MHD slip and surface roughness effects in fluid-based hydrodynamic lubrication of secant curved circular plates

Abstract

This article investigates the combined effects of magnetohydrodynamics (MHD), slip velocity, surface roughness, and non-Newtonian fluid behavior on the hydrodynamic lubrication performance of secant curved circular plate bearings. The lubricant is modelled using Stokes micro-continuum theory, and both radial and azimuthal roughness patterns are considered. A modified Reynolds-type equation is derived and solved to obtain expressions for pressure distribution, load-carrying capacity, and squeeze time. The results reveal that the presence of a transverse magnetic field significantly enhances pressure generation and load capacity. Quantitatively, the load-carrying capacity increases with increasing Hartmann number and slip parameter, while it decreases with increasing surface roughness amplitude. Bearings with azimuthal roughness patterns consistently exhibit higher pressure and load capacity compared to those with radial roughness. Furthermore, decreasing the curvature parameter leads to a substantial increase in load capacity, indicating improved bearing performance for lower curvature values. The combined influence of MHD effects and slip velocity yields superior squeeze time characteristics, demonstrating notable improvements over the no-slip and non-magnetic cases. These findings highlight the critical role of surface texture, magnetic field strength, and slip conditions in optimizing the performance of fluid-based hydrodynamic lubrication systems.