Problem 2 Air flows at 120 °C in a thin-wall stainless-steel tube with h=65 W/m²-K. The inside diameter of the tube is 2.5 cm and the wall thickness is 0.4 mm. k = 18 W/m-K for the steel. The tube is exposed to an environment with h = 6.5 W/m² K and T, = 15 °C. Calculate the overall heat transfer coefficient and the heat loss per meter of length. What thickness of an insulation having k = 0.04 W/m K should be added to reduce the heat loss by 90 percent? Problem 3