Numerical modelling and optimisation of fibre wet-out in resin-injection pultrusion processes

In this study, a numerical model for the simulation of resin flow in relation to fibre impregnation in resin-injection pultrusion processes has been developed. The model is based on Darcy’s law in a 2D finite-volume framework and a level-set method to trace the propagation of the resin flow front. With inspiration from the use of flow-enhancers in other resin transfer moulding processes, the purpose of this study is to explore how local areas with increased permeability can assist in improving the fibre impregnation. Using the numerical model, it is demonstrated how the profile-advancing pulling speed theoretically can be increased by 250-300%, while maintaining a complete resin wet-out. This is achieved by increasing the permeability of the profile near the resin inlets, which allows for additional resin flow. Finally, it is demonstrated how an increase in permeability at the centre of the profile can alter the shape of the flow front, which can facilitate complete resin wet-out over a shorter distance.