Spacer grids with mixing vanes have complex geometry and are used to support the fuel rods in nuclear fuel assemblies as well as to improve heat transfer by generating turbulence downstream of the spacer grid in the cores of the pressurized water reactors. To validate the CFD code OpenFOAM for relevant spacer grid geometries, numerical analyses on the OECD/NEA MATiS-H benchmark were performed. The flow behind two different types of spacer grid designs was analysed: split- and swirl-type. Initially, an appropriate inlet velocity profile was generated. In a next step, Computer-Aided Design models of the spacer grids were prepared and then meshed using ANSYS Mesher 19.2. Transient URANS simulations were performed with the k-ω-SST turbulence model and the results were compared with data. Good agreement was obtained for the mean velocity profile and the vorticity in the swirl-type configuration, while the numerical results slightly overestimated the transverse velocity profile at some measurements locations of the split-type configuration.
The author would like to thank KAERI for providing the detailed description of the MATiS facility and the experimental data. This work was supported by the German Federal Ministry for Economic Affairs and Energy based on a decision of the German Bundestag.
Author contributions: The author has accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The presented work is part of the project RS1591 financed by the German government.
Conflict of interest statement: The author declares no conflicts of interest regarding this article.
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