基于叶尖定时的航空发动机压气机叶片振动测量

Vibration measurement on compressor rotor blades of aero-engine based on tip-timing

基于叶尖定时的转子叶片非接触振动测试系统的基本原理和数据分析方法,将非接触振动测量技术成功应用在某型涡扇发动机高压压气机一级转子叶片排故(改型)中,获取叶片共振时的振动频率和幅值,并通过有限元分析方法得到叶尖位移与关键点的位移-应力换算系数。依据反算的关键点动应力可实现(改型)前后转子叶片的高周疲劳寿命预测。某型涡扇发动机高压压气机一级转子叶片非接触振动测试结果显示:由于加工工艺原因导致原型叶片叶型厚度变大,引起叶片固有频率升高,转子叶片在发动机工作转速范围内发生3阶激励激起的一弯振动,导致叶片发生故障。改进加工工艺后,非接触振动测试系统结果显示叶片振动状态较好。

The theory and data processing method of the non-contact vibration testing system based on blade tip timing were introduced.The system was successfully applied in the blade vibration measurement on the first stage of rotor blades of a turbo-fan engine high pressure compressor,and the blade tip amplitudes and frequencies of the whole blades at resonance were obtained.The displacement-stress conversion ratio from blade tip magnitude to the critical points stress was calculated by the finite element analysis.The vibration character of the whole blades was obtained through the non-contact vibration testing system of the turbo-fan engine.As the thickness of prototypical blades was enlarged by the processing technology,the blades were resonated in the working speed caused by the engine order of 3,which led to the failure of the blades.The vibration character of remodelled blades is very well after promotion of processing technology.