Analyses of Heat-Pipe Cooled Isothermal Journal Bearings

Abstract

An isothermal journal bearing that incorporates heat-pipe cooling technology has been developed. The heat pipe can spread frictional heat rapidly along the bearing circumference, resulting in a uniform temperature distribution in the bearing with a low peak temperature and stable transient thermal performance. A numerical model has been developed for the new bearing to facilitate a thorough understanding of its performance as well as an optimal bearing design. The heat pipe in the bearing is modeled as a heat conductor whose effective thermal conductance is determined through the correlation between the numerical results and experimental data. The heat transfer coefficients at bearing boundaries are obtained with the assistance of experimental measurements and calculations using semi-empirical correlations. Good agreement is observed between the analytical and experimental results. Once the analytical model is validated, a parametric study is conducted for the performance of new bearings with different configurations and materials. The analytical results further confirm that the isothermal journal bearing developed has the ability to battle frictional-heat-induced problems, which can significantly benefit both bearing operation and failure prevention.