Proceedings of the 10th Convention of the
European Acoustics Association
Forum Acusticum 2023


Politecnico di Torino
Torino, Italy
September 11 - 15, 2023





Session: A01-05: Active metamaterials
Date: Friday 15 September 2023
Time: 11:00 - 11:20
Title: Electro-active acoustic liner for the reduction of turbofan noise
Author(s): É. Salze, École Centrale de Lyon, LMFA, 36 avenue Guy de Collonge, 69130 Écully, France
E. De Bono, Université Bourgogne Franche-Comté, FEMTO-ST, 24 rue de l'Épitaphe, 25000 Besançon, France
K. Billon, École Centrale de Lyon, LTDS, 36 avenue Guy de Collonge, 69130 Écully, France
M. Gillet, Université Bourgogne Franche-Compté, FEMTO-ST, 24 rue de l'Épitaphe, 25000 Besançon, France
M. Volery, EPFL, Route Cantonale, 1015 Lausanne, Switzerland
M. Collet, École Centrale de Lyon, LTDS, 36 avenue Guy de Collonge, 69130 Écully, France
M. Ouisse, Université Bourgogne Franche-Compté, FEMTO-ST, 24 rue de l'Épitaphe, 25000 Besançon, France
H. Lissek, EPFL, Signal processing laboratory LTS2, acoustic group, Sation 11, 1015 Lausanne, Switzerland
J. Mardjono, Safran Aircraft Engines, Rond-point René Ravaud, 77550 Moissy-Cramayel, France
Pages: 6057-6060
DOI: https://www.doi.org/10.61782/fa.2023.0558
PDF: https://dael.euracoustics.org/confs/fa2023/data/articles/000558.pdf
Conference proceedings
Abstract

In this paper, an electro-active acoustic liner is used to lower the noise emissions of a turbofan engine. The liner is composed of an array of electro-acoustic absorbers covered by a wiremesh in order to protect the electrodynamic devices from the flow. The electro-active liner is operated using a pressure-based and current-driven control architecture, for the synthesis of specific acoustic impedances. The control strategy is either local or non-local.

Experiments are performed in the PHARE-2 test-rig at École Centrale de Lyon, representative of a real turbofan engine at the laboratory scale. Upstream and internal microphone arrays are used for the upstream noise emission measurements, and for the modal decomposition in the engine duct, respectively. Using a local control strategy, the obtained results underline the efficiency of the proposed concept on both tonal and broadband noise for a large range of operating points of the turbofan engine. Using a non-local strategy, non-reciprocity with respect to the azimuthal direction has also been shown for tonal noise with a predominance of contra-rotating modes.