On the Importance of Validation when using Commercial CFD Codes in Nuclear Reactor Safety

The commercial CFD (Computational Fluid Dynamics) CFX has been benchmarked against the HyJet dispersion experiment performed in the Battelle-Model-Containment. The dispersion process during an accidental hydrogen release is very essential for safety reasons as it defines the initial conditions for a possible hydrogen combustion event. For the experiment various turbulent models (k-epsilon, RNG and SST) and two computational grids have been applied. Reasonable prediction of the heat transfer to structures was only possible when using an innovative hybrid mesh (prism grid in the boundary in combination with a tetrahedral volume gird) in combination with the novel SST model. Also concerning the dispersion process itself only good results could be obtained when using the SST model, which worked out for the hybrid grid but also with the conventional pure tetrahedral grid.

BARALDI Daniele; 

WILKENING Heinz; 

2007-01-19

OECD Nuclear Energy Agency

JRC32833

https://publications.jrc.ec.europa.eu/repository/handle/JRC32833,