A Small Probe-Type Flowmeter Based on the Differential Fiber Bragg Grating Measurement Method

TLDR: Compared with the references existed, the proposed flowmeter in this paper was more compact with good sensitivity, wide measurement range, easy fabrication, and low pressure loss.

Abstract: A small probe-type optical fiber flowmeter was proposed for fluid flow measurement. The hollow cylindrical cantilever was first used to measure the force caused by fluid. A couple of fiber Bragg gratings (FBGs) that were stuck on the inner wall were used to measure the strain of the cantilever. The flow rate can be obtained by monitoring the difference of the two shifted Bragg wavelengths. The cross-sensitivity problem of FBG sensors can be solved by the differential FBG measurement method. Theoretical relation between the Bragg wavelength shift difference and flow rate has been established by theoretical analysis. Meanwhile, experiments have been carried out to verify the feasibility and stability. The simulation and experiment results showed that the resolution of the proposed flowmeter was 0.81 $\text{m}^{3}$ /h and the accuracy was 3.6% in the region of 0–22.5 $\text{m}^{3}$ /h. Compared with the references existed, the proposed flowmeter in this paper was more compact with good sensitivity, wide measurement range, easy fabrication, and low pressure loss.