Cavitation Boundary Shapes for Submerged Short Journal Bearings Using Newtonian Lubricants

Abstract

Cavitation boundary shapes for submerged short journal bearings are investigated in this study. In this analysis, the Reynolds lubrication equation is approximated by using the bearing slenderness ratio as a small parameter. The slenderness ratio appears explicitly in the Reynolds lubrication equation. The lubrication equation is solved subjected to the boundary condition of a subambient value for the cavitation pressure and the additional Reynolds’ free-surface boundary condition along the unknown cavitation boundary. The Ocvirk short bearing solution is shown to fail near the leading edge of the cavitation region, and a matched asymptotic theory is used to determine the shape and location of this cavitated region. Cavitation bubble location and size are shown to depend on bearing aspect ratio, journal eccentricity, and cavitation pressure. Finally the present journal bearing analysis is limited to those cases where the cavitation region has a large axial extent.