Modeling of Flow Behaviors in a Swirling Flow Tundish for the Deep Cleaning of Molten Steel

Abstract

A swirling flow tundish is developed to deeply clean the liquid steel through enhancing the coalescence of inclusions. The swirling flow is generated using the gravitational energy of liquid steel, without any external energy. Inclusions will gather to the center of the swirling flow by centripetal force, due to the density difference between inclusions and liquid steel. Thus, small inclusions can coalesce into larger ones, and then float to the top surface by their self‐buoyance. Physical experiments are carried out in a 1/2.5 scale five‐strand tundish, to investigate flow characteristics in the swirling flow tundish, compared with that in the tundish with a conventional turbulent inhibitor. Numerical modeling is developed to evaluate the swirling strength of liquid flow in swirling chambers in different sizes, which is related to the effect of inclusion coalescence. The results reveal that swirling chamber in diameter of 700 mm produces the highest swirling flow strength. The swirling system can not only improve the flow field, with a 21.75% reduction of dead volume, but also uniform flow characteristics at each strand. In addition, the swirling chamber inhibits the normal impact of the reversed flow on tundish surface, which is beneficial for remaining a stable slag layer.