On the restrictor design parameter of hybrid journal bearing for optimum rotordynamic coefficients

The precise design of bearings can be formulated after carefully studying both static and dynamic characteristics of journal bearing. The present paper deals with the investigation of restrictor design parameter of a capillary compensated hole–entry hybrid journal bearing system for optimum stiffness and dynamic coefficients of the bearing. The bearing flexibility and variation of viscosity due to temperature rise of the lubrication has been considered in the study. The numerical solution of governing equations, i.e. Reynold's, energy, heat conduction, and elasticity equations has been obtained using finite element method. The study includes performance of a double row symmetric hole–entry hybrid journal bearing configuration containing 12 holes per row. The results presented herein indicate that change in viscosity of lubricant and bearing flexibility affects the bearing design parameter, so the stability of rigid rotor also gets affected. The results show that theoretical modeling of the bearing presented in this work will certainly prove to be effective tool for the selection of restrictor design parameter, C¯s2 for optimum stability parameters.