Thermal diffusivity compares heat conduction with volumetric heat storage.
Difficulty
Intermediate
Read time
4 min
Prerequisites
Consistent SI units, algebra, and the physical assumptions listed below
Source
Teng-Jui Lin — Equation SheetsAdapted from Teng-Jui Lin, Equation Sheets — Mechanical Engineering, under CC BY 4.0.
Adapted notation and added original explanations, variables, assumptions, applications, and a worked example. Made the mass-specific heat-capacity basis explicit.
Thermal diffusivity compares heat conduction with volumetric heat storage. A high value means a temperature disturbance spreads quickly, even though conductivity alone does not describe how much energy the material stores.
| Symbol | Meaning | Units |
|---|---|---|
| Thermal diffusivity | ||
| Thermal conductivity | ||
| Density | ||
| Specific heat capacity at constant pressure |
Estimate the time scale for temperature changes within a body.
Compare how rapidly thermal disturbances spread.
A material has k = 150 W/(m·K), density 2700 kg/m³, and specific heat 900 J/(kg·K). Find α.
Adapted from Teng-Jui Lin, Equation Sheets — Mechanical Engineering, under CC BY 4.0.
Adapted notation and added original explanations, variables, assumptions, applications, and a worked example. Made the mass-specific heat-capacity basis explicit.
Assumptions
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