FABRICATION OF REALISTIC TRANSPARENT POROUS MEDIA FOR 3D OBSERVATION OF INTERNAL MASS TRANSPORT

Abstract

A new experimental system was developed to observe the migration of colloidal particles in saturated porous media in 3D, which is important in engineering processes such as contaminant migration and filtration. The system enables the observation of internal migration that is invisible from the outside by fabricating a porous body using a transparent material and a 3D printer. Non-artificial media with arbitrarily controlled internal pore sizes were fabricated by designing the porous media based on the results of numerical analysis on phase-separation phenomena. The refractive indices of the porous media and the interstitial liquid were matched, and a laser sheet was used to extract cross sections of the media. By reconstructing multiple cross-sectional images, it was possible to visualize the 3D migration of suspended particles. The developed system was then applied to the collective gravitational settling of fine particles in saturated porous media. The results showed that the particles selectively settled in the pore networks while repeatedly branching in the lateral direction.