辐照碳化硅测温晶体温度标定试验感温过程分析研究

A Study on the Thermal Calibration Experiment of Irradiated SiC Crystal Temperature Sensors

辐照碳化硅测温晶体是航空发动机研制过程中热端旋转部件温度测量的重要方法,其测量精度依赖于对其温度-缺陷浓度响应关系的精准标定,标定过程可分为温度标定试验、晶体缺陷表征测量、标定曲线建立3个阶段。温度标定试验中,温度场的波动、测温晶体与测温热电偶感温偏差以及非理想因素导致的传热是辐照晶体技术测量误差的重要来源。利用实验和数值方法,研究了辐照测温晶体在温度标定试验过程中不同阶段下主导的传热传质过程,分析了支杆材料的热物理参数、温度过冲以及准热平衡状态下的温度扰动对于测温晶体感温的影响,结果发现测量误差主要由辐射场在轴向方向的不均匀分布所导致,最后对支杆的材料和结构设计提出了相应的改进方案。

Irradiated silicon carbide(SiC)temperature sensing is a major diagnostic technique for turbine blades in the process of aero-engine development.Its measurement accuracy depends on the accurate calibration of its response relationship between temperature and its defect concentration.The entire calibration process consists of the temperature calibration experiment,crystal defect characterization and calibration curve identification.The temperature calibration deviation caused by the fluctuation of the temperature field in the calibration test is an important source of the measurement error of the irradiation thermometer crystal.The dominant heat and mass transfer mechanism during the calibration process were studied by experimental and numerical methods,and the effects of the thermophysical parameters of the strut material,temperature overshoot,and temperature disturbance in the quasi thermal equilibrium state on the temperature sensitivity of the temperature measuring crystals were analyzed.The research results found that the measurement error was governed by the non-uniform distribution of thermal radiation field in the axial direction.Finally,the corresponding improvement plans were proposed to improve the geometric configurations and material selection of struts,and to optimize the choice of thermocouples in the calibration procedure of irradiated SiC crystal sensors.