Question 6

A phase change fluid at 100°C is pumped through 3 m of a multi-layered pipe, which is

exposed to an external fluid current at 22°C. The innermost layer is made of steel

(thermal conductivity 13 W/m/K), with inner and outer radii 40 mm and 52 mm,

respectively. The second layer is made of insulating material (thermal conductivity 0.6

W/m/K), with outer radius equal to 70 mm. The convective heat transfer coefficients

associated to the internal and external fluids are respectively 1,329 W/m2/K and 150

W/m2/K. Calculate the heat transfer (absolute value) through the pipe thickness in kW

to 1 decimal place.

Note: use pi-3.1415