Stability of a System Consisting of Flexible Rotor and Flexibly Mounted Journal Bearings

Abstract

Stability characteristics of a system consisting of a flexible rotor and oil journal bearings mounted on flexible damped supports were investigated theoretically and experimentally. The stability conditions of the flexibly supported system without damping were derived analytically, and the effect of the support with damping on stability was calculated numerically from the Routh-Hurwitz criterion. Based on the analytical results, the effects of equivalent mass and damping of the flexible support on the stability of the flexible rotor-bearing system were investigated and the optimum design of the bearings mounted on flexible damped supports clarified. The experimental results were in good agreement with the analytical ones. Consequently, it was found possible to eliminate the oil whip phenomenon, using an appropriate support design.