Behavior of Hydrostatic and Hydrodynamic Noncontacting Face Seals

Abstract

In this paper, the pressure generation and static stability of face-type seals are discussed and an expression is developed to estimate the effectiveness of hydrodynamic action in these seals. Some design data are presented for the hydrostatic step seal, hydrostatic-orifice compensated seal, hybrid spiral-groove seal, and the shrouded Rayleigh step seal. These data are applicable to large-diameter seals for compressible fluids. The seal ring distortions due to initial imperfection, pressure, and thermal expansion are discussed. Approaches to estimate and to minimize the effects of these distortions are outlined. Finally, the ability of a face seal to track the vibrations of the runner is also discussed and methods required to determine the dynamic tracking for rigid or flexible seals are described.