A Comparative Linear and Nonlinear Stability Analysis of Hybrid Journal Bearing Operating with Micropolar Lubricant

Abstract

The present study discusses the effect of micropolar parameters on the stability of symmetric hole-entry hybrid journal bearing system compensated with capillary restrictor. Finite element method has been used to solve the modified Reynolds equation for the flow of micropolar lubricant through the bearing. The linearized and nonlinear equations of motion are solved numerically using fourth order Runge-Kutta Method at each integration time step. Solution of these equations provides the locus of moving journal center and the journal trajectories are plotted with the help of a computer program. A Routh-Hurwitz stability criterion has been applied to calculate the critical mass of the journal to analyze the stability of journal. A comparative analysis for linear and nonlinear models considering Newtonian and micropolar lubricants has been done. The results obtained indicate that micropolar parameters affect the performance as well as the stability margin of the hybrid journal bearing system considerably and nonlinear analysis provides quick response as compared to linear one.

Keywords

• capillary
• micropolar lubricant
• hybrid journal bearing
• symmetric
• hole-entry
• finite element method
• stability
• linear
• nonlinear