Abstract
Free surface vortex is known as the most significant cause of gas entrainment at coolant free surface in sodium-cooled fast breeder reactors (FBR). In this study, numerical simulation for the free surface vortex was carried out for Moriya's free surface vortex experiment. In order to enhance the analysis accuracy, free surface dynamics were calculated by the PLIC type of the VOF method with the CSF model for surface tension. As a result, it is revealed that the simulation accuracy considerably depends on the horizontal cell size in the simulation model. The influence of the surface tension on the simulation accuracy is not significant. The numerical diffusivity has a significant effect on the free surface configuration. Therefore, higher order accuracy scheme is needed for the advection term of the momentum equation. The numerical simulation can predict the experimental data with reasonable accuracy at the low flow rate condition. The simulation accuracy, however, decreases with the increase of the flow rate.
