ターボファンエンジン騒音低減対策に関する研究

ポリアミド系フェルトの適用

抄録

The acoustic treatment for noise reduction of turbofan engine is mainly installed to the internal wall of fan duct and absorbs the noise which is propagating thrum the duct.
In the case of high bypass ratio turbofan engine for the aircraft, peak frequency of fan noise depends on engine rotational speed and resonate type acoustic treatment modulated for take off rating is usually not effective for approach ratmg.
From this reason, the broad band homogeneous type acoustic treatment is required, and author is studying to utilize the polyamid felt for acoustic treatment for this purpose.
Test result showed that this kind of broad band treatment is effective for both take off and approach in reduction of fan noise, and durability of this felt is also demonstrated in the actual engines.