Electro-active acoustic liner for the reduction of turbofan noise

Abstract

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. Experiments are performed in the PHARE-2 test-rig at École Centrale de Lyon, representative of a real turbofan engine at the laboratory scale. 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, including transsonic conditions.