Modeling Aspects of a Rate-Controlled Seizure in an Unloaded Journal Bearing

Abstract

Thermally induced seizure can lead to a rapid catastrophic bearing failure. An analytical model was developed to study this phenomenon in an unloaded journal bearing. The model consisted of two concentric cylinders containing lubricant in which the inner one rotates at a specified rpm and the outer cylinder is stationary. The appropriate governing equations and numerical solution schemes for treating the transient heat transfer in the fluid and the bounding solids are presented. Computations indicate that, depending on the operating conditions and thermomechanical properties, a bearing can rapidly lose its operating clearance. A parametric study with an extensive amount of numerical results is presented. It is shown that the clearance loss variation with time is initially linear up to a point after which its rate of reduction becomes much greater. Closely related to this non-linearity is the behavior of the friction torque which sharply rises before the clearance totally vanishes. The effect of thermomechanical properties, operating speed, and convective heat transfer coefficient on the seizure time are investigated.

Presented as a Society of Tribologists and Lubrication Engineers paper at the World Tribology Congress in London, United Kingdom, September 8–12, 1997

KEY WORDS:

• Journal Bearing
• Hydrodynamic Lubrication
• Thermal Effects
• Heat Transfer Analysis

Notes

Presented as a Society of Tribologists and Lubrication Engineers paper at the World Tribology Congress in London, United Kingdom, September 8–12, 1997