  The void prediction in LCM processes sparks off interest within the composite
material industry because it is a significant issue to keep the expected
mechanical properties. The liquid properties, the preform geometry and the flow
conditions impact the quantity of void entrapped inside the final product. The
complex geometry of the reinforcement due to the arrangement of the bundles and
the fibres is a key point to understand and quantify this phenomenon. This
paper deals with both simple model networks which can occur inside a fabric
representing connected capillaries, so-called "Pore Doublet Model (PDM)". A
first is considering two capillaries converging on a node (T-junction) and a
second is representing two capillaries interconnected with a supplying
principle. These configurations can affect locally the evolution of flow
fronts. First, experiments of bubble formed in a T-junction device have been
performed and studied. Then a theoretical approach was proposed to forecast
microvoid and macrovoid formation, by taking into account a supplying principle
and arranged Washburn equation in forced filling.
