Effect of viscous dissipation on thermally developing forced convection duct flows (Research Report 13/2005)

A self-contained treatment of laminar duct-flow heat transfer is performed. The presentation includes all the necessary definitions and results which are required for the treatment of the thermal entrance problem in a duct with an arbitrary cross section. The special cases of a plane-parallel channel and of a circular duct are discussed in detail. A comparison is made between the results obtained when viscous dissipation is taken into account and those which are obtained when this effect is neglected. The treatment of the effect of viscous dissipation presented here differs from previous approaches available in the literature. The difference relies mainly in the prescription of the initial condition at the entrance cross-section. Unlike in similar treatments available in the literature, the effect of viscous dissipation is taken into account self-consistently, i.e. both upstream and downstream of the entrance section.