Effect of circumferential forward-skewed blade on aeroacoustic performance of axial fan

Low pressure axial fan with forward-skewed rotor blade was studied.The relationship between sound pressure level and flow rate and 1/3 octave spectrum at design condition was obtained through aerodynamic noise experiment.The effects of blade forward skew angle on aerodynamic noise were analyzed.The distributions of wake width at outlet of rotors were obtained from simulation.The effects of blade forward skew angle on wake width were also analyzed.The results show that,with the increase of blade forward skew angle,the wake width declines and then increases,leading to similar relationship curves between aerodynamic noise measurement data and flow rate.The lowest aerodynamic noise occurs at forward skew angle between 6° and 8°.The difference of aerodynamic noise among the rotors occurs mainly at frequency zone between 300 Hz and 4 000 Hz.