Nusselt Number

Nusselt number, abbreviated as Nu, a dimensionless number, describes the ratio of convective heat transfer to conductive heat across a boundary.

 

Nusselt number formula
\(\large{ Nu = \frac{h \; l_c}{k}   }\)
Symbol	English	Metric
\(\large{ Nu }\) = Nusselt number	\(\large{dimensionless}\)
\(\large{ l_c }\) = characteristic length	\(\large{ft}\)	\(\large{m}\)
\(\large{ h }\) = heat transfer coefficient	\(\large{\frac{Btu}{hr-ft^2-F}}\)	\(\large{\frac{W}{m^2-K}}\)
\(\large{ k }\) = thermal conductivity	\(\large{\frac{Btu-ft}{hr-ft^2-F}}\)	\(\large{\frac{W}{m-K}}\)

 

Nusselt number calculator