Mathematical modelling of macro- and micro-infiltration in resin transfer moulding (RTM)

A mathematical model is proposed to describe the macro-and micro-infiltration through reinforcements of bimodal porosity distribution in resin transfer moulding. The model is based on Darcy's law incorporating mechanical, capillary and vacuum pressures and covers three modes of infiltration. Permeabilities and capillary pressures are calculated at macro-and micro-levels. A numerical analysis is presented where at each numerical location the flowrate is split between three possible types of flow on the basis of mass balance and a combination of permeability magnitude and local flow potential. Parametric computational studies are carried out to study the flow of a model Newtonian fluid through woven cloths where the following parameters are varied: fibre volume fraction, fibre tow diameter and injection pressure. Predicted variables include micro-and macro-infiltration times and apparent global permeability. The latter was found to depend on the injection pressure, in the regime of relatively low injection pressures, where the variations also depended on the fabric architecture and fibre volume fraction. (C) 1997 Elsevier Science Limited.