Fourier's Law of Conduction
As mentioned above, Fourier's law of heat conduction and Newton's law of cooling are typically used for heat transfer calculations involving thermal conduction or thermal convection, when there is enough information about each individual heat transfer process.
Fourier's Law for Heat Conduction will be presented in this section. Newton's Law of Cooling will be presented in the next section. Then the procedure for rearranging the equations to make them useful for combined convection conduction heat transfer will be considered.
Fourier's Law of Thermal Conduction is: q = kA(ΔT/L), where
q = the rate of conduction heat transfer in Btu/hr,
k = thermal conductivity of the material through which thermal conduction is taking place, in Btu/hr-oF-ft,
A = area perpendicular to heat flow, ft2,
ΔT = the temperature difference that is driving the heat transfer, oF,
L = the distance through which conduction heat transfer is taking place, ft.
These parameters are illustrated for conduction heat transfer in the diagram above.