Static Analysis of Viscoelastic Supported Gas Foil Thrust Bearing with Journal Inclination

Abstract

Thrust pads in rotary machines are often used to bear the axial load, sometimes part or whole of the rotor weight is also sustained by thrust pads when the machine is not installed horizontally. Static characteristics of gas foil thrust bearing such as bearing load and friction torque play important roles in bearing-rotor system. In this paper, Finite Difference Method (FDM) was adapted to analyze compliant surface thrust gas bearing with viscoelastic support. Considering inclination of the journal, pressure distribution and film thickness between thrust disk and thrust pads were obtained by solving dimensionless governing equations, then nondimensional bearing load and nondimensional friction torque can be calculated subsequently. Based on the results of numerical calculation, effects of structural parameters and operational parameters on static characteristics were discussed. Theoretic analysis denote that: thrust foil bearing in journal inclination have higher load capacity and higher friction torque than that in no tilting condition; the optimum structure parameters for viscoelastic supported foil thrust bearing with the outer radius to inner radius ratio of 3 and dimensionless compliant coefficient of 1 is β = 90° and b = 0.5. Experiment about bearing load also has been implemented in this paper, and the results prove that the theoretical analysis is available.

Keywords

• foil bearings
• journal inclination
• load capacity
• friction torque
• static characteristics