The Role of Tortuosity in Upscaling |
| |
Authors: | Francisco J Valdés-Parada Mark L Porter Brian D Wood |
| |
Institution: | (1) Vascular Mechanics Lab, Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48109, USA;(2) Mechanical Engineering Department, University of California, Riverside, CA 92505, USA; |
| |
Abstract: | 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 of tortuosity rules are 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. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|