A CFX Simulation of the OECD/NEA T-Junction Benchmark

Abstract

In response to a solicitation for Computational Fluid Dynamic (CFD) simulations of flow in a T-junction from the Nuclear Energy Agency of the Organization for Economic Co-operation and Development (OECD/NEA) [1], Structural Integrity (SI) Associates of San Jose, CA, USA has completed a simulation using the commercially available CFD code ANSYS-CFX. The simulation was carried out for geometry and flow conditions matching an experiment underway at Vattenfall Research and Development in Sweden where two streams of differing temperature mix in a T-junction. The benchmark was to be a blind test of CFD simulations. Experimental results were not released until after benchmark participants submitted the results of their simulation to the OECD/NEA. The CFD simulation done by SI was carried out on an all hexahedral mesh of 1,881,504 elements generated using the ANSYS Mechanical Finite Element program. The mesh was then transferred into the CFX program and, after applying proper boundary conditions, a time-dependent simulation was done using the Large Scale Eddy Simulation (LES) turbulence model [2] with Wall Adjusting Local Eddy Viscosity (WALE) sub-grid scale (SGS) turbulence model [2, 3]. Comparisons of the CFD results to the Vattenfall data show close correspondence for mean and root-mean-square (rms) turbulent temperature fluctuations.