# Heat Transfer by Conduction through a Cylindrical Wall

Written by Jerry Ratzlaff on . Posted in Thermodynamics This calculation determines the heat transfer through a cylinder wall by conduction.

## Heat Transfer by Conduction through a Cylindrical Wall formula

 $$\large{ Q_c = \frac { 2 \; \pi \; k \; l \; \left( T_1 \;-\; T_2 \right) } { ln \; \left( \frac {r_2 }{ r_1 } \right) } }$$

### Where:

 Units English Metric $$\large{ Q_c }$$ = heat transfer by conduction $$\large{\frac{Btu}{hr}}$$ $$\large{W}$$ $$\large{ l }$$ = length of material $$\large{ft}$$ $$\large{m}$$ $$\large{ r_1 }$$ = radius inside diameter (ID) $$\large{in}$$ $$\large{mm}$$ $$\large{ r_2 }$$ = radius outside diameter (OD) $$\large{in}$$ $$\large{mm}$$ $$\large{ T_1 }$$ = temperature of one surface of the wall $$\large{F}$$ $$\large{K}$$ $$\large{ T_2 }$$ = temperature of the other surface of the wall $$\large{F}$$ $$\large{K}$$ $$\large{ k }$$ = thermal conductivity $$\large{\frac{Btu-ft}{hr-ft^2-F}}$$ $$\large{\frac{W}{m-K}}$$ 