# Three surfaces form a 3-surface enclosure. The surfaces have the following properties. Surface 1: A1 = 1 m2. F11 = 0. F12 = 0. T1 = 300 K. Surface 2:…

Three surfaces form a 3-surface enclosure. The surfaces have the following properties. Surface

1: A1 = 1 m2. F11 = 0. F12 = 0.2. T1 = 300 K.

Surface 2: A2 = 0.8 m2. F22 = 0. T2 = 400 K.

Surface 3: F32 = 0.3.

All temperatures are constant and uniform.

a. Determine all unknown view (shape) factors and areas. 

b. Determine the rate of heat transfer between surface 1 and 2, q12 if all three surfaces are

black bodies. 

c. Determine the temperature of surface 3, T3, if all three surfaces are black bodies and the

net rate of heat transfer from surface 3 is q3 = 2018 W. 

For parts d, e, f and g assume all three surfaces are grey bodies with emissivities of ε1 = 0.1, ε2

= 0.5 and ε3 = 0.7. q”3 = 1009 W/m2 and J3 = 5555 W/m2.

d. Determine the radiosities of surface 1 and surface 2. 

e. Determine the rate of heat transfer between surface 1 and 3, q13. 

f. Determine the net rate of heat transfer from surface 1. 

g. Determine the temperature of surface 3, T3. 