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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Reducing Thermal Radiation Between Parallel Plates in the Far-to-Near Field Transition Regime

Get access (open in a dialog) DOI: 10.1615/IHTC15.rad.009188
pages 7145-7153

Resumo

The present work investigates the conditions of interference that allow decreasing the radiative heat transfer between two semi-infinite parallel plates. For this purpose, net radiative heat transfer fluxes exchanged by the plates are calculated as a function of the distance between them for various dielectric and metallic materials. A decrease of the propagative component larger than 85% is observed in the case of highly-reflective metals, while a poor reduction of few percents is observed for dielectric materials. However, the appearance of the evanescent contribution becomes significant before this reduction starts, resulting in a total flux decrease of only few percents even in the case of metals. An analysis as a function of temperature shows that the decrease of the total flux is more significant at low temperatures despite the fact that the decrease of the propagative component is larger at high temperatures. This underlines that the distance at which interferences of propagative waves appear and the distance at which evanescent waves appear are different. In the case of aluminum, the heat flux minimum and the beginning of the interferences are respectively found at T??d=900 ???m K and T??d=4000 ???m K. Spectral and directional analyses of propagative radiative heat fluxes are also performed and show that resonances occur at frequencies given by the waveguide theory in specific directions.