Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470501979
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
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Textbook Question
Chapter 12, Problem 12.49P
An opaque surface with the prescribed spectral, hemi- spherical reflectivity distribution is subjected to the spectral irradiation shown
(a) Sketch the spectral, hemispherical absorptivity distribution.
(b) Determine the total irradiation on the surface.
(c) Determine the radiant flux that is absorbed by the surface.
(d) What is the total, hemispherical absorptivity of this surface?
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An opaque surface with the prescribed spectral, hemispherical reflectivity distribution is subjected to the spectral irradiation shown.
Assume that p₁ = 0.5 and G₁ = 650 W/m²-μm.
G₁
1.0
P₁
0 5
10
15
λ(um)
(a) Determine the total irradiation on the surface, in W/m².
G =
W/m²
(b) Determine the radiant flux that is absorbed by the surface, in W/m².
Gabs = i
W/m²
(c) What is the total, hemispherical absorptivity of this surface?
α = i
G₂(W/m².μm)
5
10
15
20
λ (um)
An opaque surface with the prescribed spectral, hemispherical reflectivity distribution is subjected to the spectral irradiation shown.
Assume that p₁ = 0.5 and G₁ = 700 W/m².um.
1.0
P₁
5
10 15
λ (um)
(a) Determine the total irradiation on the surface, in W/m².
G = i
W/m²
G₂ (W/m².um)
(b) Determine the radiant flux that is absorbed by the surface, in W/m².
W/m²
Gabs
i
(c) What is the total, hemispherical absorptivity of this surface?
α = i
G₁
10
5
10 15 20
λ (um)
An opaque surface with the prescribed spectral, hemispherical reflectivity distribution is subject
to the spectral irradiation shown. Find:
1.0
600
0.5
0
05
10
15
λ (μm)
G₂(W/m²•μm)
300
0
0
5
10
15 20
20
λ (μm)
(1) Find the spectral absorptivity distribution (αλ).
(2) Determine the total irradiation G on the surface
(3) Determine the radiant flux that is absorbed by the surface.
(4) The total absorptivity a.
Chapter 12 Solutions
Fundamentals of Heat and Mass Transfer
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