Dual-scale modeling of porous fibrous materials

Dual-scale flows in fiber-reinforced composites have great applications in science and industry. However, comparing with solid fibers, great complexities are introduced when micro-scale flow processes taking place simultaneously in both regions of inter- and intra- yarns. In this study, an analytical model is presented to predict the transverse permeability of the dual-scale fibrous materials. The proposed model is successfully verified by comparing with experimental results, numerical calculations and previous theoretical values, and its dependence on structural parameters such as porosity, fiber radius, packing configuration and cross-sectional shape is also discussed. A simple but effective semianalytical correlation, regarding the overall permeability as a sum of contributions from inter-yarn and intra-yarn flows, is put forth to give a rapid permeability estimate. The development of this model facilitates speeding design of required performances of dual-scale fibrous materials.