Thermodynamics HW Solutions 952

Thermodynamics HW - Chapter 12 Radiation Heat Transfer Radiation Exchange with Absorbing and Emitting Gases 12-61C A nonparticipating medium is

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Unformatted text preview: Chapter 12 Radiation Heat Transfer Radiation Exchange with Absorbing and Emitting Gases 12-61C A nonparticipating medium is completely transparent to thermal radiation, and thus it does not emit, absorb, or scatter radiation. A participating medium, on the other hand, emits and absorbs radiation throughout its entire volume. 12-62C Spectral transmissivity of a medium of thickness L is the ratio of the intensity of radiation leaving the medium to that entering the medium, and is expressed as L L e I I λ κ λ λ λ τ − = = , , and τ λ =1 - α λ . 12-63C Using Kirchhoff’s law, the spectral emissivity of a medium of thickness L in terms of the spectral absorption coefficient is expressed as . L e λ κ λ λ α ε − − = = 1 12-64C Gases emit and absorb radiation at a number of narrow wavelength bands. The emissivity- wavelength charts of gases typically involve various peaks and dips together with discontinuities, and show clearly the band nature of absorption and the strong nongray characteristics. This is in contrast to solids, clearly the band nature of absorption and the strong nongray characteristics....
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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