Upscaling Mixing and Reactive Transport through Random Granular Media

Modeling reactive transport of solutes in aquifers and other porous formations is a field with key applications for a wide range of problems in contaminant transport, soil remediation, subsurface CO2 sequestration and geothermal energy. The wide range of scales at which fluid flows are governed by physical heterogeneities in porous media is a major obstacle in developing practical and accurate reactive transport models. The local mixing process governs (and may limit) the ability of reactants that are at close distance to establish direct contact and enable chemical reactions. However, continuum-scale reactive transport models typically neglect the role of mixing at the pore scale (and any other model-unresolved scales). This is partly because the precise link between a porous medium's micro-structure and its resulting mixing behavior has not been rigorously established yet