Dynamic Fluid Connectivity Controls Solute Dispersion in Multiphase Porous Media Flow

Solute transport in multiphase flow through porous media plays a central role in many natural systems and geoengineering applications. The interplay between fluid flow and capillary forces leads to transient flow dynamics and phase distributions. However, it is not known how such dynamic flow affects the dispersion of transported species. Here, we use highly resolved numerical simulations of immiscible two-phase flow to investigate dispersion in multiphase flows. We show that repeated activation and deactivation of different flow pathways under the effect of capillary forces accelerates the spreading of solutes compared to single phase flow. We establish the transport laws under dynamic multiphase flows by linking the dispersion coefficient to the Bond number, the ratio of the force driving the flow and the surface tension. Our results determine the controlling factors for solute dispersion in porous media, opening a range of applications for understanding and controlling transport in porous geological systems.

Automated summary

Solute transport in multiphase flow through porous media plays a crucial role in natural systems and geoengineering applications. This study investigates dispersion in multiphase flows using highly resolved numerical simulations of immiscible two-phase flow. The results show that the activation and deactivation of different flow pathways under capillary forces accelerate solute spreading compared to single phase flow. The study establishes transport laws under dynamic multiphase flows and identifies the controlling factors for solute dispersion in porous media.