Abstract: Aiming at the investigation of internal flow and acoustic characteristics of multi-wing power frequency centrifugal fan with twisted impeller, the effects of different impeller twists on the aerodynamic performance of multi-wing centrifugal fan were studied. Firstly, the CFD calculation model of centrifugal fan was established, and the verification test of centrifugal fan flow total pressure efficiency performance curve was carried out; and then the fan performance data, velocity streamline diagram and reflux vorticity at A and B with different twist parameters were calculated by fluent; finally, based on FW-H equation, the sound pressure spectrum with different impeller twist was analyzed, and the 1/3 octave frequency spectrum of centrifugal fan with different impeller twist was analyzed.The results show that the total pressure efficiency of twisted impeller fan is 7.75% ~ 8.07% lower than that of straight impeller fan, and there is the phenomenon of the de eccentric vortex; twisted impeller can reduce the formation of eddy current and effectively reduce the fan noise. At the fundamental frequency of 1300Hz, the noise of 3 °, 6 ° and 9 ° twisted impeller fan is reduced by 0.06 dB, 1.15 dB and 8.35 dB respectively. It can be seen that the twisted impeller can be applied to the noise reduction design of a multiwing centrifugal fan.

Key words:  centrifugal fan; impeller twist; aerodynamic noise; fan performance; internal flow characteristics; noise reduction