Elapsed Time for the Decay of Thermal Transient in Fluid Film Bearing Assemblies

Ettles, C., Heshmat, H. and Brockwell, K. “Elapsed Time for the Decay of Thermal Transient in Fluid Film Bearing Assemblies,” 15th Leeds-Lyon Symposium Proceedings, Tribology Series 13, Elsevier Publication edited by Dowson et al., 1989.

The decay time of thermal transients in a bearing assembly is of practical interest, since premature measurements could be misleading.  In addition, the thermal deformation that occurs during a transient does not vary smoothly or monotonically.  In severe cases this can lead to an instability and failure of the bearing. 

The principal factors governing thermal transients are inferred from classical solutions.  More accurate predictions may be made from a coupled solution of the film and bounding components.  Experimental data from six thrust bearings and two journal bearings are examined.  It is found that, following a step change of operating condition, the heating or cooling rate varies approximately exponentially.