Tomography-based determination of transverse permeability in fibrous porous media

Precise characterization of nonwoven fabrics such as their transport properties are of paramount importance in development of advanced filtration processes. Currently majority of available knowledge on transport behavior of fibrous materials is based on macro-scale empirically researched phenomena. Thus, evaluation of transport behavior of nonwovens based on fundamental scientific principles at micro-scale still remains a challenge that has to be tackled by scientists. In this paper, an integrated approach employing high-resolution X-ray micro-computed tomography and finite volume method are presented to predict permeability of needled nonwoven fabrics. In order to achieve the objectives of this research, dimensionless permeability of needled nonwoven fabrics with various porosities was computed using CFD tools. Comparisons of simulated results with experimentally obtained data and the published empirical and analytical models were made. Considering solid volume fraction of the samples, acceptable agreement between the results and previously published findings was observed. It was also established that experimental samples ideally can be represented as a three-dimensional random structure.