高温多孔材料中气流温度的热电偶测量误差分析

发布时间：2018-01-23 12:00

本文关键词： 多孔材料温度测量热电偶蒙特卡罗法局部非热平衡　出处：《太阳能学报》2017年03期 　论文类型：期刊论文

【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。
[Abstract]:The numerical simulation of the heat transfer at the node of the thermocouple is carried out. The measurement error of air flow temperature in high temperature porous materials is studied. Firstly, the local non-thermal equilibrium model and Monte Carlo method are used to solve the radiation convection coupling heat transfer of porous materials in tubes, and the velocity field and temperature field are obtained. According to the velocity field and temperature field, the heat transfer model of thermocouple node is established based on energy balance, and the radiation heat transfer between thermocouple node and surrounding porous skeleton is solved by Monte Carlo method. According to the isothermal condition of pipe wall, the difference between thermocouple node temperature and local air flow temperature is analyzed, and the pipe wall temperature and airflow velocity are discussed. The results show that the higher the tube wall temperature, the greater the air flow temperature measurement error, and the maximum error is 10.4 when the tube wall temperature is 1500K; With the increase of inlet velocity, the deviation degree of node temperature relative to airflow temperature decreases, and the deviation peak occurs in the range of dimensionless diameter r / R ~ (0.6) ~ (0. 8); Reducing node size and nodal surface emissivity can effectively reduce the temperature measurement error.
【作者单位】：哈尔滨工业大学能源科学与工程学院;
【基金】：国家自然科学基金(51176308) 国防基础科研重点项目(B2320132001)
【分类号】：TB383.4;TH811
【正文快照】： 0引言热电偶测温已广泛应用于工业生产和科学研究;在对流体温度测量时,由于存在装配误差、传热误差和动态响应误差等,热电偶示值与流体真实温度存在差异[1]。针对传热误差的分析和修正,国内外学者已经展开大量研究[2,3]。多孔材料在传热领域具有广泛应用前景,如太阳集热器和相

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