| The most important function of the airborne fuel line measurement system is to stably and accurately measure the pressure and temperature distribution of the fuel line,and to provide early warning for aircraft over pressure and over temperature,which is of great significance to aircraft safety.Aiming at the risk of electric sparks and explosions caused by the existing electrical measurement sensors in the airborne fuel pipeline,this paper proposes a pressure/temperature composite sensor and system for airborne fuel,using Fiber Bragg Grating(FBG)is a sensitive unit,which has the advantages of intrinsic explosion-proof,anti-electromagnetic interference,small size,light weight,etc,and can be embedded into the target for detection without changing the original equipment structure,to meet the requirements of light airborne load and narrow space.Apply conditions.The main research work of this paper is as follows:(1)This paper analyzes and compares the technical characteristics of airborne fuel line measurement at home and abroad.Combined with the advantages of fiber grating sensors and the pressure-bearing mechanism of sensitive components,a research idea of fiber grating sensing system for airborne fuel line temperature/pressure measurement is proposed.(2)Based on the temperature and strain sensing mechanism and elastic mechanics principle of FBG,an airborne fuel line temperature/pressure composite fiber optic sensor is designed.The material with less thermal effect is selected as the pressure sensitive element,and the relationship between sensitivity,maximum stress and size is analyzed;the temperature grating is packaged with a single-ended structure to realize temperature measurement and self-compensation mechanism,and the double-layer sensor is studied and optimized.The metal pipe armored structure eliminates the error caused by the thermal expansion effect of the metal pipe,and simulates the temperature field distribution of the sensor;for the high pressure environment,the thread structure of the sensor is designed,and the self-locking performance and mechanical resistance of the thread are checked;Study the anti-vibration performance of the sensor,carry out modal analysis of the sensor and further analyze its working state at the resonance frequency.(3)The signal processing technology of FBG temperature/pressure composite optical fiber sensing system is studied,and an adaptive peak region segmentation algorithm based on Hilbert transform is proposed.Pre-location function;using the improved Gaussian algorithm to locate the segmented sparse sub-spectrum,the system test results show that the algorithm is accurate and reliable.On the basis of this research,the data of the FBG temperature/pressure composite optical fiber sensing system is developed Streaming real-time display of the host computer software.(4)The temperature and pressure characteristics test and anti-vibration ability analysis of the designed FBG temperature/pressure composite sensor are carried out.The experimental results show that the average pressure sensitivity of the sensor is0.0991nm/MPa,the hysteresis error is 5.614%,and the maximum deviation is 16 k Pa;The sensitivity coefficient is 0.0106nm/℃,the maximum deviation is 0.15℃,and the temperature self-compensation performance is good;the connection area between the sensor sensitive diaphragm and the metal tube can be opened,which can eliminate the difference between the response time constants of the two FBGs caused by the transient low temperature area.In the range of 0～2000Hz,the maximum wavelength drift of the two FBGs does not exceed 6.3pm,which has a certain anti-interference ability to the monitoring environment. |
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