基于叶尖定时的航空发动机涡轮叶片振动测量

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

介绍了基于叶尖定时的非接触振动测试系统应用于涡轮转子叶片的技术瓶颈,突破高温传感器结构设计、安装以及冷却等技术难点,通过设置系统触发信号保持时间,解决H型涡轮转子叶片对叶尖定时信号的二次触发问题,并给出核心机状态下转速基准实现方法。将非接触振动测量技术成功应用在某型涡扇发动机高压涡轮转子叶片振动监测中,有效获取涡轮转子叶片共振时的振动频率和幅值,并与应变计测量叶根动应变结果进行比对。结果显示:基于叶尖定时的非接触振动测试系统和接触式动应力测试系统均可监测涡轮转子叶片振动,成功辨识转子叶片8 200 r/min时的12阶激励阶次激发的一弯振动模态,两种分析方法识别共振频率相对误差在4%以内。

The difficulty of vibration non-contact measurement of the turbine rotor blade based on tip-timing was introduced. Breakthrough progress was made on the structure design, the installation on the casing and the cooling strategy of high temperature optical tip-timing sensor. The timing signal of H profile of turbine blades was acquired by setting signal hold time of the system for avoiding the secondary trigger, and a method of determining the revolution speed for the blade tip-timing system was proposed for core-engine. Such a tip-timing system was successfully used in the vibration monitoring of the turbine blades of core engine. The tip magnitudes and natural frequencies of the blades were successfully determined by the tip-timing system, and compared with the dynamic strain results from the traditional strain gage. The comparison results demonstrated that the non-contact measurement based on tip-timing and the contract measurement based on strain gage can successfully identify the vibration of turbine blades. The 1 st bending mode of the turbine blades at about 8 200 r/min on was caused by engine order of 12. The relative error of the two methods in determining the 1 st bending natural frequency of blades was less than 4%.