Under-Hood Air Flow Evaluation of Pedestrian-Friendly Front-End Style Using CFD Simulation

The efficiency of the vehicle cooling system strongly depends on the air flow through the radiator core. The flow through the radiator core in turn depends on other panels that are in the vicinity of the radiator. In this study, the effect of geometrical change at vehicle front-end including the whole bonnet, grille and bumper area is investigated by means of Computational Fluid Dynamics (CFD). Numerical modeling is carried out by means of CAE tools. Simulations are performed for maximum power and maximum torque conditions, monitoring the mass flow rate through the radiator core and velocity contribution over the radiator face. To the velocity field of the airflow, the heat exchangers are represented as porous media and fan module is modeled utilizing Multiple Reference Frame (MRF) approach. The validity of the developed simulation capability is tested by successful comparison with the available experimental data for the base model at the given operating conditions. On studying the model with complete new front-end style, local modifications are applied incorporating adding airguide, flap and anti-recycler in order to enhance the flow distribution in the vicinity of radiator and increase the mass flow rate passing through it. Modifications lead to more than 10% improvement in mass flow rate through radiator core in Pedestrian-Friendly Front-End Style.