Dynamic Analysis of a Flexible Rotor Supported on Two Turbulent Model Journal Bearings with Micropolar Fluid Lubrication

Abstract

This paper presents the complex dynamic analysis of a flexible rotor–bearing system supported by two turbulent micropolar fluid film journal bearings under nonlinear suspension. The Modified Reynolds equation based on the assumptions of turbulent flow and the micropolar parameters has been considered. The system considers Short bearing approximation to simplify the numerical computations. The pressure distribution thus obtained is used to find out the resulting forces about the journal center in the radial and tangential directions. The Non-dimensional dynamic equations are derived considering appropriate non dimensional parameters and solved using MATLAB for a wide range of non-dimensional speed ratios. Plots of the journal center trajectories and rotor center trajectories are obtained. The results show that the system undergoes undesirable nonsynchronous vibrations due to bearing center displacement. Micropolar fluid is found to stabilize the system even when the flow of the system becomes turbulent. The study presented enhances the understanding of the nonlinear dynamics of turbulent journal bearings with respect to dimensionless parameters.