Effect of index of refraction on radiation characteristics in a heated absorbing, emitting, and scattering layer

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2911352· OSTI ID:6977395

Siegel, R ^[1]; Spuckler, C M ^[2]

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1. Lewis Research Academy, Cleveland, OH (United States)
2. Heat Transfer Branch, Cleveland, OH (United States)

The index of refraction can considerably influence the temperature distribution and radiative heat flow in semitransparent materials such as some ceramics. For external radiant heating, the refractive index influences the amount of energy transmitted into the interior of the material. Emission within a material depends on the square of its refractive index, and hence this emission can be many times that for a blackbody radiating into a vacuum. Since radiation exiting through an interface into a vacuum cannot exceed that of a blackbody, there is extensive reflection at the internal surface of an interface, mostly by total internal reflection. This redistributes energy within the layer and tends to make its temperature distribution more uniform. The purpose of the present analysis is to show that, for radiative equilibrium in a gray layer with diffuse interfaces, the temperature distribution and radiative heat flux for any index of refraction can be obtained very simply from the results for an index of refraction can be obtained very simply from the results for an index of refraction of unity. For the situation studied here, the layer is subjected to external radiative heating incident on each of its surfaces. The material emits, absorbs, and isotropically scatters radiation. For simplicity the index of refraction is unity in the medium surrounding the layer.

• OSTI ID: 6977395
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 114:3; ISSN JHTRAO; ISSN 0022-1481
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
CALCULATION METHODS
CERAMICS
ENERGY TRANSFER
HEAT FLUX
HEAT TRANSFER
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIANT HEAT TRANSFER
REFLECTION
REFRACTIVITY
TEMPERATURE DISTRIBUTION