Numerical Simulation of Tracer Transport Process in Alternate Stirring Ladle

In the process of steelmaking, improving the flow field in ladle plays an important role in improving the purity of molten steel, homogenization of chemical composition and temperature, and shortening mixing time. Alternate stirring in ladle can improve the mixing process. In this paper, the water model of 1/5 scaled down 130 t ladle was numerically simulated by the STAR-CCM+ software. The changes of flow field, tracer transport process, and mixing time after alternate stirring at different time points were investigated. The results show that when alternating stirring is used, the flow field eventually forms a mirror image of single plug stirring, and the time required to achieve stable flow field is 55-76 s. After alternating stirring, owing to inertia, the tracer still transfers to ladle surface by counterclockwise circulation. After the formation of alternating flow field, the tracer transfers in clockwise main circulation. In this case, the dead zone is located at the front and rear parts at the bottom of ladle. The timing of alternate stirring affects the distribution ratio of tracer to participate in the counterclockwise circulation caused by inertia and the formed clockwise main circulation. Compared with single plug stirring, alternating stirring shortens the mixing time at the top monitoring points of ladle and increases the mixing time at the bottom monitoring points.