Large particle transport in porous media: Effect of pore plugging on the macroscopic transport properties

Large particle transport in porous media plays an important role in chemical and mechanical engineering but also in the medical field, especially in cancer treatment. The major difficulty in large particle transport results from the fact that the particles themselves influence the effective transport properties by pore plugging due to particle entrapment. In this study, we used a random walk model describing the particle transport inside the pores. The effective macroscopic transport properties are determined using the results of the random walk model. It is shown that the permeability tensor strongly depends on the particle size and the injection point location, whereas the dispersion coefficients remain independent. We also determined the maximal particle radius for which particle transport can be described by the convection-diffusion equation. Another important point in the chemical and medical field is the final particle distribution, and particularly the distribution of the quantity of liquid transported by the particles. Our results show that large particles do not lead to a homogeneous liquid distribution. Hence when a large quantity of liquid should be homogeneously distributed in the porous medium, the use of smaller particles is recommended.