Numerical study of the influence of the pivot position on the steady-state behavior of tilting-pad thrust bearings

Abstract

The coordinates of the pivot pads variation of a hydrodynamic thrust bearing can result in hydrodynamic pressure field changes that forms on the surface of the pad with consequent changes in the values of the bearing performance parameters, such as power loss, load capacity and operating temperatures. The analysis was performed by computer simulation (FORTRAN), based on the numerical solution of the two-dimensional isoviscous Reynolds equation in polar coordinates by finite difference method. The simulated bearing was based on the dimensions of a KV 9 Kingsbury thrust bearing, existing on the tribology laboratory of the university. With the pivot position variation (radius r and angle θ), starting with a bearing with central pivot pads, as well as a bearing consisting of pads with pivot located in other positions, both in the radial direction and in the circumferential direction, was possible to verify some significant changes in the bearing performance parameters. It was found that the maximum load occurs in the case of pads with pivot located approximately 60% of the average circumferential length, but for a substantially longer than the average radius of radial position. On the other hand, the minimum power loss occurs due to friction in the bearings for pivoting the pads with about 67% of the average circumferential length thereof.