Forced convective heat transfer in the thermal entrance region of a finite uniform-heat-flux rod bundle

A method for determining the heat transfer characteristics in the thermal entrance region for a developed axial laminar flow through a circular shell containing a uniform-heat-flux rod bundle is presented. It utilizes a small parameter series solution, employing the Leveque similarity variable, and accounts for both the curvature of the rods and the circumferential non-linearity of the velocity profile. The solution provides a lower bound to the turbulent Nusselt moduli and an upper bound to the rod temperature variation. Nusselt moduli for the rod bundle of several configurations are reported and discussed. Results compare favorably with published solutions to annuli and experimental data for rod bundles. (U.S.)