Refer to the diagram shown below.
Neglect the area at the ends of the pipe because 5 cm << 10 m.
The diameter of the pipe is
d = 5 cm = 0.05 m
The difference in temperature between the surface temperature and ambient temperature is
ΔT = 80 - 16 = 64 °C = 64 K
The convective heat transfer coefficient is
h = 25 W/(m²-K)
Calculate the surface area of the pipe.
A = π*(0.25 m)*(10 m) = 2.5π m²
The convective heat loss from the pipe surface is
[tex]Q=hA \Delta T \\ = (25 \, \frac{W}{m^{2}-K} )*(2.5 \pi \, m^{2})*(64 \, K) \\ = 1.2566 \times 10^{4} \, W[/tex]
That is,
Q = 12.566 x 10³ W = 12.566 kW
Answer: 12.6 kW (nearest tenth)
