On the examination of the Darcy permeability of soft fibrous porous media; new correlations

- The compression-dependent permeability of fibrous porous media was measured.
- 7 different soft fibrous materials were examined.
- The accuracy of existing theoretical/semi-empirical correlations were examined.
- We proposed two new correlations for the permeability of soft fibrous materials.
- The study is valuable for examining fluid flow in porous biological systems.

In this paper, we report a novel experimental approach to investigate the compression-dependent Darcy permeability of soft porous media. Especially, we are proposing new correlations that describe the change of the permeability of random fibrous porous media as a function of its compression. A special device was developed that consisted of a rectangular flow channel with adjustable gap thickness ranging from 3 mm to 20 mm. Air was forced through the thin gap filled with testing fibrous materials. By measuring the flow rate and the pressure gradient, we have successfully obtained the Darcy permeability of different fibrous porous materials at different compression ratios. Theoretical or semi-empirical models have been compared with the experimental results, indicating various degrees of disagreement. The new correlations were then proposed which fit with experimental data very well. The study presented herein provides a useful approach to evaluate the change of the permeability of fibrous porous media as a function of its compression. It will be valuable for examining fluid flow in fibrous porous media where the permeability is difficult to be measured directly. This kind of porous media widely exists in biological systems.