Thermohydrodynamic analysis and tribological optimization of a curved pocket thrust bearing

Texture patterns implemented on thrust bearing surfaces have been proven very beneficial in terms of load carrying capacity and friction coefficient. In the present study, the potential of thrust bearings with a curved pocket stator geometry is investigated for realistic operating conditions. Bearing performance is quantified by means of Computational Fluid Dynamics (CFD) simulations based on the numerical solution of the Navier-Stokes and energy equations for incompressible flow, taking into account conjugate heat transfer at the bearing stator and rotor. After defining a reference slider design, optimization problems are formulated and solved, to arrive at optimal curved pocket designs. Here, the slider convergence ratio, as well as the pocket size, shape and depth, are defined in terms of proper design variables, whereas the load carrying capacity and friction coefficient constitute the problem's objective functions. The present results illustrate a superior performance of the curved open pocket slider designs in comparison to corresponding open square pocket sliders. Optimal solutions are characterized by parallel slider geometries. The improved performance of optimal designs can be attributed to reduced side leakage, in comparison to open square pocket geometries. The good performance of a thrust bearing with a corresponding curved pocket geometry is verified. Overall, the present optimal geometries are rather easy to manufacture, which makes them an attractive choice for the design of thrust bearings operated in a wide range of rotor speeds.