Abstract
The developing flow with mixed laminar convection in an inclined tube has been studied numerically for four different thermal boundary conditions: a uniform heat flux is applied over the entire circumference or its top half at either the outer tube surface or the fluid-solid interface. The calculated results for local parameters (circumferential distribution of the interfacial temperature, axial velocity profile, etc.) and for average variables (circumferentially average values of the Nusselt number and of the Interfacial shear stress) are quite different, especially for high values of Grashof number. Thus, for Gr = 10(6), Re = 500 and Pr = 7, the asymptotic average Nusselt number for a uniform heat flux applied over the entire outer tube surface is 16.47; the corresponding values for a heat flux applied on the fluid-solid interface is 26.14 for uniform flux over the entire circumference and 29.71 for a hear flux applied only on the top half of the interface. (C) Elsevier Press.