民机涡扇发动机重吸入特性风洞试验

Wind tunnel test for turbo-fan engine re-ingestion characteristic of civil aircraft

民机在滑跑减速阶段一般会使用发动机的反向推力来提高其减速性能和滑跑安全性,当滑跑速度较低时使用该装置,从发动机排出的向前方喷射的气流存在被发动机重新吸入的可能,该喷流受发动机风扇的压缩做功,喷流的温度比环境温度高,如果此气流被发动机重新吸入,将会导致发动机进气气流的温度畸变,而该畸变将会引起发动机风扇叶片的颤振,影响发动机的寿命和安全性。故对于一个使用涡扇发动机的新型飞机,有必要通过风洞试验来得到其在各工况下的重吸入特性,并且根据其重吸入特性,设定截止使用反推力的滑跑速度。本文主要论述通过风洞试验获得发动机重吸入特性,并且确定反推力使用截止滑跑速度的方法。

For civil aircraft it is common method to use thrust reverser to improve the deceler- ation and the safety during landing run. However, if the ground running speed of the aircraft is too low, the forward moving plume flow can be re-ingested by the engine. The temperature of the plume flow is much higher than ambient temperature since it gains energy from fan compressor. As a result the re-ingestion may lead to the temperature distortion for inlet flow causing the flut- ter of the fan blade, thus harming the engine life and safety. Therefore, for a new turbo-fan air- craft it is necessary to obtain the re-ingestion characteristic of the engine through wind tunnel test in order to determine the turn-off speed limit for thrust reverser. This paper mainly states the method to get the A/C＇s re-ingestion characteristics from the wind tunnel test and acquire the thrust reverser cut-off taxiing speeds.