CFD investigation of flow in the MATIS-H test facility
23rd Symposium of AER on VVER Reactor Physics and Reactor Safety (2013, Štrbské Pleso, Slovakia)
Nuclear applications of computational fluid dynamics (CFD)
In nuclear energy, continuous developments aim for safer operation and higher efficiency.
In order to achieve these goals, detailed knowledge of thermal hydraulics of fuel assemblies has
high importance. The advanced and properly used CFD (Computational Fluid Dynamics) codes
can give detailed information on thermal hydraulic processes in fuel assemblies. In this paper
steps of the calculations for the bare rod bundle and so-called swirl type spacer grid are showed
and the effects of choice of model details are examined. The modeled pin bundle and spacer grid
geometry is related to rectangular western type PWR fuel assemblies.
First a CFD model has been developed for a subchannel in order to carry out a mesh
independence study. Based on the results a model for the half cross section of the test bundle has
been developed and calculations are carried out with different turbulence models. Translational
periodicity is applied in axial direction in order to calculate a fully developed flow, which will be
used as inlet boundary conditions for spacer grid calculations. Results are compared with LDA
(Laser Doppler Anemometry) measurements published in the frame of the OECD NEA MATISH benchmark. As a last step a model for the swirl type spacer grid is developed and calculations
are carried out with different turbulence models using the results of the bare rod bundle
simulations as inlet boundary condition.