Chapter 13, Problem 13.84P

Consider a cylindrical cavity of diameter $D=100\text{mm}$ turn and depth $L=50\text{mm}$ whose sidewall and bottom are diffuse and gray with an emissivity of 0.6 and are at a uniform temperature of 1500 K. The top of the cavity is open and exposed to surroundings that are large and at 300 K.
(a) Calculate the net radiation heat transfer from the cavity, treating the bottom and sidewall of the cavity as one surface (q_A).
(b) Calculate the net radiation heat transfer from the cavity, treating the bottom and sidewall of the cavity as two separate surfaces (q_B).
(c) Plot the percentage difference between q_Aand q_Bas a function of L over the range $5\text{mm}\le L\le 100\text{mm}$ .