一种新型光纤Bragg光栅流量传感器的仿真与实验研究

Simulation and Experimental Research of a Novel Flow Sensor Based on Fiber Bragg Grating

为了克服传统单个光纤布喇格光栅传感器对温度交叉敏感的问题，设计制作了一种基于双光纤布喇格光栅的以阻流件和弹性体为换能元件的流量传感器．该流量传感器采用弹性伞状结构体作为流量传感器的换能元件，用硅胶树脂封装双光纤光栅的弹性伞状结构体，起到了温度补偿的作用且提高了应变测量灵敏度．用有限元优化传感器结构，在1～20m／s的流速下利用ANSYS对传感器结构和传感器周围的流体场进行模拟分析，并计算了传感器的灵敏度，实验证明了硅胶树脂作为封装材料的优越性．进行了砝码千校法模拟实验，完成传感器封装前后的性能测试，通过提取该传感器的反射谱信号特征值，得到封装前后传感器的载荷响应灵敏度分别为：1．71nm／kg，0．103nm／kg．表明该流量传感器结构简单、安装方便、具有较好的线性度和灵敏度．

A novel flow sensor based on double fiber Bragg grating was designed and made to overcome the temperature cross-sensitivity problems of traditional single fiber Bragg grating sensor. The elastic umbrella structures were employed as conversion elements and silicone resin as encapsulating material, and an effective solution double-grating structure was taken. The temperature natural compensation and its measuring sensitivity were improved. Finite element was used to optimize the structure of the flow sensor. Its structure and the fluid field around it were simulated and analyzed by ANSYS software within the velocity of 1~ 20 m/s and the sensitivity of the sensor was calculated. The advantages of silicone resin as encapsulating material and its temperature sensitivity were verified through experiments. The performances of the sensor packaging before and after were tested and the reflection spectrum signal characteristic values of the fiber grating were extracted with good linearity, high response sensitivity of 1.71 nm/kg and 0. 103 nm/kg, respectively. The experiment results show that the flow sensor owns simple structure, good linearity and high sensitivity.