Method Of Gas Flow Measurement Based On Metallic Coated Fiber Bragg Grating Array

A Multi-Probe gas flowmeter based on metallic-coated fiber Bragg gratings(FBGs) which is base on temperature-sens ing characteristic of FBG supported by the National Natural Science Fund ’Mechanism and method of gas flow measurement based on metallic coated fiber Bragg grating array’(No.61203205). By making comprehensive utilization of the dynamic thermal equilibrium relation between the laser energy absorbed by the metallic thin film and the heat taken away by the gas flow, the flow measurement for large-diameter(mainly 50mm) and low-velocity gas flow is eventually realized. The main work of this paper includes:(1) This paper first reviews the development and application of traditional sensors and fiber optic flow sensor. Introduced a variety of optical fiber active flow sensor which is depend on fiber optic sensing technology and flow measurement technology.(2) Then the research on the sensing mechanism of this thermal gas flow meter is carried out and the mathematical model is derived. The arrangement of multi probe optical fiber Bragg grating sensor is designed and optimized by using the simulation software Fluent as well.(3) Characteristic experiments of multiple different sensing probes are launched, from which the optimal probe is chosen to packing. All these compose the primary instrument of the flowmeter. We build a detection optical path for gas flow measurement. A device has been built with a plurality of flowmeter.(4) Then the equipment is improved before carrying out a series of flow calibration and measurement experiment. The results show that the measurable range is 0～10m3/h and the minimum resolution can be defined as 0.01 m/s on the basis of the accuracy of OSA. This flowmeter performs well and is worth to be developed.