Effects of Interphase Forces on Multiphase Flow and Bubble Distribution in Continuous Casting Strands

A three-dimensional computational model, combining the large eddy simulation (LES) turbulent model, VOF multiphase model for air phase, and discrete phase model (DPM) for injected bubbles, was established to evaluate the effects of drag force, lift force, pressure gradient force, virtual mass force, and wall lubrication force on the fluid flow and spatial distribution of bubbles in a continuous casting (CC) strand. The effect of lift force and wall lubrication force on the fluid flow was achieved via a user defined subroutine (UDF). The contribution of interphase forces was quantitatively evaluated using UDF. The appropriate interphase force model was determined by comparing the predicted fluid flow and bubble distribution in the CC strand with the measured results one using particle image velocimetry (PIV). The interphase force had a significant effect on the spatial distribution of bubbles and the flow field near the meniscus. The drag force and buoyancy force were the dominant ones at low turbulent kinetic locations. Moreover, the magnitude of the lift force, pressure gradient force, and virtual mass force was increased sharply at high turbulent kinetic locations, approximately one to two orders greater than that of the buoyancy force.