RANS STUDIES OF A T-JUNCTION: A COMPARISON OF TURBULENCE MODELS ON LOW y+ MESHES

Thermal fatigue is a major concern in the service-life management of nuclear plant thermal-hydraulics systems. Hybrid LES/RANS techniques have the po-tential to provide predictions which are computation-ally affordable for studies of this problem in industry, however they require further development and valida-tion. The present work compares various RANS mod-els for use in future hybrid LES/RANS studies of pipes and T-Junctions. We show that traditional RANS mod-els provide poor predictions for low Reynolds num-ber pipe flows and demonstrate the significant effect of an upstream elbow on the mixing at a T-Junction. Finally we compare results for an industrially relevant T-Junction geometry. Results herein suggest the suit-ability of the elliptic blending k − ε − v2/k model and future work will involve benchmarking the RANS models against results from a fine LES.