Lubrication mechanism analysis of textures in journal bearings using CFD simulations

Purpose This paper aims to study the lubrication mechanism of textured journal bearings. Design/methodology/approach CFD models for textured journal bearings are established. The effect of texture coverage on the pressure distribution is studied to find the proper texture distribution. To enhance the local load-carrying capacity at textures, the micro-hydrodynamic pressure and microflow at different texture depth ratios are captured. The interaction between the texture-induced microflow and the bearing lubrication film is analyzed from the microflow perspective. Findings The bearing performance is on the one hand enhanced by the micro-hydrodynamic pressure generated by textures. On the other hand, the main bearing land and maximum pressure can be interfered by textures, leading to the reduction of load-carrying capacity. To minimize the interference effect, textures are suggested to distribute downstream of the minimum film thickness location. As the lubrication film thickness increases, the corresponding optimum texture depth ratio rises. The vortices influence the local flow rate through the lubrication film at textures and further affect the micro-hydrodynamic pressure and local load-carrying capacity. The texture depth ratio, at which vortices begin to occur, generates the maximum micro-hydrodynamic pressure. Originality/value The proper texture distribution is introduced, which is capable to generate the micro-hydrodynamic pressure without interfering with the primary load-carrying capacity of the bearing. The microflow effect is found to considerably influence the local load-carrying capacity at textures. The necessity of sub-regional optimization in textured journal bearings is pointed out. This study provides the fundamental reference for the design and optimization of textured journal bearings.