Reduction of noise from centriugal fans

Research Project, 2017 – 2022

BACKGROUND

Modern ventilation systems are often driven by isolated centrifugal fans which produce tonal and broadband noise. Exposure to tonal noise for a long-term can affect human bodies. It affects autonomous and hormonal systems in the body, which can lead to diseases such as high blood pressure, hearing  loss and cardiac arrest. Also, mental disorders  such as aggressiveness and mood swings [1][2]. The broadband noise can be decreased when the fan efficiency is optimized. However, the tonal noise is difficult to reduce.

The flow-induced interior noise for vehicles is mainly generated due to vibration of glass windows. The vibration can be excited by exterior turbulent flows that are developed from A-pillars and side-view mirrors as well as other accessories upstream of windows. It can also be excited by the exterior noise that is emitted from the turbulent flows. The research field on the flow-induced interior noise is aero-vibro-acoustics. However, as an innovative research filed, numerical and experimental tools and
methodologies are not matured to date.

THE PROJECT

The aim of this project is to investigate the tonal noise from an isolated centrifugal fan, with unsteady RANS and Detached Eddy Simulation. We will develop a numerical method to predict and minimize fan tonal noise. The benefits are the energy saving in the ventilation system due to less pressure
drop of silencers and healthier humans, because of the decrease of tonal noise.

A blog discussing practical issued can be found here

http://blog.swegon.com/sv/hemligheten-bakom-en-halsosam-ljudmiljo#

http://blog.swegon.com/sv/finns-det-halsofarliga-ljud-i-vanliga-vistelsemiljoer#