# Heat Transfer by Conduction Resistance through a Cylindrical Wall

on . Posted in Thermodynamics

## Heat Transfer by Conduction resistance through a Cylindrical Wall Formula

$$\large{ R_t = \frac { ln \; \left( \frac {r_2 } { r_1 } \right) } { 2 \; \pi \; k \; l } }$$
Symbol English Metric
$$\large{ R_t }$$ = thermal resistance $$\large{\frac{hr-F}{Btu}}$$ $$\large{\frac{K}{W}}$$
$$\large{ l }$$ = length of material $$\large{ft}$$ $$\large{m}$$
$$\large{ ln }$$ = natural logarithm $$\large{dimensionless}$$
$$\large{ \pi }$$ = Pi $$\large{3.141 592 653 ...}$$
$$\large{ r_1 }$$ = radius inside diameter (ID) $$\large{in}$$ $$\large{mm}$$
$$\large{ r_2}$$ = radius outside diameter (OD) $$\large{in}$$ $$\large{mm}$$
$$\large{ k }$$ = thermal conductivity $$\large{\frac{Btu-ft}{hr-ft^2-F}}$$ $$\large{\frac{W}{m-K}}$$