CFD modelling of axial fans for thermal management applications
In CFD multiple methods of varying complexity are available to simulate the fan rotation. The more computational expensive approach, called the Rigid Body Motion (RBM), physically resolves the rotation, while the less expensive approach, called the Multiple Reference Frame (MRF), rotates the air in proximity to a stationary rotor around the blades. In the first study presented in this thesis, the flow field downstream of an axial fan is investigated for these two methods and in addition, a third hybrid approach is also evaluated. The results are compared to experimental data, which were obtained in the Volvo Cars Model-scale Wind Tunnel by using Laser Doppler Anemometry. In the second study, the interaction between the MRF approach and different upstream and downstream conditions were investigated. For this study, a temperature variation upstream of the rotor is introduced, as well as different geometric obstacles up- and downstream.
As a result of the presented investigations it could be confirmed that the RBM approach gives the best representation of the flow field downstream of the fan. The MRF on the other hand showed severe limitations that the users need to be aware of. Especially the rotation of an upstream temperature source, that was found in Paper II, can lead to misleading results of component temperatures. However, when the temperature field is uniformly distributed or of minor importance, the MRF is still the most feasible approach for large applications.
Chalmers, Mekanik och maritima vetenskaper, Fordonsteknik och autonoma system
Validation of Different Fan Modelling Techniques in Computational Fluid Dynamics
Proceedings of the 21st Australasian Fluid Mechanics Conference ,; (2018)
Paper i proceeding
Franzke, R., Sebben, S., Bark, T., Willeson, E., "Evaluation of the Multiple Reference Frame Approach for the Modelling of an Axial Cooling Fan"
Industriell applicerbar simuleringsmodell för hybrid- och elbilar för analys av termodynamisk status i komplett bil
Energimyndigheten, 2016-10-25 -- 2019-12-31.
Strömningsmekanik och akustik
Thesis for the degree of Licentiate – Department of Mechanics and Maritime Sciences: 2019:06
Chalmers tekniska högskola
HA2, Hörsalsvägen 4
Opponent: Mihai Mihaescu, KTH Royal Institute of Technology, Sweden