Question

Determine F12 and F21 for the following configurations: (a) A long semicircular duct with diameter of 0.1 meters: (b) A hemisphere-disk arrangement, with hemisphere diameter of 0.1 meters:

Answer 1

Answer:

long duct: 1.0 and 0.424

Hemisphere 1.0 ; 0.125; 0.5

Explanation:

For a long duct:

By inspection, $F_{12} = 1.0$

Calculating by reciprocity, $F_{21} = \frac{A_{1} }{A_{2}F_{12} } = \frac{2RL}{\frac{3}{4}*2\pi RL }* 1.0\\ = 0.424$

Hemisphere:

By reciprocity gives = 0.125

using the summation rule: $F_{21} + F_{22} + F_{23} = 1$

However, because this is a hemisphere, the value will be= 0.5 * 1

                                                                                               = 0.5