# Thermal Diffusivity

## Description

In heat transfer analysis, thermal diffusivity (usually denoted α but a, κ and D are also used) is the thermal conductivity divided by density and specific heat capacity at constant pressure. It measures the ability of a material to conduct thermal energy relative to its ability to store thermal energy. It has the SI unit of m^2/s. In a sense, thermal diffusivity is the measure of thermal inertia. In a substance with high thermal diffusivity, heat moves rapidly through it because the substance conducts heat quickly relative to its volumetric heat capacity or 'thermal bulk’.

Related formulas## Variables

a | thermal diffusivity (m^{2}/s) |

k | thermal conductivity (W/m*K) |

ρ | density (kg/m^{3}) |

c_{p} | specific heat capacity (J/kg*K) |