Research on the Influence of the Inner Wall Structure of the Continuous Casting Submerged Nozzle on the Stream of Molten Steel

The behavior of molten steel stream in submerged entry nozzle (SEN) of the continuous casting machine affects nodulation inside the nozzle and stability of the nozzle outlet flow, etc., which directly affect the quality of the continuous casting billet. In this work, the effect of the SEN inner wall structure with addition of hemispherical crowns on the dynamic behavior of flow and the nozzle outlet velocity distribution was analyzed by means of water model experiments and numerical simulations. The overall results of this study show that after the hemispherical crowns are added to the nozzle inner wall, swirling flow is induced inside the nozzle, which reduces the dead region and the internal longitudinal flow velocity and accordingly reduces nodulation. Moreover, the nozzle outlet flow pattern is changed from a straight flow to a swirling flow, which significantly decreases the outlet flow velocity and thus reduces the impact on the steel shell in the mold.