In this work, a correlation for the calculation of a suitable correction term has been derived with the aim of allowing a more accurate prediction of the length averaged Nusselt number in the laminar forced convection in thick-walled ducts where the effects of axial heat conduction in the solid material cannot be neglected. To that purpose, an in-house FEM procedure has been used to perform a parametric investigation in order to produce the set of data to be fitted.
