Unsaturated and Saturated Permeabilities of Fiber Reinforcement: Critics and Suggestions

Frontiers in Materials. 2015;2 DOI 10.3389/fmats.2015.00038


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Journal Title: Frontiers in Materials

ISSN: 2296-8016 (Online)

Publisher: Frontiers Media S.A.

LCC Subject Category: Technology

Country of publisher: Switzerland

Language of fulltext: English

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Chung Hae ePARK (Ecole Nationale Supérieure des Mines de Douai (MINES DOUAI))
Patricia eKRAWCZAK (Ecole Nationale Supérieure des Mines de Douai (MINES DOUAI))


Blind peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 12 weeks


Abstract | Full Text

In general, permeability measurement results show a strong scattering according to the measurement method, the type of test fluid and the fluid injection condition, even though permeability is regarded as a unique property of porous medium. In particular, the discrepancy between the unsaturated and saturated permeabilities for the same fabric has been widely reported. In the literature, relative permeability has been adopted to model the unsaturated flow. This approach has some limits in the modeling of double-scale porosity medium. We address this issue of permeability measurement by rigorously examining the mass conservation condition. Finally, we identify that the pressure gradient is non-linear with positive curvature in the unsaturated flow and a misinterpretation of pressure gradient is the main reason for the difference between the saturated and unsaturated permeabilities of the same fiber reinforcement. We propose to use a fixed value of permeability and to modify the mass conservation equation if there are air voids which are entrapped inside the fiber tow. Finally, we also suggest some guidelines and future perspectives to obtain more consistent permeability measurement results.