A New Theoretical Model for Analysis of the Fluid Film in the Cavitation Zone of a Journal Bearing

Abstract

Recent studies of the cavitation zone in the journal bearing indicate that a sublayer of lubricant adheres to the journal surface. Based on this observation, it is proposed in the present work that centrifugal force and surface tension should be considered as the primary cause for the lubricant film to be in equilibrium in the cavitation zone. Using this concept a cavitation model is proposed. The effect of the supply pressure on fluid film reformation is also studied. The proposed model is applied to study the cavitation zone of: (1) a journal bearing with lubricant entry along the line of centers and (2) a journal bearing with inlet groove located along the load line. It is found that the thickness of the lubricant layer adhering to the journal surface is an exponential function of the speed while the eccentricity ratio rather than speed has a predominant effect on the width of the streamers. The supply pressure has a remarkable effect on the film reformation when the lubricant supply is along the line of centers, with the possibility of film reformation at the supply groove, which does not happen when the lubricant inlet is located along the load line.