Noise analysis of sirocco fan using sound transparent wall

Abstract

We performed a noise analysis of a sirocco fan by simulations and experiments using a sound-transparent wall that the pressurized condition is imposed to the impeller. It is obtained that the sirocco fan generates both the noise of DFN and large turbulent noise. The turbulent noise is mainly located from the end of scroll to the exit of scroll casing. The relative velocity and the circumferential variation of it is large about the end of scroll. The leading edge separation is occurred and the separation generates the large pressure fluctuation on the blade surface that the circumferential relative velocity becomes large at the inlet of blade. The sound source is mainly located at the leading edge of the impeller blade from the end of scroll to the exit of scroll casing.