Influence of sea wave shock on transient start-up performance of water-lubricated bearing

The water-lubricated bearing in ship propulsion system is easily impacted by sea wave shock, which is a great threat to the smooth start-up of the bearing system. Therefore, in the present research, the Euler equations, average Reynolds equation, and sea wave shock function are combined together to build the start-up model of water-lubricated bearing. The influences of amplitude, direction, and entry time of sea wave shock on the startup performance of bearing are studied. The result shows that the shaft has a strong instantaneous vibration under the influence of friction force at the initial start-up stage, and the shock load with appropriate direction and amplitude can suppress or even eliminate this vibration phenomenon. The earlier the shock enters the start-up process, the more serious asperity contact gets, and the worse the system's stability becomes. The increase of the shock load amplitude and the advance of the shock load entry time can help the shaft rapidly lift off. This study can provide a reference for the smooth start-up of ship propulsion system in a sea wave environment.

Automated summary

This study established a start-up model of water-lubricated bearing and analyzed the influence of sea wave shock on the startup performance of the bearing, indicating that appropriate shock load can suppress the vibration phenomenon. Moreover, the study also pointed out that the earlier the shock load enters, the worse the system's stability becomes.