Reynolds Boundary Condition Approximation in Journal Bearings Based on Dynamic Mesh Method

Abstract

This paper proposed a new approach to Reynolds boundary condition approximation in journal bearing CFD analysis. Dynamic mesh method was applied to approach the location where the rupture of oil film or cavitation started. A numerical model of half bearing geometry was constructed to obtain the Half-Sommerfeld solution. Using the solution, a pseudo-transient analysis was subsequently conducted. The boundary at the minimum film thickness was treated as the moving boundary. The Reynolds boundary condition was satisfied at a certain point when the pressure derivative of boundary nodes approached zero over the course of mesh growth. The analytical results were compared against the results of published works. It was discovered that the resulting cavitation angle and oil film pressure were consistent with those obtained by taking the Reynolds equation approach, with only slight differences observed from those obtained via the cavitation experiments and models. The proposed method is an extension of Reynolds boundary condition according to the CFD approach. It is considered an alternative to other cavitation models intended for journal bearings.

Keywords

• journal bearing
• reynolds boundary condition
• cavitation
• dynamic mesh
• bearing analysis