A 4-cm-diameter cylindrical enclosure with black surfaces, as shown in the accompanying sketch, has a 2-cm hole in the top cover. Assuming the walls of the enclosure are at the same temperature, determine the percentage of the total radiation emitted from the walls that escapes through the hole in the cover.
GIVEN
• Cylindrical enclosure of black surfaces shown above
• Cylinder diameter (D) = 4 cm = 0.04 m
• Diameter of hole in top (Dh) = 2 cm = 0.02 m
FIND
• The percentage of the total radiation emitted from the wall which will escape through the hole in the cover (Fe4).
ASSUMPTIONS
• The walls of the enclosure are at the same temperature
The total area of the interior of the enclosure (Ae) is
The shape factor between A4 and the enclosure is unity F4e = 1.
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