Chapter 9, Problem 9.96P

The top surface $\left(0.5\text{m}\text{×}\text{0}\text{.5}\text{m}\right)$ of an oven is 60°C for a particular operating condition when the room air is 23°C. To reduce heat loss from the oven and to minimize burn hazard, it is proposed to create a 50-mm air space by adding a cover plate.

(a) Assuming the san oven surface temperature $T_s$ , for both situations, estimate the reduction in the convection heat loss resulting front installation of the cover plate. What is the temperature of the cover plate?
(b) Explore the effect of the cover plate spacing on the convection heat loss and the cover plate temperature for spacings in the range $5\le L\le 50\text{mm}$ . Is there an optimum spacing?