Large-Eddy Simulation of Transient Horizontal Gas–Liquid Flow in Continuous Casting Using Dynamic Subgrid-Scale Model

Euler–Euler simulations of transient horizontal gas–liquid flow in a continuous-casting mold are presented. The predictions were compared with previous experimental measurements by two-channel laser Doppler velocimeter. Simulations were performed to understand the sensitivity to different turbulence closure models [k–ɛ, shear stress transport (SST), Reynolds stress model (RSM), and large-eddy simulation (LES)] and different interfacial forces (drag, lift, virtual mass, wall lubrication, and turbulent dispersion). It was found that the LES model showed better agreement than the other turbulence models in predicting the velocity components of the liquid phase. Furthermore, an appropriate drag force coefficient model, lift force coefficient model, and virtual mass force coefficient were chosen. Meanwhile, the wall lubrication force and turbulent dispersion force did not have much effect on the current gas–liquid two-phase system. This work highlights the importance of choosing an appropriate bubble size in accordance with experiment. Finally, coupled with the optimized interfacial force models and bubble size, LES with a dynamic subgrid model was used to calculate the transient two-phase turbulent flow inside the mold. More instantaneous details of the two-phase flow characteristics in the mold were captured by LES, including multiscale vortex structures, fluctuation characteristics, and the vorticity distribution. The LES model can also be used to describe the time-averaged gas–liquid flow field, giving reasonably good agreement with mean experimental data. Thus, LES can be used effectively to study transient two-phase flow inside molds.