New Two-Phase Flow and Transport Model with Interphase Mass Exchange.

摘要

The focus of the numerical investigation is on modelling the emplacement and subsequent removal, through dissolution, of a Denser-than-water Non-Aqueous Phase Liquid (DNAPL) in a saturated groundwater system. Specifically the model must address two flow and transport regimes. First is the emplacement of DNAPL in the subsurface. Here two-phase flow dominates as the DNAPL displaces the water. The second flow and transport regime involves the dissolution of the immobile residual through interphase mass exchange and transport of the dissolved contaminant in the water phase. Numerical simulation of the problem is computationally intensive involving the iterative simultaneous solution of coupled nonlinear partial differential equations over fine time and space discretizations. The paper presents an overview of the equation development including the constitutive relations necessary to describe DNAPL emplacement (hysteresis) and dissolution (kinetic mass exchange), and describes an efficient collocation based parallel algorithm to solve the governing equations. In addition, model results are reported.