Отправлено: 27.07.15 11:03. Заголовок: Particle Shape Effects on Hydraulic and Electric Tortuosities: A Novel Empirical Tortuosity Model Ba

Particle Shape Effects on Hydraulic and Electric Tortuosities: A Novel Empirical Tortuosity Model Based on van Genuchten-Type Function
Hidetaka Saomoto · Jun Katagiri
Transp Porous Med
Received: 21 November 2014 / Accepted: 27 January 2015
© Springer Science+Business Media Dordrecht 2015
Abstract The tortuosity is one of the key parameters to characterize the transport properties
of porous media. Since the tortuosity is strongly related with the shape of particles constituting
the porous media, we need to investigate the shape effect of particles on the tortuosities. We
have, respectively, performed a series of finite element simulations for the hydraulic and the
electric tortuosity to reveal the relationship between the tortuosity and the particle shape.
The results reveal that: (1) A concise computational expression for tortuosities proposed by
Duda et al. is numerically validated through our simulations. (2) On average, the hydraulic
tortuosity is 15% greater than the electric tortuosity within the porosity range from 0.5 to
0.9. (3) The high particle aspect ratio (5.0) results in the amplifications of both the hydraulic
and the electric tortuosities up to 15% greater than the values with the low particle aspect
ratio (1.0). Using the simulation results, we propose a novel tortuosity model based on
the van Genuchten-type function, which can precisely describe the relationship between
the tortuosities and the porosity for elliptic particle having the aspect ratio ranging from
1.0 to 5.0.