Controlling the solidification microstructure of metallic materials is the main objective of several researches developed nowadays due to its strong influence on the mechanical properties. The natural convection in the bulk liquid caused by the action of the gravitational field during solidification process can modify the final structural morphology of the materials. The objective of this study is to develop a numerical and experimental approach to verify the evolution of the grain morphology, segregation of the eutectic phase and predictions about the action of the natural convection over the final grain structure of an Al-7wt%Si alloy in the presence of refining particles (0,5wt% Al-Ti-B). The experiments were carried out by using Bridgmann technique and the numerical analysis was done by using the cellular automaton with finite element model. The experimental results presented good agreement with the simulations.