Solve the below:
Q: A natural convection air heater consists of an array of parallel, equally spaced vertical plates, which may be maintained at a fixed temperature Ts by embedded electrical heaters.
The plates are of length and width L = W = 300 mm and are in quiescent, atmospheric air at T8 = 20°C. The total width of the array cannot exceed a value of War = 150 mm. For Ts = 75°C, what is the plate spacing S that maximizes heat transfer from the array? For this spacing, how many plates comprise the array and what is the corresponding rate of heat transfer from the array?
