Estimation of thermal and mass diffusivity in a porous medium of complex structure using a lattice Boltzmann method
Estimation of thermal and mass diffusivity in a porous medium of complex structure using a lattice Boltzmann method
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DOI：
10.1016/j.ijheatmasstransfer.2007.11.045
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发表时间：
2008-07
影响因子：
5.2
通讯作者：
N. Jeong;D. Choi;Ching-Long Lin
中科院分区：
文献类型：
--
作者：
N. Jeong;D. Choi;Ching-Long Lin
用格子Boltzmann方法研究了复杂结构多孔介质中的热扩散率和质扩散率。所考虑的介质包括具有周期性分布的圆形和方形柱体阵列的二维介质、具有不同尺寸的重叠或不重叠的球形和立方体夹杂物的三维颗粒介质以及随机生成的纤维介质。计算的有效扩散系数与现有的分析和数值计算结果时，夹杂物，无论其形状，不重叠。对于重叠夹杂物介质，有效扩散系数偏离现有的相关性作为夹杂物分数的增加。特别地，如果夹杂物的热扩散率大于介质中的流体的热扩散率以增强热传导，则偏差急剧增加。提出了一个新的重叠夹杂物介质的有效扩散系数与体积分数之间的经验关系式。
The thermal and mass diffusivity in a porous medium of complex structure is studied by using the lattice Boltzmann method. The media under consideration include two-dimensional medium with an array of periodically distributed circular and square cylinders, three-dimensional granular medium of overlapping or non-overlapping spherical and cubical inclusions of different size, and randomly generated fibrous medium. The calculated effective diffusivities are in good agreement with existing analytical and numerical results when the inclusions, regardless of their shapes, are not overlapped. For the medium of overlapping inclusions, the effective diffusivity deviates from existing correlations as the inclusion fraction increases. In particular, the deviation increases dramatically if the thermal diffusivity of the inclusion is greater than that of the fluid in the medium for enhanced thermal conduction. A new empirical correlation between the effective diffusivity and the volume fraction for the medium of overlapping inclusions is proposed.