Analysis of the Shrouded Rayleigh Step Pad for an Incompressible Fluid Film with the Centrifugal Inertia Effect Included

A computer program was developed to calculate the load capacity of the hydrodynamic forces generated within an incompressible fluid film by a shrouded Rayleigh step pad for application in a radial seal design. The program makes use of the central-difference operator, defined for cylindrical coordinates, to approximate the pressure gradient over the pad. Solution of the lubrication equation with the centrifugal inertia effect included is achieved by employing a noniterative numerical routine. Pressure maps and flow fields based on the geometry for a Rayleigh pad were obtained. Results indicate that the selection of a pad geometry such that the design load intersects the dimensionless load capacity curve at a separation ratio between two and four will yield the most favorable operating characteristics, i.e., the best trade-off between high load capacity, high film stiffness, high tangential flow, and a minimum temperature rise. Presented at the 27th ASLE Annual Meeting in Houston, Texas, May 1–4, 1972