气体介质条件下的热电偶动态特性

Dynamic characteristics of thermocouple in gas medium

针对热电偶动态特性的评估问题,实现热电偶测试性能评估与气体介质条件的匹配,开展了气体介质条件下热电偶动态特性研究。通过对传统激波管的结构和功能改造,设计了动态气体温度校准装置,开展了动态温度校准标准信号溯源方法的研究,建立了热电偶动态数学模型,实现了热电偶动态特性的定量描述和试验验证。动态校准试验结果表明:基于传统激波管改造的动态气体温度校准装置可以产生频域覆盖范围宽、阶跃幅值稳定的标准温度信号,基本可以覆盖常规温度传感器的动态校准需求;所采用的动态建模方法可以较为准确地评估热电偶动态模型的阶次和参数。经实验验证,建立的热电偶动态数学模型响应与实际响应信号的相关系数可以达到0.9967,基本可以满足热电偶动态特性评估的工程需要。

In order to estimate the dynamic characteristics of the thermocouples and fulfill the matching requirement of dynamic characteristics estimation with the gas medium,the dynamic characterization research of the thermocouples with the gas medium was studied.Based on the improvement of structure and function of traditional shock tube,dynamic calibration equipment for the gas temperature was designed,the traceability method of standard signal of dynamic temperature calibration was analyzed,the dynamic model of thermocouple was established,and precise description and experimental verification was realized.The result of dynamic calibration experiment showed that the dynamic calibration equipment for the gas temperature based on traditional shock tube transformation could generate standard temperature signal featuring wide frequency coverage and steady step amplitude.The dynamic calibration requirement of the conventional thermocouples can basically be fulfilled by the generated standard temperature signal;the thermocouple dynamic model and the order can be estimated very accurately with the adopted dynamic modelling method.With the verified results of the experiment,the correlation coefficient between the response signal of the established thermocouple dynamic model and the testing response signal could achieve 0.9967,which can generally satisfy the requirement of dynamic characterization estimation of thermocouple in the engineering applications.