Ch13-Radiation from Surfaces

Ch13-Radiation from Surfaces - Chapter 13 Radiation...

Info iconThis preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 13 Radiation Exchange Between Surfaces
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The View Factor (also Configuration or Shape Factor) The view factor, is a geometrical quantity corresponding to the fraction of the radiation leaving surface i that is intercepted by surface j . ij F , i j ij i i q F A J = The view factor integral provides a general expression for F ij . Consider exchange between areas . ij F i j dA and dA : 2 1 i j i j ij i j A A i F dAdA A R θ π = ∫ ∫ cos cos 2 i j i j i i i j i i i j dq I dAd J dAdA R ϖ - = = cos cos cos
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
P. 13.106
Background image of page 10
Radiation Shields High reflectivity (low ) surface(s) inserted between two surfaces for which a reduction in radiation exchange is desired. α ε = Consider use of a single shield in a two-surface enclosure, such as that associated with large parallel plates: Note that, although rarely the case, emissivities may differ for opposite surfaces of the shield.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Radiation Network: ( 29 4 4 1 2 12 1 2 31 3 2 1 2 1 1 1 13 31 3 3 2 3 3 32 2 2 1 1 1 1 1 1 T T q q q A A F A A A F A σ ε - = = - = - - - - + + + + + , , , , The foregoing result may be readily extended to account for multiple shields and may be applied to long, concentric cylinders and concentric spheres, as well as large parallel plates.
Background image of page 12
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Directional Considerations and the Concept of Radiation Intensity Radiation emitted by a surface will be in all directions associated with a hypothetical hemisphere about the surface and is characterized by a directional distribution. Direction may be represented in a spherical coordinate system characterized by the zenith or polar angle and the azimuthal angle .
Background image of page 14
Image of page 15
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 23

Ch13-Radiation from Surfaces - Chapter 13 Radiation...

This preview shows document pages 1 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online