Thermal Diffusivity
Thermal Diffusivity
Thermal diffusivity measures how fast a temperature change propagates through a material — high for metals, low for insulators.
It is α = k/(ρ·c_p). where k is the conductivity, ρ the density and c_p the specific heat.
Inputs
k := 45 W/(m·K)=45 kg·m/K/s^3
rho := 7850 kg/m^3=7850 kg/m^3
c_p := 480 J/(kg·K)=480 m^2/K/s^2
Form the conductivity-to-heat-capacity ratio.
alpha := k/(rho·c_p)=1.19e-05 m^2/s
Results
A high diffusivity means temperature changes spread quickly, so the material heats and cools fast. It governs transient conduction and thermal-shock behaviour.
Assumptions & limitations
- Constant properties.
- Homogeneous material.
- Governs transient conduction.