Abstract
The effects of surface roughness on the molecular gas lubrication (MGL) characteristics have been studied in order to confirm the application limit of the MGL equation against the surface roughness. The study has been done by comparing the calculated results by the MGL equation with those by direct simulation Monte-Carlo (DSMC) method which is expected to give more correct solution. In this study, we investigated the applicability of MGL equation in the case of pressure flow, where the pressure at the one side of the lubrication film is higher than that of the other. The lubrication film is assume to be two dimensional and consists of two stationary parallel wall with random rough surface. It is clarified that the transverse flow, which causes the difference of two calculated results, is generated at the wall by the effect of slip flow. The roughness slope of the surface has the great deal in generation of transverse flow. The difference of both calculation methods starts to increase against the roughness slope greater than the specific value. These characteristics, resulted from this study, are same as those shown in the previous study related to the shear flow.
