Model validation of mechanical face seals in two-phase flow conditions

A steady-state one-dimensional axisymmetric numerical model of a mechanical seal in two-phase flow is presented. In this work a non-linear thermal model is implemented using a coupled (monolithic) approach, linking the fluid film and sealing rings. It is solved for the temperature fields of the fluid and solids, heat fluxes between fluids and solids, enthalpy of the fluid, and the vapor mass fraction, using Newtons method. The novelty of this approach lies in 1) the thermal coupling between fluid and solids, and 2) the implementation of saturation curves to couple temperature, enthalpy, and vapor mass fraction. The temperature across the seal gap is described by an analytical parabolic temperature profile by assuming a plane Couette flow in the radial direction. From this assumption, an equation for the wall heat fluxes is derived, which couples the temperature fields of the fluid and solids. The IAPWS-IF97 standard for the thermodynamic properties of water is used to obtain non-linear equations that couples the fluid temperature, enthalpy and the vapor mass fraction. The model and its implementation is described in detail. Several cases of seal behavior and two-phase flow are studied and show good agreement with other results from literature, validating the coupled approach for modelling phase-change in mechanical seals.