Introduction of intra-tow release/storage mechanisms in reactive dual-scale flow numerical simulations

Classical dual-scale reactive simulations of the RTM process assume permanent intra-tow resin storage in the saturated domain. However, recent experimental investigations revealed that permanent storage is occurring only in a limited volume of the tows. In the remaining volume, fluid is released in the channels with a rate that depends on the architecture of the textile and on the fiber volume fraction. Based on experimental observations, a new model is proposed to refine the simulation of the high speed reactive RTM process: a simplified microstructural model is used to enable permanent and partial transient storage within the tows. Additionally, a new sink term is proposed to reproduce the kinetics of the convective tow-channel fluid exchanges in the saturated domain. After a state of the art on dual-scale and reactive flow, the experimental inputs of the study are presented. The new model is then introduced, validated and characterized using the experimental inputs. Additionally, the influence of the release mechanisms on a reactive dual-scale injection is estimated by conducting comparative single-scale, and dual-scale simulations with transient or permanent storage. The new model has been demonstrated to be appropriate to reproduce accurately the release mechanisms, and simulations reveal the interest of taking these release mechanisms into account to simulate reactive dual-scale injections with an increased accuracy.