Effects of longitudinal roughness on fluid temperature in point elastohydrodynamic lubrication contacts

Abstract

The effects of longitudinal surface roughness on the oil film temperature are studied numerically based on Eyring and Newtonian fluid flow models under point contact rolling and sliding elastohydrodynamic lubrication (EHL) conditions. There is a significant difference in oil film temperature distribution between the Eyring or shear thinning fluid and the Newtonian fluid. In shear thinning fluids, the relationship between the oil film temperature distribution and the roughness around the central contact area becomes out-of-phase, i.e. the temperature of oil film is higher at the valley than at the ridge of asperity. Such a phenomenon occurs easily under short wavelength and low amplitude of roughness, and moderate entrainment velocities depending on the slide-roll ratio.