Abstract
The influence of wall heat conduction on laminar mixed convection in externally finned vertical pipes are investigated numerically. Buoyancy in both aiding and opposed modes is considered. Results are presented in terms of the streamwise variation of the fluid bulk temperature and tube-side Nusselt number, axially averaged and periodically fully developed Nusselt number values, and axial velocity and temperature profiles. For opposed flows, buoyancy forces decrease the overall heat transferred to the fluid, while for buoyancy-aided flows, buoyancy causes an enhancement in the overall heat transferred to the fluid. Inclusion of longitudinal wall conduction increases the heat transfer to the fluid and enhances the effects of buoyancy.