Bifurcation Analysis of Bearing Number in Ultra Short Gas Bearing System

Abstract

This paper studies the nonlinear dynamic behaviors of a rigid rotor supported by ultra short gas bearing (USGB) system. A hybrid numerical method combining the differential transformation method and the finite difference method are used to calculate pressure distribution of USGB system and rotor orbits. The results obtained for the orbits of the rotor center are in good agreement with those obtained using the traditional finite difference approach. Moreover, the hybrid method avoids the numerical instability problem suffered by the finite difference scheme at low values of the rotor mass and computational time-step. The results presented summarize the changes which take place in the dynamic behavior of the USGB system as the bearing number are increased and therefore provide a useful guideline for the bearing system.

KEYWORDS:

• Ultra short gas bearing
• Hybrid method
• Bearing number