Fluid and Thermodynamic Underhood Simulations

Abstract: The thermal model and simulation of vehicles components is necessary within the development phase of the vehicle production process. It is important to understand the thermal processes of high temperature components in the vehicle, such as the exhaust system. The exhaust system presents a high thermal activity that increases the temperature of the exhaust system itself and the nearby surrounding engine components, due to the large amount of heat transferred by radiation. The aim of this thesis is to develop a method that predicts the surface temperature of the exhaust system to ensure that no component overheats. This method includes coupling CFD software with heat transfer software. This model was validated against a tunnel test proving that the steady-state simulations match closely with the tunnel test data, while taking into consideration the possible sources of errors and discrepancies. Furthermore, a sensitivity analysis is performed in order to evaluate the robustness of the method. In conclusion, this thesis showed the feasibility of coupling a thermal model with a CFD model to successfully simulate the temperature of the exhaust system and surrounding engine components. This modeling process allows modifying the design without involving new experimental tests, contributing to a reduction of both time and cost. Consequently, this method will be used in future projects within the VCC verification efficiency processes.