Hydrodynamic lubrication study of plain journal bearings lubricated with couple stress fluids: surface texture effects

This study investigates the static characteristic of textured bearings lubricated with oils containing viscosity additives, thus influencing their tribological performance. The texture model adopted is that of the positive sinusoidal half-wave, a configuration that enables lubrication to be optimized by modifying the distribution of the fluid film. The lubricant used has a non-Newtonian rheological behavior, and is modeled as a couple stress fluids, taking into account the effects of fluid microstructure on flow. The results obtained are analyzed by comparing them with those of a plain bearing lubricated by a conventional Newtonian fluid, enabling the influence of the lubricant’s texturing and properties on bearing performance to be assessed. It is shown that the combination of the surface texturing of the pad and lubrication with polar fluids has significant effects on the static characteristics of the journal bearing, such as: load-carrying capacity, friction factor, attitude angle, and side leakage flow. It is also found that the sensitivity of these effects increases with the couple stress parameter and the eccentricity ratio.