A Numerical Study on the Aeroacoustic of a Vaned Centrifugal Fan

High speed vaned centrifugal fans are widely used in several manufacturing and home appliances. For the designers the noise generated by these machines is one of the most important parameters to be reduced. The centrifugal fan used for this study is made up of an impeller, a diffuser and a return channel. The impeller turns at a relatively high speed about 35000 rpm. The objective of this study is to understand the mechanism of the noise generation within this type of machines. The contribution of the tangential and radial forces is highlighted. These fluctuating forces are due to the unsteady flow at the impeller-diffuser interface. The obtained result shows the effect of monopole and dipole sources on the overall noise.