Modeling the Pressure-Density Relationship in Thin Films at Asperity Contacts in Mixed Lubrication

In mixed lubricated contact, the asperity contact regions may be separated by a thin layer of lubricant film. Simulations of mixed lubrication often use empirical formulae to describe the change of density with pressure in the lubricated areas. However, these models may not be applicable to molecularly thin films at asperity contact regions. We present a molecular simulation approach for density characterization of the fluid at asperity contact regions in mixed lubrication. The resultant density-pressure relationship is compared to the traditional Dowson-Higginson model. It is found that the two models predict comparable densities at low pressures but diverge at higher pressures.