Heat flux

Heat flux (or thermal flux, sometimes also referred to as heat flux density or heat flow rate intensity) is a flow of thermal energy per unit of area per unit of time.


the subscript \(q\) specifying heat flux, as opposed to mass or momentum flux. Fourier’s law is an important application of these concepts. It has both a direction and a magnitude, and so it is a vector quantity. To define the heat flux at a certain point in space, one takes the limiting case where the size of the surface becomes infinitesimally small.

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