Analyses of Heat - Pipe Cooled Isothermal Journal Bearings

Isothermal journal bearings have been developed by incorporating heat-pipe cooling. The heat pipe assists in spreading heat rapidly along the bearing circumference, resulting in a very small temperature gradient, low peak temperature, and stable transient thermal behavior. This paper presents a model for the isothermal journal bearings and the results of analyses. The heat pipe in the isothermal journal bearing is modeled as a heat conductor whose effective thermal conductance is determined through the correlation between the analytical and experimental data. The heat-transfer coefficients at the bearing boundaries are obtained with the assistance of the experimental measurement and calculation using a semi-empirical correlation method. Good agreement is observed between the analytical and experimental results. The effects of bearing geometry and materials on the performance of the isothermal journal bearing are numerically investigated using the model thus developed. The analyses further confirm that the isothermal journal bearings have the ability to battle the heat-induced problems, which can significantly benefit bearing operation and failure prevention. *Corresponding author Mechanical Engineering Northwestern University Evaston, IL 60208 847-467-7510, [email protected]