基于微带天线的动叶片叶尖间隙和定时参数测量方法研究

Rotor blade is the core working component of large rotating machinery, and its operation state parameters directly affect the work of equipment performance and operation safety. The online measurement of tip clearance and vibration parameters under high temperature is the key to ensure the performance and operation safety of equipment. This project intends to develop a novel method which measures the tip clearance and tip timing parameters (time of arrival) at the same time based on microstrip antenna, using the phase information of microwave reflection signal to solve the tip clearance, and the strength information to solve the time of arrival of the blades. This project builds the models of microstrip antenna structure and the coupling with end face reflection, analyzes the effect of the material parameters changes on the performance of microwave sensor under limited structure and high temperature environment and realizes its optimal design; the orthogonal demodulation, arctangent algorithm and the transmission path phase compensation are used to realize the accurate measurement of phase difference; to overcome the shortcomings of the low quality of the demodulated phase signal and eliminate the effect of the reflection signal by the sensor end face, a measurement method is proposed to realize the high precision measurement of the time of arrival of blade tip, which uses the orthogonal demodulation to obtain the strength information of reflection signal and uses both edges of the signal to calculate the time of arrival; the carrier frequency adaptive adjustment method is introduced to track the minimum standing wave point of the antenna, thus improving the resistance of the sensor parameters to temperature drift; the project develops the rotor blade tip clearance and tip timing parameters measurement system, and makes the calibration , the evaluation and test of system performance.

动叶片作为大型旋转机械的核心做功元件，其运行状态参数直接影响设备的工作性能及运行安全，高温下叶尖间隙和振动参数的在线测量是保证设备工作性能和运行安全的关键。本项目拟发展一种基于微带天线的动叶片叶尖间隙和定时（到达时间）参数同时测量新方法，利用叶尖微波反射信号相位信息求解叶尖间隙，并利用反射信号强度信息求解叶片到达时间。建立微带天线结构及端面反射耦合模型，研究受限结构及高温环境下材料参数变化对微波传感器性能的影响，实现其优化设计；基于正交解调、反正切算法及传输路径相位补偿技术实现相位差的准确测量；为克服相位信号边沿质量不高的缺点，消除端面反射信号的影响，提出一种通过正交解调反射信号强度信息，并采用双边沿联合检测的方法，实现叶尖到达时刻的高精度测量；引入载波频率自适应调整方法，跟踪天线最小驻波点，提高传感器抗温漂的能力；研制动叶片叶尖间隙及定时参数测量系统，并进行系统标定及性能测试评价。

动叶片作为大型旋转机械的核心做功元件，其运行状态参数直接影响设备的工作性能及运行安全，高温下叶尖间隙和振动参数的在线测量是保证设备工作性能和运行安全的关键。本项目拟发展一种基于微波传感的动叶片叶尖间隙和定时（到达时刻）参数同时测量的新方法，利用叶尖微波反射信号相位信息求解叶尖间隙，利用反射信号强度信息求解叶片到达时间。基于正交解调、反正切算法及传输路径相位补偿技术实现微波相位差的准确测量，进而实现基于微波相位差的叶尖间隙高精度测量；为克服相位信号边沿质量不高的缺点，消除端面反射信号的影响，利用微波正交解调信号平方和实现反射信号强度信息的提取，并采用双边沿联合检测方法，实现基于微波反射信号强度信息的叶尖到达时刻高精度测量。建立微带贴片天线结构及开口谐振腔结构的传感器模型，利用电磁场仿真软件和热场仿真软件研究受限空间及高温环境对微波传感器天线形式、尺寸、材料、方向性、耐高温等性能特征的要求。研究微波传感器高温制作工艺，提出基于高抗补偿的微波传感器高温过渡段设计方法以消除同轴线缆对传感器端面耐1300℃高温性能的约束。设计耐高温和结构小巧的微波传感器结构，研制耐高温开口谐振腔式微波传感器，开展传感器耐高温性能评价，实验结果表明，传感器具有耐1300℃高温的能力。研制基于微波传感的动叶片叶尖间隙及定时参数测量系统，开展系统标定及性能测试评价，实验结果表明，叶尖间隙测量范围可达0.5-6mm，测量精度优于25μm，传感器信号带宽满足叶尖间隙达到200kHz， 叶尖定时达到5MHz，可适应转子转速范围300-18000rpm。