Computing hydrodynamic pressure in mixed lubrication by modified Reynolds equation

Nowadays, even with the available computing power, complete deterministic solutions of large or dynamically loaded bearings are not possible in acceptable amounts of computing time. Therefore, in order to model mixed lubrication conditions, the Reynolds equation is modified by the introduction of flow factors that take into account the roughness effects. Patir and Cheng proposed the most known model. In their model, flow factors are obtained from the statistical parameters of the surface roughness. The flow factors can also be computed from deterministic calculation on a sample of the studied surface or by using the homogenization technique on the same surface sample. In this article, three approaches are compared. Moreover, the influence of the surface deformation due to asperity contact over the flow factors is investigated.