Influence of electromagnetic stirring on the flow field and argon bubble distribution in the continuous casting mold of slab based on high-temperature online measurement of flow velocity near the mold surface

A coupling model of the flow field, initial solidification, alternating magnetic field (AM-field) and movement of argon bubble in the mold was established by combining the k - ε turbulence model with solidification model, Discrete Phase Model (DPM), Volume of Fluid (VOF) model and magnetohydrodynamics model. The industrial measured magnetic flux density (MFD) is consistent with the calculated MFD at a 15 mm interval from the wide wall, which verifies the reliability of the magnetic field model calculation. As the electromagnetic stirring (EMS) current intensity (EMSCI) grows, the calculated velocity of molten steel at 1/4 of the width direction of the mold surface decreases, which coincides well with measurement results. In addition, as the EMSCI is increased, the upper roll flow weakens, the horizontal rotational flow increases. The thickness of the solidified shell in the lower part of the narrow wall is increased due to the decreased impact force of the molten steel on the solidified shell of the narrow wall caused by the upward movement of the circulating flow. The volume fraction of argon bubbles around the SEN further decreases, and the distribution of them becomes more dispersed. Based on the research results, the optimal EMSCI under the present operating conditions is recommended as 700 A.