基于参考键相动态追踪的无转速叶尖定时测量方法

Blade tip timing measurement method without once-per-revolution sensor based on dynamic tracking of reference key phase

针对叶尖定时系统在测量转子叶片振动过程中转速同步传感器安装困难的问题,提出基于参考键相动态追踪的叶尖定时测量方法。假设整级转子叶片间存在随机失谐,则在变转速工况下各叶片并非同时达到共振状态,在每转内,利用各叶片到达传感器的实测到达时间,计算叶片在相邻叶尖定时传感器间的局部平均转速与转子整圈平均转速的偏差值,判断同级所有叶片的振动状态,选择几乎不振动的叶片作为该圈的参考键相,计算目标叶片在该圈的振动位移值,依此类推,计算各圈目标叶片的振动位移,实现转子叶片在无转速参考下的非接触式振动测量。试验验证结果表明,与传统叶尖定时方法相比,利用该方法计算出的叶片振动位移所辨识出的叶片振动频率相对误差小于0.2%,振动位移相对误差小于10%,说明基于参考键相动态追踪的叶尖定时测量方法不仅能在无转速参考的情况下准确计算出叶片的振动位移,更能准确地辨识出叶片振动参数。

To overcome the difficulty of mounting the once-per-revolution sensor to detect rotor blade vi⁃bration,a novel method for blade tip timing measurement based on dynamic tracking of the reference key phase is proposed.Assuming that there is a random mistuning among the blades of the full-stage rotor,the blades would not resonate at the same time under the condition of variable speed.In each revolution,by using the measured ar⁃rival time of each blade,the difference between the local average speed of the blades between adjacent blade tip timing sensors and the average speed of the rotor in the whole revolution is calculated.The vibration state of differ⁃ent blades is determined,and the blade with almost no vibration is selected as the reference key phase of the revo⁃lution,and the vibration displacement value of the target blade in the revolution is calculated.Similarly,the vi⁃bration displacement of the target blade in each revolution is calculated,and the non-contact vibration measure⁃ment of the rotor blade is realized without the once-per-revolution sensor.The experimental validation results demonstrate that,in comparison to the traditional blade tip timing method,the relative error in identifying the blade vibration frequency using the blade vibration displacement calculated with this method is less than 0.2%,and the relative error in the vibration displacement is found to be less than 10%,which indicates that the blade tip timing measurement method based on dynamic tracking of reference key phase can not only accurately calcu⁃late the blade vibration displacement without once-per-revolution sensor,but also accurately identify the blade vibration parameters.