Effects of surface roughness on transient squeeze EHL motion of circular contacts with micropolar fluids.

A numerical method was developed to study the effects of the micropolar (MP) lubricants at pure squeeze action in an isothermal elastohydrodynamic lubrication point contact with surface roughness under constant load condition, but without asperities contact. The modified transient stochastic Reynolds equation was derived in polar coordinates by means of the Christensen's stochastic theory and the Eringen's MP fluid theory. The Gauss–Seidel method and the finite difference method were both used to solve simultaneously the modified transient stochastic Reynolds, the load balance, the lubricant rheology and the elasticity deformation equations. The simulation results revealed that the effect of the MP lubricant was equivalent to enhancing the lubricant viscosity. Therefore, the central pressure and film thickness for MP lubricants were larger than those of Newtonian fluids under the same load in the elastic deformation stage. The maximum central pressure of the radial type roughness (RN) was greater than that of the circular type RN. The film thickness of the radial type RN was smaller than that of the circular type RN. [ABSTRACT FROM AUTHOR]