The stability of liquid lubricated journal bearings

Abstract

The dynamio characteristics of journal bearings have been predicted by solving Reynolds equation with a common cavitation model. A perturbation analysis has been used to express the equations governing the fluid film pressure and cavitation region state in terms of a dynamic journal displacement vector. The use of these equations has been demonstrated on the long and short bearing approximations. The stability performance has been predicted for both rigid and flexible bearing systems. A perspex test bearing has been used to observe cavitation under steady and dynamio loads, and a high speed test apparatus was developed for the measurement of lubricating film performance at whirl onset conditions. Although the test results were consistent and repeatable, the stability performance of the bearings tested was substantially less than the predictions of the simple bearing theory and other workers results. It is thought that the poor performance was due to oil starvation.