Performance of a Rarefied-Gas Viscoseal with a Leakage

Abstract

This type of seal can seal fluids with zero leakage by means of its pumping action, but even if a small leakage occurs in such a case as labyrinth seals, it is sometimes necessary to seal a higher pressure difference (or pressure ratio) than one which is achieved under zero leakage conditions.
A theory for the performance of the seal with a leakage is presented, and the seals with various geometries. The results show that spiral grooves work as the sealing elements only when the rate of leakage is small and that the grooves promote leak when the rate of leakage exceeds a certain value.