Application of Average Flow Model to Thin Film Gas Lubrication

Abstract

The flow factors for the average Reynolds equation introduced by Patir and Cheng (1978, 1979) are extended to be valid for thin film gas lubrication. The effects of molecular mean free-path on the roughness-induced flow factors are included on the assumption that the local compressibility is small. The derivation of flow factors is carried out by means of the perturbation approach developed by Tripp (1983). The results are expressed in terms of Knudsen number, Peklenik parameter and nondimensional film thickness defined as the ratio of average film thickness and standard deviation of composite roughness. Two-dimensional roughness effects on the load-carrying capacity of a gas lubricated finite slider are also investigated.