Performance evaluation of bidirectional dry gas seals with special groove geometry

Abstract

There are a very few studies of bidirectional gas seals particularly those with certain profiles used in the industry. Parametric study of performance of bidirectional dry gas seals under a set of operating conditions is presented. The expounded approaches uses solution of 3D Navier-Stokes momentum and continuity equations for various forms of grooved gas seals, particular for the trapezoidal shape variety for which there has been a particular dearth of in-depth analysis. It is shown that such groove geometries enhance the load carrying capacity of the seal through increased hydrodynamic lift. This is as the result of enhanced localised wedge flow particularly with a reduced seal gap. Therefore, there is the opportunity of gap minimisation, whilst reducing leakage rate and power loss. For given operating loading, kinematic and thermal conditions as well as seal geometry and topography, the operating minimum film thickness may be considered as the main design parameter.