Comparative Study of the Aeroacoustic Behavior of Two Axial Flow Fans With Different Sweep Angles

The purpose of this study is to determine the effect of the sweep angle used in axial flow fans on their aerodynamic and acoustic behavior. To do so, two fans, having the same aerodynamic characteristics, were designed with forward and radial sweep angles. The 3D numerical simulation allowed obtaining steady and unsteady loading on the blades. Instantaneous velocity profiles, located downstream of the fans, will be presented and compared to the experimental data. The Ffowcs Williams & Hawkings formulation was used to model the acoustic spectra. The results from CFD simulation (acoustic rotating dipole) were used as input data for the acoustic modeling. Predicted and measured acoustic spectra will be presented. It was found that the forward fan has a uniform radial distribution of kinetic turbulence. Also, the three downstream velocity components have better radial distributions. This result was confirmed by the experimental and predicted aeroacoustic results.