Cu/CuNi薄膜热电偶动态特性理论与实验研究

Study on Dynamic Characteristics of Cu/CuNi Thin-film Thermocouple Based on Theory and Experiment

具有快速响应特性的薄膜热电偶非常适用于测量瞬变温度,其动态特性理论分析一直都是研究的重点和难点。以流体为被测对象,提出了以对流换热为边界条件的薄膜热电偶一维非稳态传热模型,并依据此模型模拟Cu/CuNi薄膜热电偶阶跃温度响应,同时利用迅速投掷法对用磁控溅射法制备的热结点厚度为1μm的Cu/CuNi薄膜热电偶进行动态标定。模拟和实验结果都表明薄膜热电偶阶跃响应近似于一阶系统,可以用时间常数来反映动态特性,理论和实测的时间常数分别为4.28ms和7.89ms。从结果可以看出,理论值接近实验值,从而验证了该模型的合理性,为进一步提高薄膜热电偶的动态特性提供了理论基础。

For the characteristic of rapid response, thin-film thermocouples were always utilized to measure transient temperatures. The theoretical analysis of dynamic characteristics plays a signifi- cant role in the research of thin-film thermocouples. As the target medium was fluid, one-dimen- sional and unsteady heat transfer model for Cu/CuNi thin-film thermocouple was introduced herein with the boundary conditions of heat convection which was fabricated by means of magnetron sputte- ring with thickness of 1/~m. After dynamic calibration was carried out by means of quickly throwing method, the response time of the thin-film thermocouple was obtained as 7.89ms, which was close to the theoretical calculation value of 4.28ms. From the results of experimental and theoretical analy- sis, it can be seen that the heat transfer model is reliable, which lays the foundation for theoretical a- nalysis on improving dynamic characteristics of thin-film thermocouple.