Super-Darcy flow behavior in fracture-confined porous media

• 成果类型: Article
• 署名作者: Zhang, Shuai; Ma, Qing; Xie, Weiqiang; Liu, Kai; Su, Yanlin; Zhao, Mingxin; Wang, Zefan; Zhao, Jinpeng; Liu, Xiaoli
• 署名单位: China Institute of Water Resources & Hydropower Research; Tsinghua University; Ministry of Water Resources; Tsinghua University; University of Science & Technology Beijing; University of Science & Technology Beijing; Xizang Agricultural & Animal Husbandry University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2613597123
• 发表日期: 2026-07-21
• 页码: e2613597123
• 关键词: particle deposition; pressure drop; flow rate; non-Darcy behavior; super-Darcy behavior; fluid-flow; FORCHHEIMER EQUATION; HYDRAULIC APERTURES; heat-transfer; roughness; permeability; transport

摘要

Particle deposition and migration within fractures can reorganize open void space into heterogeneous fracture-confined porous media (FCPM), yet the macroscopic flow behavior of these emergent systems remains unresolved. Here, Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations were used to resolve particle migration and deposition, whereas a coupled free-flow and seepage-flow model was employed to characterize fluid flow in FCPM. We find that at a fixed Reynolds number, modest particle deposition can lower the overall pressure drop relative to that of the initially open fracture. At high Reynolds numbers, the pressure drops across FCPM not only exceed Darcy's law predictions (non-Darcy behavior) but, intriguingly, can also fall below them, which is a phenomenon we term super-Darcy behavior. This counterintuitive effect arises from flow exchange between the deposited porous region and the adjacent open region, which modifies eddy formation and growth, thereby broadening the main flow channel. This effect is pronounced when the permeability of the deposited porous region lies from 1 & times; 10-12 to 1 & times; 10-7 m2, identifying a permeability window in which deposition-migration most strongly couples pore-scale structure to fracture-scale hydraulics. This study reveals how particle deposition and transport govern macroscopic flow behavior in fractured channels, offering critical insights for fluid flow control and prediction from microfluidic devices to subsurface energy reservoirs.