›› 2015, Vol. 24 ›› Issue (1): 14401-014401.doi: 10.1088/1674-1056/24/1/014401

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Near-field radiative heat transfer in mesoporous alumina

李静a, 冯妍卉a, 张欣欣a, 黄丛亮a, 王戈b   

  1. a School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China;
    b School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
  • 收稿日期:2014-08-01 修回日期:2014-09-09 出版日期:2015-01-05 发布日期:2015-01-05
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51422601), the National Basic Research Program of China (Grant No. 2012CB720404), and the National Key Technology Research and Development Program of China (Grant No. 2013BAJ01B03).

Near-field radiative heat transfer in mesoporous alumina

Li Jing (李静)a, Feng Yan-Hui (冯妍卉)a, Zhang Xin-Xin (张欣欣)a, Huang Cong-Liang (黄丛亮)a, Wang Ge (王戈)b   

  1. a School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China;
    b School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2014-08-01 Revised:2014-09-09 Online:2015-01-05 Published:2015-01-05
  • Contact: Feng Yan-Hui E-mail:yhfeng@me.ustb.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51422601), the National Basic Research Program of China (Grant No. 2012CB720404), and the National Key Technology Research and Development Program of China (Grant No. 2013BAJ01B03).

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摘要： The thermal conductivity of mesoporous material has aroused the great interest of scholars due to its wide applications such as insulation, catalyst, etc. Mesoporous alumina substrate consists of uniformly distributed, unconnected cylindrical pores. Near-field radiative heat transfer cannot be ignored, when the diameters of the pores are less than the characteristic wavelength of thermal radiation. In this paper, near-field radiation across a cylindrical pore is simulated by employing the fluctuation dissipation theorem and Green function. Such factors as the diameter of the pore, and the temperature of the material are further analyzed. The research results show that the radiative heat transfer on a mesoscale is 2～ 4 orders higher than on a macroscale. The heat flux and equivalent thermal conductivity of radiation across a cylindrical pore decrease exponentially with pore diameter increasing, while increase with temperature increasing. The calculated equivalent thermal conductivity of radiation is further developed to modify the thermal conductivity of the mesoporous alumina. The combined thermal conductivity of the mesoporous alumina is obtained by using porosity weighted dilute medium and compared with the measurement. The combined thermal conductivity of mesoporous silica decreases gradually with pore diameter increasing, while increases smoothly with temperature increasing, which is in good agreement with the experimental data. The larger the porosity, the more significant the near-field effect is, which cannot be ignored.

关键词: cylindrical pore, thermal conductivity, near-field radiation, mesoporous alumina

Abstract: The thermal conductivity of mesoporous material has aroused the great interest of scholars due to its wide applications such as insulation, catalyst, etc. Mesoporous alumina substrate consists of uniformly distributed, unconnected cylindrical pores. Near-field radiative heat transfer cannot be ignored, when the diameters of the pores are less than the characteristic wavelength of thermal radiation. In this paper, near-field radiation across a cylindrical pore is simulated by employing the fluctuation dissipation theorem and Green function. Such factors as the diameter of the pore, and the temperature of the material are further analyzed. The research results show that the radiative heat transfer on a mesoscale is 2～ 4 orders higher than on a macroscale. The heat flux and equivalent thermal conductivity of radiation across a cylindrical pore decrease exponentially with pore diameter increasing, while increase with temperature increasing. The calculated equivalent thermal conductivity of radiation is further developed to modify the thermal conductivity of the mesoporous alumina. The combined thermal conductivity of the mesoporous alumina is obtained by using porosity weighted dilute medium and compared with the measurement. The combined thermal conductivity of mesoporous silica decreases gradually with pore diameter increasing, while increases smoothly with temperature increasing, which is in good agreement with the experimental data. The larger the porosity, the more significant the near-field effect is, which cannot be ignored.

Key words: cylindrical pore, thermal conductivity, near-field radiation, mesoporous alumina

中图分类号:  (Thermal radiation)

  • 44.40.+a
65.80.-g (Thermal properties of small particles, nanocrystals, nanotubes, and other related systems)