描述微纳米多孔复合绝热材料的单元体传热模型  

Unit cell model for micro,nano-porous composite insulation material

作　　者：魏高升[1] 张欣欣[2] 于帆[2] 

机构地区：[1]华北电力大学能源与动力工程学院,电站设备状态监测与控制教育部重点实验室,北京102206 [2]北京科技大学机械工程学院,北京100083

出　　处：《北京科技大学学报》2008年第7期781-785,共5页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(No.50276003);华北电力大学博士学位教师科研基金资助(No.200622013)

摘　　要：根据硬硅钙石-气凝胶复合绝热材料的微观结构特点,建立了描述材料内气固耦合导热的三维单元体传热模型.通过模型计算对硬硅钙石型硅酸钙、气凝胶及硬硅钙石-气凝胶复合绝热材料的导热系数进行了对比研究.结果表明:硬硅钙石型硅酸钙密度是影响复合绝热材料有效导热系数的关键因素,而气凝胶密度的影响不大;在高温下,复合绝热材料的导热系数要明显低于硬硅钙石型硅酸钙及二氧化硅气凝胶的导热系数.Based on the microstructure features of xonotlite-aerogel composite insulation material, a three dimensional unit cell model was developed for the coupled heat transfer of gas and solid in the material. The effective thermal conductivities of xonotlite-type calcium silicate, aerogel and xonotlite-aerogel composite insulation material were compared by model calculation. The results show that the density of xonotlite-type calcium silicate has great influence on the effective thermal conductivity of xonotlite-aerogel composite insulation material, but the density of aerogel has little influence. The effective thermal conductivity of xonotlite-aerogel composite insulation material is apparently lower than those of xonotlite-type calcium silicate and aerogel at an elevated temperature.

关 键 词：有效导热系数 纳米孔绝热材料 硬硅钙石型 硅酸钙 气凝胶 多孔介质 

分 类 号：TB332[一般工业技术—材料科学与工程] TK121[动力工程及工程热物理—工程热物理]