A two-dimensional thermo hydrodynamic analysis of journal bearings characteristics



A numerical thermohydrodynamic analysis of journal bearings operating under laminar flow and steady conditions is presented. Numerical solutions of full Navier-Stokes equations, coupled with energy equation in the lubricant field and heat conduction equation in the bearing, are obtained for a bearing of infinite length. Using conformal mapping, an orthogonal grid is generated and the governing equations are transformed for use in the computational plane. Finite difference forms of the transformed equations are obtained by control volume method, and the SIMPLE algorithm is used for the pressure-velocity coupling. Regarding the cavitated flow region, a cavitation criterion based on the lubricant vapor pressure is defined and the extent of the cavitated region is determined in the course of iterative numerical calculations. A homogenous mixture of lubricant and vapor is assumed in the cavitated region and the mean physical properties of the mixture are obtained based on the continuity requirement. To study the effect of different parameters, solutions are obtained for different values of eccentricity and radial clearance and also for different values of Reynolds number. To validate the computational results, comparison with experimental data of other investigators is made for several test examples, and reasonable agreement is obtained for each example