Thermal conductivities study on silica aerogel and its composite insulation materials
Thermal conductivities study on silica aerogel and its composite insulation materials
复制标题
二氧化硅气凝胶及其复合绝热材料的导热性能研究
DOI：
10.1016/j.ijheatmasstransfer.2011.02.026
复制
发表时间：
2011-05-01
影响因子：
5.2
通讯作者：
Du, Xiaoze
中科院分区：
文献类型：
--
作者：
Wei, Gaosheng;Liu, Yusong;Du, Xiaoze
本文对白炭黑、硬硅钙石型硅酸钙和硬硅钙石-气凝胶复合绝热材料的导热系数进行了理论和实验研究。通过红外光谱测量得到了二氧化硅气凝胶和硬硅钙石型硅酸钙样品的透射光谱。然后应用比尔定律得到三种材料的相应消光系数谱。采用瞬态热条法（THS），在300 ~ 970 K和0.045 Pa ~大气压范围内测量了气凝胶、硬硅钙石型硅酸钙和硬硅钙石-气凝胶复合绝热材料的导热系数。将基于单胞法建立的气固耦合传热的导热系数模型与实验测量结果进行了比较。结果表明，有效导热系数模型与实验数据吻合较好。在整个光谱范围内，硬硅钙石型钙的比光谱消光系数大于10 m（2）kg（-1），气凝胶的比光谱消光系数大于7 m（2）kg（-1）。硬硅钙石型硅酸钙的密度是影响硬硅钙石-气凝胶复合绝热材料有效导热系数的关键因素，气凝胶的密度对其影响不大。两种材料在高温下复合后，有效导热系数会大大降低。(C)2011爱思唯尔有限公司保留所有权利。
This paper presents a theoretical and experimental study on thermal conductivities of silica aerogel, xonotlite-type calcium silicate and xonotlite-aerogel composite insulation material. The transmittance spectra of silica aerogel and xonotlite-type calcium silicate samples are obtained through FTIR measurements. The corresponding extinction coefficient spectra of the three materials are then obtained by applying Beer's law. The thermal conductivities of aerogel, xonotlite-type calcium silicate, and xonotlite-aerogel composite insulation material are measured from 300 to 970 K and from 0.045 Pa to atmospheric pressure with the transient hot-strip (THS) method. The thermal conductivity models developed for coupled heat transfer of gas and solid based on the unit cell method are compared with the experimental measurement results. It is shown that the effective thermal conductivity models matches well with the experimental data. The specific spectral extinction coefficients of xonotlite-type calcium are larger than 10 m(2) kg(-1), and the specific spectral extinction coefficients of aerogel are larger than 7 m(2) kg(-1) over the whole measured spectra. The density of xonotlite-type calcium silicate is the key factor affecting the effective thermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has little influence. The effective thermal conductivity can be lowered greatly by composite of the two materials at an elevated temperature. (C) 2011 Elsevier Ltd. All rights reserved.