Analysis of Noise Characteristics of Centrifugal Impeller by Transparent Wall

Abstract

Acoustic characteristics of centrifugal impeller was investigated in experiments by using the transparent wall. It is cleared that the transmittance of the transparent wall is gradually decreased with the pressure increment. And the variation of the transmittance is different with the sound frequency. By using the transparent wall, the sound source characteristics of the fan is cleared in upstream and downstream radiation. The large sound distribution at the inlet section is moved with the impeller rotation. The large sound distribution at the outlet of the impeller is moved with the impeller rotation, but the speed of it very larger than the rotating speed of impeller.