effect of runout on the variation in friction and wear failures that occur during the sliding of magnetic recording heads against carbon-coated, thin-film disks was investigated. The shape of disk runout was modified by sandwiching metallic shims between the disk and the hub of a test spindle as well as by varying the torque on the clamping screws. These procedures smoothed the complicated runout curve to a simple sinusoid-like curve, and at the same time increased the peak-to-trough runout. Drag tests were conducted on delubricated disks until failure occurred. The test results have shown that smoothing the runout curve to a simple sinusoidal shape increases the time to failure by a factor of ten, provided that the peak-to-trough runout stays roughly below 65 μm. Smoothing the runout curve does not prolong the time to failure when the peak-to-trough runout is larger than about 70 μm. Elementary dynamical analysis of the head further suggests that small wavelength runouts induce head oscillation and early disk failure.Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991

ISSN:1040-2004    

DOI:10.1080/10402009208982084

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two versions of a model for the thermal behavior of the lubricant film in the cavitation region of a journal bearing are presented and incorporated into a solution algorithm for the operating characteristics of an axially grooved bearing. The model is based on an approximation of the flow as two parts: Couette-like streamers plus uniform velocity portions adhered to the journal. One version (CH) results from assuming a constant ratio between the cavity height and the local gap height. The other (FH), results from assuming a constant thickness of the adhered fluid layer. An approximate energy equation is derived for the rupture zone and applied to the calculation of the bearing wall temperature. Parametric studies of the effects of the choice of cavity dimensions indicate that for appropriate choices the agreement between theory and published experiment is significantly better for the new methods. Agreement is lightly better for the FH model that for the CH model, and because of physical arguments the FH model is preferred. Results for the cases examined are consistent with an adhered layer having a thickness approximately 40 percent of the gap height at the rupture boundary.Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991

ISSN:1040-2004    

DOI:10.1080/10402009208982085

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A number of substituted aryloxycyclotriphosphazenes were synthesized and studied, with the objective of meeting the lubricant requirements of the Integrated High Performance Turbine Engine Technology (IHPTET) initiative. These compounds were evaluated for pour point, oxidative stability, and lubricity behavior. Further property evaluations were performed on a leading candidate fluid, bis(4-fluorophenoxy)-tetrakis(3-trifluoromethylphenoxy) cyclotriphosphazene, code-named X-1P. The results of this study are discussed, along with comparative data of other leading commercial high temperature fluids.Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991

ISSN:1040-2004    

DOI:10.1080/10402009208982086

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The lubrication problem of infinitely long slider bearings with a mixture of fluid and particulate solid at small volume fraction level is studied. Closed-form analytical solutions for pressure and shear stress are obtained for a class of solid aggregates. The results reduce to those of pure fluid in the limiting case. A parametric study of the bearing performance with particulate solid is presented.

ISSN:1040-2004    

DOI:10.1080/10402009208982087

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The purpose of this paper is to present, analyze and optimize the geometry of the bi-directional radial groove film-riding gas seal (1). Performance is both hydrodynamic and hydrostatic and is independent of rotational direction. The hydrodynamic geometry is an equally spaced set of alternating lands and grooves.

ISSN:1040-2004    

DOI:10.1080/10402009208982088

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper describes the shortcomings in the determination of wear in equipment where the predominant wear mechanism is that due to sliding erosion with a very low angle of impact. A description is given of the design and operation of the novel erosion tester which overcomes the limitations of existing testers.

ISSN:1040-2004    

DOI:10.1080/10402009208982089

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Gas film riding seals have found wide acceptance in pipeline and process industry turbomachinery. The seals have not found many applications in either industrial or aircraft gas turbines, however. Gas turbine engines currently being designed will have higher compression ratios (greater than 30:1). The combination of increased pressure and more aggressive engine efficiency goals will severely tax the capability of present sealing systems. The film riding face seal (FRFS) has emerged as an attractive candidate for providing sealing for the hot high pressure engine compressor discharge air.

ISSN:1040-2004    

DOI:10.1080/10402009208982090

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In designing an optimum connecting rod, it is necessary to determine the oil film pressure (OFP) distribution at the big end under the actual engine operating conditions because it is used as the boundary conditions in a structural analysis. Since it is very difficult to measure the OFP distribution, a bearing test rig has been developed to simulate the load of an operating engine. The measured data on the cap side of the connecting rod obtained with this test rig shows a lower maximum oil film pressure and a wider pressure angle than those on the rod side.Presented at the 46th Annual Meeting in Montreal, Quebec, Canada April 29–May 2, 1991

ISSN:1040-2004    

DOI:10.1080/10402009208982091

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor