Effects of Fluid Inertia Forces on the Performance of a Plane Inclined Sector Pad for an Annular Thrust Bearing Under Laminar Condition

Abstract

The hydrodynamic wedge of a plane inclined sector pad is analyzed in relation to the lubricant inertia forces under incompressible laminar conditions. Based on the usual assumptions of thin film lubrication theory without the thermal effects, modified Reynolds equations are derived by averaging out all the inertia terms of the Navier-Stokes equations across the film thickness. The equations are linearized with respect to the inertia parameter, and solved numerically for a plane inclined, sectorial configuration. The boundary value of the film pressure at the leading edge is set at the ambient pressure, under the assumption of a negligibly small rampressure thereat. The inertial effects on the static and dynamic performance such as the load carrying capacity, flow rate, frictional torque, position of pressure center, film stiffness, and damping coefficient are discussed, in which the effects of the centrifugal force and those of the other convective inertia forces are compared with each other.