Modified oil film force model for investigating motion characteristics of rotor-bearing system

The oil film force induced from bearings has a direct influence on the stable operation of a rotor system because the change in motion characteristics will lead to variation of the oil film force. An accurate oil film force model is therefore critical to predict the motion characteristic state of a rotor system. The linear oil film force model and the Muszynska model are employed by many scholars to predict linear force and nonlinear oil film force respectively. When the rotor system has a larger eccentricity ratio, the changing law of the rotor system is not predicted by the Muszynska model. In this paper an improved oil film force model is developed for the motion changing law. This model is based on short bearing assumption with the turbulence effect and rotor motion equation included. The motion law is well described by this model. In particular the dynamic characteristics can be described well by the modified model. To verify the simulation results of the modified model, an experiment is carried out. Finally, there is a comparison between theoretical and experimental results and it is found that the theoretical results are in good agreement with the experimental results. This paper provides a reference for further research of the motion changing law of rotor systems.