Improving the static characteristics of hydrodynamic bearings using the viscosity-temperature relations of lubricants

Abstract

The possibility of improving the static characteristics of hydrodynamic bearings using the inverse viscosity-temperature relations of liquid lubricants is theoretically examined. A simplified model that comprises the Reynolds equation with a change in the mean oil viscosity across the film as a function of temperature and that is based on the thermal lubrication theory is applied. The solutions are numerically obtained for linear sliding bearings, tapered land bearings, and cosine pad bearings, wherein the temperature distributions are given as known values and the viscosity distributions are determined beforehand. The bearing geometry and temperature profiles are selected as parameters. When the temperature in the converged region close to the minimum clearance is low, the fluid pressure becomes larger; thus, the friction coefficient becomes smaller, whereas the leakage flow rate changes slightly. This behavior may contribute to improving the static characteristics of hydrodynamic bearings.