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设计了一种基于双光纤布拉格光栅的新型流速传感器,它包括双光纤光栅压强传感机构和文丘里管。导出了双光纤布拉格光栅的波长漂移差与流速的关系。压强传感机构中的密闭铝箔管横截面两边的压力差导致等腰三角形悬臂梁变形,从而导致安装在悬臂梁两边的光纤布拉格光栅的布拉格波长漂移。通过检测两个布拉格光栅的波长漂移差,得到被测流体的流速。双光纤布拉格光栅通过补偿温度效应,解决了光纤布拉格光栅传感器的交叉敏感问题。该流速传感器的动态测量范围为8～200mm/s。实验表明,双光纤布拉格光栅的中心波长随流速的增加分别向长波和短波方向漂移,而带宽几乎不变,实验和理论符合得较好,该设计方案是切实可行的。
A new type of flow sensor based on dual fiber Bragg grating is designed, which includes dual fiber grating pressure sensing mechanism and venturi. The relationship between the wavelength drift and the flow rate of a two-fiber Bragg grating is derived. The pressure difference across the cross-section of the closed foil tube in the pressure sensing mechanism causes the deformation of the isosceles triangular cantilever resulting in a Bragg wavelength shift of the fiber Bragg grating mounted on either side of the cantilever. By detecting the wavelength shift difference between two Bragg gratings, the flow rate of the measured fluid is obtained. The dual fiber Bragg grating solves the cross-sensitivity issue of fiber Bragg grating sensors by compensating for temperature effects. The dynamic measurement of the flow rate sensor range of 8 ~ 200mm / s. Experimental results show that the center wavelength of the dual fiber Bragg grating drifts toward the longwave and the shortwave respectively with the increase of the flow rate, but the bandwidth is almost unchanged. The experiment and theory are in good agreement with each other. The design scheme is feasible.