Evaluate the net heat transfer between the disks described in Problem 23.33 if they are bases of a cylinder with the side wall considered a nonconducting, re-radiating surface. How much energy will be lost through the hole?

Data From Problem 23.33

Two disks are oriented on parallel planes separated by a distance of 10 in., as shown in the accompanying figure. The disk to the right is 4 in. in diameter and is at a temperature of 500°F. The disk to the left has an inner ring cut out such that it is annular in shape with inner and outer diameters of 2.5 in. and 4 in., respectively. The disk surface temperature is 210°F. Find the heat exchange between these disks if
a. They are black
b. They are gray ε₁ = 0.6, ε₂ = 0. 3

Transcribed Image Text:

4 in. 2.5 in. 10 in. 2.