Phase-Field Navier-Stokesモデルによる繊維間隙スケール樹脂流れにおける気液界面ダイナミクスの検討

Abstract

To investigate void formation during resin transfer molding (RTM) processes, we developed a numerical code of a multiphase fluid model that employs Navier-Stokes equation including the interfacial tension term and Cahn-Hilliard equation for capturing the resin-air interface. We performed preliminary numerical simulations of microscale resin-air flow around a regular-lattice array of four single filaments. From the analysis, we found that (1) Laplace pressure arisen from the finite curvature of the resin-air interface could drive a capillary-driven flow penetrating into the gap between the two filaments located in longitudinal direction; (2) there was another dual time scale even at the microscale on the determination of flow patters: one was caused by the main flow, and the other by capillary driven transverse flow; (3) voids could be formed when the time scale of the main flow was shorter than that of capillary flow; (4) two modes of void formations were revealed numerically: longitudinal gaps fully capped by the resin-air interface leading to the void formation under a high interfacial tension coefficient; and a small bubble left at the back-step of the filament under a relatively weak interfacial tension coefficient.