靶式光纤Bragg光栅流速传感器的研制

A target-type fiber Bragg grating flow velocity sensor

设计了一种基于等强度悬臂梁的靶式光纤Bragg光栅(FBG)流速传感器,传感器利用杠杆结构将置于流体中迎流靶片所受的与流速成对应关系的冲击力转化成FBG波长的漂移,利用对称粘贴于悬臂梁上下表面的双FBG结构有效解决了温度与应变的交叉敏感问题。建立了流速与FBG波长变化幅度的关系,并采用流体分析软件FLUENT对放置靶片的流体管道流场进行仿真。仿真结果表明,在靶径比为0.7的管道系统中,传感器灵敏系数为2.54×10-3s2/m2。对传感器进行标定试验,得传感器分辨率为0.02m/s,在0～1.40m/s范围内最大满量程误差为1.5%FS。

A target-type fiber Bragg grating（FBG） flow velocity sensor based on equal-strength cantilever has been designed.The force which has corresponding relationship with velocity is induced by the fluid on the target,and then the lever is adopted to transform the force into the Bragg wavelength shift.A couple of fiber Bragg gratings（FBGs） are separately mounted at either side of the cantilever to solve the cross-sensitivity between temperature and strain.The precise relationship between velocity and variation magnitude of FBG central wavelength is established.Moreover,the pipeline flow field is simulated by fluid analysis software FLUENT.Simulation results show that the sensitivity coefficient is 2.54×10-3s2/m2 when the pipeline inner diameter is 0.7 time of target disc diameter.The pipeline calibration experiments have been carried out and the results indicate that the velocity resolution of the proposed sensor is 0.02 m/s and the maximum full scale error is 1.5% FS in measuring range of 0-1.40 m/s.