Abstract: In order to detect and identify the foreign object impact events of fan in the process of aero-engine operation， a non-contact tip vibration measurement system was used to collect and detect the vibration displacement of fan blade tip in real time. According to the statistical analysis on non-contact blade tip vibration displacement data of fan， it is found that vibration displacement of fan blade tip obeys normal distribution， which is proved by Epps-Pulley hypothesis test. Based on the statistical characteristics， an algorithm for detecting the vibration displacement of the blade tip impacted by the foreign object is designed. Meanwhile， with this method， the detection threshold of the vibration displacement of blade tip impacted by the foreign object is obtained at different rotational speeds of the fan. The vibration displacement data of the projectile with the diameter of 16mm and the mass of 2.9g impacting on a fan blade at the rotor speed of 3000r/min are analyzed. Furthermore， the reliability of the identification result is verified by a high-speed camera system. The results show that the detection method based on statistical characteristics can accurately identify the event of foreign object impacting the fan blade and the number of the impact blade.

Key words: Aero-engine;Foreign object impact;Blade tip vibration;Non-contact measurement;Statistical characteristics;On-line detection

摘要： 为了检测识别航空发动机工作过程中的风扇外物撞击事件，采用非接触叶尖振动测量系统对风扇叶片叶尖振动位移进行实时采集与检测。通过风扇叶片非接触叶尖振动位移数据统计分析，发现叶尖振动位移服从正态分布，并采用Epps-Pulley假设检验证明。设计了基于统计特征的风扇叶片外物撞击叶尖振动位移检测算法，采用该方法获取了风扇转子不同转速下外物撞击叶尖振动位移检测阈值。对风扇转子转速为3000r/min状态下，直径16mm、质量为2.9g的外物弹体撞击风扇叶片的振动位移数据进行分析，并采用高速摄像系统对该方法识别结果的可靠性进行验证。结果表明：基于统计特征的发动机风扇外物撞击检测方法，能够准确识别外物撞击风扇叶片事件及发生撞击的叶片编号。

关键词: 航空发动机;外物撞击;叶尖振动;非接触测量;统计特征;在线检测