Numerical Study on the Effects of Variable Mushy Zone Constants on Fluid Flow and Heat Transfer in Bloom Mold

Abstract

In previous studies, the mushy zone constant was assigned a fixed value or a value associated with dendrite characteristics at room temperature. However, elucidating the constitutive behaviors of mushy dendrites at high temperatures using solid dendrite characteristics at room temperature poses challenges. In this study, a numerical model was constructed to investigate the effects of variable mushy zone constants on fluid flow and heat transfer in the mold. The results revealed that “Zone Z-1/2” exhibited a thinner solidified shell compared with the other zones, indicating a close correlation between heat transfer and thickness differences. Under default simulation conditions, the liquid steel cooled rapidly, leading to the dissipation of superheat. The mushy zone exhibited a wide range, with almost no pure liquid phase present in the mold. In cases 2, 3, and 4 within “Zone Z-1/2”, the average thickness of the solidified shell gradually increased during solidification, indicating the absence of evident remelting phenomena in the mold. As the variable mushy zone constants increased, the local temperature gradient increased, while the local cooling rate decreased. The accuracy of the numerical model was validated through actual measurements and empirical formulas. The simulation results for case 4 exhibited a high degree of fitting.