Nonlinear Transient Stability Analysis of Meso-Scale Rotor Supported on Gas Foil Journal Bearings

Abstract

To understand the nonlinear behaviour of foil bearing, a nonlinear transient stability analysis of meso-scale rotor with bump foil journal bearings is presented. A mathematical model is used to simulate the dynamics of rotor-bearing system. The effect of stability parameter: threshold rotor mass on bearing design parameters is studied. A bearing design parameters viz. foil compliance, bearing radial clearance and operating speed are considered. It is observed that the threshold rotor mass is significantly influenced by bearing design parameters. The meso-scale rotor, under its weight alone remains unstable. With increase in foil compliance, threshold rotor mass decreases while increase in bearing clearance, threshold rotor mass increases. As the rotor speed increases, threshold rotor mass decreases. The present analysis is useful for estimating the preload or additional external load required for maintaining stability of rotor.