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

`(Q)/(L) = 148.54 w/m`

Step-by-step 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

`(Q)/(L) = ((T_O - T_(\infty)) * 2\pi K)/(ln( (8.9/2 + 2)/(8.9/2)))`

`(Q)/(L) = ((200.5 - 25) (2 \pi (0.05)))/(ln 1.449)`

`(Q)/(L) = 148.54 w/m`