Effect of Reynolds Number and Bundle Geometry on the Turbulent Flow in Tight Lattice Bundle

Abstract

The flow structure in tight lattice is still of great interest to nuclear industry. The accurate prediction of flow parameter in subchannels of tight lattice is likable. Unsteady Reynolds Averaged Navier Stokes(URANS) is a promising approach to achieve this goal. The implementation of URANS（Unsteady Reynolds Averaged Navier Stokes）approach will be validated by comparing computational results with the experimental data of Krauss (1998). In this paper, the turbulent flow with different Reynolds number(5000~215000) and different P/D(1.005~1.2) are simulated with CFD code CFX12.The effects of the Reynolds number and the bundle geometry(P/D) on wall shear stress, turbulent kinetic energy, turbulent mixing and large scale coherent structure in tight lattice are analyzed in details. It is hoped that the present work will contribute to the understanding of these important flow phenomena and facilitate the prediction and design of rod bundles.