高温多孔材料中气流温度的热电偶测量误差分析  

THERMOCOUPLE ERROR ANALYSIS OF THE GAS TEMPERATURE MEASUREMENT IN POROUS MATERIALS AT HIGH TEMPERATURES

作　　者：陈学[1] 刘博[1] 夏新林[1] 

机构地区：[1]哈尔滨工业大学能源科学与工程学院,哈尔滨150001

出　　处：《太阳能学报》2017年第3期846-851,共6页Acta Energiae Solaris Sinica

基　　金：国家自然科学基金(51176308);国防基础科研重点项目(B2320132001)

摘　　要：通过对热电偶结点传热的数值模拟,研究高温多孔材料内气流温度的测量误差。首先采用局部非热平衡模型和蒙特卡罗法求解管内多孔材料的辐射对流耦合换热,获得速度场和温度场;根据所得速度场和温度场,基于能量平衡建立热电偶结点的传热模型。再次利用蒙特卡罗法求解热电偶结点与周围多孔骨架的辐射换热,进而计算结点温度。针对管壁等温条件,分析稳态测量时热电偶结点温度与当地气流温度的差异,讨论管壁温度、气流速度、结点发射率和结点尺寸的影响。结果表明,管壁温度越高,气流温度测量误差越大,管壁温度1500 K时的最大误差为10.4%;气流入口速度增大,结点温度相对于气流温度的偏离程度减小,偏离峰值出现在无量纲管径r/R=0.6~0.8范围内;减小结点尺寸和降低结点表面发射率可有效减小测温误差。The error analysis of gas temperature measurement in porous materials using thermocouples was investigated by simulating the heat transfer process for the thermocouple junction. Firstly, the local thermal non-equilibrium model with Monte Carlo method （MCM） was used to solve the coupled heat transfer in porous material. The temperature and velocity fields of porous material were obtained and the heat transfer model of thermocouple junction was built based on a lumped energy balance. Then, MCM was adopted for the radiation simulation between the junction and solid matrix. The junction temperature was computed and compared with the local gas temperature at steady state. The temperature difference and effects of wall temperature, inlet velocity and the emissivity and diameter of junction were analysed. The results showed that the measurement errors increase with the increasing of wall temperature. The maximum error is 10.4% at the wall temperature 1500 K. As the inlet velocity increases, the discrepancy between the junction temperature and gas temperature decreases. The maximum discrepancy occurs in the region r/R=0.6 to 0.8. In addition, measurement errors can be reduced by using small diameter and low emissivity of junction.

关 键 词：多孔材料 温度测量 热电偶 蒙特卡罗法 局部非热平衡 

分 类 号：TK124[动力工程及工程热物理—工程热物理]