Simplified in-plane permeability model for textile fabrics

In this paper, a simplified in-plane permeability model for textile fabrics is developed. The model is based on a rectangular unit cell geometry, the one-dimensional Stokes equation for flow in the channels or gaps between fiber tows, and the one-dimensional Brinkman equation for flow in fiber tows. Three different textile fabrics are considered in the model: plain woven, 4-harness, and bidirectional stitched fiberglass mats. The model incorporates the effect of porosity changes on permeability of fiber preforms under compression, which usually occurs in the molding process. To verify the validity of the model, the theoretical values are compared with a set of permeability measurements. Good agreement is found between the model prediction and the permeability measurements in the porosity ranges of φ ≤ 0.59 for plain woven fiber mats, φ ≤ 0.60 for 4-harness fiber mats and φ ≤ 0.62 for bidirectional stitched fiber mats.