Study on the influence of unresolved CFD-DEM coupling strategy on solute dispersion behavior in porous media

To deeply understand the complex solute transport behavior under the fluid-solid coupling effect in porous media, a numerical model for solute transport in porous media is developed based on CFD-DEM. The influence of coupling strategies (particle mapping strategy, grid-to-particle size ratio GSR) on solute dispersion in porous media is systematically investigated. The results show that the solute dispersion is significantly affected by the coupling strategies, and the difference in dispersion coefficient under different coupling strategy conditions intensifies with the increase of the Péclet number (Pe). It is recommended to use the divided particle volume method and GSR=0.5 for solute transport modeling. A dispersion coefficient correction formula based on the GSR is proposed to improve the modeling accuracy of solute transport using unresolved CFD-DEM. The study will provide an important reference for the research in environmental geotechnical engineering using CFD-DEM.