Analysis of laminar forced convection heat transfer in the entrance region of a flat duct with uniform wall temperature

Laminar forced convection for simultaneously developing profiles in the entrance region of parallel plates with uniform wall temperature is investigated for fluids with Prandtl numbers of 0.1-50. Accounting for the transverse momentum and the axial conduction in the analysis resulted in requiring relatively longer thermal entrance lengths. In the entrance region Nusselt number results are generally lower than those reported in the literature. In addition, when Nusselt number is plotted versus x/aRe, there is a separate curve for each Reynolds number and Prandtl number.