Abstract: Blade tip clearance and blade vibration are important parameters which affect the efficiency, operation safety and life span of turbomachinery. To meet the requirements of blade tip clearance and tip timing measurement under harsh working environments such as aircraft engine, a tip parameter measurement system based on microwave method is proposed, and the system can achieve the measurement of tip clearance and tip timing simultaneously. The system structure and measuring principle is analyzed. Microwave sensors of 24GHz based on microstrip antenna and PIFA are designed, the diameter of the sensor is less than 8mm. The sensors and measurement system prototype are tested in experiment and compared with the fiber optic tip timing system, the result indicates that the microwave measurement system can realize the dynamic measurement of blade tip clearance and tip timing, the measurement accuracy of tip clearance is ±35μm.

Key words: Blade tip clearance, blade tip timing, microwave sensor

摘要： 叶尖间隙和叶片振动是影响涡轮机工作效率、安全和寿命的重要参数，叶尖定时是目前广泛应用的非接触式叶片振动测量方法。传统的光学等叶尖参数测量方法难以实现实际工况下的长时间测量,为满足航空发动机等恶劣工作条件下的叶尖间隙和叶尖定时测量要求，提出了一种基于微波传感器的叶尖参数测量系统，实现叶尖间隙和叶尖定时的同时测量，分析了系统组成和测量原理，设计了采用微带天线的24 GHz的微波传感器以及采用金属结构PIFA的微波传感器，传感器直径在8 mm以内。对制作的传感器和测量系统样机进行了实验测试，并与已有的光纤式叶尖定时测量系统进行对比，结果表明基于微波传感器的测量系统能够有效实现叶尖间隙和叶尖定时的动态测量，叶尖间隙测量精度为± 35μm。

关键词: 叶尖间隙, 叶尖定时, 微波传感器