Phase-field modeling and effective simulation of non-isothermal reactive transport

TL;DR

This paper develops a phase-field model for non-isothermal reactive transport involving fluid-mineral interfaces, incorporating temperature effects and a conservative reformulation, solved efficiently with an iterative scheme.

Contribution

It introduces a conservative diffuse interface model with temperature-dependent reactions and an efficient L-scheme iterative solver for coupled transport equations.

Findings

The proposed numerical scheme is efficient and accurate.

The model effectively captures temperature-dependent mineral reactions.

The iterative coupling scheme reduces computational cost.

Abstract

We consider single-phase flow with solute transport where ions in the fluid can precipitate and form a mineral, and where the mineral can dissolve and release solute into the fluid. Such a setting includes an evolving interface between fluid and mineral. We approximate the evolving interface with a diffuse interface, which is modeled with an Allen-Cahn equation. We also include effects from temperature such that the reaction rate can depend on temperature, and allow heat conduction through fluid and mineral. As Allen-Cahn is generally not conservative due to curvature-driven motion, we include a reformulation that is conservative. This reformulation includes a non-local term which makes the use of standard Newton iterations for solving the resulting non-linear system of equations very slow. We instead apply L-scheme iterations, which can be proven to converge for any starting guess, although giving only linear convergence. The three coupled equations for diffuse interface, solute transport and heat transport are solved via an iterative coupling scheme. This allows the three equations to be solved more efficiently compared to a monolithic scheme, and only few iterations are needed for high accuracy. Through numerical experiments we highlight the usefulness and efficiency of the suggested numerical scheme and the applicability of the resulting model.