Squeeze film characteristics of finite journal bearings : couple stress fluid model

Hydrodynamic lubrication of rough slider bearings with couple stress fluids

An inverse solution for finite journal bearings lubricated with couple stress fluids

Interferometry proves to be an efficient way to measure thin lubricant film thickness. However, there are very few reports on the film thickness measurement of conformal lubricated contacts using optical interferometry due to experimental difficulties. In this article, a custom-built test apparatus is introduced, in which a lubricated conformal contact is made between a stationary fixed-incline slider and a moving transparent disc. With a flexible holder, the slider can be positioned in such a way that a specified inclination with respect to the flat disc plane can be obtained. When the disc rotates and the slider is loaded against it, lubricating films are generated. The minimum film thickness h
 m at the exit can be determined by interference intensity changes. Measurement error correction in the film thickness was discussed. Case experiments were carried out using the new test apparatus. The credibility of the measurement system is validated by good correlation between the experiments and the theoretical results. The applicability is demonstrated by the film thickness measurement under different inclinations, loads, velocities, lubricants and slider materials. Amongst those case experiments, it is highlighted that the influences of solid/liquid interface properties on the lubrication behaviours can be clearly identified in terms of film thickness.

Interferometry Measurement of Lubricating Films in Slider-On-Disc Contacts

A theoretical study of combined effects of non-Newtonian rheology and viscosity-pressure dependence in the sphere-plate squeeze-film system

Theoretical study of porous slider bearing with couple stress fluid as lubricant is made and the lubrication qualities of couple stress fluid are examined. The lower surface is covered by a thin porous material and the upper one, having arbitrary shape, moves in its own plane with constant velocity. Analytical expressions for load capacity, frictional force and the centre of pressure are derived. It yields increase in, load capacity and ensures the decrease in coefficient of friction. The problem is also discussed in the context of various geometries viz, (1) Rayleigh step bearings and (2) inclined slider bearings. Bounds on flow rate, frictional coefficient, centre of pressure and time-height relation are obtained and compared with classical case, Gross [1]. Suitable design parameters are predicted for the efficient lubrication of slider bearings.

Porous slider bearing with couple stress fluid

An analysis of squeeze film action in porous layered bearings

The present theoretical study investigates the effects of surface roughness and couple-stress fluid between two rectangular plates, of which an upper rough plate has a roughness structure and the lower plate has a porous material in the presence of transverse magnetic field The lubricant in the gap is taken to be a viscous, incompressible, and electrically conducting couple-stress fluid This gap is separated by a film thickness H which is made up of nominal smooth part and rough part The modified Reynolds equation in the film region is derived for one-dimensional longitudinal roughness structure and solved numerically using multigrid method The numerical results for various physical parameters are discussed in terms of pressure distribution, load capacity, and squeeze film time of the bearing surfaces Our results show that, the pressure distribution, load capacity and squeeze film time are predominant for larger values of Hartman number and roughness parameter, and for smaller values of couple-stress parameters when compared to their corresponding classical cases

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H. P. Patil

Papers

Porous slider bearing with couple stress fluid

An analysis of squeeze film action in porous layered bearings

Numerical Solution of the MHD Reynolds Equation for Squeeze-Film Lubrication between Porous and Rough Rectangular Plates

The effect of variable permeability and rotation on the performance characteristics of porous bearings

The effects of variable permeability and roughness of porous bearings