Numerical evaluation of the aerodynamic and noise characteristics of an axial flow fan in a large aeroacoustic wind tunnel

This study numerically investigates the flow field and aerodynamic performance of the axial fan system in the 4 m × 3 m low-turbulent and aeroacoustic wind tunnel of Beihang University (BHAW). A hybrid CFD/ACTRAN approach is employed to evaluate the aerodynamic noise characteristics of the fan. The axial fan is designed using an arbitrary vortex blade row method with a vortex index of 0.85, calibrated with cascade data. The final configuration consists of 16 rotor blades and 7 counter-swirl stator vanes. The rotor uses GOE797 airfoils (16% relative thickness) at the root and GOE796 airfoils (12% relative thickness) at the tip, while the stator vanes uniformly adopt the C4 airfoil (12% relative thickness). Numerical results agree well with experimental measurements: at the design speed of 310 r/min, the deviation in flow rate is less than 2.3%, and motor power output deviation is below 4.6%. The simulated total pressure rise is 2364.9 Pa, showing a 3.4% deviation from the design value. Flow field analysis confirms well-preserved axial flow without separation across all operating conditions. Acoustic evaluation shows that at 310 r/min, corresponding to a maximum test-section speed of 80 m/s, the overall sound pressure levels measured at 10 m from the inlet and outlet are 124 dB and 123 dB, respectively. The discrete noise at the fundamental frequency of 82 Hz reaches 115 dB at the inlet and 113 dB at the outlet, meeting the low-noise design objectives.