An overall optimum design of a sector-shaped thrust bearing with continuous circumferential surface profiles

Abstract

The effects of continuous circumferential surface profiles on the performance characteristics of a sector-type thrust bearing have been investigated. A computer-aided finite difference numerical solution of the Reynolds equation in polar form is used to determine pressure distributions for an optimum inclination of a sector pad. These pressure distributions are then used to calculate the performance characteristics such as load-carrying capacity, flow rate, side leakage, friction power loss, coefficient of friction and temperature rise. The values of optimum inclinations or film thickness ratios are found for the optimum characteristics such as maximum load-carrying capacity and minimum coefficient of friction for a wide range of pad dimensions. The results for the non-dimensional performance coefficients which are defined as a function of the aspect ratio are then presented in the form of design charts. As compared with a conventional circumferential taper fluid film shape, new surface profiles are found to offer a significant increase in the load-carrying capacity as well as a considerable reduction in the coefficient of friction. For given inner and outer radii of a thrust bearing a design procedure is presented for determining the optimum aspect ratio or an optimum number of pads, required to have maximum load-carrying capacity. A numerical example is also discussed to illustrate the application of the optimization approach and the design charts.