【作者】 徐刚； 戴玉堂； 王俊杰； 南秋明； 桂鑫；

【Author】 Gang Xu Yutang Dai Junjie Wang Qiuming Nan Xin Gui(Wuhan University of Technology National Engineering Laboratory for Fiber Optic Sensing Technology Hubei Wuhan 430070)

【机构】 武汉理工大学光纤传感技术国家工程实验室；

【摘要】 根据汽轮机、压缩机等大型旋转机械对振动检测的特殊要求,设计了一种基于光纤FBG光栅技术的非接触式振动传感器,采用弹性膜片和磁耦合技术通过改变光纤光栅的轴向应变实现振动检测。文中阐述了该传感器的结构和工作原理,从理论、有限元分析和实验上研究了该传感器的静态和动态特性。磁耦合探头直径12mm、厚度8mm,弹性膜片有效直径32mm、厚度0.25mm、硬心直径12mm。研究表明:在被测物与传感探头0.5mm~3.5mm间距范围内,间距变化与光纤光栅波长输出为非线性关系,但在部分小量程范围内线性度良好。在探头与被测物间距为0.5mm~1mm范围内,灵敏度为1.63pm/μm,非线性度5.56%;到3mm~3.5mm范围内,灵敏度仅为0.109pm/μm,非线性度1.08%;动态特性方面,谐振频率为210Hz,并且0~140Hz范围内幅频特性较为平坦。更多还原

【Abstract】 According to special requirements of vibration monitoring of large rotating machinery,such as Turbine and compressor,a non-contact fiber Bragg grating(FBG) based vibration detection sensor is designed.The magnetic coupling technology and elastic diaphragm are adopted to achieve the vibration detection by changing the axial strain of optical fiber grating.This paper describes the structure and working principle of the sensor,and studies the static and dynamic characteristics of the sensor in theory,finite element analysis and experimental.The diameter and thickness of Magnetic coupling probe is respectively 12 mm and 8 mm,the effective diameter,thickness and hard-core diameter of elastic diaphragm is respectively 32 mm,0.25 mm and 12 mm.The results show that: the relationship of distance and fiber grating wavelength is nonlinear in range 0.5mm~3.5mm of the probe and the analyte,but it has a good degree of linearity in some small-scale range.when the distance range between the probe and the analyte was 0.5 mm ~ 1 mm,the sensitivity was 1.63 pm/μm,nonlinearity was 5.56%;the distance range was 3 mm ~ 3.5 mm,sensitivity was only 0.109 pm/μm,nonlinearity was 1.08%;In the dynamic aspects,the resonance frequency is 210 Hz,and the amplitude-frequency curve of the receiving sensitivity response is relatively flat within the frequency range of 0~140 Hz.更多还原