Two-Dimensional Numerical Analysis of Non-Darcy Flow Using the Lattice Boltzmann Method: Pore-Scale Heterogeneous Effects
Two-Dimensional Numerical Analysis of Non-Darcy Flow Using the Lattice Boltzmann Method: Pore-Scale Heterogeneous Effects
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DOI：
10.1115/1.4049689
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发表时间：
2021-06
影响因子：
2
通讯作者：
Y. Takeuchi;Junichiro Takeuchi;T. Izumi;M. Fujihara
中科院分区：
文献类型：
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作者：
Y. Takeuchi;Junichiro Takeuchi;T. Izumi;M. Fujihara
本研究采用晶格玻尔兹曼方法，模拟不同孔隙尺度非均质性的圆形颗粒组成的多孔介质中孔隙尺度的二维流动，分析非达西流动对不同类型多孔介质的影响。利用Forchheimer方程计算了非达西流的临界雷诺数和非达西系数的大小。虽然模拟的多孔材料具有相似的孔隙度和具有代表性的粒径，但非达西系数更大，非达西流动开始时间更早。将模拟结果与已有关联进行比较，预测非达西系数，发现非达西系数对孔隙尺度非均质性的敏感性较大。利用参与数对孔隙尺度非均质性和产生的流场进行了评价。从计算的参与数和可视化的流场来看，与均匀介质相比，非均匀介质在达西流型中具有显著的通道效应。然而，当非达西流动发生时，这种通道效应被缓解。本研究以非达西效应为特征，通过参与人数的增加来量化疏导效应的缓解。我们的研究结果表明，非达西效应的大小和开始对孔隙尺度非均质性具有很强的敏感性，并暗示通过对通道效应的数值分析来评估非达西效应的可能性。
This study simulates pore-scale two-dimensional flows through porous media composed of circular grains with varied pore-scale heterogeneity to analyze non-Darcy flow effects on different types of porous media using the lattice Boltzmann method. The magnitude of non-Darcy coefficients and the critical Reynolds number of non-Darcy flow were computed from the simulation results using the Forchheimer equation. Although the simulated porous materials have similar porosity and representative grain diameters, larger non-Darcy coefficients and an earlier onset of non-Darcy flow were observed for more heterogeneous porous media. The simulation results were compared with existing correlations to predict non-Darcy coefficients, and the large sensitivity of non-Darcy coefficients to pore-scale heterogeneity was identified. The pore-scale heterogeneity and resulting flow fields were evaluated using the participation number. From the computed participation numbers and visualized flow fields, a significant channeling effect for heterogeneous media in the Darcy flow regime was confirmed compared with that for homogeneous media. However, when non-Darcy flow occurs, this channeling effect was alleviated. This study characterizes non-Darcy effect with alleviation of the channeling effect quantified with an increase in participation number. Our findings indicate a strong sensitivity of magnitude and onset of non-Darcy effect to pore-scale heterogeneity and imply the possibility of evaluating non-Darcy effect through numerical analysis of the channeling effect.