介孔二氧化硅双重孔隙的导热特性研究  

Study on Thermal Conductance in Bimodal-Pore Structure of Mesoporous Silica

作　　者：魏高升[1] 黄超[1] 崔柳 杜小泽[1] WEI Gaosheng;HUANG Chao;CUI Liu;DU Xiaoze(Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education,North China Electric PowerUniversity,Beijing 102206,China)

机构地区：[1]华北电力大学电站能量传递转化与系统教育部重点实验室,北京102206

出　　处：《工程热物理学报》2023年第2期517-524,共8页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.51776066,No.51806064)。

摘　　要：介孔二氧化硅颗粒的双重孔隙分布特征对材料的导热性能具有显著影响。本文通过微观形态表征分析了介孔二氧化硅的复合孔道,并基于受限空间内的气体分子动力学理论,构建了双重孔隙结构的热导率关联模型。为了验证理论模型的合理性与准确性,采用瞬态热带法测量了介孔二氧化硅材料(MCM-41和SBA-15)在0~30 MPa和20~550℃的环境压力及温度变化下的有效热导率。实验测量结果表明,本文理论模型可以有效预测介孔二氧化硅颗粒热导率的变化规律。进一步根据模型分析可知,材料热导率随着环境温度及压力的升高而增长,表现出明显的正相关性,同时其微观结构的差异也是热导率变化的决定性因素。The bimodal-pore distributed features of mesoporous silica particles have great effects on their thermal insulation properties. In this paper, the actual packing state of mesoporous silica particles is simplified based on their microstructure characterizations. Moreover, a thermal conductivity prediction model of bimodal-pore distributed mesoporous silica is proposed according to the gas molecular dynamics theory. To verify the rationality and accuracy of the proposed model, the thermal conductivity of mesoporous silica particle samples is measured via the transient hot-strip method in a nitrogen atmosphere of 0~30 MPa and a temperature of 20~550℃. The experimental measurement results show that the theoretical model can effectively predict the variation of thermal conductivity of particle materials. Further analysis of the model shows that the thermal conductivity of the material increases as the ambient temperature and pressure increase. The difference in microstructure is also a decisive factor in the change of thermal conductivity.

关 键 词：介孔二氧化硅颗粒 双重孔隙结构 有效热导率 模型预测 

分 类 号：TK121[动力工程及工程热物理—工程热物理]