HYDROSTATIC PERFORMANCE OF A CIRCULAR THRUST PAD BEARING WITH DIFFERENT RECESS SHAPES

Abstract

Circular Pad Hydrostatic Thrust Bearings are extensively used in number of engineering applications owing to their large number of favourable characteristics. Scan of literature related to Hydrostatic Thrust Pad Bearing reveals that most of the studies uses recess shape to be circular one because of their relatively ease of manufacturing and simplicity. However, in the present technological scenario with the advent of the latest manufacturing techniques, the other bearing shapes could also be manufactured. Thus, the objective of the present study is to theoretically study the static and dynamic performance of a capillary compensated hydrostatic circular thrust pad bearings having different recess shape. The finite Element method has been used in the present study to compare the performance of eight different bearings having different recess shapes i.e. Circular, Square, Triangular, Rectangular, Trapezoidal, Elliptical, Annular and a 4 Circular Pocket bearing. The performance has been compared among the various bearings on the basis of same bearing operating and geometric parameters i.e. the same ratio of bearing to pocket area, same restrictor design parameter (S2) same restrictor and same external load (W0). Further, a comparative study of the eight bearing configurations as mentioned above has been carried out for the different compensating devices such as orifice and constant flow valve compensated so as to find out the combined effect of recess shapes and compensating device on the bearing performance. The computed results indicates that from the point of view of fluid film stiffness, an annular recessed bearing is most suitable among the various bearing configurations studied. A capillary compensated elliptical recessed circular thrust pad bearing provides the maximum value of fluid film damping coefficient for a given . value of restrictor design parameter(CSZ ). It has also been observed that in order to get a desired bearing performance a proper selection of recess shapes, type of restrictor, restrictor design parameter (CS2) and .external load (Wa) is essential. The study in expected to be helpful to the bearing designers and to academic community to make a proper use of the recess shape during a design process.