Orbit Induced Journal Temperature Variation in Hydrodynamic Bearings

Abstract

A method for evaluating the asymmetric heat input into the synchronously vibrating journal of a hydrodynamic bearing is presented. CFD techniques are used to analyze the dynamic flow and heat transport in the lubricant film and the heat input into the journal is obtained by orbit time averaging. The procedure is applied to a two-inlet circular bearing with backward and forward circular whirl journal orbits over a range of rotational speeds. The steady asymmetric heat input into the journal is found to have a sinusoidal component, which causes a steady surface temperature differential across the journal. The maximum temperature on the journal surface is always upstream of the minimum film point for forward whirl orbits and downstream for backward whirl orbits. The results provide a greater understanding of the nature of rotor thermal bending.