A CFD simulation of 5 × 5 rod bundles with split-type spacers

Atomic Energy of Canada Limited (AECL) has a program to develop Computational Fluid Dynamics (CFD) capability to simulate single- and two-phase flows in rod bundles. In the current work, a 5 × 5 rod assembly with a split-type spacer grid is simulated with ANSYS Fluent 14 using unsteady simulations with a fully conformal hybrid mesh (wall y+∼30). This work represents results of AECL's recent participation in the OECD/NEA organized CFD benchmarking exercise on the MATiS-H experiment performed at Korean Atomic Energy Research Institute (KAERI). The Reynolds stress model (RSM) is used as well as the standard kε model. Reasonable agreement is achieved between the calculated and experimental velocity values in the region close to the spacer grid, whereas turbulence intensity values are underpredicted compared to the experiments.