A parametric investigation on the microelastohydrodynamic lubrication of power law fluid lubricated line contact

Abstract

A parametric study of microelastohydrodynamic lubrication contact between rough cylinder and plane lubricated with non-Newtonian power law fluid is carried out. A Gaussian rough surface is considered and modeled using stochastic approach. A theoretical solution of pressure distribution, fluid film thickness, and friction for given speeds, material properties, slide-to-roll ratio, and power law index, is obtained by solution of Reynolds equation using finite element method techniques. An isotropic roughness pattern is considered and results are obtained for wide range of operating parameters. The results indicate that the shear-thickening fluids provide thicker lubricant films as compared to shear-thinning fluids. The minimum fluid film thickness is observed to decrease with an increase of load and it increases with an increase of speed and material parameter. Slide-to-roll ratio has a marginal influence of the minimum film thickness. Under certain operating conditions, softer materials with shear-thickening lubricants yield thicker lubricant films than the harder materials lubricated with shear-thinning fluids. The coefficient of friction too is influenced by the rheology of lubricants with shear-thinning fluids providing larger values of coefficient of friction than the shear-thickening fluids.