Direct Numerical Simulations of Flow and Reactive Transport in Pervious Concrete

Abstract

This work presents a numerical study of reactive scalar transport of NOx in pervious concrete, aimed at assessing its potential for air decontamination in urban and industrial applications. The porous geometry used in the simulations was reconstructed from X-ray computed tomography of real perviousconcrete specimens, enabling a high-fidelity representation of the internal microstructure. Based on these geometries, we performed direct numerical simulations of steady, laminar, three-dimensional flow. On the resulting flow fields, we solved the advection-diffusion-reaction of a reactive scalar with surfacereaction boundary conditions, modeling adsorption and heterogeneous photocatalysis at the pore walls. The model reaction considered was the TiO2-catalyzed photocatalytic oxidation of NO and NO2 to nitrate (NO3) immobilized within the concrete matrix. The analysis quantifies the material’s efficiency as a passive reactive medium or catalyst support by evaluating residence-time distributions and the utilization of the available internal surface area.