Equivalent Stiffness and Damping Investigation of a Hydrostatic Journal Bearing

Abstract

The aim of this research is to study the dynamic characteristics of a hydrostatic journal bearing, with four hydrostatic bearing flat pads fed by diaphragm restrictors and supporting a rotor. We assumed that the fluid flow is incompressible, laminar, isothermal, and steady-state. Linear modeling was performed using a numerical method in order to investigate the effects of the film thickness, the recess pressure, and the geometric configuration on the equivalent stiffness and damping of a hydrostatic journal bearing. In the first step, the variation of equivalent stiffness and damping is studied according to the pressure ratio for different geometric configurations of a hydrostatic bearing at the point of operation. In the second step, the variation of the equivalent stiffness and damping is studied according to the ratio of the film thickness for different geometric configurations of a hydrostatic bearing when one moves away from the point of operation. The results show that the hydrostatic journal bearing has good dynamic characteristics and excellent stability because of its higher stiffness, damping, and zero cross-coupling terms.

KEY WORDS:

• Hydrostatic Bearing
• Squeeze Film Lubrication
• Rotor Bearing Dynamics
• Stiffness
• Damping

ACKNOWLEDGMENTS

The authors gratefully acknowledge the financial support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC).

Review led by Ted Keith