Optimal design of surface texture in meso scale air journal bearing

Meso scale air journal bearing has widespread application in miniaturized systems and there is a strong need to improve its tribological performance. Although surface texturing can improve its performance, very few studies have addressed this issue. Therefore, this paper investigates the influence of texture geometrical parameters on the tribological performance of meso scale air journal bearing. A numerical study is carried out in a thin-film model of the COMSOL 5.2 package. The effect of texture geometrical parameters viz. position, depth, orientation, and slender ratio on tribological characteristics such as load-carrying capacity and friction coefficient is first analyzed by response surface methodology based Box-Behnken design. Further, a multi-objective optimization study is carried out using grey relational analysis. For the optimum design, textured air bearing has obtained 12.15% more load carrying capacity, and 19.65% lesser friction coefficient than the plane air bearing. For this improvement, texture depth and orientation are found to be the most and the least significant parameters, respectively. Also, at variable bearing parameters such as eccentricity ratio and rotational speed the optimum textured bearing performed better than the regularly textured bearings.