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A NEW TWO-PHASE FLOW AND TRANSPORT MODEL WITH INTERPHASE MASS EXCHANGE
Citation:
Guarnaccia, J. AND G. Pinder. A NEW TWO-PHASE FLOW AND TRANSPORT MODEL WITH INTERPHASE MASS EXCHANGE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-92/156 (NTIS PB92206564), 1992.
Description:
The focus of this 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. pecifically the model must address two flow and transport regimes. irst is the emplacement of DNAPL in the subsurface. ere two-phase flow dominates as the DNAPL displaces the water. n addition, as the slug of DNAPL migrates into the system it leaves behind an immobile residual held in place by capillary forces. ontamination via this scenario occurs over a relatively small portion of the area of interest and encompasses relatively short time scales (on the order of days). 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. ontamination via this scenario can occur over a relatively large areal extent, and because dissolution is a slow process, the source for the contaminant can persist for long periods of time (on the order of years). umerical simulation of this problem is computationally intensive involving the iterative simultaneous solution of coupled nonlinear partial differential equations over fine time and space discretizations. his 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. n addition, model results are reported.
