On elastic deformation, inter-asperity cavitation and lubricant thermal effects on flow factors

Separate or combined effects of elastic deformation and inter-asperity cavitation of rough surfaces and lubricant thermal effect, resulting from different lubrication conditions, on flow factors were investigated based on an extended Reynolds equation and associated equations. The numerical results reveal that the flow factors given by Patir and Cheng are valid only over the range of big ratio of film thickness to roughness (h/σ), while their validities obviously drop for small h/σ due to the separate or combined effect of the above influencing factors. Moreover, variations of flow factors due to the combined effect of deformation and inter-asperity cavitation are significantly different from those by separate effects of these influencing factors. Therefore, Patir and Cheng's flow factors should be used with caution and corrected according to specific lubrication conditions.