Fourier Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Fourier number, abbreviated as Fo, also called Fourier modulus, a dimensionless number, is the ratio of heat conduction rate to the rate of thermal energy storage in a solid.  This is mainly used in unsteady state heat transfer.


Fourier number formula

\(\large{ Fo = \frac{\alpha \; t_c }{l_c^2  }  }\) 
Symbol English Metric
\(\large{ Fo }\) = Fourier number \(\large{ dimensionless }\)
\(\large{ l_c }\) = characteristic length \(\large{ ft }\) \(\large{ m }\)
\(\large{ t_c }\) = characteristic time \(\large{ sec }\) \(\large{ s }\)
\(\large{ \alpha }\)  (Greel symbol alpha) = thermal diffusivity \(\large{\frac{ft^2}{sec}}\) \(\large{\frac{m^2}{s}}\)


Fourier number calculator



P D Logo 1

Tags: Heat Transfer Equations Temperature Equations Calculators