The Role of High-Permeability Inclusion on Solute Transport in a 3D-Printed Fractured Porous Medium: An LIF–PIV Integrated Study

Abstract It is well-known that the presence of geometry heterogeneity in porous media enhances solute mass mixing due to fluid velocity heterogeneity. However, laboratory measurements are still sparse on characterization role high-permeability inclusions transport, particularly concerning fractured media. In this study, transport solutes quantified after a pulse-like injection soluble fluorescent dye into 3D-printed medium with distinct (H-k) inclusions. The concentration and pore-scale determined using laser-induced fluorescence particle image velocimetry techniques. migration delineated its breakthrough curve (BC), temporal spatial moments, metrics (including scalar dissipation rate, volumetric dilution index, flux-related index) different regions medium. With same H-k inclusions, compared matrix, low-permeability (L-k) matrix displays higher peak BC, less retention, velocity, smaller dispersion coefficient, lower pore volume being occupied by solute. index clearly captures striated plume tails following streamlines along dead-end fractures interface between L-k matrices. We propose normalization rate respect maximum regional total mass, which offers generalized examination for an open region varying mass. Our study presents insights interplay geometric features behaviors at scale.