Phase Saturation Control on Mixing-Driven Reactions in 3D Porous Media

Transported chemical reactions in unsaturated porous media are relevant to environmental and industrial applications. Continuum scale models based on equivalent parameters derived from analogy with saturated conditions cannot appropriately account for incomplete mixing. It is also unclear how the third dimension controls mixing reactions. We obtain three-dimensional (3D) images by magnetic resonance imaging using an immiscible nonwetting liquid as a second phase fast irreversible bimolecular reaction. study impact of saturation dynamics reaction front. quantify temporally resolved effective rate describe it lamellar theory mixing, which explains faster than Fickian (t0.5) product formation accounting deformation interface between two reacting fluids. For given Péclet, although stretching folding reactive front enhance decreases, enhancing formation, larger increases. After breakthrough, extinction takes longer decreases because nonmixed volume behind These results basis general model better predict transport not achievable current continuum paradigm.