Heat is to be transferred from an unknown fluid to air through an aluminum wall. It is proposed that rectangular fins 1.2 mm thick and 6.35 mm long be added to the surface to increase the heat transfer. The fins will be spaced 2.0 mm apart. The wall is 3 mm thick and the air-side convective heat transfer coefficient is 45 W/m2-K.
(a) If the fins are made from aluminum and the unknown fluid’s he is 550 W/m2-K, then:
(1) Find the percent of increase in q if the fins are added to the air side.
(2) Find the percent of increase in q if the fins are added to the other fluid’s side.
(3) Find the increase in heat transfer if fins are added to both sides.
(b) Rework part (a) assuming the fins are made of copper.
(c) Rework part (a) if he of both sides is changed to 55 kW/m2 -K.
(d) Discuss the implications of the answers from parts (a), (b), and (c).