Dynamic Coefficient Prediction in Multi-lobe Journal Bearings Using a Mass Conservation Algorithm

Abstract

A numerical procedure incorporating cavitation modeling in the predication of dynamic coefficients for four multi-lobe bearings is presented. A first order perturbation solution of the density (or fractional film content) is obtained by using the Elrod universal equation. The Elrod algorithm conserves mass throughout the bearing and automatically predicts the full film and cavitation regions using a switch function. In this work, the cavitation boundary predicted under steady state is considered for calculation of four unsteady pressure gradients. Results of stiffness and damping coefficients are presented for four multi-lobe bearing configurations, viz., two-axial groove, elliptical, three-lobe and offset cylindrical bearing for various L/D and eccentricity ratios. The results of bearing dynamic coefficients obtained using the cavitation algorithm agree well with the published work based on Reynolds boundary on the conditions as the film rupture boundary is predicted based on the continuity of fluid flow in the journal bearings.

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003

Notes

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003