Question

A horizontal steam pipe (d i = 7.8 cm, d 0 = 8.9 cm) carries saturated steam at 200.5 0 C. A 2 cm thick insulation ( k = 0.05 w/m-K) is installed to reduce heat loss to the ambient air at 25 0 C. Neglecting internal convection resistance and radiation loss from the external surface, Calculate the rate of heat loss per meter length of the pipe.

Answer 1

Answer:

$\frac{Q}{L} = 148.54 w/m$

Explanation:

Given data:

$D_i = 7.8 cm$

$D_O = 8.9 cm$

saturated steam = 200.5 degree C

thickness of insulation is 2 cm

$T_{\infty} = 25$ degree C

Heat loss per minute is calculated as

$\frac{Q}{L} = \frac{(T_O - T_{\infty}) * 2\pi K}{ln( \frac{8.9/2 + 2}{8.9/2})}$

$\frac{Q}{L} = \frac{(200.5 - 25) (2 \pi (0.05))}{ln 1.449}$

$\frac{Q}{L} = 148.54 w/m$