Study on bending fiber Bragg grating target flow sensor

A bending target type flow sensor based on fiber Bragg grating(FBG) is designed. The strain distribution of bending target is simulated by COMSOL software and measured by two FBGs adhered on outside and inside surface of the target. Simulation and experiment results show that outer and inner sides of the target produce tensile strain and compressive strain respectively, and FBGs reflection wavelength have red shift and blue shift under external force. At the same time, temperature characteristics of the structure are tested and two FBGs reflection wavelength and temperature are linear at 20 ℃~40 ℃. Thereby the method can eliminate the effect of temperature in practical applications. Then measuring device of bending target type flow sensor is built, results show that two FBGs reflection wavelength and water flow have a good linearity within 0 L/H~800 L/H, and corresponding flow sensitivity is 48 L/H.