Application of Computational Fluid Dynamics and Fluid-Solid-Interaction Method to Rotor-Bearing System

A powerful computational approach was developed for a complex rotor-bearing system to analyze the elasto-hydrodynamic lubrication (EHL) using computational fluid dynamics (CFD) and fluid solid interaction (FSI) techniques. To investigate the interaction of the dynamics and elastic deformation of the shaft and the lubrication of the journal bearing, a pure fluid bearing model and a rotor-bearing FSI model were created. The shaft was modelled as rigid and elastic respectively. Three different boundary conditions: Sommerfeld, Gu¨mbel and cavitation, were employed and compared in this study. The cavitation boundary was implemented based on the phase change caused by the pressure change between a liquid phase and a vapor phase. The load applied on the model was in the vertical direction, with a rotational velocity, representative of real working conditions of an experiment of a marine journal bearing. The results for the hydrodynamic case were compared with an in-house lubrication code based on Reynolds equation and the Reynolds boundary condition, and showed that the phase change method was adequate to deal with the cavitation problem of a rotor-bearing system. FSI was shown to be a powerful tool for the investigation of the hydrodynamic and elasto-hydrodynamic lubrication of a rotor-bearing system.