The Role of Tortuosity in Upscaling
The Role of Tortuosity in Upscaling
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DOI：
10.1007/s11242-010-9613-9
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发表时间：
2011-05
影响因子：
2.7
通讯作者：
F. Valdés-Parada;M. L. Porter;B. Wood
中科院分区：
文献类型：
--
作者：
F. Valdés-Parada;M. L. Porter;B. Wood
扭曲度的概念是描述多尺度系统输运模型的一个组成部分。传统上，扭曲度被定义为微观结构中有效路径长度与最短路径长度之比。虽然最短路径长度可以明确指定，但有效路径长度却不能明确指定，因为它会从一种传输类型变化到另一种传输类型。因此，在同一系统中发生的不同输运过程可能具有不同的弯曲度值。这很方便，因为在这种方法下，不同的传输过程可以涉及相同类型的微尺度信息过滤器，但这些信息的性质是每种传输过程的特征。为了避免出现不明确的解释，我们提出了一套扭曲度规则，这些规则只将这个概念与微观几何结构联系起来。在这些规律的基础上，我们考察了在质量输运中引入扭曲度概念的必要性。特别地，我们研究了多孔介质中有无化学反应和对流的质量扩散。在所有这些情况下，我们的分析表明，扭曲的概念只适用于被动扩散，因为在其他情况下，不可避免地存在决定溶质有效路径的输运现象的耦合。
The concept of tortuosity is an integral part of models that describe transport in multiscale systems. Traditionally, tortuosity is defined as the ratio of an effective path length to the shortest path length in the microstructure. While the shortest path length can be unambiguously specified, the same is not true for the effective path length, since it changes from one type of transport to another. Consequently, it is possible to have different values of tortuosity for different transport processes taking place in the same system. This is convenient since, under this approach, different transport processes can involve the same type of filters of the microscale information, but the nature of such information is what characterizes each type of transport process. In order to avoid running into unclear interpretations, a set oftortuosity rulesare proposed, which relate this concept only to the microscale geometry. On the basis of these rules, we examine the pertinence of introducing the tortuosity concept in mass transport. In particular, we study mass diffusion with and without chemical reaction and convection in porous media. Of all these cases, our analysis indicates that the concept of tortuosity is only adequate for passive diffusion, since in the other cases there is an unavoidable coupling of the transport phenomena that determine the effective path of the solute.