基于多键相的变转速下旋转叶片振动监测方法

为了解决传统的叶尖定时技术在变转速条件下难以有效监测到叶片振动信息的问题,提出了一种基于多参考键相的变转速下叶片振动监测方法,即在转轴上均匀布置多个键相参考点,实现转速的精确估计,同时在参考键相间按照所囊括叶片数量插入虚拟参考点,以虚拟参考点为标记实现变转速下叶片振动的测量,该方法同样适用于恒转速下叶片振动的测量。基于所提方法推导了变转速状态下叶片振动测量的表达方程,并通过数值建模和实验仿真验证了该方法的可行性和适用性,分析结果表明:基于多键相的变转速下旋转叶片振动监测方法与传统方法相比,平均相对测量误差从200%以上降至7%以下,突破了叶尖定时技术在变转速下难以测量的技术瓶颈。

A multi-phase based vibration monitoring method for rotating blade at variable speed

The traditional blade tip timing(BTT)technique cannot monitor the blade vibration information effectively under the condition of variable speed.In order to solve this problem,a new blade vibration monitoring method based on multiphase at variable speed was proposed in this paper.In this method,interphase reference points are arranged evenly on the rotating shaft to estimate the rotation speed accurately.In the meantime,some virtual reference points are inserted between these multi-phase according to the number of involved blades,and they are used as markers to measure blade vibration at variable speed.This method is also applicable to the measurement of blade vibration at constant rotation speed.Then,the formula of blade vibration measurement at variable rotation speed was deduced based on this method.Finally,the feasibility and applicability of this method were verified by means of numerical modeling and experimental simulation.It is shown that the average relative measurement error of this multi-phase based vibration monitoring method for rotating blade at variable speed is lower than 7%while that of the traditional method is above 200%.Obviously,this new method breaks through the technical bottleneck of BTT technique which cannot monitor the blade vibration at variable speed.