2024/11/06 by Saif Farhat, Farhat, Saif, Guillem Sole‐Mari +3
Engineering · #Enhanced Oil Recovery Techniques #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn)
paper · pdf · doi:10.48550/arxiv.2411.04099
openalex publication_date 2024/11/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the pore-scale transport of a conservative scalar forming an advancing mixing front, which can be re-interpreted to predict instantaneous mixing-limited bimolecular reactions. We investigate this using a set of two-dimensional, high-resolution numerical simulations within a poly-disperse granular porous medium, covering a wide range of Peclet numbers. The aim is to show and exploit the direct link between pore-scale concentration gradients and mixing interface (midpoint concentration isocontour). We believe that such a perspective provides a complementary new lens for better understanding mixing and spreading in porous media. We develop and validate a theoretical model that quantifies the temporal elongation of the mixing interface and the upscaled reaction kinetics in mixing-limited systems accounting for pore-scale concentration fluctuations. Contrary to the classical belief that, given sufficient time, pore-scale fluctuations would eventually be washed out, we show that for Pe>1 advection generates pore-scale concentration fluctuations more rapidly than they can be fully dissipated. For such P'eclet numbers, once incomplete mixing is established, it will persist indefinitely.