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

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