Thermal non-Newtonian elastohydrodynamic lubrication of line contacts under sliding-rolling and simple sliding conditions

A thermal Reynolds-Eyring equation is derived to study the elastohydrodynamic lubrication of line contacts. This lubrication condition is usually found in spur gears, roller bearings and cams. The inlet region with back-flow is treated with a control volume scheme to obtain the temperature solution. A computationally-simple formulation for the stationary surface temperature is developed for simple sliding conditions. The most influential dimensionless groups are identified from the complete sets of dimensionless groups. Numerical results obtained for sliding and rolling and for simple sliding conditions are used to develop formulas for the thermal and non-Newtonian (Ree-Eyring) film thickness reduction factor. Even when thermal effects are small, these formulas can still give a film thickness reduction due to the non-Newtonian effects. Results for the maximum temperatures and traction coefficient are also presented. The pressure dependence of lubricant thermal conductivity is found to significantly affect the maximum lubricant temperature. The thermal effects on film thickness and traction are found to be more pronounced for simple sliding than for combined sliding and rolling conditions. Under simple sliding, the heat transferred to the stationary surface is found to be very small compared to that transferred to the moving surface and lubricating fluid.