Simulations of liquid-vapor water flows with non-condensable gases on the basis of a two-fluid model.

• A two-fluid model for water-incondensable gases and including heat and mass transfer is proposed. • Out-of-equilibrium source terms are modeled in a non-classical form considering two-fluid models. • The pressure relaxation effect is discretized using a new scheme. • Influence of the different relaxation effects is examined thanks to experimental results of a blowdown. Two phase flows including liquid water, vapor and non-condensable gases are often encountered in industrial applications. In this paper, an extension of the classical Baer-Nunziato two-fluid model is presented in order to account for the non-condensable gases. In this model, the vapor and non-condensable gases form a miscible mixture of gases at temperature equilibrium and kinematic equilibrium. The complete model then allows to account for the full kinematic and thermodynamic disequilibrium between the liquid phase and the gas phase. Moreover, a new form for the mass-transfer source-term has been retained. It leads to a more straightforward numerical integration. When focusing on the numerical scheme, a new algorithm is proposed here for the pressure relaxation effect. At last, some numerical experiments are performed in order to assess the behavior of the model with respect to the relaxation time-scales. [ABSTRACT FROM AUTHOR]