Question-

A mild steel pipe of 50 mm inside diameter and 2 mm wall thickness carries hot water under pressure at a temperature of 120 C, whilst ambient temperature is 20 C. Calculate;

a) The overall heat transfer co-effecient based upon the outside diameter of the pipe.

b) Using the heat transfer coefficient from part (a), the rate of heat loss per metre length of pipe.

Data:

i) the thermal conductivity of mild steel is 45 W/mK.

ii) the inside surface heat transfer coefficient is 1500 W/m2K.

iii) the outside surface heat transfer coefficient is 20 W/m2K.

Use the overall heat transfer coefficient method to calculate the above.