Simulation of a Gas Jet in the Secondary Side of a Steam Generator Bundle Following a Tube Rupture Sequence

The main objective of the following work is to simulate flow in the secondary side of a steam generator (SG) tube bundle during tube rupture sequence using approaches for turbulence simulation. The interest in this topic stems from experimental findings at PSI in the framework of the ARTIST program (Aerosol Trapping in a Steam Generator) which show that particles that are injected into a dry SG tube bundle through a tube breach are principally retained in the region close to breach (the so-called “break-stage”). This region is characterized by highly non-uniform flow, with very high velocities near the breach, and low-velocity recirculating flow away from the breach. Owing to complexity of the flow, 3D simulations with highly resolved computational mesh near the breach were done. First, the flow inside an isolated tube with a guillotine tube breach has been studied. The next part is devoted to simulation of a gas jet entering the tube bundle SG via the guillotine tube breach. Comparison of the calculated flow with the experimental data of axial velocity distribution at different vertical levels have been performed, and we have found good agreement of the obtained results with the experiments.