Abstract: The swirling flow tundish is the tundish that adds a swirl chamber in the injection zone. The gravity potential energy is converted into rotating kinetic energy when the molten steel flows into the tundish along the tangent direction from the bottom of the swirl chamber through the long nozzle. Inclusion follows the molten steel rotating in the swirling chamber and is more likely to collide and grow. The PBM model of the commercial software Fluent was used to simulate the behavior of inclusion colliding growth during the process of inclusion flowing into the tundish with molten steel. The simulation result showed that considering the collision and polymerization between inclusions，the polymerization and growth of inclusion was obvious. The number density of inclusion was decreased and the average diameter of inclusion was increased. The same size parameter of the swirling flow tundish was compared with the non-swirling chamber tundish. The average diameter of non-swirling chamber tundish increased from 3.93μm to 4.25μm, increased by 8.12%. The average diameter of inclusion in swirling tundish increased from 3.93μm to 4.35μm, increased by 10.68%. Swirling flow tundish is more conducive to the collision growth of inclusion.

Key words: swirling flow tundish, inclusion, aggregation and growth, numerical simulation