Question

2. Two parallel plastic plates 1 and 2 with large surface areas are maintained at uniform temperatures of T1=900 K and T2=650 K, respectively. Their emissivities are ?1 = 0.5 and ?2 = 0.8, respectively. A thin aluminium sheet with an emissivity of 0.15 on both sides is placed between these two plates. The plates exchange heat with each other and with the aluminium sheet, but only the plate surface facing each other are to be considered. Determine the reduction in the net rate of radiation heat transfer per unit surface area between two plastic plates when the aluminium sheet is placed.

Answer 1