低温管路动应变光纤光栅测量的光谱畸变抑制  

Fiber Bragg grating spectral distortion suppression in low-temperature pipeline's dynamic strain measurement

作　　者：唐才杰[1,2] 高红春 王学锋 杨勇[1,2] 蓝天 杨飒[3] TANG Caijie;GAO Hongchun;WANG Xuefeng;YANG Yong;LAN Tian;YANG Sa(Beijing Institute of Aerospace Control Devices,Beijing 100854,China;Beijing Engineering Research Center of Optical Fiber Sensing System,Beijing 100094,China;Xi'an Aerospace Propulsion Institute,Xi'an 710100,China)

机构地区：[1]北京航天控制仪器研究所,北京100854 [2]北京市光纤传感系统工程技术研究中心,北京100094 [3]西安航天动力研究所,陕西西安710100

出　　处：《火箭推进》2024年第6期154-160,共7页Journal of Rocket Propulsion

摘　　要：动应变是分析和治理火箭发动机管路振动问题的重要测量参数。针对低温管路动应变光纤光栅测量面临的光谱畸变问题,开展了抑制光纤光栅应变传感器光谱畸变的方法研究。选择了3种适用于直径≤30 mm的小管路应变测量的光纤光栅应变传感器封装和安装方法并开展了试验验证。第一种方法是拉伸光纤光栅并将光纤光栅及其两侧光纤整体粘接到管路表面;第二种方法是拉伸光纤光栅并将光纤光栅之外的两侧光纤粘接到管路表面;第三种方法是光纤光栅套毛细管拉伸并将毛细管及两侧光纤整体粘接到管路表面。在液氮试验中,套毛细管的4只光纤光栅未发生谱峰分裂,其中3只光纤光栅的反射谱半峰全宽相对变化≤5%、谱峰强度相对变化≤6%,光谱畸变得到了有效抑制;光纤光栅应变测量值与通过管件热膨胀施加的应变吻合。结果表明,光纤光栅套毛细管拉伸整体粘接方法可用于火箭发动机低温小直径管路动应变测量。Dynamic strain is an important measuring parameter for analyzing and treating pipeline vibration problems in rocket engines.Methods for suppressing fiber Bragg grating(FBG)spectral distortion in low-temperature pipeline s dynamic strain measurement were studied.Three methods of packaging and installing FBG strain sensor,which are suitable for small pipeline with a diameter of no more than 30 mm,have been picked up and evaluated experimentally.The first method is bonding the whole stretched FBG and its both sides to the pipeline surface.The second method is bonding the both sides of stretched FBG to the pipeline surface.The third method is bonding the capillary tube covering stretched FBG and both sides of the FBG to the pipeline surface.In the liquid nitrogen test,four FBGs covered with capillary tubes did not undergo spectral peak splitting.Among them,3 FBGs reflection spectra of three FBGs had no more than 5%relative changes in the full width at half maxim(FWHM)and no more than 6%relative changes in peak intensity,which shows that spectral distortion was suppressed successfully.Meanwhile,Measured result of FBG covered with capillary tube is consistent with the strain induced by pipeline s thermal expansion of pipelines.The method bonding the capillary tube covering stretched FBG and both sides of the FBG is prospected to be applied to the dynamic strain measurement for rocket engines with small-diameter and low-temperature pipelines.

关 键 词：动应变 光纤光栅 光谱畸变抑制 低温 管路 

分 类 号：O433.1[机械工程—光学工程] TN253[理学—光学]