Numerical microfluidic chip modeling of laminar vortex dynamics induced by biomineralization in evolving porous media

Abstract

Naturally evolving porous media, such as those undergoing mineral precipitation, biofilm growth, and freeze-thaw cycling, dynamically alter pore structure, inducing vortices that influence mass transport and mixing. Yet, due to their transient nature and structural complexity, vortex dynamics in evolving porous systems remain poorly understood. Here, using a three-dimensional numerical microfluidic model, we systematically investigate how precipitation-driven pore structure evolution regulates vortex formation, distribution, strength, and mixing efficiency in microbially induced calcium carbonate precipitation (MICP) at the pore scale. Our results show that vortices primarily develop as recirculating flows within narrow pore throats, with their spatial patterns and strength significantly controlled by the structural heterogeneity and dynamic clogging of flow channels. Notably, we uncover a nonlinear relationship: while vortices initially enhance mass transport processes and mixing, extensive precipitation accumulation eventually restricts fluid mobility and diminishes vortex-driven transport efficiency. These findings advance the current understanding of vortex-induced mixing in evolving porous media, providing a theoretical foundation for optimizing biochemical reaction processes.