Full Content is available to subscribers

Subscribe/Learn More  >

Study on the Effective Thermal Conductivity of Macro, Mirco and Nano Porous Materials in the Light of the Knudsen Conduction/Radiation Coupling Effect

[+] Author Affiliations
Ulrich Gross, Khaled Raed

Technische Universität Bergakademie Freiberg, Freiberg, Germany

Paper No. IHTC14-22297, pp. 893-900; 8 pages
  • 2010 14th International Heat Transfer Conference
  • 2010 14th International Heat Transfer Conference, Volume 6
  • Washington, DC, USA, August 8–13, 2010
  • Conference Sponsors: Heat Transfer Division
  • ISBN: 978-0-7918-4941-5 | eISBN: 978-0-7918-3879-2
  • Copyright © 2010 by ASME


Thermal transport phenomena in porous media are characterized by conduction through solid matrix and filling gas, and also by radiation. The gas is dispersed in the porous system depending on the pore size distribution. In each pore, the gas contributes to the heat transfer between the pore surfaces. This effect is strongly influenced by pore size, gas atmosphere, accommodation coefficient and other factors. A recent publication of the present authors focused on modeling the change of the effective thermal conductivity when the gas atmosphere is changed. In the current contribution, the effect of pore size distribution on heat transfer in macro, micro, and nano insulation materials is presented. Samples were chosen from five different highly porous materials with different pore size distribution within the macro, micro, and nano classes. Porosity and pore size distribution of the samples were chosen to get a clear characterization of the materials. The effective thermal conductivity was measured by applying the radial heat flow method at temperatures up to 1000 °C. Evaluating Knudsen effect from the pore size distribution alone does not give plausible explanation for the measured thermal conductivity. However, it is important to consider the kind of connections between the pores. In case of nano materials, the radiation effect proves to be strongly dependent on the Knudsen number.

Copyright © 2010 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In