The objective of this numerical study is to characterize temperature and airflow within a ventilated pallet of heat-generating products. Thus, it takes into account the resulting effect of forced and natural convection. An original Computational Fluid Dynamics (CFD) hybrid approach was developed. It combines porous medium approach for the container and direct CFD method for the external cardboard wall, including vent characteristics. The computational domain is limited to one pallet level. The simulations are performed on steady state. The model was validated by comparison with experimental results related to velocity profiles and product temperature. When compared to direct CFD model, the hybrid approach shows also a good accuracy and allows reducing the mesh size and computational time. The model will be extended to an unsteady state to predict the cooling and heating kinetics of heat-generating products.