Noise attenuator, eg for turbofan engine air bleed system

摘要

Noise attenuator, especially for an aircraft turbofan engine air bleed system, comprises a perforated attenuator plate (16) extending over the outlet of an air bleed valve (1) and an intermediate attenuator plate (20) upstream of the first. The intermediate plate (20) is domed and spaced from the valve outlet (26) to balance air flow through the plates. The intermediate plate (20) may have peripheral notches or serrations.