CFD SIMULATION OF SWARM FLOW BEHAVIOR AND BUBBLE RESIDENCE TIME UNDER POOL SCRUBBING CONDITIONS

抄録

In severe accidents of nuclear power plants, large amounts of fission products existing as radioactive aerosols are generated. Pool scrubbing plays an important role in the removal of radioactive fission products. Since previous studies have shown that the washing out process within the swarm flow makes a very important contribution to aerosol removal efficiency. It is of great significance to investigate the hydrodynamic behavior in swarm flow. The main focus of the current work is on the flow velocity and the residence time of the gas phase as well as the turbulence of the flow. The Euler-Euler two fluid method and the Lagrangian Particle Tracking (LPT) method are applied, the former is used to get the flow field information, and the LPT method is used to track the bubble movement to obtain the bubble residence time. The feasibility of the baseline model under pool scrubbing conditions was examined. Finally, the preliminary results of bubble residence time distribution (RTD) are obtained. The results obtained with the baseline model show good agreements with the experimental data. Liquid recirculation generated near the water surface in large volume gas flow rate slightly increases the bubble residence time. Residence time shows a flat trend with radial injection position.