基于旋涡发生体的光纤Bragg光栅流量计的研究

Research of fiber optical Bragg grating flowmeter based on vortex occurred body

结合光纤光栅传感检测技术与旋涡分离原理,研制了一种基于三角柱型旋涡发生体的光纤Bragg光栅流量计,在三角柱旋涡发生体中部设置导压腔,腔内设置粘贴Bragg光栅的等强度悬臂梁,流体经过发生体两侧时,交替分离旋涡,导压腔内部产生脉动流体,等强度悬臂梁产生振动且振动频率与旋涡分离频率成正比,通过检测悬臂梁振动频率测量流体流量。实验表明,该流量计的线性度为4.38%FS,仪表系数为K=3.659,光纤光栅波长移位频率对流量的响应度为1.182Hz/(m3/h)。

By combining the fiber grating sensing technique with vortex separation principle, a model of FBG vortex flow meter is researched based on triangular columnar. A pilot pressure cavity is installed in the central of triangular prism spiral bluff body, inside the cavity. Equal strength cantilever beam is set which is pasted Bragg grating. When the fluid passes through both sides of the body, alternate vortex is separated. Pulsating fluid pressure is produced inside the pilot pressure cavity. Vibration of equal strength cantilever beam is produced which vibration frequency is proportional to the frequency of vortex separation. The fluid flow is measured by detecting the vibration frequency. Experiment results show that the linearity of the flow meter is 4. 38% FS, instrument coefficient is K= 3. 659, and the fiber Bragg grating wavelength shift frequency respond to flow rate is 1. 182Hz/（m3/h）.