热电偶检定炉的温度场性能在廉金属热电偶的校准中产生重要影响,是评价校准准确度的一个重要参量。廉金属热电偶校准规范中提出使用均温块改善检定炉温场性能,为进一步探究均温块对温度场改善的传热原理,针对检定炉内实现温升的主要传热方式展开理论分析,认为检定炉稳定保温阶段炉膛内传热方式主要为热传导,而采用导热性能良好和体积热容大的合金均温块能有效提高内部导热效率并增强温场稳定性。进一步地,采用数值模拟计算炉膛内部温度场分布,计算结果指出,放置均温块的温度场与不放置的温度场相比,轴向最大温差缩小为原来的1/3,径向最大温差缩小为原来的1/2,与理论分析相吻合,表明放置均温块是优化检定炉温度场的重要手段。
Abstract
The temperature field performance of thermocouple calibration furnace plays an important role in the calibration of base metal thermocouple and is an important parameter to evaluate the accuracy of thermocouple calibration. In the calibration specification for base metal thermocouples, it is proposed to use thermostatic block to improve temperature field performance of thermocouple calibration furnace.In order to explore how does the thermostatic block improve the uniformity, theoretical analysis was carried out on the main heat transfer methods to achieve temperature rise in the thermocouple calibration furnace. It is holds that the main heat transfer mode in furnace is heat conduction, and the use of alloy thermostatic block with large thermal conductivity and large volume heat capacity can effectively improve the internal thermal conductivity efficiency and enhance the stability of temperature field.Furthermore, numerical simulation was used to calculate the temperature field distribution inside the furnace. The calculation results showed that compared with not placing the thermostatic block, the maximum temperature difference in the axial direction is reduced to 1/3 of the original value, and the maximum temperature difference in the radial direction is reduced to 1/2 of the original value, which is consistent with the theoretical analysis. It is shows that placing thermostatic block is an important means to optimize the temperature field of thermocouple calibration furnace.
关键词
温度计量 /
热电偶校准;温度场性能;均温块;传热方式;热传导;数值模拟
Key words
temperature measurement /
thermocouple calibration /
temperature field properties /
thermostatic block /
heat transfer method /
heat conduction /
numerical simulation
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基金
上海市协同创新发展项目(2020-jmrh2-kj3)
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