Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows

Coaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat tran...

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Main Authors: Shizhong Zhang, Qiu Wang, Jinping Li, Xiaoyuan Zhang, Hong Chen
Format: Article
Language:English
Published: MDPI AG 2020-09-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/20/18/5254
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author Shizhong Zhang
Qiu Wang
Jinping Li
Xiaoyuan Zhang
Hong Chen
author_facet Shizhong Zhang
Qiu Wang
Jinping Li
Xiaoyuan Zhang
Hong Chen
author_sort Shizhong Zhang
collection DOAJ
description Coaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat transfer, and changes in the physical parameters of the materials with increasing temperature influence the accuracy of heat transfer measurements. A numerical analysis of coaxial thermocouples is conducted to determine the above influences on the measurement deviation. The minimum deviation is obtained if the thermal effusivity of chromel that changes with the surface temperature is used to derive the heat flux from the surface temperature. The deviation of the heat flux is less than 5.5% when the Fourier number is smaller than 0.255 and 10% when the Fourier number is smaller than 0.520. The results provide guidance for the design of test models and coaxial thermocouples in long-duration heat transfer measurements. The numerical calculation results are verified by a laser radiation heating experiment, and heat transfer measurements using coaxial thermocouples in an arc tunnel with a test time of several seconds are performed.
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spelling doaj.art-3900dfe99f514566bbba10eb8e8211182023-11-20T13:43:05ZengMDPI AGSensors1424-82202020-09-012018525410.3390/s20185254Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy FlowsShizhong Zhang0Qiu Wang1Jinping Li2Xiaoyuan Zhang3Hong Chen4State Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaState Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaCoaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat transfer, and changes in the physical parameters of the materials with increasing temperature influence the accuracy of heat transfer measurements. A numerical analysis of coaxial thermocouples is conducted to determine the above influences on the measurement deviation. The minimum deviation is obtained if the thermal effusivity of chromel that changes with the surface temperature is used to derive the heat flux from the surface temperature. The deviation of the heat flux is less than 5.5% when the Fourier number is smaller than 0.255 and 10% when the Fourier number is smaller than 0.520. The results provide guidance for the design of test models and coaxial thermocouples in long-duration heat transfer measurements. The numerical calculation results are verified by a laser radiation heating experiment, and heat transfer measurements using coaxial thermocouples in an arc tunnel with a test time of several seconds are performed.https://www.mdpi.com/1424-8220/20/18/5254heat transfer measurementcoaxial thermocouplelong-durationsemi-infinitehigh enthalpy
spellingShingle Shizhong Zhang
Qiu Wang
Jinping Li
Xiaoyuan Zhang
Hong Chen
Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
Sensors
heat transfer measurement
coaxial thermocouple
long-duration
semi-infinite
high enthalpy
title Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
title_full Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
title_fullStr Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
title_full_unstemmed Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
title_short Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows
title_sort coaxial thermocouples for heat transfer measurements in long duration high enthalpy flows
topic heat transfer measurement
coaxial thermocouple
long-duration
semi-infinite
high enthalpy
url https://www.mdpi.com/1424-8220/20/18/5254
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AT jinpingli coaxialthermocouplesforheattransfermeasurementsinlongdurationhighenthalpyflows
AT xiaoyuanzhang coaxialthermocouplesforheattransfermeasurementsinlongdurationhighenthalpyflows
AT hongchen coaxialthermocouplesforheattransfermeasurementsinlongdurationhighenthalpyflows