Turbulent Two-Phase Flow in Face Shaft Seals

Abstract

A general theory is presented for the calculation of leakage rates and quasi-static opening force for aligned face seals operating in a turbulent, two-phase flow regime. Here, the fluid is assumed to be a homogeneous mixture of liquid and vapor in thermodynamic equilibrium. Full account of inertial effects and heat generation due to viscous dissipation is made. Solution of the model governing differential equations is accomplished through the use of a fourth-order Runge-Kutta numerical integration scheme. Several numerical examples are presented. The calculation of mass leakage rates and opening force under choked and unchoked conditions are discussed and the phenomenon of all-liquid choked flow is explained. Opening force curves are generated as a function of gap height for some situations of interest and their relation to seal axial stiffness is examined.