Multidirectional permeability simulation for fiber network based on the pore structure 3D characterization by CT scanning

Understanding the pore structure of paper and its permeability behavior is important for designing paper-based materials. In this study, the three-dimensional structure of paper was investigated using X-ray computed tomography, and the representative elementary volume (REV) was determined to be 400 x 400 x 450 pixels by the porosity criterion. The pore structural parameters of the REV were experimentally validated. Permeability simulations were carried out in the thickness direction (perpendicular to the paper plane, denoted as the Z direction), horizontal direction (any direction of the paper plane, denoted as the X-Y plane), double outlet, and triple outlet conditions. The simulated permeability in the thickness direction (1.69 mu m2) was very close to the experimental value (1.88 mu m2). The calculated permeability in the horizontal direction (8.38 mu m2) was much greater than that in the thickness direction, revealing that the paper had a high pore connectivity and large pore size in the horizontal direction, giving it a high permeability. Compared with the single outlet case, in the case of the double and triple outlet boundary conditions, more fluid flowed out from the side outlets, and the internal pressure declined faster. This study provides an approach for the structural design and performance optimization of paper-based materials.

Automated summary

This study used X-ray computed tomography to investigate the three-dimensional structure of paper and its permeability behavior. The results showed that paper has high pore connectivity and large pore sizes in the horizontal direction, resulting in higher permeability.