Research On Thermal Gas Flow Sensor Based On Fiber Grating

Natural gas is an important clean energy which transport and supply mainly through the pipeline installation flow sensor to achieve.The electronic thermal type gas flow sensor has been widely used,but the gas in the flammable and explosive occasions resistance heating will bring unsafe factors,flow sensor need safety explosion-proof and high precision.This paper uses without electricity measurement of fiber Bragg grating(FBG)to replace the conventional resistance heating type flow sensor,method of traditional measurement of gas flow in the are analyzed and summarized.Studied based on Kim's law of heat flow measurement principle,a detailed analysis of the fiber grating packaging method for measuring temperature of the basic principles and sensor.In this paper,a sensitive and reliable optical fiber grating temperature sensor based on the metal probe and the metal tube is used,and the temperature calibration is made.Light source light heating scheme based on using thermal conversion absorbing coating,design of the packaging structure design will each part of components are integrated to realize fiber thermal flow sensor was designed.Build the fiber thermal flow sensor test platform,using variable frequency speed pump as a gas source,pipeline circumflex flow meter on-line calibration.The flow rate increased from 60 to 140 m~3/h,and the temperature difference decreased from 8.9?to 0.8?.In the flow of 44.6~147m~3/h,the temperature difference between the data of 13.9?degree to0.6?,resolution is0.05m/s and 0.04m/s,flow measurement can be carried out.Thermal flow meter based on thermal conversion,intrinsically safe,has a good application prospects.