Hydrodynamic Performance Characteristics of a Fluid Film Journal Bearing with a Rectangular Jacking Pocket

To compensate for an extremely heavy journal, jacking pockets can be added to the surface of pads in fluid film bearings. Jacking pockets can range in size and shape and will have an influence on the hydrodynamic performance of the bearing. Computational fluid dynamics (CFD) was used to better understand the influence of the geometry of a rectangular/ stadium-shaped, jacking pocket on the performance of bearings. First, the influence of the pocket depth on the pressure profile of the bearing was investigated. A varying profile occurred with jacking pocket depths less than 6.6 x C-b. After this threshold, the pocket depth ceased to have an influence on the pressure profile. A second study examined the circumferential length of the pocket, and the pressure profile was found to approach the smooth case as the pocket circumferential length decreased. Response surface models were created to map the influence of the jacking pocket geometry on the journal location in the bearing, power loss, and stiffness characteristics of the bearing. This is the first study on influence of the geometry of a jacking pocket on the operation and linear stiffnesses of the bearing in fluid film journal bearings.