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contributor authorL. P. Wang
contributor authorS. Basu
contributor authorZ. M. Zhang
date accessioned2017-05-09T00:45:00Z
date available2017-05-09T00:45:00Z
date copyrightJuly, 2011
date issued2011
identifier issn0022-1481
identifier otherJHTRAO-27917#072701_1.pdf
identifier urihttp://yetl.yabesh.ir/yetl/handle/yetl/146666
description abstractThe determination of emissivity of layered structures is critical in many applications, such as radiation thermometry, microelectronics, radiative cooling, and energy harvesting. Two different approaches, i.e., the “indirect” and “direct” methods, are commonly used for computing the emissivity of an object. For an opaque surface at a uniform temperature, the indirect method involves calculating the spectral directional-hemispherical reflectance to deduce the spectral directional emissivity based on Kirchhoff’s law. On the other hand, a few studies have used a combination of Maxwell’s equations with the fluctuation-dissipation theorem to directly calculate the emissivity. The present study aims at unifying the direct and indirect methods for calculating the far-field thermal emission from layered structures with a nonuniform temperature distribution. Formulations for both methods are given to illustrate the equivalence between the indirect and the direct methods. Thermal emission from an asymmetric Fabry–Pérot resonance cavity with a nonuniform temperature distribution is taken as an example to show how to predict the intensity, emissivity, and the brightness temperature. The local density of states, however, can only be calculated using the direct method.
publisherThe American Society of Mechanical Engineers (ASME)
titleDirect and Indirect Methods for Calculating Thermal Emission From Layered Structures With Nonuniform Temperatures
typeJournal Paper
journal volume133
journal issue7
journal titleJournal of Heat Transfer
identifier doi10.1115/1.4003543
journal fristpage72701
identifier eissn1528-8943
keywordsTemperature
keywordsEmissivity
keywordsEmissions
keywordsCavities
keywordsResonance AND Brightness (Photometry)
treeJournal of Heat Transfer:;2011:;volume( 133 ):;issue: 007
contenttypeFulltext


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