Apparent Radiative Properties of an Isotropically Scattering Medium on a Diffuse Substrate

Abstract

The apparent directional and hemispherical radiative properties of a finite scattering medium bounded by a diffuse substrate are investigated. The isothermal medium emits, absorbs and isotropically scatters radiation. Specifically, the emittance and reflectance are determined. Using the principle of superposition, exact but simple equations are developed which express the apparent properties in terms of the properties of a medium not bounded by a substrate. Any arbitrary directional distribution of incident radiation can be handled. Integrodifferential equations of the initial value type for the radiative properties are developed and solved. In general, when the substrate emittance is less than the emittance of a semi-infinite scattering medium, the scattering layer acts as a source and increases the apparent emittance. Conversely when the substrate emittance is greater, the scattering layer acts as a shield and decreases the apparent emittance.

Department(s)

Mechanical and Aerospace Engineering

International Standard Serial Number (ISSN)

0022-1481

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1979 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Jan 1979

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