Fourier Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Fourier Number

Fourier number ( \(Fo\) ) (dimensionless number) is giving 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

\(\large{ Fo = \frac{\alpha t}{l^2}  }\)         

Where:

\(\large{ Fo }\) = Fourier number

\(\large{ \alpha }\)  (Greel symbol alpha) = thermal diffusivity

\(\large{ t }\) = time

\(\large{ l }\) = characteristic length

Solve for:

\(\large{ \alpha = \frac{  Fo l^2    }{ t }   }\)

\(\large{ t = \frac{  Fo l^2    }{ \alpha }   }\)

\(\large{ L =  \sqrt   { \frac{ \alpha t }{ Fo }  }   }\)

 

Tags: Equations for Heat Transfer Equations for Temperature