641 An Effect of Design Variables on Stability Threshold Speed of Hydrodynamically Air-Lubricated Foil Journal Bearings

Abstract

This study aims at predicting the stability threshold speed of the horizontal rigid rotor supported in bump foil journal bearings, by using two model bearings, one of which corresponds to the bearing with an excessive static friction between the top and the bump foils and the other to the bearing without the friction. It is found from the modified stability charts that some of the design variables of the bearing, such as rigidity, attached angle and angular extent of top foil and stiffness of bump foil, have a perceivable effect on the speed of the rotor-bearing system.