Design Of Differential Pressure Flow Sensor Based On Fiber Bragg Grating

The classic differential pressure flow measurement technique, the standard differential producers and common differential pressure sensors are referred in brief. The fiber Bragg grating (FBG) sensing technology and its applications are introduced in detail. Applications of FBG in flow measurement, the demodulation techniques and the temperature compensation methods are reviewed.The flow signal is transformed into differential pressure signal by using the classic standard orifice differential pressure flowmeter in this thesis. The differential pressure sensor is designed by combining FBG sensing element and the diaphragm elastic element, and the FBG sensing technology is used in the differential pressure flow measurement, as the differential pressure flow sensor based on FBG is shaped.The principles of flow measurement based on FBG, FBG differential pressure sensor and its temperature compensation methods are described in detail. The character modules of flow measurement, differential pressure and temperature compensation are given. The FBG pressure sensor is designed by using 316 stainless steel diaphragms. The LED broadband light source is designed and the experimental bench is established. The experimental results show that the FBG pressure sensor has very good characters of hysteresis, repeatability, linearity. The sensitivity of FBG pressure sensor is～3.0pm/KPa, and the full scale resolution is 0.15%. The differential pressure flow measurement based on FBG is proved to be feasible.A FBG demodulation module is raised by using InGaAs linear image sensor, and the DSP signal processing circuit is designed and debugged.A comprehensive analysis is given for the experimental results of FBG pressure sensor, and several improving steps are tabled in detail.