Development of a guard-heated thermistor probe for the accurate measurement of surface temperature
Development of a guard-heated thermistor probe for the accurate measurement of surface temperature
复制标题
开发用于精确测量表面温度的防护加热热敏电阻探头
DOI：
10.1016/j.ijheatmasstransfer.2017.01.072
复制
发表时间：
2017
影响因子：
5.2
通讯作者：
S. Maruyama
中科院分区：
文献类型：
--
作者：
T. Okabe;J. Okajima;A. Komiya;S. Maruyama
通过热电偶或热敏电阻等普通方法很难准确测量材料表面温度的绝对值。这是由于沿着元件的电引线沿着的热损失，这会导致传导误差并最终影响结果。在本文中，我们提出了一个热敏电阻探头，利用保护加热器。该设计的目标是在比环境温度更高的温度下获得材料表面温度的准确测量。探头由两个电阻组成，每个电阻的直径为0.43 mm。一个热敏电阻用于温度传感器，而另一个与保护加热器一起使用以最小化热损失，并插入氟化乙烯丙烯（FEP）管中。保护加热器放置在半暴露的热敏电阻上方，并且作为传感器和加热器两者操作，以最小化两个热敏电阻之间的温差。为了评估在表面温度测量中沿热敏电阻的引线的热损失沿着的最小化，在两种情况下用加热到35.00 °C的铝块的表面进行实验。使用带和不带保护加热的保护加热热敏电阻探头进行测量。实验结果表明，在使用防护加热的情况下，表面温度测量为34.98 °C，在不使用防护加热的情况下，表面温度测量为34.79 °C。因此，实验结果表明，保护加热器允许热敏电阻探头提供更准确的表面温度测量，无论接触方法如何。此外，还进行了二维轴对称热传导分析。目的是定量评估在测量被加热材料的表面温度时通过热敏电阻引线的热量。计算结果证实，保护加热器成功地减少了通过引线的热损失。最小化的热损失为-0.016 mW，这是在没有防护加热的情况下测量的损失的六分之一。
It is difficult to accurately measure the absolute value of the surface temperature of a material through ordinary methods such as with a thermocouple or a thermistor. This is due to heat loss along the electrical lead wires of the component, which causes conduction error and can ultimately influence the results. In this paper, we propose a thermistor probe that utilizes a guard heater. The goal of this design is to obtain an accurate measurement of the surface temperature of a material at a higher temperature than the ambient temperature. The probe consists of two thermistors, each with a diameter of 0.43 mm. One thermistor was utilized for the temperature sensor, while the other was used with the guard heater to minimize heat loss, and inserted into a fluorinated ethylene propylene (FEP) tube. The guard heater was placed above a half-exposed thermistor, and operated as both a sensor and a heater in order to minimize the temperature difference between the two thermistors. To evaluate the minimization of heat loss along the thermistor’s lead wires in a surface temperature measurement, experiments were conducted with the surface of an aluminum block heated to 35.00 °C in two scenarios. Measurements were taken using a guard-heated thermistor probe with and without guard heating. The experimental results showed that the surface temperature was measured as 34.98 °C in the scenario where guard heating was utilized, and 34.79 °C in the scenario where it was not utilized. Therefore, the results experimentally demonstrated that the guard heater allowed the thermistor probe to provide a more accurate measurement of the surface temperature, regardless of the contact method. In addition, a two-dimensional axisymmetric heat conduction analysis was also conducted. The purpose was to quantitatively evaluate the amount of heat that passes through the lead wires of a thermistor while it is measuring the surface temperature of a heated material. The calculation results confirmed that a guard heater successfully minimized heat loss through the lead wires. The minimized heat loss was −0.016 mW, which was one-sixth of the loss measured in the scenario without guard heating.