Theoretical basis of the response compensation for fine-wire temperature sensors and development for its practical

1.对热电偶、冷丝等细丝温度传感器的频率响应进行了理论分析，通过严格处理感温元件与其相邻支承之间热传递的边界条件，得到了响应的严格解。所得解具有很强的通用性，可以用一个方程表示细丝热电偶和冷丝的频率响应。通过实验验证了理论解的正确性，并在此基础上提出了一种广泛适用于细丝温度传感器的响应补偿技术。目前的响应补偿技术可以很好地与商业上最快的温度传感器之一--0.63μm铂丝--相比，用一根3.2μm的钨丝来测量波动温度。2.TH…的理论分析进一步发展了细丝热电偶探头的频率响应，以研究组成对接焊接细丝热电偶的两根焊丝的物理性能差异对测量结果的影响。所得到的解显示了铜-康铜(T型)热电偶的频率响应的复杂行为，该热电偶的物理性质在两种本构导线之间差别很大。研究还表明，在气流中，热电偶丝横截面上的频率响应几乎是均匀的，但在水流中，频率响应变得非常不均匀。3.提出了一种稳健的响应补偿方案，在频域中对细丝温度传感器的热时间常数进行了在线估计。时间常数值可以通过最大化由具有不同时间常数的两个传感器同时测量的两个“补偿”温度信号的相干函数来获得。实验验证了该方法的有效性，与以往的方法相比，该方法对仪器噪声的容忍度最高。较少

The research results are summarized as follows:1.Theoretical analysis of the frequency response of a fine-wire temperature sensor such as a thermocouple or a cold wire was performed, and a strict solution of the response was derived by treating rigorously a boundary condition of heat transport between the temperature-sensing part and its adjoining support. The solution obtained is highly universal and can express the frequency response of both a fine-wire thermocouple and a cold wire with a single equation. The validity of the theoretical solution was examined experimentally, and a response-compensation technique widely applicable to fine-wire temperature sensors was developed based on the theoretical results. The present response-compensation technique can perform fluctuating temperature measurement by a 3.2 μm tungsten wire well comparable to that by a 0.63 μm platinum wire which is regarded as one of the fastest temperature sensors commercially available.2.Theoretical analysis of th … More e frequency response of a fine-wire thermocouple probe has been further developed to investigate influences of the difference in physical properties between the two wires composing a butt-welded fine-wire thermocouple. The solution obtained demonstrates complex behaviors of the frequency response of the copper-constantan (type-T) thermocouple whose physical properties differ greatly between the two constitutive wires. It was also shown that, in an air flow, the frequency response is almost uniform in the cross-section of the thermocouple wire, but, in a water flow, it becomes remarkably non-uniform.3.A robust response-compensation scheme has been developed to estimate in situ the thermal time constants of fine-wire temperature sensors in the frequency domain. The time-constant values can be obtained by maximizing a coherence function of two "compensated" temperature signals measured simultaneously by two sensors having different time-constants. The scheme was validated experimentally and showed the highest tolerance to instrumentation noise compared with our previous methods. Less