摘要:

A mixing length approach is applied to the case of a spiral flow, where pressure flow acts across a Couette flow as in the case of end leakage around a shaft. The mixing length is expressed as a dimensionless function of the modulus of the local velocity vector, drawing upon an empirical relationship based upon wall-law flow data. Results are shown to be in approximate agreement with a set of experimental measurements. This indicates that the computation scheme accounts for the major factors in such flows, where the shear stress chances direction outward from a wall.Contributed to ASLE by the authors.

ISSN:0569-8197    

DOI:10.1080/05698196808972221

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Various boundary conditions of fluid lubrication theories have been presented for the trailing edge of the lubricant film of a journal bearing, but they do not seem to be clearly investigated physically in connection with the lubricant film rupture. The reverse flow and, hence, the separation of fluid are observed experimentally to cause the film rupture. This condition is brought to be the boundary condition of the bearing film rupture in this paper. By using this condition, the bearing characteristics, such as eccentricity, load capacity, and attitude angle, are investigated theoretically. The experimental results, obtained by using the transparent bearing for the direct observation of the bearing film behavior, agree well with the theoretical ones.Presented at the 23rd ASLE Annual Meeting in Cleveland, May 6–9, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196808972222

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Vibration of the seal ring induced by the axial pulsation, wobbling and initial distortion of the rotor surfaces in a face-seal assembly consisting of a seal ring and a carrier are analyzed. The analyses are divided into two parts: a rigid body analysis dealing with vibrations due to the axial pulsation and wobbling; and an elastic ring analysis dealing with vibration induced by the initial surface waviness of the rotor. The fluid film characteristics are approximated by linear springs having two direct and two cross-coupling spring stiffnesses in the transverse and angular directions with negligible damping. Results are obtained in terms of natural frequencies and influence coefficients characterizing the response of the seal ring to the rotor motion.Presented at the 23rd ASLE Annual Meeting in Cleueland, May 6–9, 1968

ISSN:0569-8197    

DOI:10.1080/05698196808972223

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The current drop-weight test methods for evaluating the compatibility of materials with liquid oxygen under impact are briefly discussed, with particular emphasis upon the characteristically poor repeatability of the “threshold value” impact sensitivity ratings yielded by these methods. It is pointed out that this trait is primarily due to the poor statistics of the test procedures used. It is further shown that impact sensitivity alone, even when measured by the most accurate and reliable technique, is not an adequate description of the potential fire or explosion hazard of a material; reaction intensity must also be considered. With this background, typical results from two new test techniques are presented and discussed. In one of these, impact sensitivity is measured in terms of the drop height at which a material has a 50% probability of reaction. In the other, reaction intensity is measured in terms of the maximum peak pressure of the air shock wave generated by the reaction.Presented at the 23rd ASLE Annual Meeting in Cleveland, May 6–9, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196808972224

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

A resume of the current state-of-knowledge concerning rarefied gas flow through passages with static boundaries is presented. A brief development of the theoretical gas flow models which have been used for long tubes and annuli is included. These theoretical models have been developed to cover the flow regime extending from laminar continuum flow to free molecular flow. The analysis required to use these models is simple and straightforward. Experimental data are presented for the flow of argon through a long tube and for the flow of argon and xenon through annuli. The experimental values of mass flow rate per unit pressure drop as a function of Knudsen number are graphically presented for a long tube and for two annuli. Also presented on the same figures are the values predicted by the theoretical models. The agreement between theory and experiment for the complete regime between continuum and free molecular flow is very good.Presented at the ASLE Annual Meeting in Cleveland, May 6–9, 1968.

ISSN:0569-8197    

DOI:10.1080/05698196808972225

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The sliding of polytetrafluoroethylene (PTFE) was experimentally examined with a sled type apparatus and with a conventional three pins-on-flat frictometer. Friction hysteresis and time-and speed-dependent phenomena were observed with both instruments and were compared. With the sled apparatus, the relation between friction and sliding speed of PTFE sliding on PTFE at different ambient temperatures was examined and is described.

ISSN:0569-8197    

DOI:10.1080/05698196808972226

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

The wear and friction of pure gold and gold alloy electrodeposits were determined. These platings are widely used in sliding electric contacts and include golds hardened with silver, cadmium, nickel, cobalt, or cobalt and indium. In preliminary work, the microstructures, hardnesses, crystallographic orientations of the surface, and topographies of the golds were examined; these properties vary widely, and relationships among them are discussed. Sliding was with thick deposits to eliminate effects of substrate. The experimental method involved repeat-pass unidirectional sliding at 100g in a rider-flat apparatus with plated flats against wrought gold or gold-plated riders. Wear and friction are described for both as-plated samples, and to eliminate distinguishing surface textures, with flats abraded to a common roughness.

ISSN:0569-8197    

DOI:10.1080/05698196808972227

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

This paper presents a portion of the work done by the authors in developing a new approach to evaluation techniques for wear of solid film lubricants. The theory and experimental requirements are presented that are necessary to adapt the use of “wear coefficient” to the extremely thin films required for these materials. A method for correlation of wear data obtained on various testers is included. Experimental results have covered an environmental temperature range from —320F to 1100F. Design formulas for linear motion, journal, thrust, and spherical bearings have been derived to utilize experimental data in the estimation of hardware bearing wear.Presented at the 22nd Annual Meeting of the American Society of Lubrication Engineers held in Toronto, May 1–4, 1967.

ISSN:0569-8197    

DOI:10.1080/05698196808972228

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

摘要:

Fatigue tests were conducted in a modified five-ball fatigue tester on SAE 52100 steel ball specimens, at atmospheric pressure and at the approximate lubricant vapor pressure with two different lubrication methods, using a super-refined naphthenic mineral oil as the lubricant. Additional tests were conducted with AISI M-50 ball specimens with polyphenyl ether lubricants. Differences in fatigue life, deformation and wear with the mineral oil lubricant were insignificant regardless of the ambient pressure environment or lubrication method employed. Polyphenyl ether lubricants exhibited large amounts of wear both at atmospheric and reduced pressures, indicating a lack of an elastohydrodynamic film with this lubricant under the stresses and sliding velocities present in the five-ball fatigue tester.Presented at the ASLE Annual Meeting held in Toronto, May 1–4, 1967.

ISSN:0569-8197    

DOI:10.1080/05698196808972229

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor

ISSN:0569-8197    

DOI:10.1080/05698196808972230

出版商:Taylor & Francis Group    

年代:1968

数据来源: Taylor