| With the adjustment of China’s energy structure,wind power has been vigorously developed as a green and renewable energy source.75% of China’s wind turbines are installed in high-latitude and high-altitude areas with relatively high wind resources.With frequent extreme weather such as heavy snow and freezing,wind turbine blades are prone to icing,resulting in adverse consequences such as reduced power generation and blade damage.Although many new wind turbines are equipped with automatic de-icing systems,how to accurately obtain temperature information at the icing area so as to start and stop the heating de-icing system reasonably is still a problem that needs to be solved urgently in practice.In response to the above problem,this article proposes a preparation method of ultra-thin composite material fiber Bragg grating(FBG)temperature sensor,which realizes widetemperature-range temperature measurement and maximum suppression of corresponding changes.The main research contents of this article include:1.This article reviews the research status of wind turbine blade icing mechanism and wind turbine blade icing detectors,summarizes the existing packaging methods of FBG sensors,and focuses on discussing the temperature-strain cross-sensitivity problem and strain transfer influencing factors of FBG sensors.2.The structural design and performance analysis of FBG temperature sensor.Based on the shear lag theory,the composition structure and function of FBG temperature sensor are analyzed.On this basis,the overall scheme design of the sensor structure is carried out.The sandwich structure form of the sensor using the saddle-shaped wide-temperature-range FBG temperature sensor geometric structure parameters and the sleeve fiber stacking after embedding damping blocks and epoxy resin filling in the upper and lower protective layers is determined.Combined with the matrix material of wind turbine blades,fiber-reinforced composite materials are used as the main structure and food-grade silicone rubber is used as the damping block material.The finite element simulation model of FBG temperature sensor is established to carry out statics and thermal deformation simulation,study the strain isolation effect and temperature sensitivity of FBG sensor.The results show that the saddle-shaped structure has a good strain isolation effect and high temperature sensitivity linearity under widetemperature-range.3.The wide-temperature-range sensing performance of FBG sensor is studied.A saddleshaped wide-temperature-range FBG temperature sensor with epoxy resin tube seal and without epoxy resin tube seal is prepared.The temperature sensing coefficients of the two saddle-shaped FBG sensors are calibrated in the low-temperature zone(-35℃～25℃),medium-temperature zone(25 ℃ ～55 ℃)and wide-temperature range(-35 ℃ ～55 ℃)respectively by using a temperature control box,and the consistency of the three temperature sensing coefficients is analyzed and compared.Then,according to the obtained temperature sensing coefficients,the temperature measurement experiments of each section are carried out to compare and verify the temperature sensing performance of the two saddle-shaped wide-temperature-range FBG temperature sensors developed in the wide-temperature range(-35℃～55℃).4.Experimental study on strain suppression of FBG sensor.The strain suppression effect of the saddle-shaped FBG temperature sensor is tested by static strain loading experiment and dynamic strain loading experiment of equal-strength cantilever beam at constant temperature(room temperature).The experimental results show that the saddle-shaped FBG sensor still has a strain suppression rate of 99% for up to 3500 micro-strains. |
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