Effect of Shell Surface Texture Geometry on the Steady State Performance Indexes of Hydrodynamic Journal Bearings

Improvement of behavioral indicators of oil journal bearings has particular importance due to the increasing development of their application as support of rotary components in industrial machinery. Creation of regular roughness (texture) with various geometries on the inner surface of a bearing shell is one of the newest methods proposed by the lubrication researchers to enhance the performance of the hydrodynamic journal bearings. In this study, the comparison of the performance of circular bearings with variable cubic, cylindrical and ellipsoid textures of different depths arranged in a different zone of the shell has been evaluated. For this purpose, the governing Reynolds equation on hydrodynamic lubrication of oil journal bearing was modified considering the changes of the film thickness affected by the geometry and position of the textures. This equation was solved by finite element numerical method, applying the assumption of the Reynolds boundary condition for determining cavitation zone. After obtaining the lubricant pressure profile, the parameters of steady-state performance of the bearing with different texture types were calculated and compared together. Results indicate that the creation of textures with any geometry reduces the lubricant pressure and changes the parameters of the bearing performance. Also, the placement of textures in the maximum pressure area leads to significant changes in performance components while their positioning in the lubricant cavitation region has a weak effect on the bearing behavior. Further, the results show that the difference in characteristics of bearing performance with shallow textures is more considerable and with the increase of textures depth the effect of geometry form on the performance will be reduced.