A 15-mm OD copper tube conveys hot hydraulic oil. In order to dissipate the heat and cool the oil, someone suggests that the bare tube be covered with a tight-fitting, silicone rubber hose. Was this person napping in the nut pile the day God was cracking nuts? Evaluate this suggestion, assuming the copper surface temperature is 150'C, the rubber is 5-mm thick and has a thermal conductivity of 0.21 W/m-K, and the tube is surrounded by air where h = 14 W/m2-K and
T\infty = 25'C. Determine the
a) heat loss per unit length (W/m) from the bare tube;
b) heat loss per unit length (W/m) from the tube covered with 5mm-thick rubber;
c) thickness of rubber that maximizes the heat loss.
Hope you include the assumptions in your answer.