Numerical Study on the Influence of a Swirling Flow Tundish on Multiphase Flow and Heat Transfer in Mold

Abstract

The effect of a new cylindrical swirling flow tundish design on the multiphase flow and heat transfer in a mold was studied. The RSM (Reynolds stress model) and the VOF (volume of fluid) model were used to solve the steel and slag flow phenomena. The effect of the swirling flow tundish design on the temperature distribution and inclusion motion was also studied. The results show that the new tundish design significantly changed the flow behavior in the mold, compared to a conventional tundish casting. Specifically, the deep impingement jet from the SEN (Submerged Entry Nozzle) outlet disappeared in the mold, and steel with a high temperature moved towards the solidified shell due to the swirling flow effect. Steel flow velocity in the top of the mold was increased. A large velocity in the vicinity of the solidified shell was obtained. Furthermore, the risk of the slag entrainment in the mold was also estimated. With the swirling flow tundish casting, the temperature distribution became more uniform, and the dissipation of the steel superheat was accelerated. In addition, inclusion trajectories in the mold also changed, which tend to stay at the top of the mold for a time. A future study is still required to further optimize the steel flow in mold.

Continuous Casting

“…I would also like to give special thanks to all staff at the Metals Editorial Office, especially to Toliver Guo, Assistant Editor, who managed and facilitated the publication process. Commencing from the start of the process and working downwards [2,5,7], it is important to consider flow in the tundish. Huang et al [2] use particle image velocimetry (PIV) and numerical simulation to investigate the flow characteristics for a two-strand tundish in continuous slab casting.…”

“…Fourteen research articles have been published in this Special Issue of Metals. Twelve of these [1][2][3][4][5][6][7][8][9][10][11][12] relate to the continuous casting of steel, a general schematic for which is shown in Figure 1. As is evident from this figure, the overall process consists of a ladle and a tundish through which molten steel passes, a cooling mould region where solidification starts and at which electromagnetic stirring (EMS) may be applied, secondary cooling regions where water is sprayed on the solidified steel, a so-called strand electromagnetic stirrer, a further region at which final EMS is applied, and withdrawal rollers, by which point the steel has completely solidified.…”

“…Huang et al [2] use particle image velocimetry (PIV) and numerical simulation to investigate the flow characteristics for a two-strand tundish in continuous slab casting. On the other hand, Ni et al [5] present a numerical study on the influence of a swirling flow tundish on multiphase flow and heat transfer in the mould, whereas Qin et al [7] conduct a simulation study on the flow behavior of liquid steel in a tundish with annular argon blowing in the upper nozzle. Su et al [9] use machine-learning techniques for mold-level prediction by means of variational mode decomposition and support vector regression (VMD-SVR), whereas Cho and Thomas [1] review the literature on electromagnetic forces in continuous casting of steel slabs.…”

Effect of swirling flow tundish submerged entry nozzle outlet design on multiphase flow and heat transfer in mould

“…The liquid steel flows from the tundish to the mould to be solidified from a high-temperature to a low-temperature state for subsequent processes. With the help of the swirling flow from the tundish, the impingement jet flow can be offset compared to the flow in a conventional casting process [26]. The swirling flow made the liquid steel flow towards the solidification front, which resulted in a larger region of activated steel flow and heat transfer near the meniscus [26].…”

“…It was studied by both mathematical and physical modelling [25]. This new tundish design could also improve the steel flow characteristics and temperature distribution in mould [26]. The immersion depth of SEN was also investigated for decreasing the interfacial velocity and reducing the risk for the slag entrainment [27].…”