DARCY SCALE NAPL DISSOLUTION IN HETEROGENEOUS STRATIFIED POROUS MEDIA

The aim of this study is to develop NAPL dissolution in heterogeneous porous media by one and two dimensional physical model at macroscopic Darcy scale. The model describes the movement of a water phase in the presence of a trapped polluting phase at residual saturation. Two limit cases of dissolution were studied: local equilibrium case and the local non equilibrium case. The construction uses the finite volume methods for the approximation of equations. The numerical tests emphasize particularly the evolution of the zone of exchange between the organic and water phases. Local non equilibrium situations obtained following the mechanisms hereafter, heterogeneity effects of the medium and heterogeneity effects of the initial saturations induced by hydrodynamic instabilities or particular conditions of installation, were characterized.