Effect of 3D fiber orientation distribution on transverse air permeability of fibrous porous media

In the recent past years, there was a resurgence of interest to study the air permeability of fibrous porous media, but the results reported on the effect of 3D fiber orientation on the transverse permeability of fibrous porous media appeared to be contradictory. While Stylianopoulos et al. [Physics of Fluids 20, 123601 (2008)] observed that the highly aligned network was more permeable than the moderately aligned network, which, in turn, was more permeable than the isotropic fiber network, but Tahir and Tafreshi [Physics of Fluids, 21, 083604 (2009)] found that the transverse permeability was increased with the increase in the deviations of the fibers through-plane angle from zero. In order to resolve this contradiction, in this work, a series of virtual fibrous structures were generated on computer by varying the degree of anisotropy of 3D fiber orientation and the transverse permeability of such structures was obtained by solving stokes equation. It was observed that the transverse permeability of the fibrous porous media was increased with the increase in degree of anisotropy of 3D fiber orientation.

Three-dimensional virtual fibrous porous media with different degrees of anisotropy (η) of fiber orientation. 3D orientation anisotropy (η) determined transverse permeability (k) of fibrous porous media.Figure optionsDownload as PowerPoint slideHighlights
► A series of computer models of 3D anisotropic fibrous structures were generated.
► Stokes equation was solved to find out transverse permeability of these structures.
► Higher degree of anisotropy of fiber directions resulted in higher permeability.