Morphology and transport properties of fibrous porous media

• Layered structural feature of fiber network was verified through 3D image.
• Mean fiber segment length is close to the mean pore diameter.
• Tortuosity of pore space is negligible at the highly connected porosity.
• RVE determined geometrically is close to that obtained with Brinkman screen length.
• The linear relationship between square pore diameter and permeability was verified.

The exploration of flow permeability of fibrous media is of great important significance in many industrial applications. Flow permeability strongly depends on the pore-scale structures. In order to explore the morphology of fibrous porous media and furthermore evaluate the transport properties, high-resolution X-ray tomography was employed to study the porous media in this paper. Morphology statistics data of porosity, specific surface area, tortuosity, and pore diameter were obtained. The size of representative volume element (RVE) determined according to geometry statistical deviation was consistent with that estimated with Brickman screening length criterion. The lattice Boltzmann simulation was then performed based on RVE to explore macroscopic transport properties. The transverse flow permeability obtained with Darcy's law at the steady state was consistent with the results in analytical models of layered fiber arrangement. Moreover, the impacts of the size and spatial resolution of simulation domain on the numerical results were discussed. Finally, the linear relationship between permeability and square pore diameter was quantitatively evaluated.

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