Influence of the environment on the aeroacoustic behavior of axial fans

The work presented here forms part of a very broad specific action undertaken in the LEMFI (Laboratoire d'Energetique et de Mecanique des fluides interne) concerning the unsteady flows in compression turbo machinery in general and the aeroacoustic of fans in particular. The principal objective is the determination of the influence of the environment on the acoustic and aeraulic behavior of axial fans. After an analysis of the various sources of noise existing in turbo machinery, our centre of interest was focused on the influence of the distortion of the velocity field on the suction caused by the absence of a centre fairing and a shaped inlet. This will make it possible to confirm the effect of the level of turbulence on the generation of noise and in particular of broad band noise.