| Summary: | This is a master thesis report in vehicle aerodynamics and cooling air management. The thesis is carried out at China Euro Vehicle Technology (CEVT) AB and is part of the course P7010T, Master Thesis in Space Engineering at Luleå University of Technology (LTU). The thesis has been supervised by Mattias Olander at CEVT and Gunnar Hellström at LTU and was done over 20 weeks during the spring semester of 2019. As the vehicle industry moves from mostly using combustion engines to hybrid and electric power systems the importance of decreasing cooling air drag has increased. Cooling air drag can be around 5-15% of the total drag, and a lot of research has been done over the years on how to decrease it. Cooling drag is defined as the force acting in x-direction from the cooling air flowing through the engine bay. The air is let in through the grilles to cool down the engine and escapes through different outtakes usually below the vehicle and through the wheelhouse. The air loses a lot of energy inside the engine bay as well as it changes in temperature. In this study a method has been developed to include the energy equation in the aerodynamic computational fluid dynamics (CFD) simulation. Research has also been done on which design parameters that affect the cooling air drag and how air ducts could be designed to better transport the flow to and from the radiators without loosing to much in energy. In the first part of this study a method was developed to solve the vehicle aerodynamics with energy equation included. All method development and design parameter tests weredone on the Sport Utility Vehicle (SUV) A model, which is a CEVT concept car. The model was first implemented on a simple symmetric model and then on a full model. It was tested both with a normal steady state solution and a pseudo transient solutions. The pseudo transient solution proved to solve for a faster convergence, although both methods worked well. Therefore the design parameter testing was chosen to be done with the pseudo transient solver.The ...
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