叶尖定时技术在转子叶片故障排除中的应用

Application of blade tip timing technology in rotor blade fault elimination

介绍了基于叶尖定时的非接触振动测试系统的基本原理和数据分析方法,并将之应用于某型航空发动机压气机第5级转子叶片掉块故障分析。通过优化传感器的轴向分布和周向布局,分别测量3类叶片(原型、优化和削角)前缘和尾缘位置高阶振动信息,包括共振转速、频率和幅值。分别对比原型、优化叶片的前缘和尾缘测试结果,每类叶片的前缘和尾缘位置的共振幅值基本一致;对比3类叶片的前缘位置振动参数,优化叶片的共振转速较原型叶片有所增加,削角叶片的共振转速较优化叶片有所增加;对比原型、优化叶片尾缘位置振动参数,优化叶片的共振转速较原型叶片有所增加。可以判断:原型叶片发生疲劳断裂主要原因是其在工作转速4200 r/min出现高阶模态共振现象;优化叶片的共振转速较原型叶片增加40~80 r/min,叶片故障率降低,而削角叶片的共振转速较原型叶片增加140~180 r/min,且对应尾缘位置削角,可以排除叶片掉块故障。

The principle and data processing method of the non-contact vibration measurement system based on blade tip timing(BTT)were introduced,and applied for analyzing losing-corner fault of aero-engine compressor blades of the fifth stage.The axial and circumferential positions of timing-tip sensors were optimized.Leading and trailing edges of three typical blades(original profile,optimized profile and chamfered profile blades)were measured by non-contact vibration measurement,and the natural frequency and magnitude of the whole blades were obtained.Comparing the vibration parameters of the leading edge with the trailing edges of original profile and optimized profile blades,the resonant amplitudes were almost same.Comparing the vibration parameters of the leading edge of three typical blades,the resonance speeds of the optimized profile blades were a little higher than those of original profile blades,and those of the chamfered blades were larger than the optimized profile blades.Comparing the vibration parameters of the trailing edge of original profile and optimized profile blades,the resonance speeds of the optimized profile blades were a little higher than those of original profile blades.It can be judged that the main reason of the original profile blades occurring losing-corner fault was that the blades were resonant at the working speeds of 4200 r/min.The resonant speeds of the optimized profile blades were about 40–80 r/min higher than the original profile blades,leading to the reduction of the losing-corner fault.The resonant speeds of the chamfered blades were about 140–180 r/min higher than the original profile blades,and the fault can be eliminated.