The flow and reactions in porous media affect many natural processes and engineering applications. Especially the mineral precipitation and crystallization processes that occur on the surface of pores can affect the porosity and permeability of the medium, thereby affecting its conductivity. Existing research focuses on micro nucleation processes or macro precipitation processes, but lacks research on the multi-scale coupling mechanism and cross scale mutual feedback mechanism of these two processes.

The Institute of Mechanics of the Chinese Academy of Sciences combines the multiphase multiphysics model with the classical nucleation theory to discuss the interaction between nucleation, precipitation and material transport and their impact on the permeability of porous media. Recently, the relevant research results have been published in the Geophysical Research Letters.

Research has shown that the topological morphology of solid-phase precipitation in pore reaction flow is regulated by the Damkohler number, leading to differentiation of pore permeability and affecting conductivity. In addition, under a constant rate of solid-liquid interface phase transition reaction, adjusting the surface nucleation rate can change the mode of mineral precipitation from selective precipitation to uniform precipitation. Furthermore, the study found through comparison with traditional methods that previous methods for determining sedimentation rates underestimated pore permeability in specific situations. Therefore, it is crucial to consider microscopic probabilistic nucleation phenomena when there is selective precipitation and heterogeneous nucleation at the interface between minerals and surrounding liquids. This achievement provides a new perspective for better analyzing the process of mineral formation and further improves the theoretical system of cross scale phase transition of pore reaction flow.

This work was completed in collaboration between the Institute of Mechanics and the Oak Ridge National Laboratory in the United States. The research work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences strategic leading science and technology project (Category B), and the Chinese Academy of Sciences US inter agency cooperation project.

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