Question

A metal pipe with an outside diameter (OD) of 12cm is covered with an insulation material [k-0.07W/m.°C] of 2.5cm thick. If the outer pipe wall is at 100°C and the outer surface of the insulation is at 20°C, find the heat loss from the pipe per meter length

Answer 1

Q= 65.57 W

Step-by-step explanation:

Given that

Outer diameter=12 cm

Thickness = 2.5 cm

So inner diameter = 7 cm

Outer wall temperature =100° C

Outer surface of insulation = 20 °C

As we know that thermal resistance of cylinder pipe is given as follows

`R_(th)=(ln(r_2)/(r_1))/(2\pi Kl)`

Now by putting the values

Lets put l = 1 m because given that find heat loss per unit length

`R_(th)=(ln(6)/(3.5))/(2\pi * 0.07* 1)`

So

`R_(th)=1.22 (W)/(m-K)`

now heat loss Q

`Q=(\Delta T)/(R_(th))`

`Q=(100-20)/(1.22)`

Q= 65.57 W