Reduction of Tonal Noise in a Centrifugal Fan using Guide Vanes
Regular paper
MJIIT, Universiti Teknologi Malaysia
Wednesday 3 june, 2015, 15:00 - 15:20
0.3 Copenhagen (49)
Abstract:
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