The effect of shell texturing on the performance of noncircular hydrodynamic two lobe journal bearings

Use of oil journal bearings in recent decades has grown considerably because of their desirable performance in light and heavy loading condition and also for reducing noise pollution, as a suitable supports in different industrial equipment such as turbomachines, combustion engines and nuclear reactors .Due to the influence of the geometry of these bearings on their performance, a variety of models such as elliptical, lobed, waved, pivoted pad and axial grooves have been introduced to market for purposeful improvement in their steady-state and dynamic operating conditions. In recent decade, with the development of advanced non-traditional machining equipment, the ability to create textures on the bearings shell has been provided by manufacturers. Cubic, cylindrical, spherical and cone shaped textures can have a different effect on the performance of journal bearings. In this study, the performance of two lobe bearings with cylindrical textures is evaluated. For this purpose, the governing Reynolds equation of Newtonian lubrication has been investigated, regarding to the changes in the lubricant film thickness according to the geometry and position of textures, by the FEM using the Reynolds boundary condition for determining the cavitation zone. Then, the bearing performance is evaluated based on the pressure distribution of the lubricant film and the location of the textures. The results show that the location of the textures, to achieve a more favorable performance, is different for various values of noncircularity index. Also, with increasing the bearing noncircularity, the effect of textures formation on the bearing performance will be more noticeable.