Two-phase flow in porous media: local non-equilibrium model.

The assumption of local thermal non-equilibrium that leads to a one-tempera ture macroscopic heat equation is often called into question. This is the c ase. for instance, when describing the water flooding of an overheated nucl ear debris bed with an important heat source term in the solid phase. Using a technique of Volume averaging as described in Carbonell and Whitaker (19 84), Zanotti and Carbonell (1984), Quintard and Whitaker (1993), and Quinta rd et al. (1996), we obtain, starting with the pore-scale equations and und er some constraints, a three-equation or three-temperature macroscopic mode l for describing heat transfer in a porous medium subject to a two-phase fl ow. Effective properties can be calculated from several local closure probl ems which are given in the paper. These closure problems are solved in the case of simple unit cells. (C) Elsevier, Paris.