COMPUTATIONAL FLUID DYNAMICS EVALUATION OF THE MULTINOZZLE OIL-JET LUBRICATION FOR ROLLING BEARINGS

The lubrication design of rolling bearing is mostly based on empirical correlations derived from experience and test. To achieve precise lubrication, a further investigation into the flow field inside the rolling bearing is necessary. The paper proposes a CFD model for the flow field analysis inside the oil-jet lubricated ball bearing with the multi-nozzle oil-jet lubrication. The volume-of-fluid methodology is used to track the air-oil two-phase flow. The sliding mesh plane is proposed at the edge of the rotary flow field. The CFD model is verified through the outer ring temperature distribution test. The results suggest that the air-oil distribution inside the bearing is not uniform in both the circumferential direction and the radial direction. The oil volume fraction close to the nozzle is larger than other positions. Most of the oil flows to the outer ring and the oil volume fraction around the inner ring is small. The air-oil distribution inside the bearing with the multi-nozzle oil-jet lubrication becomes more uniform. With the increase of the nozzle number, the ripple of the air-oil flow decreases and the average oil volume fraction increases. However, the oil volume fraction improvement becomes unapparent with more than six nozzles. The nonuniform air-oil distribution should be considered for the heat transfer analysis of the rolling bearing. Optimising the bearing lubrication according to the air-oil distribution inside the bearing is significant to achieve lower drag loss and greater cooling effect.