Thermal and normal squeezing effects in lubrication of rollers by a power-law fluid

Abstract

A theoretical study of hydrodynamic lubrication in pure rolling of identical rigid cylinders has been carried out using the usual two-parameter power-law fluid model. Normal squeezing motion together with cavitation has been investigated. In this study the effects arising from the variation of viscosity with hydrodynamic pressure and temperature have been incorporated in the analysis. The resulting governing equations have been transformed to a set of ordinary differential equations which have been solved numerically using the Adams-Moulton method. A non-uniform grid was employed to achieve more accurate predictions of pressure and temperature, especially in the high pressure region. A detailed examination of the theoretical results obtained herein seems to suggest that the temperature dependence of the lubricant viscosity causes a reduction in both the load-carrying capacity and the surface traction of the system, whereas the normal squeezing motion (in a direction perpendicular to that of the fluid flow) leads to a substantial increase in pressure and also displaces the pressure peak towards the centre-line of contact. This observation appears to be true for all the values of the power-law flow behaviour index studied herein.