Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media.
Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media.
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DOI：
10.1103/physreve.94.053118
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发表时间：
2016-11
期刊：
影响因子：
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通讯作者：
Eleonora Crevacore;Tiziana Tosco;R. Sethi;G. Boccardo;D. Marchisio
中科院分区：
文献类型：
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作者：
Eleonora Crevacore;Tiziana Tosco;R. Sethi;G. Boccardo;D. Marchisio
本文研究了孔隙空间几何形状对多孔介质中溶质运移的影响，并对流体流动和溶质运移进行了计算流体力学孔隙尺度模拟。由三种不同的孔结构构型，即面心立方(FCC)、体心立方(BCC)和球状立方体(SIC)排列得到了三维周期磁区。尽管传输模拟是用具有相同粒度和相同孔隙度的介质进行的(在FCC和BCC配置中)，但所产生的突破曲线呈现出显著的差异，例如增强的尾矿。这种差异的原因被归因于回流区的存在，即使在低雷诺数时也是如此。提出了利用孔隙尺度数据容易地识别回流区并量化其大小的各种方法。从这一分析中获得的信息然后被用来定义能够提供对观察到的异常运输的适当描述的宏观模型。应用传质模型估计了相关的宏观尺度参数(首先是流体动力学弥散)及其在介质中的空间变化，并提出了描述这些宏观尺度参数的空间变化的函数关系。
In this work, the influence of pore space geometry on solute transport in porous media is investigated performing computational fluid dynamics pore-scale simulations of fluid flow and solute transport. The three-dimensional periodic domains are obtained from three different pore structure configurations, namely, face-centered-cubic (fcc), body-centered-cubic (bcc), and sphere-in-cube (sic) arrangements of spherical grains. Although transport simulations are performed with media having the same grain size and the same porosity (in fcc and bcc configurations), the resulting breakthrough curves present noteworthy differences, such as enhanced tailing. The cause of such differences is ascribed to the presence of recirculation zones, even at low Reynolds numbers. Various methods to readily identify recirculation zones and quantify their magnitude using pore-scale data are proposed. The information gained from this analysis is then used to define macroscale models able to provide an appropriate description of the observed anomalous transport. A mass transfer model is applied to estimate relevant macroscale parameters (hydrodynamic dispersion above all) and their spatial variation in the medium; a functional relation describing the spatial variation of such macroscale parameters is then proposed.