کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
659526 | 1458108 | 2011 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Thermal conductivities study on silica aerogel and its composite insulation materials
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
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 970Â K and from 0.045Â 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 10Â m2Â kgâ1, and the specific spectral extinction coefficients of aerogel are larger than 7Â m2Â kgâ1 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.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 54, Issues 11â12, May 2011, Pages 2355-2366
Journal: International Journal of Heat and Mass Transfer - Volume 54, Issues 11â12, May 2011, Pages 2355-2366
نویسندگان
Gaosheng Wei, Yusong Liu, Xinxin Zhang, Fan Yu, Xiaoze Du,