摘要:

Analyses and predicted performance of a 50-mm diameter, spiral-groove face seal to seal liquid oxygen at 5.17 MPa pressure, and operating at surface speed of 183 mls are described. The pressure-balanced spiral-groove concept is introduced that circulates spiral-groove flow independent of leakage flow. Independent flow paths preclude overheating from vaporization and consequent flow blockage. The analysis accounts for fluid turbulence and inertia, thermoelastic distortions, and dynamic response. An operating-range map was developed as a function of speed and pressure. The fluid-film analysis is summarized in the Appendix.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981559

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Preliminary tribological studies on new polyimides formulated from the diamine 2,2-bis [4-(4-aminophenoxy)phenyl] hexafluorapane (4-BDAF) indicate that polyimides formulated from this diamine have excellent potential for high-temperature tribological applications. The dianhydrides used to make the polyimides were pyromellitic acid (PMDA) and benzophenonetetracarboxylic acid (BTDA). Friction and wear studies at 25° and 200°C indicate that polyimides formulated using 50 mole percent of the PMDA dianhydride and 50 mole percent of the BTDA dianhydride perform better than polyimides formulated solely with the RTDA dianhydride. Graphite-fiber-reinforced polyimide (GFRPI) composites were formulated with the polyimide made from the BTDA dianhydride, both graphitic and nongraphitic fibers were evaluated. Graphitic fibers produced better tribological results, since thin, flowing, “layerlike” transfer films were produced which did not buildup with long sliding durations. Nongraphitic fibers did not produce this type of transfer.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981560

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

An analysis is presented for reciprocating sliding seals and pumping rings with an arbitrary clearance between the seal and rod and preload caused by axial tightening of the gland follower. The analysis is implemented by a fourth-order Runge-Kutta technique applied to the fluid equations in combination with a simple plane strain finite-element calculation for the seal. Results are presented for a variety of pressure differentials and preloads for both outstroke and instroke and both for soft elastomers and hard-filled PTFE material. Preload and initial clearance are shown to play an important role in seal and pumping-ring performance.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981561

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In oil/water/solid contact angle experiments, aluminum alloy surfaces with a high percentage of MgO in the oxide layer were wetted by naphthenic oil and naphthenic oil containing 1 percent oleic acid. The opposite behavior, poor wetting, was observed on alloy surfaces of almost pure aluminum oxide. On the latter surfaces, however, oil wetting was increased by decreasing the pH and by adding magnesium ions to the water being displaced.

ISSN:0569-8197    

DOI:10.1080/05698198408981562

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Whenever there are changes in surface chemistry of the magnetic tape caused by various tribological or environmental parameters, such as humidity and temperature, they may significanty increase the adhesive interaction between the magnetic tape and the drive components. Exposure to high humidity at elevated temperatures for extended periods can result in the hydrolytic degradation of the tape-binder system. The products of hydrolytic degradation have lower molecular weight and may be tacky in nature. Changes in the binder can be monitored by measuring molecular weight, extractable binder-to-lubricant ratio, and modulus of elasticity. A chemically stable binder system minimizes the risk of high friction. In the case of tapes tested at low humidity, the frictional behavior shows little dependence on the chemistry of the binder and primarily on the thermomechanical response of the magnetic coating. It is also noted that in most commercial tapes, the friction is high when measured at high humidities (above 60 percent RH).Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981563

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The paper is concerned with surface roughness analysis as a means of investigating lubricant action in cutting. An experimental setup involving a high-resolution signal analyzer has been used to obtain power spectrum characteristics, as well as conventional surface roughness parameters, of surfaces machined using different work materials and cutting fluids. Across the lay, conventional roughness parameters are dominated by the feed marks, and discrimination between different lubricating conditions is difficult. Frequency analysis, on the other hand, permits one to isolate the feed component, thus making it possible to ascertain the effect of lubrication at other wavelengths. The lubricating action is even more pronounced when measurements are performed in the machining direction, though a larger scatter among the results is experienced here. The averaged power spectrum ratios of surface roughness measured in the direction of cutting are used to describe the lubricating action.Presented at the 37th Annual Meeting in Cincinnati, Ohio May 10–13, 1982.

ISSN:0569-8197    

DOI:10.1080/05698198408981564

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981565

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A study to obtain a fluorescent dye suitable for use in detecting the presence of thin-film electrical contact lubricants has been conducted, and it has been found that BBOT [2,5-bis (5-tert-butyl-2-benzoxazolyl) thiophene], a scintillation-grade blue fluorescent dye, is a much improved replacement for the presently used proprietary green fluorescent organic dye. Using quantitative fluorometry, it was determined that the fluorescence intensity from a lubricant film deposited from a solution containing 0.01 percent BBOT is about six times greater than that from a film deposited from a solution containing 0.02 percent of the organic phosphor. The fluorescence intensity of the BBOT changes very little with time and exposure. With the organic phosphor, after seven days the intensity decreases by about 90 percent, below that which can be visually detected using ordinary long wave UV-light. BBOT, in amounts twenty times (0.20 percent) the concentration required, appears to have no detrimental effect on contact resistance, giving a maximum shift in contact resistance distribution of about 200 micro ohms. BBOT is nontoxic and safe for use. On the basis of this, contact lubricant specifications are being revised to replace the organic phosphor with BBOT. These studies suggest that fluorescence techniques can also be used to measure and monitor contact lubricant film thickness and distribution.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981566

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

An analytical approach was developed for the difficult problem of predicting the dynamic variation in fluid-film thickness of elastic-isoviscous line contacts under isothermal conditions. A numerical solution procedure was constructed and applied to the experiments of Hirano and Murakami who were investigating the lubrication of O-ring seals. Reasonable agreement was obtained. The present approach was extended to the lubrication of compliant layered surfaces as part of a study of human ankle joint lubrication. Although dependent on many assumptions, the present analysis provided a simple method for predicting the film thickness in both Hertzian and non-Hertzian contacts subject to cyclic time-varying loads and entrainment velocities.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 16–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981567

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Rates of adsorption and desorption, of di-isopropyldithiophosphoric acid and tetraisopropylthioperoxydiphosphate from hexade-cane on to steel, have been measured wing14C radiolabelled compounds. Concentration, temperature, and stirring dependence have been examined. The adsorption is surface controlled and the kinetics can be represented by a Langmuir model. Correlation of rate data with antiwear properties is examined.Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981568

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor