Hydrodynamic Porous Journal Bearings. Part I—Finite Full Bearings

Abstract

The Reynolds condition is shown to correctly describe the film termination in hydrodynamic porous journal bearings. A practical and accurate numerical method for calculating bearing performance is developed, which permits the use of realistic boundary conditions, including the Reynolds condition. It also accounts for slip at the film-bearing interface by means of Darcy’s law. Results show that performance predicted on the basis of the Reynolds condition is closely approximated when the Gumbel and Everting condition is used, but that the Sommerfeld condition yields a substantial difference. For practical bearings, it is found that (a) slip at the interface is negligible, (b) the “thin wall” assumption is valid, (c) sealing the axial ends of the bearing produces only a small increase in load capacity, and (d) axial flow in the film is significant.