CONTROLLED INFLOW CONDITIONS FOR RADIAL FANS - AN AEROACOUSTIC RADIAL FAN TEST RIG

Czwielong F, Uffinger T, Becker S (2023)

Publication Type: Conference contribution

Publication year: 2023

Publisher: European Conference on Turbomachinery (ETC)

Conference Proceedings Title: 15th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics 2023, ETC 2023

Event location: Budapest HU

Abstract

Radial fans are a common type of machine used in ventilation and air conditioning systems. As well as moving air and creating a pressure increase, the radial turbomachine also emits noise, which is often perceived as disturbing by people in the vicinity. The sound generating mechanisms within the centrifugal blower are complex and often overlapping. As a result, it is difficult to isolate the individual mechanisms. Many of the sound generation mechanisms depend on the inflow to the centrifugal fan, which is usually very inhomogeneous and difficult to control, making it even more difficult to separate the sound mechanisms. In order to better understand the acoustic and fluid mechanical interactions in the centrifugal fan, a new type of dedicated aeroacoustic centrifugal fan test rig has been developed. The test rig can be used to acoustically quiet the inflow of the radial fan and to modify the inflow of the fan. In the future, this will allow a better understanding of the aeroacoustic sound sources of centrifugal fans and their dependence on the flow field. This paper presents the novel test rig and the different inflow conditions. Using an integrated telemetry system, it is possible to determine the pressure fluctuations in the rotating system on the fan blades. This allows a correlation to be made between the inflow conditions, the blade pressures and the far field sound emission. Flow fields with azimuthal, radial and axial velocity gradients were analysed as inflow conditions to the impeller. This distinguishes the test rig from other centrifugal fan test rigs, which usually use undefined inflow conditions from a large chamber. It was found that transient pressure fluctuations in the rotating system at the blade surface could provide new insights into the far-field sound emission of the machine. It was possible to establish a direct link between the flow phenomena at the fan blades and the sound pressure spectra in the far field. The initial investigations confirm the unique investigative capabilities of the novel test rig.

Authors with CRIS profile

Felix Czwielong Lehrstuhl für Strömungsmechanik Thomas Uffinger Lehrstuhl für Prozessmaschinen und Anlagentechnik Stefan Becker Lehrstuhl für Strömungsmechanik

How to cite

APA:

Czwielong, F., Uffinger, T., & Becker, S. (2023). CONTROLLED INFLOW CONDITIONS FOR RADIAL FANS - AN AEROACOUSTIC RADIAL FAN TEST RIG. In 15th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics 2023, ETC 2023. Budapest, HU: European Conference on Turbomachinery (ETC).

MLA:

Czwielong, Felix, Thomas Uffinger, and Stefan Becker. "CONTROLLED INFLOW CONDITIONS FOR RADIAL FANS - AN AEROACOUSTIC RADIAL FAN TEST RIG." Proceedings of the 15th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics 2023, ETC 2023, Budapest European Conference on Turbomachinery (ETC), 2023.

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