Effect of the Number of Clogged Bottom-Blowing Elements on the Flow Characteristics of Liquid Steel in Converter
This study established a three-dimensional transient gas-liquid two-phase flow model based on a 150-tonne converter to investigate the influence of the number of clogged bottom-blowing elements on the stirring efficiency of the molten pool. The numerical simulation results were validated against actual converter operating conditions. The findings revealed that the primary reason for deteriorated flow characteristics under multiple clogged tuyeres was the overall reduction in stirring energy input from the bottom-blowing gas. Specifically, when the number of clogged tuyeres reached three, the numerically simulated mixing time increased from 150.6 s to 219.3 s, a significant increase of 45.62%. This numerical result was in good agreement with water model experiments, indicating that prompt furnace bottom maintenance and tuyere replacement should be considered under such circumstances. At the same bottom-blowing intensity, the effective stirring area of a single inner-ring tuyere was 0.919 m2, while that of a single outer-ring tuyere was 1.651 m2. The combined effective area achieved through the synergy of inner and outer ring tuyeres was 2.940 m2, which was 14.4% greater than the sum of their individual areas. Clogging disrupted this synergistic stirring effect. A single clogged tuyere had a negligible impact on the distribution of dead zones. However, when tuyeres in both the inner and outer rings were clogged, dead zones became more numerous and concentrated. With 3 and 4 clogged tuyeres, the dead zone volume reached 3.703 and 5.946 m3, accounting for 17.31% and 27.79% of the total molten pool volume, respectively. An industrial plant trial conducted based on the numerical simulation scheme showed that key performance indicators deteriorated as the number of clogged tuyeres increased. With three clogged tuyeres, the average end-point oxygen content reached 0.0669wt%, which was 22.1% higher than that under non-clogged conditions. Concurrently, the total iron content in the slag reached 19.44%, a 24.5% increase compared to the non-clogged baseline.