The Study On Sapphire Fiber Fabry–Perot High Temperature Sensing System

Combustion efficiency is one of the most important technical indexes of aeroengine,which directly determines the engine's thrust(power)performance.Real-time monitoring of the engine's internal temperature is necessary to ensure efficient and stable operation of the engine.So the temperature sensing technology,especially high-temperature sensing technology has a very important role in aviation and other fields.With the development of science and technology,Thermocouple sensors and other temperature sensing device have been unable to meet the needs of the engine temperature measurement because of its poor oxidation resistance in high temperature and vulnerable to electromagnetic interference.Therefore,high stability,miniaturization and high temperature of a new generation of engine high temperature sensor and test system is the important direction of research at home and abroad.In view of the above requirements,a high-temperature sensing technique of sapphire fiber Fabry-Perot is analyzed theoretically and systematically..A demodulation algorithm based on interference spectrum phase analysis was proposed.Temperature measurement with high accuracy and large dynamic range was realized.Its good adaptability in harsh environments has been proved.In the paper,specific research contents include:1?The optical and temperature properties of sapphire crystal were analyzed.The theory of fiber Fabry-Perot temperature sensing was studied.The Fabry-Perot interferometric fiber coupling model and the temperature characteristics of the sapphire wafer was established.The optical parameters and fabrication process of the sensor were designed and optimized.2?The basic structure of Sapphire fiber Fabry-Perot high-temperature sensor demodulation system was built.The characteristics of interferometric spectral signals of the sensing system were analyzed.A phase analysis and demodulation algorithm based on interference spectrum was proposed.The influence of Fabry-Perot cavity length and SNR on the temperature demodulation of Sapphire fiber Fabry-Perot sensor was analyzed.3.A temperature sensing system of sapphire fiber Fabry-Perot was established.The temperature performance and aging characteristics of the sensor are studied experimentally.Experiments showed that the sensor's temperature measurement accuracy was 0.26% F.S.in the temperature range of 130 ? ~ 1080 ?,and had a good temperature repeatability,temperature sensitivity and temperature stability.Based on the requirement of temperature measurement of the aeroengine,the temperature response,temperature shock and flame eruption of the sensor were tested.The temperature measurement capability of the sensor under harsh conditions was studied.