1. Nov 24, 2015

### aerograce

1. The problem statement, all variables and given/known data
A hemispherical cavity of radius 1.0 m is covered with a plate having an opening of 0.2 m
diameter drilled at its centre. The inner surface of the plate is maintained at 700 K by a heater
embedded in the surface. Let the inner surface of the plate be 1, the surface of the hemisphere
be 2, and the virtual surface of the opening be 3. The surface can be assumed to be black and
the hemisphere taken to be well insulated.
(a) Determine View Factor F2-2.
(b) Determine the temperature of the surface of the hemisphere.
(c) Determine the power input to the heater.

2. Relevant equations
E=σT^4

3. The attempt at a solution
First, by energy balance, F2-2+F2-1+F2-3=1
And it is known that F1-2=1, so A1F1-2 = A2F2-1 (Reciprocity Rule)
Then it is obtained that F2-1=0.495
Similarly, F2-3=0.005
so F2-2=0.5
However, I dont know how to continue with question b and c. Could you help me with it?

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2. Nov 29, 2015