ABSTRACT In this paper, flashing phenomena are studied in the case of water-steam and air outflow in a vertical porous channel . The presence of air, the nature of the porous environment, as well as injected fluid thermo-physics parameters are analyzed. The separate flow model approach which takes the individual properties of air and water separately is considered. On the other hand, we consider that water and its steam are represented as a mixture characterized by the mean properties according to the quality (x)(the ratio of the vapor mass and the total mass). Some results show that the porous environment as well as the presence of air represent a resistance to the water outflow. When the effective permeability (or the relative permeability) decreases, the pressure of injection of water increases to maintain the same flow rate. In this case, a decrease of steam generated is observed
