A pipe, 2cm diameter at $40^0C$ is placed in

(i) an air flow at $50^0C$ with $h = 20W/m^2K OR in (ii) water at $30^0C$ with $h = 70 W/m^2K$.

Find the heat transfer per unit length of the pipe and comment on the results in both cases.

Given,

d = 2cm = 0.02m (Diameter of pipe)

t1 = 40℃ = 313K (Temperature of pipe)

t2 = 50℃ = 323K (Surrounding temperature)

h = 20W/m2K (Convective heat transfer coefficient of surrounding medium)

l = 1m (Length of pipe)

Find: (1) Q (Heat transfer rate)

Solution:

Heat transfer rate …