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

Abstract

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).