Friction Factor Correlation for Molten Metals Flow in a 3-Rod Bundle in Cylindrical Shroud, With Smooth and Scalloped Inner Wall

Abstract

Abstract Thermal-hydraulic experiments to help develop and qualify new fuel designs for advanced liquid metal cooled reactors could use reduced-size triangular pitch, 3 rods within a circular shroud. In such an arrangement, scalloping the shroud wall helps achieve lateral flow uniformity and high velocity, but at the expense of increasing the pressure losses. Owing to the practical challenges of conducting experimental investigations with molten lead, Computational Fluid Dynamics (CFD) could a practical alternative to generate large enough database to develop a friction factor correlation. This work performed CFD analyses of molten lead flow in 3-rod bundle with circular shroud to investigate the effect of scalloping the shroud wall on the lateral flow uniformity and pressure. The developed friction factor correlation is very smooth, spanning the laminar, transition, and turbulent flow regions. Scalloping the shroud wall increases the pressure losses, but not the friction factor in the transition and turbulent flow regions. In the laminar flow region, however, scalloping the shroud wall only slightly increases the friction factor.