Fluid flow regime transition in water lubricated spiral grooved face seals

Abstract

Spiral grooves are used to enhance the generation of a fluid film between the sliding surfaces of a mechanical face seal when fluids with poor lubrication properties are to be sealed. This technical solution allows reducing asperity contact, wear, and friction during operation, due to the full film between the surfaces. However because of the thickness of the film, the fluid flow regime can turn from laminar to turbulent. This transition can significantly affect the performance of the seal and needs to be evaluated. Simulations have been performed of a water lubricated seal with spiral grooves. The numerical model solves the Reynolds equation and the energy equation in the fluid film. The thermo-mechanical fluid–solid coupling is considered. The theoretical predictions of the temperature are compared with experimental findings obtained on a dedicated test rig with face seals of different groove depths. This comparison allows to identify the critical Reynolds numbers corresponding to a transition of the fluid flow regime.