Influence of the Gas-film Inertia Forces on the Dynamic Characteristics of Externally Pressurized, Gas Lubricated Journal Bearings : Part II, Analyses of Whirl Instability and Plane Vibration

Abstract

By using the modified Reynolds equations and their boundary conditions which have been proposed in Part I[1], influences of the gas-film inertia forces on the whirl instability and on the plane vibration in externally pressurized, gas lubricated journal bearings are analyzed. Analytical results agree well with the experimental results, and the following are concluded: 1) The inertia forces raise the whirl ratio and the damping coefficient considerably even if the bearings are normally designed. 2) This is remarkable when the feed hole diameter, the number of feed holes, the bearing clearance and the supply pressure are large. 3) The proposed modified Reynolds equations and their boundary conditions yield good predictions of such characteristics in a wide range of designing conditions.