Effects of electric field on hydrodynamic characteristics of finite-length ER journal bearings

A numerical analysis is performed on the hydrodynamic characteristics of electrorheological (ER) fluid flows in journal bearings based on computational fluid dynamics (CFD) techniques. The bearing has a finite-length and operates under incompressible laminar flow with steady conditions. The analysis is based on the numerical solution of full three-dimensional Navier-Stokes equations. The applied electric field is imposed partially along a contractive section of the journal bearings and the modified Bingham plastic model is used to describe the behavior of ER fluid. The results presented are obtained by using finite-volume-methods and solved by the semi-implicit method for pressure-linked equations (SIMPLE) algorithm. In this study, cavitation effects are also considered by using the viscosity modeling. The results have shown that the influences of ER effects, caused by the applied electric field, on the journal bearing characteristics are significant and not negligible. Compared with the Newtonian lubricant case, the effects of the ER effects provide an enhancement in the load-carrying capacity, but do have little effects on the attitude angle. The quantitative effects on load-carrying capacity are more pronounced for journal bearings operating at higher values of eccentricity ratio or lower rotary speed. (c) 2005 Elsevier Ltd. All rights reserved.