Multiscale Analysis of Hydrodynamic Wedge-Platform Thrust Slider Bearing

A multiscale analysis is presented for the performance of the hydrodynamic wedge-platform thrust slider bearing where the surface separation is so low that it is comparable with the thickness of the adsorbed layer on the bearing surface. There are the flows of two adsorbed layers and the intermediate continuum fluid flow, which are respectively modeled by the flow equation for nanoscale flow and the Newtonian fluid model. The flow equations are respectively given for the adsorbed layers and the continuum fluid, showing the coupled effect in this multiscale flow. The calculation results show that when the minimum bearing surface separation is below 100 nm, for the medium and strong fluid-bearing surface interactions, the adsorbed layer effect significantly increases the load-carrying capacity of the bearing, and it is more pronounced for smaller bearing surface separations. The multiscale analysis gives the carried load of the bearing much larger than the classical hydrodynamic theory calculation with qualitatively good agreement with the experimental observation, showing the significant contribution of the adsorbed layer in a hydrodynamic bearing with low surface separations.