Thermal Diffusivity

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Thermal diffusivity, abbreviated as \(\alpha\) (Greek symbol alpha), is a measure of the transient thermal reaction of a material to a change in temperature.

Thermal Diffusivity formula

\(\large{ \alpha = \frac{ k }{ \rho \; Q }   }\)

\(\large{ \alpha = \frac{  Fo \; l_c^2    }{ t }   }\)     (Fourier number)

\(\large{ \alpha = Le \; D_m }\)     (Lewis number)

\(\large{ \alpha = \frac{ \nu }{  Pr  }  }\)     (Prandtl number)

\(\large{ l_c =   \frac{ We \; \sigma  }{ \rho \;  v^2 }   }\)     (Weber number)

Where:

\(\large{ \alpha }\)  (Greek symbol alpha) = thermal diffusity

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

\(\large{ \rho }\)  (Greek symbol rho) = density

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

\(\large{ \nu }\)  (Greek symbol nu) = kinematic viscosity

\(\large{ Le }\) = Lewis number

\(\large{ D_m }\) = mass diffusivity

\(\large{ Pr }\) = Prandtl number

\(\large{ Q }\) = specific heat capacity

\(\large{ \sigma }\)  (Greek symbol sigma) = surface tension

\(\large{ k }\) = thermal conductivity

\(\large{ t }\) = time

\(\large{ v }\) = velocity

\(\large{ We }\) = Weber number

 

Tags: Equations for Thermal Equations for Heat