It is presented in this study a methodology based on numerical simulation by means of the computational fluid dynamics for the analysis of air flow inside the engine tunnel for commercial vehicles, aiming primarily at the performance of the cooling system. The simulations have been carried out with the software Ansys CFX v12.1.
Starting from the geometries of the water and engine charge air radiators, a 3D finite volume model is automatically generated for this system by means of a macro written with Excel, taking into account the dimensions, forms and quantity of tubes, as well as the fluid inside them, in order to represent the heat exchanges which occur on the water and air radiators.
Besides the models of the radiators, the geometry and the movement of the ventilator, as well as the surfaces inside the engine tunnel, as the engine, gear box, vehicle suspension, and the external surface of the vehicle body are all included in the complete finite volume mesh, which includes also the openings on the frontal area of the vehicle for the air to enter in the engine tunnel. The speed of the vehicle is also considered in the numerical simulation, in order to represent the actual test conditions.
As results, one obtains detailed visualizations in vector form regarding the velocity of the air which flows inside the engine tunnel, making the decision process of putting additional surfaces easier, in order to avoid regions of hot air recirculation in the cooling system, or even the suction of hot air by the engine air filter.
Detailed visualizations of the temperature development inside the tubes of the air and water radiators are also possible, and provide information for the performance evaluation of the cooling system for different configurations of commercial vehicle bodies.
This procedure aims at a reduction of time and costs in the development of commercial vehicles, as well as the improvement of quality of the final product.