Reduction of Tonal Noise in a Centrifugal Fan using Guide Vanes

Regular paper

Kishokanna Paramasivam

MJIIT, Universiti Teknologi Malaysia

Wednesday 3 june, 2015, 15:00 - 15:20

0.3 Copenhagen (49)

This study investigates the effects of diffuser vane on the aeroacoustics characteristics of a centrifugal fan. It is well known that tonal noise is the dominant noise source generated in the centrifugal fan is due to the aerodynamic interaction between rotating impeller and stationary diffuser vane. The tonal noise occurs due to pressure fluctuation that is related to the rotating speed. The tonal noise is periodic in time where it consists of the blade passing frequency (BPF) and its harmonics. Analysis on the experiment and numerical simulation results have shown that the stationary diffuser vane causes the generation of tonal noise and generation of non- rotational turbulent noise. On the other hand, omitting diffuser vanes leads to increase of non-rotational turbulent noise resulting from the high velocity of the flow leaving the impeller. Hence in order to reduce the tonal noise and the non-rotational noise, guide vanes were designed replacing the diffuser vanes. The behavior of the fluid flow was studied using computational fluid dynamics (CFD) tools and the acoustics characteristics were determined through an experiment in an anechoic chamber

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