Design Of Fibre Infrared Low Temperature Measuring System For Turbine Rotor Temperature Measurement

As one of the core components of steam turbine,the real-time and accurate monitor of its rotor surface temperature is related to the condition adjustment and stable operation of the unit.The existing temperature measurement equipment can neither directly measure the turbine rotor in high-speed rotation,non-contact infrared temperature measuring equipment is nor good in the vacuum,water mist and dynamic internal environment of turbine.In addition,to avoid damaging the stress structure of the cylinder,the volume of the temperature probe is strictly limited.In order to effectively solve the above problems,this paper designs and implements a set of miniaturized infrared temperature measurement system by optical fiber,including real-time temperature monitoring,data processing,emissivity correction,data upload and other functions.Firstly,the research status of infrared temperature measurement technology and the infrared temperature measurement method in turbine environment at home and abroad is investigated.The research content of this paper is determined and the basic theory of infrared temperature measurement is clarified.Secondly,according to the required temperature measurement position and the temperature range of 70～300 ℃,the hardware design scheme of optical fiber infrared temperature measurement system is determined.The received infrared radiation is focused by Zn Se lens and transmitted to MLX90614 infrared temperature measurement module through silver halide polycrystalline infrared fiber for detection,and the hardware circuit is designed based on STM32F103 microprocessor.Thirdly,according to the hardware design,the overall function of the embedded software is planned.The program of MLX90614 module is designed based on SMBus protocol.Real time temperature measurement and emissivity modification are realized by reading RAM and writing registers in EEPROM.Meanwhile,the system display,communication,filtering,human-computer interaction and main function are programmed and designed to realize the overall function of the system.Finally,the radiation heat transfer model simulation of steam turbine environment is carried out,and the simulation results are obtained at different time and target temperature.The simulation environment of steam turbine is built,the calibration experiment and the water vapor influence verification experiment are carried out for the system.The segmented function is obtained by analyzing the data;the measurement error caused by optical system loss and water vapor environment is carried out.The accuracy of the temperature measurement results is within ± 10%.