lämpötilajohtavuuden

Lämpötilajohtavuus, also known as thermal diffusivity, is a material property that describes how quickly temperature diffuses through a substance. It is a measure of a material's ability to conduct heat relative to its ability to store heat. A high thermal diffusivity means that temperature changes propagate quickly through the material, while a low thermal diffusivity indicates that temperature changes propagate slowly.

This property is important in many engineering and scientific applications, particularly in heat transfer analysis. For example, in the design of heat sinks, materials with high thermal diffusivity are preferred to efficiently dissipate heat away from electronic components. Conversely, in thermal insulation, materials with low thermal diffusivity are used to minimize heat transfer.

Mathematically, thermal diffusivity (often denoted by the Greek letter alpha, $\alpha$) is defined as the ratio of thermal conductivity ($k$) to the product of density ($\rho$) and specific heat capacity ($c_p$): $\alpha = \frac{k}{\rho c_p}$. The units of thermal diffusivity are typically square meters per second ($m^2/s$) in the SI system. Different materials have widely varying thermal diffusivity values, influenced by their atomic structure and bonding.