Interfacial drag of two-phase flow in porous media

In this paper, the influence of the interfacial drag on the pressure loss of combined liquid and vapour flow through particulate porous media is investigated. Motivation for this is the coolability of fragmented corium which may be expected during a severe accident in a nuclear power plant. Cooling water is evaporated due to the particles decay heat. To reach coolability, the outflowing steam has to be replaced by inflowing water. essure loss for the resulting two-phase flow through the debris is determined by the friction forces at the particles as well as at the interfacial drag between the fluids. In return, the resulting pressure field influences the coolant inflow through the boundaries and thus the coolability of the fragments. ng from commonly used friction correlations, it is shown that only those with explicit consideration of the interfacial drag can represent the pressure loss. Enhancements for the formulation of the interfacial drag are proposed. This modified model fits experimental data of isothermal air/water experiments as well as data of boiling particle beds.