Research and Development on the Hydrodynamic Pressure Generation Between Contacting Flat Surfaces

Abstract

The lift-off distance between two nominally flat seal ring surfaces immersed in lubricant oil was measured at various sliding speeds using electrical resistance. Lift-off appeared very gradual, requiring 20∼50 minutes to stabilize, depending on the degree of truncation of asperities on the wearing surface.

The observations were explored analytically using a simplified model of truncated asperities in Stokes' flow that allowed pressure variation across the film thickness. The analysis and flow visualization led to the hypothesis that pressure generation between the surfaces could be attributable to generation of elongated, forced vortices in the recessed cavities between well-truncated asperities.

An optimum recess depth was predicted for support of a specified load.

Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

Notes

Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985