Investigations on noise sources on a contra-rotating axial fan with different modifications

Abstract

An Acoustic Camera was applied to examine modifications of fan blade designs regarding their noise emissions. A so-called rotational beamforming algorithm allows for the detection of sound sources on the rotating blades by using a virtual rotation of the microphones. Depending upon the frequency different sources could be localized. Both the leading and the trailing edge were modified. This paper shows the performed modifications and tests with the Acoustic Camera. It also presents first results and gives an outlook on future work.

Sound source localisation at an axial contra-rotating fan by means of PIV and rotational beamforming

“…The camera in the centre of the ring array allows the concentric alignment of the ring array with the fans axis of rotation. The measurements are carried out as described by Krause et al (2018) at a test stand complying with ISO 5081 (2008). Category C is selected as mode of installation, implying that there is a pipe at the suction side and a free outlet at the pressure side of the fan.…”