Question

A steel pipe has an inner diameter of 50mm and other diameter of 100mm. The outside temperature is 400°C and the inside temperature is 120°C. The thermal conductivity 60W/mK. Calculate the heat flow from the outside to the inside for 1m length.

Answer 1

Heat flow equals 152.287 kW

Step-by-step explanation:

For a hollow cylinder the resistance to heat flow is given by

`R_(cylinder)=(ln((r_(2))/(r_(1))))/(2\pi KL)`

where,

`r_(2)=` outer radius

`r_(1)=` inner radius

`K=` conductivity of heat

`L=` length of cylinder

Applying the given values we get

`R_(cylinder)=(ln((100)/(50)))/(2\pi * 60(W)/(mK)* 1)`

`\therefore R_(cylinder)=0.001838`

Now the heat flow is given by

`\dot{Q}=(\Delta T)/(R_(cylinder))\\\\\dot{Q}=(400-120)/(0.001838)=152.287kW`