Influence of Couple Stress Lubricant on the Performance of Orifice Compensated Non-Recessed Hole-Entry Hydrostatic/Hybrid Journal Bearing

Abstract

The lubricants are generally additized in order to enhance their lubricating properties. As a consequence of this, they exhibit nonlinear relationship between the shear stress and shear strain. One class of lubricants which has received considerable attention in recent years is the couple stress lubricants. The study of couple stress fluid flows has been the subject of increased interest owing to its widespread industrial and scientific applications such as synthetic fluids, polymer-thickened oils, liquid crystals and animal bloods. The present work is therefore aimed to study analytically the influence of couple stress lubricant on the performance of an orifice compensated non-recessed hole-entry hydrostatic/hybrid journal bearings. The modified Reynolds equation based on Stoke’s couple stress fluid theory has been solved by using the Finite Element Method. The numerically simulated results have been presented for various valves of couple stress parameters and external loads. The numerically simulated results reveal that the influence of couple stress lubricant increases the value of minimum fluid film thickness at constant value of external load for hybrid journal bearing vis-a-vis Newtonian lubricant. Further, it has been observed that the value of direct fluid film damping coefficient (C22) is larger for hydrostatic journal bearing lubricated with couple stress lubricant.