Simulations of water-vapor two-phase flows with non-condensable gas using a Noble-Able-Chemkin equation of state

In order to simulate some accidental scenarii which might affect a pressurized water re-actor, a homogeneous two-phase water-vapor flow model taking into account noncon-densable gas is considered. The liquid phase and the gaseous phase are assumed to beimmiscible, but the gaseous phase is composed of two miscible components. Due to thesehybrid hypotheses of miscibility, the configurations with at least one missing field arecarefully examined. A semi-analytical equation of state is chosen for the liquid water,which is an extension of the Noble-Able stiffened gas equation of state. Its accuracy isassessed with respect to the reference equation of state IAPWS. The homogeneous modelis first verified thanks to Riemann problems. Then, some simulations aiming at repro-ducing SUPERCANON experiment are presented. The amount of air dissolved in liquidwater is shown to have a strong influence on numerical results, in particular on the soundspeed. Some out of thermodynamical equilibrium simulations are also presented, usingtwo time scales describing the return towards equilibrium.