Measurement of Vehicle Cooling Fan Air Flow using Laser Doppler Anemometry
Examensarbete för masterexamen
Applied mechanics (MPAME), MSc
When a combustion engine in a vehicle is operating it generates large amount of heat. Therefore it is crucial to provide cooling in the engine bay to prevent components from overheating. The axial fan in the front of the engine bay is a very import component of the cooling procedure, since it drives fresh air through the heat exchangers into the engine bay. To study the behaviour of the cooling air ow in the engine bay, numerical simulations are commonly used today, but in order to verify and develop numerical tools, physical testing is needed. In this thesis, LDA has been used to investigate how the actual ow eld behaves in the wake of a circular cylinder and the cooling fan used in a Volvo V40. Laser Doppler Anemometry, LDA is a non-intrusive optical technique used for velocity measurements of turbulent and laminar ows. The measurements were performed in the model scale wind tunnel at Volvo Cars. From the cylinder measurements, the performance of the experimental equipment could be con rmed to yield precise results. The downstream ow behaviour of the fan was investigated for cases with different contributions of wind tunnel velocity and fan rotation speed. Results of the downstream velocity eld in all three directions are presented at different distances downstream of the fan. Furthermore, the in uence of the mesh resolution on the measured velocity elds is shown and discussed. Lastly, a spectral analysis of the vortex shedding downstream the blade span was performed.
Strömningsmekanik och akustik , Grundläggande vetenskaper , Innovation och entreprenörskap (nyttiggörande) , Transport , Fluid Mechanics and Acoustics , Basic Sciences , Innovation & Entrepreneurship , Transport