研究岩石粗糙单裂隙中发生的流体流动行为是全面了解裂隙网络渗流特性的基础。

基于分形理论生成人工合成岩石裂隙，采用COMSOL Multiphysics软件开展渗流数值模拟研究；利用3D打印技术制备与数值模型具有相同几何特征的裂隙试样，并结合自主搭建的渗流实验装置开展一系列不同注入流量下的渗流试验，研究了不同注入方向对三维粗糙单裂隙非达西流动微观和宏观流动行为的影响。

结果表明：(1)不同注入方向条件下岩石裂隙表面粗糙度的差异会显著影响裂隙的渗流特性，在表面粗糙度更大的方向上流体流动阻力、流动路径迂曲度和非达西效应更大。(2)裂隙中涡旋区发育程度与表面粗糙度呈正相关，在表面粗糙度更大的注入方向上涡旋区的发育程度比表面粗糙度较小的注入方向上涡旋区发育程度更高。(3) Forchheimer方程在描述裂隙中的非达西流动时不能适用于整个雷诺数范围，只有在非达西流动充分发生时才能有足够的准确性。(4)裂隙表面粗糙度各向异性程度越大则裂隙在粗糙度更大的方向上越容易发生非达西流动，两个注入方向上的流动行为差异也越明显。(5)基于三维裂隙渗流模拟研究建立了裂隙临界雷诺数与表面粗糙度各向异性因子以及平均开度的定量化表征模型，并通过开展渗流试验验证了所建立模型的有效性。研究成果可为更全面研究粗糙裂隙中非达西流动行为的各向异性提供借鉴。

Investigating the flow behavior of fluids in individual rough-walled rock fractures is fundamental for fully understanding the seepage characteristics of fluids in rock fracture networks.

Rock fractures were artificially synthesized based on the fractal theory, and numerical simulations of seepage along these fractures were performed using the COMSOL Multiphysics software. Then, fracture specimens with the same geometric characteristics as numerical models of fractures were prepared using 3D printing technology. In combination with the self-designed equipment for seepage experiments, this study conducted seepage experiments on these fracture specimens under different injection flow rates to investigate the impacts of varying injection directions on the microscopic and macroscopic behavior of non-Darcy flow in 3D individual rough-walled fractures.

The results indicate that the differences in the surface roughness of rock fractures under different injection directions significantly influenced the seepage characteristics of fractures, with greater flow resistance, flow path tortuosity, and non-Darcy flow effect occurring in the injection direction with higher fracture surface roughness. The developmental degree of eddies in fractures was positively correlated with the fracture surface roughness. Specifically, eddies in the injection direction with higher fracture surface roughness manifested a higher developmental degree compared to those in the direction with lower surface roughness. The Forchheimer equation did not apply to the entire range of Reynolds numbers when describing non-Darcy flow in fractures. Instead, it was sufficiently accurate only in the case of the sufficient occurrence of non-Darcy flow. The higher anisotropy in the surface roughness, non-Darcy flow was more prone to occur along fractures in the direction with higher surface roughness, accompanied by more pronounced differences in flow behavior between both injection directions. Quantitative characterization models for describing the relationships of the critical Reynolds number with the anisotropy factor in the fracture surface roughness and average fracture aperture were established based on the seepage simulations of 3D fractures. The effectiveness of the established models was verified using seepage experiments. The results of this study serve as a reference for more comprehensive research on the anisotropy in non-Darcy flow behavior in rough-walled fractures.