Abstract
In recent years, it has been discovered that the noise generated from the cooling fan of electric vehicles (EVs) is relatively loud because the level of noise of the motor is lower than that of the engine of the conventional vehicle. Thus, the development of the low-noise fan is urgently required, considering the cooling performance. To accomplish this, it is considerably important to determine the flow structure that generates noise at each frequency level. Thus, the objective of this study is to clarify the relation between the noise generated from the cooling fan and the flow structure around its blades. In particular, a computational method is employed that uses large eddy simulation (LES) coupling with an overset method. The measurement of P-Q characteristics are carried out to validate the predictive accuracy of the simulation. In addition, proper orthogonal decomposition (POD) was employed to analyse the unsteady data obtained by LES calculations to reveal the typical flow structures. In short, this paper describes the possibility of clarification on the relation between the noise generated from the cooling fan and the flow structure around the blades using POD.
KEYWORDS – Engine cooling fan, Computational Fluid Dynamics (CFD), Proper Orthogonal Decomposition (POD)