Triggering interfacial instabilities during forced imbibition by adjusting the aspect ratio in depth-variable microfluidic porous media

• DOI: 10.1073/pnas.2310584120
• Publication Date: 2023-12-04T20:12:07Z
• Authors: Wenhai Lei; Xukang Lu; Wenbo Gong; Moran Wang
• Keywords: Imbibition; Aspect ratio (aeronautics); Capillary pressure

We present a comprehensive description of the aspect ratio impact on interfacial instability in porous media where wetting liquid displaces nonwetting fluid. Building microfluidic experiments, we evidence imbibition scenarios yielding instabilities and macroscopic morphologies under different depth confinements, which were controlled by capillary number. report phenomenon whereby smaller depth-variable lower number trigger during forced imbibition; otherwise, larger uniform-depth higher will suppress instability, seemingly ignored or contradicts conventional expectations with compact faceted growth imbibition. Pore-scale theoretical analytical models, numerical simulations, as well experiments combined for characteristics microscopic dynamics displacement results function ratio, variation, Our complete dynamic view process over full range regimes from stabilization to destabilization. predict mode based pore-scale behavior, fits experiments. The study provides insights into role controlling media. finding design prediction principles engineered media, such devices, membranes, fabric, exchange columns, even soil rocks concerning their desired immiscible behavior.