Analysis of Face Seals With Shrouded Pockets

The paper offers an analysis of face seals, using incompressible fluids, aimed at arriving at a quantitative basis for the design and optimization of seals. To improve its hydrodynamic and dynamic capabilities, the parallel face seal is provided with pockets pressurized by the sealed fluid, and shrouded at both the inner and outer peripheries. The relevant Poisson equation is solved for its hydrodynamic, hydrostatic, and squeeze-film components. A parametric study of various geometric permutations and operating conditions is then obtained from the computerized solutions. The results show that the contribution of the hydrostatic forces to stiffness is insignificant, and that both K₃ and W₃ can be ignored in the optimization of seal dimensions. For high seal pressures, the dominant force and leakage are geared to the hydrostatic component, whereas for low seal pressures, both the hydrodynamic and squeeze-film effects are important.