Performance of Flat Capillary Compensated Deep/Shallow Pockets Hydrostatic/Hydrodynamic Journal-Thrust Floating Ring Bearing

Abstract

This article presents a theoretical study concerning the static and dynamic performance of an externally pressurized deep/shallow pockets hydrostatic/hydrodynamic journal-thrust floating ring bearing compensated by a flat capillary restrictor. A new fluid-lubricated hybrid bearing that can support a radial and an axial load at the same time is designed and manufactured that can satisfy modern rotary machinery at high speed. The equations governing the flow of the inner and the outer and the radial and the axial fluid film in the journal-thrust floating ring bearing together with the pressure boundary condition and the restrictor flow equation are solved by using the finite element method. The study describes the influence of the eccentricity ratio and journal rotational speed on the static and dynamic characteristics such as the load-carrying capacity, the friction moment, the friction power efficiency, the volume flow rate, the stiffness, the damping, the critical mass, etc. By analyzing the journal center motion, it is theoretically proved that the journal section plays a decisive effect on the stability and the thrust section makes the journal-thrust bearing more stable. This bearing has been applied to certain turbine expansion units and rotates stably at 45,000 rpm. The result shows that the bearing has the advantages of low friction, high stability, and can be easily controlled and applied in turbine machinery and other high-speed rotational machinery.

Keywords:

• Hydrostatic/Hydrodynamic Bearing
• Fluid Film Bearing
• Journal-Thrust Bearing
• Floating Ring
• Flat Capillary Restrictor

ACKNOWLEDGEMENT

This research is subsidized by the Nature Science Foundation, China (No. 50575212).

Review led by Luis San Andres