Recent studies on fluid film lubrication with non-Newtonian lubricants

Abstract

This review describes the recent studies of fluid film lubrication by non-Newtonian lubricants. Present-day lubricating oils contain a large quantity of high-molecular-weight polymers as a viscosity index improver and a viscosity thickener. Greases have been widely used in various types of equipment and machinery to simplify the lubricating system. These lubricants exhibit a non-Newtonian behavior. However, the classical theory of fluid film lubrication deals with the lubricants whose behavior is Newtonian. In recent years, several investigators have studied the fluid film lubrication characteristics of non-Newtonian lubricants in various bearings by considering different rheology models. In this paper, the problems of fluid film lubrication for such lubricants are reviewed by classifying the studies by rheology models.