Conference_programme: 2.1 - Aeroacoustics
Lecture: Experimental Investigation of the Aeroacoustics of Cross Flow Friction Ventilators
Author(s): Renz Andreas, Becker Stefan
Summary:
A friction ventilator is a special type of fan which is suited for constricted installation spaces and acoustically sensitive applications. The rotor of such a ventilator consists of multiple circular discs which are mounted equidistantly on a driven shaft and with their rotating axis perpendicular to the main flow direction. The discs are encased by an 180° elbow with a rectangular cross section which connects an inlet to an outlet duct. The two parallel ducts share a duct wall which ends with a contactless sealing element towards the rotor to separate the ducts from another. Air flowing through the system impinges the discs in tangential direction, is then guided by the 180° elbow along the rotating discs before leaving the rotor towards the outlet duct in tangential direction. Regarding the energy transfer from the rotor to the fluid, there is a fundamental difference to conventional turbomachinery, as the transfer is solely based on the aerodynamic drag between the rotating discs and the fluid. A friction ventilator has two distinctive advantages compared to axial or radial fans. First is the non-axial direction of inflow, which enables a variety of installation possibilities. Secondly there is a very low aeroacoustic noise emission due to the missing of periodic rotating pressure fluctuations from rotating fan blades. The investigation included the measurement of the flow field, the acoustics and the aerodynamic characteristics of different rotor geometries. The measurement of the aeroacoustics emission of the rotors showed the predicted low overall sound pressure levels without tonal components. The performed LDA measurements focused on the flow field between the rotating discs and downstream of the rotor to investigate the occurring aerodynamic losses. Overall the investigation showed the suitability of the concept and lead to further improvements in rotor and duct geometry.
Corresponding author
Name: Mr Andreas Renz
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Country: Germany
