Inlet Gap Effect on Tonal Noise Generated from a Voluteless Centrifugal Fan

Abstract

In this study, three voluteless centrifugal fans are compared for their aeroacoustic performances. The tonal noise is predicted by coupling the IDDES with Formulation 1A of Farassat. The sources of the tonal noise at the blade passing frequency (BPF) are identified. It is found that the sources are related to the fan inlet gap, which introduces higher velocity intensities and turbulent fluctuations interacting with the blade leading edge. By redesigning the gap, the tonal noise at the BPF is reduced effectively.