NUMERICAL-ANALYSIS OF FLUID-FLOW IN CONTINUOUS-CASTING MOLD BY BUBBLE DISPERSION MODEL

Surface and internal defects of cold rolled steel sheet attributable to steelmaking conditions arise from the entrapment, by the solidifying shell in the continuous casting mold, of alumina clusters, mold power, and argon gas bubbles blown into the immersion nozzle. In order to prevent such defects, it is necessary to control the fluid flow of molten steel in the mold. In this study, actual-scale water model experiments were first carried out to investigate in detail the fluid flow pattern and distribution of local gas holdup in the mold. Subsequently, a hydrodynamic analysis model was developed considering the effect of the buoyant force of gas bubbles on fluid flow and the continuity of local gas holdup (bubble dispersion model). This model has made it possible to estimate the liquid velocity profile, and the distributions of local gas holdup and inclusions in the mold.