Abstract
Multi-dimensional flow patterns in measurement equipment together with non-Newtonian effects and a fluid-dependent permeability can make it difficult to characterize porous material quantitatively with respect to their resistance to polymer flow. The latter is of interest in composite materials manufacturing processes such as resin-transfer moulding or tape impregnation involving highly viscous thermoplastic melts. In the present experimental data analysis it was found as useful to introduce a `geometric permeability' concept which can approximately represent multi-dimensional flow patterns and can be interpreted with respect to material and fluid properties. By using a one-dimensional analytically solvable flow model, the well-known power-law modification of Darcy's law and ideas developed by Cai, a geometry factor representing three-dimensional flow effects could be defined. Flow experiments involving a polypropylene matrix at two temperatures and six different porous materials were used to illustrate the validity of this approach.