Concept explainers
Consider a flat plate or a plane wall with a thickness L and a long cylinder of radius
The characteristic length for a long cylinder and flat plate
Explanation of Solution
Characteristic length for long cylinder:
For long cylinders heat transfer through ends can be neglected, as the surface area at ends is negligible in comparisons with the total surface area of cylinder.
“r” is radius of the cylinder.
“L” is length of the cylinder.
Characteristic length for plane wall or flat plate:
The plate should be very thin so that internal resistance of the plate is negligible and lumped parameter analysis can be used.
For thin plates heat transfer through ends can be neglected as, heat transfer area at ends is negligible in compression with total surface area of the plate.
L = thickness of the plate.
“b” and “h” are width and height of the plate.
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Chapter 3 Solutions
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