Li Zhiling, Yin Jianping, Wang Gao, Liang Haijian, Zhang Congchun, Huang Manguo, Liu Yundong, Zhang Jie
College of Mechatronics Engineering, North University of China, Taiyuan 030051, China.
School of Information and Communication Engineering, North University of China, Taiyuan 030051, China.
Sensors (Basel). 2022 Jul 15;22(14):5294. doi: 10.3390/s22145294.
This paper mainly studies the model design of a thin-film heat-flux sensor (TFHFS), and focuses on the comparison of three dynamic calibration methods. The primary motivation for studying this came from the urgent need for heat-flux dynamic measurements in extreme environments, and the one-sidedness of the dynamic performance evaluation of the corresponding TFHFS. The dynamic theoretical model of the TFHFS was originally established on the principle of a temperature gradient on the basis of a thermal radiation boundary. Then, a novel TFHFS sensor was developed, which can be used at temperatures above 880 °C and has a high sensitivity of 2.0 × 10 mV/(W/m). It can function stably for long durations under a heat-flux density of 3 MW/m. The steady-state, transient, and frequency calibration of a TFHFS were compared to comprehensively analyze the dynamic characteristics of the TFHFS. The steady-state response time measured by the step excitation method was found to be 0.978 s. The QR decomposition method was applied to the steady-state response experimental model construction, and the fitting degree of a second-order transfer function model obtained was 98.61%. Secondly, the transient response time of the TFHFS was 0.31 ms based on the pulse-excitation method. The transient relationship between the surface temperature and the heat flux, and the pulse-width dependence of the TFHFS transient response time were established. Surprisingly, the response frequency of the TFHFS, about 3000 Hz, was efficiently tested using the frequency response function (FRF), which benefitted from the harmonic characteristics of a periodic square-wave excitation signal. Finally, a comprehensive evaluation of the dynamic performance of the TFHFS was realized.
本文主要研究薄膜热流传感器（TFHFS）的模型设计，并着重比较三种动态校准方法。开展此项研究的主要动机源于极端环境下热流动态测量的迫切需求，以及相应TFHFS动态性能评估的片面性。TFHFS的动态理论模型最初是基于热辐射边界条件下的温度梯度原理建立的。随后，开发了一种新型TFHFS传感器，其可在880℃以上的温度下使用，灵敏度高达2.0×10mV/(W/m²)。在热流密度为3MW/m²的条件下，它能够长时间稳定运行。通过比较TFHFS的稳态、瞬态和频率校准，全面分析了TFHFS的动态特性。采用阶跃激励法测得的稳态响应时间为0.978s。将QR分解法应用于稳态响应实验模型构建，得到的二阶传递函数模型拟合度为98.61%。其次，基于脉冲激励法测得TFHFS的瞬态响应时间为0.31ms。建立了表面温度与热流之间的瞬态关系以及TFHFS瞬态响应时间与脉冲宽度的依赖关系。令人惊讶的是，利用频率响应函数（FRF）有效测试了TFHFS约3000Hz的响应频率，这得益于周期性方波激励信号的谐波特性。最后，实现了对TFHFS动态性能的综合评估。
