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Heat transfer on micro- and nanoscale

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High quality heat insulators may save running costs of heating in most of modern buildings. Therefore, a large effort is introduced in order to improve the insulation capabilities of various materials. This study aims at polymer foams, which currently present the best combination of the insulating properties and price. Heat transport in this material occurs mainly by mechanisms of conduction and radiation because the pores are too narrow for any kind of convection. Very often the description of heat transfer in foams is oversimplified or the radiation term is neglected. This work tries to mend this problem. Reconstructed polymer foams generated by Voronoi tesselation were employed as the input for the computation of thermal properties of polymer foams. 

It is known that when the characteristic length of the system (i.e., the foam cell dimension) is comparable to the mean free path of the gas molecules, the thermal conductivity of such gas begins to decrease.

Due to the nanoscalle effects the profile of temperature in nano-structured foam becomes non-linear, because the radiation effects becomes significant. 

 Published Results:

Ferkl P., Pokorný R., Kosek J.: Multiphase approach to coupled conduction–radiation heat transfer in reconstructed polymeric foams, International Journal of Thermal Sciences, 2014, 83: 68–79.

Ferkl P., Pokorný R., Bobák M., Kosek J.: Heat transferinone-dimensionalmicro-andnano-cellularfoams, Chemical Engineering Science, 2013, 97, 50–58.

 

Contact

Juraj Kosek
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+420 220 443 296

University of Chemistry and Technology Prague
Department of Chemical Engineering
Technicka 5
166 28 Prague 6
Czech Republic

University of West Bohemia
New Technologies Research Centre (NTC)
Univerzitní 8
306 14 Pilsen
Czech Republic