Evaluation of the applicability of the dual-domain mass transfer model in porous media containing connected high-conductivity channels

Abstract

[1] This paper evaluates the dual-domain mass transfer (DDMT) model to represent transport processes when small-scale high-conductivity (K) preferential flow paths (PFPs) are present in a homogenous porous media matrix. The effects of PFPs upon solute transport were examined through detailed numerical experiments involving different realizations of PFP networks, PFP/matrix conductivity contrasts varying from 10:1 to 200:1, different magnitudes of effective conductivities, and a range of molecular diffusion coefficients. Results suggest that the DDMT model can reproduce both the near-source peak and the downstream low-concentration spreading observed in the embedded dendritic network when there are large conductivity contrasts between high-K PFPs and the low-K matrix. The accuracy of the DDMT model is also affected by the geometry of PFP networks and by the relative significance of the diffusion process in the networkmatrix system.