Noise reduction in the inlet of stationary gasturbines or aeroengines is usually achieved by passive absorbers (acoustic liners) the efficiency of which is limited due to the confined length. Higher sound level reductions can be obtained - in particular for the tonal components - by using additionally active noise control techniques (ANC): The rotorspeed-coherent tonal components of the primary sound field are superimposed with an anti-phase sound field which is produced by secondary acoustic sources. In the present investigation, which is supported by the German Ministry for Research and Technology (BMBF) within the framework of AG Turbo Turbotech II, the ANC-technique was applied to a scale model of a counter-rotating propfan which was run on the compressor test stand of the MR in Cologne. The model rotor diameter of 1 m allows mounting of a sufficiently large number of loudspeakers in order to control the complex modal content of the primary sound field. ANC was performed in the inlet duct of the fan model, using 32 microphones as error-sensors and 32 loudspeakers as secondary sources, driven by a 32-channel controller provided by DC-FT. The multi-channel control algorithm is described in detail. The sound fields in the inlet duct with and without ANC were measured by using 96 microphones mounted flush with the inner duct wall. The results of azimuthal and radial mode decomposition techniques are presented.
Active control of fan noise from high-bypass ratio aeroengines: experimental results
Aktive Regelung des Bläsergeräusches von Flugmotoren mit hohem Nebestromanteil: Experimentelle Ergebnisse
2000
8 Seiten, 8 Bilder, 7 Quellen
Aufsatz (Konferenz)
Englisch
Active control of fan noise from high-bypass ratio aeroengines: Experimental results
Online Contents | 2002
|Active control of fan noise from high-bypass ratio aeroengines: A numerical study
Online Contents | 2001
|Active control of fan noise from high-bypass ratio aeroengines: a numerical study
Tema Archiv | 2000
|Active Control of Fan Noise from High-Bypass Ratio Aero Engines: Experimental Results
British Library Conference Proceedings | 2001
|Containment of high-energy fragments in aeroengines
British Library Conference Proceedings | 1998
|