Mixed-lubrication analysis of thin polymer film overplayed metallic marine stern bearing considering wall slip and journal misalignment

To study the tribological properties of thin polymer film overplayed metallic stern bearings, in this paper a mixed-lubrication model considering two-dimensional wall slip and journal misalignment is developed. Based on the average flow model proposed by Patir and Cheng, an extended average Reynolds equation considering circumferential and axial slip is derived in terms of interfacial limiting shear stress model. The calculation procedure is established by using finite difference method and over-relaxation iterative method. The results show that both wall slip and journal misalignment reduce the minimum nominal film thickness, increase friction coefficient of bearing in mixed-lubrication regime, and raise journal's speed at which transition from mixed-lubrication to hydrodynamic lubrication occurs.