摘要:

A survey of gas path seals is presented with particular attention given to sealing clearance effects on engine component efficiency. The effects on compressor-pressure ratio and stall margin are pointed out. Various case-rotor relative displacements, which affect gas path seal clearances, are identified. Forces produced by nonuniform sealing clearances and their effect on rotor stability are discussed qualitatively, and recent work on turbine-blade-tip sealing for high temperatures is described. The need for active clearance control and for engine structural analysis is discussed. The functions of the internal-flow system and its seals are reviewed.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978.

ISSN:0569-8197    

DOI:10.1080/05698198008982942

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The lubrication condition of sliding concentrated steel contacts can be described in terms of transition diagrams, relating the mode of lubrication [i.e. (partial) elastohydrodynamic (EHD), boundary and virtually unlubricated] to load, speed and temperature.

ISSN:0569-8197    

DOI:10.1080/05698198008982943

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Basic components of a spiral-groove, face-type gas seal are shown. Analyses of flow, of thermal environment and heat transfer were made to improve stability, decrease sensitivity to contaminants and reduce leakage. Analysis suggested reduced film thickness and the advantages of spiral-groove design over Rayleigh pad design for thin gas film operation. Experimental program started with static leakage tests to verify pressure deflections at various pressures; a 1000 h dynamic test followed where 114.3 mm (4.5 in.) diameter seals ran successfully at pressures up to 6.2 MPa (900 psig) and speeds up to 73.66 m.s.−1(14 500 fpm).Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

ISSN:0569-8197    

DOI:10.1080/05698198008982944

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The lubricant film thickness of grease-lubricated, cylindrical roller thrust bearings was measured, using a capacitance type displacement probe. For comparison, the same tests were also performed with the bearings lubricated with mineral oils. The film thickness and friction torque as a function of rotational speed were determined both under fully flooded and starved lubrication conditions. The test results show that the lubricant film thickness in grease-lubricated bearings is influenced by the base oil, and the thickener.Presented as an American Society of Lubrication Engineers paper at the ASLEIASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

ISSN:0569-8197    

DOI:10.1080/05698198008982945

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A versatile pin-on-disk-type friction and wear apparatus is described which permits close control of environments both in vacuo and mixed gas atmospheres.

ISSN:0569-8197    

DOI:10.1080/05698198008982946

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A discussion is presented concerning the choice of boundary conditions to be used in converging-diverging lubrication films. It is concluded that, although no unique solution exists, under usual lubrication conditions (film rupture), the well-known conditiondp/dx= 0 seems to hold indeed true, on the physical ground that this condition corresponds to a maximum accumulated mechanical energy from the moving surface via friction stresses.

ISSN:0569-8197    

DOI:10.1080/05698198008982947

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The inadequacy of average roughness values such as AA and RMS for describing surface topography in metalworking is discussed. It is suggested that an expression involving asperity height, asperity form and roughness direction is needed.

ISSN:0569-8197    

DOI:10.1080/05698198008982948

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Experimental work to study the effects of balance ratio, seal face divergency, shaft speed and number of pockets on leakage and tilt stability, for a 9.5 cm pocket-type, hydrostatic rotary end face seal in high-pressure water, is described and discussed. It is shown that leakage and tilt stability, for a given pressure, both depend primarily on balance ratio and parallelity of the sealing gap. It is also shown that seal face separation prevails even if the sealing gap is slightly divergent. For the seal, the data indicate that at least six pockets are required to obtain close to maximum tilt stability.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

ISSN:0569-8197    

DOI:10.1080/05698198008982949

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Using a pin-on-disk apparatus, experiments were carried out to determine the wear coefficients of the nine elemental metals which form little or no oxide in air (ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold) when sliding against each other. The tests mere unlubricated in air at room temperature. It was found that the lowest wear coefficients involved hexagonal metals and incompatible metal pairs. For pairs of metals differing in hardness, the ratio of wear volumes of the two metals was the inverse of the ratio of penetration hardness. In general, the scatter of wear volumes was far lower than that observed in previous tests using oxide-forming metals, in which cases the oxide layers were perturbing factors. The test results suggest that the current practice of using alloys based on gold, platinum and palladium in sliding electric contacts is not optimum, and that combinations involving rhodium and ruthenium deserve consideration.Presented as an American Society of Lubrication Engineers paper at the ALSE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

ISSN:0569-8197    

DOI:10.1080/05698198008982950

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The authors have studied fundamentally and experimentally the explanation of the sealing mechanism of oil seals. It will be generally noticed that the suction of air occurs to the rubbing portion of the lip of an oil seal which is operating under sealing condition. For the purpose of studying sealing characteristics of an oil seal in the authors' investigations, the volume, [Qbar], of transferred lubricating oil instead of air is used as a means of estimating the sealing status.

ISSN:0569-8197    

DOI:10.1080/05698198008982951

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor