  The aim of this work is to contribute in improving fibrous preforms
impregnation for Liquid Composite Molding (LCM) processes. The void prediction
in LCM sparks off interest within the Composite Material elaboration because it
represents a significant issue to keep the expected mechanical properties of
the final product. The liquid properties, the preform geometry and the flow
conditions impact the void or bubble entrapped inside and outside the yarns.
Nevertheless, due to the complex geometry of the reinforcement, experimental
characterization of bubble formation remains delicate. Thus, our study deals
with two simple model networks representing connected pores so called "Pore
Doublet Model". A first is considering two capillaries converging on a node
(T-junction) and a second is representing two capillaries interconnected with a
supplying principle. In this paper, we emphasize on microfluidic and
millifluidic approaches where wetting and capillary forces are significant
during bubble formation mechanism.
