Thermal Diffusivity

`alpha = k / (rho * c_p)`

Enter a value for all fields

The Thermal Diffusivity calculator computes the thermal diffusivity (α) of a material based on the thermal conductivity (κ), density (ρ) and the material's specific heat capacity.(c_p).

INSTRUCTIONS: Choose units and enter the following:

(k) This is the thermal conductivity expressed as power (e.g. Watts) per (m•K)
(ρ) This is the density of the material
(c_p) This is the material's specific heat capacity expressed as energy (e.g. Joule) per (kg•K)

The Math / Science

The Thermal diffusivity of a material at a constant pressure is equal to the material's thermal conductivity divided by its density and its specific heat capacity. Thermal diffusivity is often used in Geosciences / Atmospheric Science. The formula for thermal diffusivity is:

α = k / (ρ•cp)

where:

α is the thermal diffusivity (m²/s)
k thermal conductivity (W /(m•K))
ρ is the density (kg/m³)
cp is the specific heat capacity (J/(kg•K))

Note: this calculator permits the user to adjust the units of power in the thermal conductivity factor. However, the power is converted to Watts and then placed in a ratio of Watts per meter-degrees Kelvin (W /(m•K)). In a similar vein, this calculator permits the user to adjust the units of energy in the specific heat capacity factor. However, the energy is converted to Joules and then placed in a ratio of Joules per kilogram-degrees Kelvin (J/(kg•K)).

The Math / Science

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