Numerical Study of Thermohydrodynamic Characteristics of Oil Tilting-Pad Journal Bearings with a Self-Pumping Fluid Flow Circulation

Abstract

A thermohydrodynamic numerical code is developed for analyzing the steadily loaded finite tilting-pad journal bearings for vertical hydropower plants. The Reynolds equation and the two-dimensional energy equation in fluid film lubrication are solved by the central difference technique with a successive overrelaxation scheme and the backward difference with an iterative technique, respectively. In the simulation, the lubricant viscosity is changed with the temperature variation (in both axial and sliding directions) and the pad deformation is brought up in calculations. Oil circulation is considered as a self-pumping fluid flow through pad side leakage via a circumferential groove. Self-lubricating approach is guaranteed the oil cooling procedure and bearing performance in hydropower plants. The effects of pad number, preload factor, pivot position, and shaft rotational speed on the bearing performance are illustrated. Power friction loss, maximum oil film temperature, circulated oil fluid flow, minimum oil film thickness, and pad tilting angle are the most important results.