Effect of wettability on impregnation process of viscous fluid to woven fiber bundles

In order to realize high-quality resin transfer molding processes, it is important to understand the impregnation behavior of viscous fluid inside and between fiber bundles where the flow paths are complicated. In this research, a series of numerical simulations of liquid impregnation into single layer of woven fibers are conducted. We mainly focus on the microvoid formation due to complex convective field between the fiber bundles. Quantitative discussion on the temporal variation of the microvoid rate is also addressed. It is found that the impregnation process drastically changed by varying the kinematic viscosity as well as the contact angle between the viscous liquid and fibers. It is also revealed that the wettability has a greater impact on the impregnation process and microvoid formation than the viscosity in terms of the capillary and modified capillary numbers.