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

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

Where:

 Units English Metric
\(\large{ \alpha }\)  (Greek symbol alpha) = thermal diffusivity \(\large{\frac{ft^2}{sec}}\) \(\large{\frac{m^2}{s}}\)
\(\large{ \rho }\)  (Greek symbol rho) = density \(\large{\frac{lbm}{ft^3}}\) \(\large{\frac{kg}{m^3}}\)
\(\large{ Q }\) = specific heat capacity \(\large{\frac{Btu}{lbm-F}}\) \(\large{\frac{kJ}{kg-K}}\)
\(\large{ k }\) = thermal conductivity \(\large{\frac{Btu}{hr-ft^2-F}}\)  \(\large{\frac{W}{m-K}}\)

 

Related Thermal Diffusivity formulas

\(\large{ \alpha = \frac{  Fo \; l_c^2    }{ t }   }\)  (Fourier number
\(\large{ \alpha = Le \; D_m }\)  (Lewis number
\(\large{ \alpha = \frac{ \nu }{  Pr  }  }\) (Prandtl number)

Where:

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

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

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

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

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

\(\large{ D_m }\) = mass diffusivity

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

\(\large{ t }\) = time

 

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Tags: Equations for Thermal Equations for Heat Equations for Diffusion