Show that the effective conductance. A1 F 1-2 for two black parallel plates of equal area connected by re-radiating walls at a constant temperature is
GIVEN
• Two black parallel planes of equal area connected by re-radiating walls at a constant temperature
FIND
• Show that
SKETCH
Since A1 and A2 cannot see themselves, F1–1 = F2–2 = 0.
The shape factors from a single surface must sum to unity
Substituting this and A1 = A2 into the expression for A1 F12
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