ANISOTROPIC TURBULENT TRANSPORT MODELING FOR ROD-BUNDLE.

Abstract

It is well known in the literature that eddy-diffusivity turbulence models can only lead to isotropic turbulent coefficients for linking the Reynolds Stresses/Fluxes to the gradients of the mean velocity/temperature. In the particular case of axial flow through rod-bundles, however, transport coefficients for channel faces aligned with rod centers are known to be considerably higher than those calculated by simple isotropic theories. Based on the foregoing application, this work presents an attempt to describe the anisotropy of turbulent transport in rod presents an attempted to describe the anisotropy of turbulent transport in rod arrays by means of an Algebraic Stress Model. Results for all three normal components of the Reynolds Stress tensor are presented and compared with experimental data. Predictions show good agreement for the Reynolds number and the range of aspect ratio (Rod pitch/Diameter) investigated.