Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture
Pore-Scale Modeling of Mixing-Induced Reaction Transport through a Single Self-Affine Fracture
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通过单个自仿射裂缝混合诱导反应传输的孔隙尺度模型
DOI：
10.1155/2018/9095143
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发表时间：
2018-06
期刊：
影响因子：
1.7
通讯作者：
Dou Z
中科院分区：
文献类型：
--
作者：
Dou Zhi;Zhou Zhifang;Wang Jinguo;Liu Jin;Dou Z
对单个自仿射裂缝的孔隙尺度模拟研究表明，非均质流场对混合诱导的反应输运有显著影响。我们用连续随机相加(SRA)技术产生了单个自仿射断裂。将N-S方程(NSE)和对流扩散方程(ADER)与反应相耦合，建立了孔尺度模型。由于雷诺数的增加和孔洞的突然扩张，自仿射断裂中捕获了涡流。反应产物的通量加权穿透曲线(BTC)表现出典型的非费克特性(即“早到”和“重尾”)。研究发现，反应物参与了旋涡，并在旋涡控制区内发生了反应。因此，涡流对阻碍涡控区域与主流道之间的质量交换过程起到了重要的作用，从而导致了BTCs的“重尾”现象。随着雷诺数的增加，穿透时间增加，BTCs的浓度峰减小。此外，描述浓度概率分布的Shannon熵指数的稀释指数被用来量化反应物的混合程度。结果表明，非反应输运的稀释度与混合诱导反应输运的结果吻合较好。较高的雷诺数和Peclet数在早期对混合过程有负面影响，而在后期对混合过程有强化作用。
This pore-scale modeling study in single self-affine fractures showed that the heterogeneous flow field had a significant influence on the mixing-induced reaction transport. We generated the single self-affine fracture by the successive random additions (SRA) technique. The pore-scale model was developed by coupling the Navier-Stoke equation (NSE) and advection-diffusion equation with reaction (ADER). Eddies were captured in the self-affine fracture due to the increasing Reynolds number and the sudden expansion of aperture. The flux-weighted breakthrough curves (BTCs) of reaction product showed the typical non-Fickian characteristics (i.e., “early arrival” and “heavy tail”). It was found that the reactant was involved in eddies and then reacted inside the eddy-controlled domain. Consequently, eddies played a significant role in delaying the mass exchange process between the eddy-controlled domain and the main flow channel, which resulted in the “heavy tail” in BTCs. As the Reynolds number increased, the breakthrough time increased while the concentration peaks of BTCs decreased. Furthermore, the dilution index presenting the exponential of the Shannon entropy of a concentration probability distribution was used to quantify the degree of reactant mixing. The results showed that the quantification of dilution for nonreaction transport was in good agreement with the outcomes of mixing-induced reaction transport. The high Reynolds number and Peclet number had a negative influence on the mixing process at the early time whereas they led to the enhanced mixing process at the late time.
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影响因子：
2.7
作者：
R. Zimmerman;G. Bodvarsson
通讯作者：
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影响因子：
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影响因子：
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影响因子：
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