Transient elastohydrodynamic analysis of elliptical contacts. Part 2: Thermal and Newtonian lubricant solution

Abstract

Transient thermal elastohydrodynamic lubrication (EHL) of general elliptical point contacts was investigated numerically in this study. Both entrainment directions along the major and the minor axes of the contact ellipse were considered, together with a transient load impulse. In this study, a Newtonian lubricant was assumed to highlight the thermal influence. The transient solution was achieved at every instant, starting from a steady state thermal EHL solution. At each instant, a multilevel solver was used for pressure and surface deformation, whereas a column-by-column relaxation technique was used for solving temperature. The unknown rigid central distance between the contact bodies was adjusted after each iteration between the transient fields of pressure and temperature, so that in each iteration, only one W cycle was required for pressure and only a few relaxation cycles were required for temperature. With these numerical techniques, the computing time required for a typical transient case was reduced to ∼ 12 h on a personal computer with a 3.0 GHz central processing unit. The transient thermal results were compared with those corresponding to isothermal conditions presented in Part 1 of this series of papers. It was found that, in general, the transient behaviour under thermal conditions was similar to that under isothermal conditions, however, the former was weaker than the latter when the slide-roll ratio was large enough.