High-performance computing of flow and transport in physically reconstructed silica monoliths

This work presents an approach towards resolving hydrodynamic flow in real porous media by carrying out direct numerical simulations in the reconstructed macroporous (flow-through) domain of a silica monolith. The macroporous domain of a 60 microm x 60 microm x 12 microm segment of a 100 microm i.d. capillary silica monolith was reconstructed by confocal laser scanning microscopy. A 60 microm x 12 microm x 12 microm segment of the reconstructed domain was then used as the 3D matrix for simulation of fluid flow by the lattice-Boltzmann method on a high-performance computing platform. Excellent agreement is observed between the experimental and simulated Darcy permeabilities without any assumptions or further adjustments on the monolith morphology. The flow velocity field is analyzed in detail, including longitudinal and transverse velocity distributions, the occurrence of negative longitudinal velocities, as well as the beginning transition to the viscous-inertial flow regime. The presented methodology promises great potential for resolving the key relationships between morphology and band broadening in monolithic columns for HPLC applications.