3D Pore-Scale Mixing Interface Evolution

TL;DR

This paper introduces a mechanistic lamella model based on pore-scale simulations to describe the evolution of mixing interfaces in porous media, bridging microscopic dynamics with macroscopic transport modeling.

Contribution

The paper develops a single parabolic lamella model (SPLM) that accurately captures interface evolution across different scales and Péclet numbers, advancing mixing modeling in porous media.

Findings

Model shows near-perfect agreement with 2D scenarios

Establishes Péclet regimes for equilibrium area

Identifies temporal regimes for transient interface behavior

Abstract

The effective mixing behavior of solutes in porous media is fundamentally connected to the development of a local mixing interface between the two initial solutions, which is characterized by a complex lamellar structure. The deformation of the interface is controlled by the interplay of advection and diffusion, which generate the mechanisms of lamella stretching and shrinking, respectively. Based on the results of pore-scale numerical simulations, we develop a mechanistic single parabolic lamella model (SPLM) to capture the interface evolution across various temporal and P\'eclet number scales. The model shows near-perfect agreement with a 2D parallel plates scenario and promising results for a 3D porous medium. The SPLM model also establishes P\'eclet regimes for the equilibrium area and temporal regimes for the transient behavior of the interface. These findings represent a step forward towards eventually incorporating mixing limitation into general macroscopic reactive transport models.