Abstract In this paper, different pore network models to simulate single-phase flow in porous media are built and their accuracy is evaluated. In addition to the conventional pore network model (CPNM) which consists of regular pore bodies and throat bonds, three improved pore network models (IPNMs) are developed allowing to better describing the real pore and throat geometry. The first improved pore network model (IPNM1) replaces the regular throat bond with a throat bond showing the real throat cross section. The second improvement (IPNM2) uses a series of sub-throat bonds with varying cross sections to better describe the real throat geometry, which is firstly proposed in this paper. The third model (IPNM3) extracts the real pore-throat-pore geometry without simplification. The conductance of fluid flow through these more realistic throat bonds is calculated by the lattice Boltzmann method (LBM). The accuracy and computational efficiency of the different pore network models are evaluated taking the LBM simulation over the whole porous medium as reference solution. The global permeability and detailed pressure distributions in the pores for the different pore network models are validated. The results show that the accuracy of the pore network model increases from CPNM to IPNM3, but at the expense of increasing computational cost. This study suggests that IPNM3 can replace a whole-domain LBM simulation with similar accuracy but much lower computational cost. As a first-order approximation the newly proposed IPNM2 is suggested as good compromise between accuracy and computational cost.

中文翻译：

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结合格子 Boltzmann 方法改进孔隙网络模型模拟多孔介质中的单相流

摘要 本文建立了模拟多孔介质中单相流动的不同孔隙网络模型并对其精度进行了评价。除了由规则孔体和喉道键组成的传统孔隙网络模型 (CPNM) 之外，还开发了三种改进的孔隙网络模型 (IPNM)，可以更好地描述真实的孔喉几何结构。第一个改进的孔隙网络模型 (IPNM1) 用显示真实喉道横截面的喉道键合代替了常规的喉道键合。第二个改进（IPNM2）使用一系列具有不同横截面的喉下键来更好地描述真实的喉咙几何形状，这是本文首次提出的。第三个模型 (IPNM3) 在没有简化的情况下提取了真实的孔喉孔几何结构。流体流过这些更真实的喉道键的电导是通过格子玻尔兹曼方法 (LBM) 计算的。以整个多孔介质的 LBM 模拟为参考解，评估了不同孔隙网络模型的准确性和计算效率。验证了不同孔隙网络模型的孔隙中的全局渗透率和详细压力分布。结果表明，孔隙网络模型的精度从 CPNM 提高到 IPNM3，但以增加计算成本为代价。这项研究表明，IPNM3 可以以相似的精度代替全域 LBM 模拟，但计算成本要低得多。作为一阶近似，新提出的 IPNM2 被认为是准确性和计算成本之间的良好折衷。