The mechinism of film generation in mechanical face seals

Examination of mechanical seals that have operated succesfully has shown that both faces develop a circumferential waviness. Numerical analysis of fluid film between two faces with circumferential waviness suggests that this can provide the necessary hydrodynamic pressure generation to maintain the faces in equilibrium, separated by a continuous fluid film. In order to give sensible leakage rates, the waviness amplitude is found to be an order of magnitude less than that measured on such faces removed from service after successful operation.