# Heat transfer coefficient

The heat transfer coefficient (or film coefficient) is the proportionality constant between the heat flux q and the temperature difference $\Delta T$ as the thermodynamic driving force for the flow of heat. It is used in calculating the heat transfer, typically by convection.

Calculation of $h_{tr}$ using the second equation is based on a paper from 2014 by Sujit Purushothaman by the use of the Fourier transformation to convert the two-dimensional problem into a simple one-dimensional problem.

Symbol
$h_{tr}$
Unit
W/(K.m$^2$)
Formulae
 $\frac{q}{DeltaT}$ general formula $\frac{\mathrm{Nu}_{L} k_{gas}}{L_{char}}$ for horizontal plates
Related
$k_{gas}$
$\mathrm{Nu}_{L}$
Used in
$d_{im}$
$T_{surf}$