Numerical analysis of turbulent lubrication in plain full journal bearings

Purpose - The purpose of this paper is to assess the turbulent thermohydrodynamic (THD) performance characteristics of an axially grooved finite journal bearing for a variety of simulated operating conditions. Design/methodology/approach - The set of governing equations consisting the Navier-Stokes, turbulent kinetic energy and its dissipation rate equations coupled with the energy equation in the lubricant flow and the heat conduction equation for the bush are solved to obtain the three dimensional steady state THD characteristics of journal bearings. The lubricant flow in turbulent regime is modelled using the AKN low-Re k - epsilon turbulence model. The problem is formulated mathematically and solved numerically using the computational fluid dynamics (CFD) approach with appropriate boundary conditions. Findings - It was found that shaft rotational speed has dramatic effects on the maximum temperature of the bearing and lubricant, also on the maximum hydrodynamic pressure and the oil flow rate. Besides, it was revealed that the clearance ratio and eccentricity ratio significantly change the performance of the journal bearing. Practical implications - The paper presents a very useful numerical method for the prediction of the pressure and temperature fields inside the lubricant and thermal simulation of the bearing. Originality/value - The paper provides the numerical simulation of the flow and heat transfer inside the journal bearing. Present computational approach is valuable to the practical modeling of the journal bearing operating under turbulent regime and in preparing the design charts in prediction of both hydrodynamic and thermal behaviors of journal bearings.