Effect of microridges on the performance of three-lobe journal bearing considering cavitation and lubricant compressibility

Abstract

This study presents a numerical study of the effect of microridges on the performance of the three-lobe journal bearing considering lubricant compressibility and cavitation effects. A mathematical model based on the Reynolds equation that has been modified to take into account the effects of lubricant compressibility and cavitation has been proposed to achieve the primary goal of this work. Lubricant compressibility is considered by using lubricating oils with different bulk moduli while Elord's algorithm was used to consider the effect of cavitation. The governing equations for finite length journal bearing lubricated with Newtonian oil in laminar flow and isothermal condition are numerically discretised using the finite difference method and solved by using a suitable prepared computer program. The performance of the rough and smooth bearings was compared for plain and three-lobe journal bearings. The numerical model was demonstrated by comparing the pressure distribution for smooth and microridges three-lobe journal bearing with that published by El-Said et al. and they were found in good agreement. It was found that the pressure and the load were considerably enhanced and the coefficient of friction decreased by 15 % for three-lobe journal bearing with microridges in comparison with that of smooth surfaces.

Keywords

• three-lobe bearing
• micro ridges
• cavitation effect
• compressibility effect
• hydrodynamic lubrication