Simulating the Volvo Cars Aerodynamic Wind Tunnel with CFD
Examensarbete för masterexamen
Automotive engineering (MPAUT), MSc
The study presented in this report is the result of a Master of Science thesis performed in cooperation between Chalmers University of Technology and Volvo Car Corporation in Gothenburg, Sweden. The purpose has been to improve the existing numerical model of the Volvo slotted wall wind tunnel (PVT) with an aim to enable accurate prediction of the primary flow features in the empty wind tunnel. The main goal of this master thesis has been to deliver an updated and improved numerical model of the Volvo slotted wall wind tunnel that enables an accurate correlation of the results from experiments and from Computational Fluid Dynamic (CFD) simulations. A numerous amount of configurations has been simulated with CFD using the solver from ANSYS Fluent with the aim to match the experimental data measured in the Volvo Cars wind tunnel. The main findings were that the flow near the floor is greatly affected by having a proper geometry representation of the basic suction scoop. However, the flow at a distance from the test section floor did not seem to be as affected by this additional geometry. Also, the flow of the PVT tunnel is much more asymmetric than the one generated by the CFD tunnel and this could not be explained by any obvious reason. It was concluded that despite the update of the numerical model, this can still not be considered as an accurate reproduction of the PVT tunnel and more work is needed before it can be implemented as an alternative computational domain in the standard CFD procedure at VCC. Also, it is important to obtain knowledge about which geometry features in PVT that has a significant or no impact on the flow field in the tunnel to be able to accurately reproduce the results from PVT with CFD simulations and to possibly keep the amount of computational cells on a reasonable level. Based on the results obtained during this thesis, the recommendations for future work is to try and scan the test section inlet velocity/pressure profile in the PVT tunnel and implement this as a user defined inlet boundary condition in the CFD tunnel. This could probably provide more information and understanding of the asymmetric flow field present in the PVT tunnel. Because of the fact that it has been shown that both the PVT and the CFD tunnel are sensitive to small geometry changes another recommendation for future work would be to perform a sensitivity analysis of the geometric details and their effect on the PVT flow.
Energi , Grundläggande vetenskaper , Strömningsmekanik och akustik , Hållbar utveckling , Energy , Basic Sciences , Fluid Mechanics and Acoustics , Sustainable Development