Assessment of the influence of scaling on turbulent mixing in downcomer and core-inlet flow distribution

Abstract

In the present article, Computational Fluid Dynamics (CFD) simulations are used to assess the effects of classical scaling approaches on turbulent mixing in the downcomer and core-inlet regions of typical Reactor Pressure Vessels (RPVs), applying validated CFD models in two sets of numerical tests. In the first set, simulations of ROCOM Tests 1.1. and 2.2 performed under two different geometric scales showed that the modeling of single-phase flow with mixed convection on a scaled-down geometry is able to provide a very good approximation of the core inlet mixing dynamics in the reference reactor. For the second set, the effects of the selection of global non-dimensional parameters to compare RPVs of varying designs under steady-state operating conditions are studied via the injection of a passive component, and a radial grouping of the mixing scalar is proposed for comparisons involving different core configurations.