Full EHL Simulations Using the Actual Ree–Eyring Model for Shear-Thinning Lubricants

Abstract

The Eyring sinh law, which is the most widely used model to describe the shear-thinning behavior of elastohydrodynamic lubrication (EHL) lubricants, fails to replicate the experimentally measured flow curves for shear-thinning lubricants. Interestingly, this law was rejected by Eyring for shear-thinning fluids and, in fact, it was found useful only for fluids thought to exhibit thixotropy. The “actual Ree–Eyring model” for shear-thinning involves multiple flow units with appropriate relaxation times. This paper presents an extensive set of full EHL line and point contact simulations to investigate the usefulness of the actual Ree–Eyring model in EHL applications with shear-thinning lubricants. Comparisons with published experimental data establish the validity of the actual Ree–Eyring model. Also presented is the application of an appropriate shifting rule expected to improve the agreement between simulations and experiments.