This study revisited the single-phase fluid flow in two-dimensional model porous media using pore network simulation (PNS). Some throats were randomly blocked to increase the tortuosity. Then single-phase fluid flow simulations were carried out in these networks using direct numerical simulation (DNS). Different correlations are usually used to estimate the pressure drop in throats, contractions, and expansions. We critically reconsidered the correlations available in the literature and introduced new correlations based on the results obtained from DNS. Trapezoidal and circular half-pore sections were studied separately, and it was concluded that the correlations are very sensitive to the pore body’s geometry. The correlations extracted for throats and expansions precisely predict the permeability of corresponding elements in the network. The correlation for the contraction section did not match the respective DNS data in the network. A large discrepancy was observed by comparing the streamlines in the networks with the flow paths in isolated flow paths (not in the network). We found that the correlation for contraction section based on uniform flow at the inlet is not suitable for networks with complex pore structures. We showed that PNS’s applicability with current correlations is limited to situations where throat resistance controls the permeability. By analyzing Darcy and Forchheimer’s parameters, a large deviation was seen between PNS and DNS results. We demonstrated that eddies might form within the Darcy regime. In the model porous media studied in this paper, eddies and inertial core flow were known to play a prominent role in deviation from Darcy flow, which are not considered by PNS. It was concluded that short-range correlations are essential in modeling fluid flow at sub-pore level.

本研究使用孔隙网络模拟 (PNS) 重新审视二维模型多孔介质中的单相流体流动。一些喉咙被随机堵塞以增加弯曲度。然后使用直接数值模拟 (DNS) 在这些网络中进行单相流体流动模拟。通常使用不同的相关性来估计喉部、收缩和扩张的压降。我们批判性地重新考虑了文献中可用的相关性，并根据从 DNS 获得的结果引入了新的相关性。分别研究了梯形和圆形半孔截面，得出的结论是相关性对孔体的几何形状非常敏感。为喉道和扩展提取的相关性精确地预测了网络中相应元素的渗透率。收缩部分的相关性与网络中的相应 DNS 数据不匹配。通过将网络中的流线与孤立流路（不在网络中）中的流路进行比较，观察到了很大的差异。我们发现基于入口均匀流动的收缩截面相关性不适用于具有复杂孔隙结构的网络。我们表明，PNS 与当前相关性的适用性仅限于喉部阻力控制渗透率的情况。通过分析 Darcy 和 Forchheimer 的参数，发现 PNS 和 DNS 结果之间存在很大偏差。我们证明了涡流可能会在达西政权内形成。在本文研究的模型多孔介质中，已知涡流和惯性核心流在偏离达西流中起着重要作用，PNS 不考虑这些。得出的结论是，短程相关性对于模拟亚孔隙水平的流体流动至关重要。