Zhang Jilong, Duan Fajie, Niu Guangyue, Jiang Jiajia, Li Jie
State Key Laboratory of Precision Measuring Technology and Instruments; Tianjin University, Tianjin 300072, China.
China Gas Turbine Establishment; Chengdu 610500, China.
Sensors (Basel). 2017 May 11;17(5):1097. doi: 10.3390/s17051097.
Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy.
叶片尖端定时是涡轮机械中测量叶片振动的一种有效方法。这种方法越来越受欢迎，因为它是非侵入性的，并且与传统应变片方法相比有几个优点。已经为叶片尖端定时开发了不同类型的传感器，包括光学、涡流和电容传感器。然而，这些传感器在有污染物或高温的环境中不适用。微波传感器为克服这些限制提供了一种有前景的潜在解决方案。在本文中，提出了一种基于微波传感器的叶片尖端定时测量系统。使用贴片天线探头来发射和接收微波信号。分析了信号模型和处理方法。采用零中频结构来保持定时精度和动态性能，并且接收到的信号还可用于测量叶尖间隙。定时方法利用信号的上升沿和下降沿以及自动增益控制电路来减少叶尖间隙变化的影响。为了验证系统的准确性，将其与光纤尖端定时系统进行了实验比较。结果表明，微波尖端定时系统具有良好的准确性。
