Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.
In this work, new correlations are proposed for the mean
Nusselt number in the entrance region of concentric annular
ducts with uniform heat flux boundary conditions specified at
the inner wall. These correlations are obtained on the basis
of the numerical results of a previous parametric investigation
on the effects of temperature dependent viscosity and thermal
conductivity in simultaneously developing laminar flows of liq-
uids in straight ducts of constant cross-sections. A superposi-
tion method is applied for the estimation of the Nusselt number
by considering separately the effects of temperature dependent
viscosity and thermal conductivity.