ANALYSIS OF MULTI-LAND HIGH-PRESSURE OIL SEALS

An analysis for the laminar/turbulent flow in high pressure oil ring s eals is presented. A fully-developed bulk-flow model for low axial Rey nolds numbers is introduced to predict the static and dynamic force re sponse of multi-land oil seals. The model includes the effects of bear ing surface roughness, variable seal clearances, fluid inertia and vis cous loss effects at the inlet of the first land in a multi-land oil s eal. Internal groove pressures in the seals are determined via a mass conservation algorithm with Reynolds condition at the cavitation incep tion zone. Predictions show that the viscosity effect at the seal inle t is minimal for turbulent flow across the seal. However, for laminar oil seals, the entrance loss viscous effect can substantially increase the direct stiffness. Load capacity and rotordynamic force coefficien ts for one-land, two-land and three-land seal examples are discussed i n detail.