Heat flux

The heat flux, also called, is a physical quantity for the quantitative description of heat transfer processes. She is a power density.

( Basis ) heat flux

The heat flux density is defined as the change of the thermal energy across the boundaries of a homogeneous system of time, related to a specific cross-section and a certain time interval. One can therefore speak from the analogous heat flow per unit area:

Thus, it describes the amount of heat transferred per unit time or transmission surface and the thermal capacity per unit area.

The SI unit of heat flow density is W/m2 ( watts per square meter ).

Frequently, the heat flux density is used as a vector. The direction of the vector indicates the direction of heat flow. This allows capture, in which the heat flow is not necessary passes perpendicularly through an area also cases.

Volumetric heat flux

For the calculation of some problems the volumetric heat flux is used. It describes the heat flow per unit volume:

The SI unit of volumetric heat flux density is W/m3 ( watts per cubic meter).

Context

The relationship between volumetric and area-related heat flux via the heat conduction