Liquid Composite Molding (LCM) is a popular manufacturing process used in many industries. In Resin Transfer Molding (RTM), the liquid resin flows through the fibrous preform placed in a mold. Numerical simulation of the filling stage is a useful tool in mold design. In this paper the implemented method is based on coupling a Boundary Element Method (BEM) with a Level Set tracking. The present contribution is a two-dimensional approach, decoupled from kinetics, thermal analysis and reinforcement deformation occurring during the flow. Applications are presented and tested, including a flow close to industrial conditions.