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.
INCROPERA F P, DEWITT D P, BERGMAN T L, et al. Fundamentals of Heat and Mass Transfer ［M］. 6th ed. New Jersey: John Wiley & Sons, 2006.
HOU S L, WANG H, GAO F S, et al. JJF 1637-2017 Base Metal Thermocouples Calibration Specification interpretation［J］. China Metrology, 2018(5): 129-130.
MEYER C W, GARRITY K M. Updated uncertainty budgets for NIST thermocouple calibrations［J］. AIP Conference Proceedings, 2013, 1552(1): 510-514.
JIANG H, LIU H S. Experimental study on the influence of thermostatic block on the temperature performance of thermocouple verification furnace［J］. China Metrology, 2022(3): 124-126.
［6］
廉金属热电偶校准规范:JJF 1637—2017［S］. 北京: 中国质检出版社, 2018.
［10］
LI X Y, HUANG Q H, LUO X G, et al. Thermocouple correction method evaluation for measuring steady high-temperature gas［J］. Applied Thermal Engineering, 2022, 213: 1-10.
［14］
袁若浩. 基于ANSYS热分析炉均温场模拟及优化［D］. 杭州: 中国计量学院, 2016.
CHEN Q Q, PAN J, YUAN D K. Development of a New High Temperature Thermocouple Performance Testing System［J］. Acta Metrologica Sinica, 2022, 43(11): 1424-1430.
［1］
ÌÇ Y T, GLER E S, AKIR Z E. Reducing Uncertainty in a Type J Thermocouple Calibration Process［J］. International Journal of Thermophysics, 2019, 40, 5: 8-17.
［3］
NUGRAHA H, IMADUDDIN A, ACHMADI A, et al. Real-Time Monitoring System for Thermocouple Inhomogeneity Equipment［J］. Journal of Physics: Conference Series, 2022, 2243(1): 1-5.
LIU H Y, ZHANG S X, XU Z Z, et al. Research on Temperature Uniformity of the Calibration Furnace with Multiple Calorifiers［J］.Acta Metrologica Sinica, 2022, 43(2): 228-234.
LI Z, LIU R, HOU Y A. Application of Temperature Block in Thermocouple Calibration［J］. Metrology & Measurement Technology, 2018, 38(4): 17-19.
［11］
SUN Y G, TENG F, GUO S, et al. Research of high temperature redundant thin film thermocouple［J］. Journal of Physics: Conference Series, 2022, 2338(1): 2-4.
［16］
OJANEN M, HAHTELA O M, HEINONEN M. Blackbody comparator for thermocouple calibration［J］. AIP Conference Proceedings, 2013, 1552(1): 468-470.
WU Q, HAO X P, SONG J, et al. The Investigation on the Temperature Field Uniformity of a High-precision Vacuum Blackbody［J］. Acta Metrologica Sinica, 2022, 43(10): 1279-1284.
2024, Vol. 45 
