Non-intrusive hybrid model of reactive transport in chemically heterogeneous porous media

Abstract:

Flow and transport in the subsurface can be modeled at different scales, ranging from the pore- to the continuum- (Darcy-) scale. While accurate, pore-scale models are computationally intensive and impractical for field scale applications. Continuum-scale models have low computational costs, yet they rely on a set of applicability conditions, which, if violated, may affect the model’s predictive capabilities. Hybrid models combine pore- and continuum-scale descriptions in different portions of a computational domain. They are emerging as the method of choice when a localized breakdown of macroscopic equations occurs. We present a non-intrusive hybrid scheme without overlap region and model reactive transport in chemically heterogeneous porous media. The hybrid coupling guarantees continuity of state variables and fluxes at the boundaries between the pore- and the continuum-scale domains through an iterative procedure. The algorithm is tested against different transport regimes and porous media geometries.