Physical and Mathematical Simulation on the Bubble Entrainment Behavior at Slag-Metal Interface
ZHOU Xiaobin1(), ZHAO Zhanshan2, WANG Wanxing1, XU Jianguo1, YUE Qiang1
1.School of Metallurgical Engineering, Anhui University of Technology, Ma'anshan 243032, China 2.ESP Department, Rizhao Steel Holding Group Co., Ltd., Rizhao 276806, China
Cite this article:
ZHOU Xiaobin, ZHAO Zhanshan, WANG Wanxing, XU Jianguo, YUE Qiang. Physical and Mathematical Simulation on the Bubble Entrainment Behavior at Slag-Metal Interface. Acta Metall Sin, 2023, 59(11): 1523-1532.
The flow and interaction between slag, metals, and bubbles are very complicated phenomena in metallurgical processes, such as desulfurization in hot metal pretreatment, steelmaking process in a converter, and second refining process. The molten steel or hot metal can be entrained into the slag when a bubble or bubbles flow through the slag-metal interface during the metallurgical process. The bubble entrainment behavior can increase the heat and mass transfer and, in turn, increase the chemical reaction efficiency of the slag-metal interface. Investigating the entrainment behavior helps in understanding the interaction between bubbles and liquid phases. The current study focuses on the effects of bubbles and slag properties on the bubble entrainment behaviors at the slag-metal interface. The results show that the bubble size is the most important factor influencing the entrainment, followed by the slag density. The slag viscosity and interfacial tension of the slag-metal interface show a weaker effect on the entrainment. In particular, the entrainment volume of steel and maximum area of the slag-metal interface increase by 7.41 and 3.67 times when the bubble diameter increased from 10 to 16 mm, respectively. When the slag density increases from 2000 to 5000 kg/m3, the entrainment volume of steel and maximum area of the slag-metal interface increase by 62.3% and 13.1%, respectively. The increasing in slag viscosity and interfacial tension is less affected by slag entrainment and interface area. The entrainment volume of steel and maximum area of the slag-metal interface are decreased by 30.6% and 6.4% when the interfacial tension of the slag-metal interface increases from 0.65 to 1.10 N/m, respectively. Similarly, when the slag viscosity increases from 0.05 to 2.0 Pa·s, the entrainment volume of steel and maximum area of the slag-metal decrease by 18.4% and 10.2%, respectively.
Table 1 Physical parameters of the applied fluid for the experiment
Fig.2 Schematic of the computational domain and boundary conditions (d—diameter)
Fig.3 Schematic of mesh of the geometric model
Parameter
Value
Unit
Molten steel density
6080
kg·m-3
Molten steel viscosity
0.0062
Pa·s
Molten steel density surface tension
1.7
N·m-1
Bubble density
1.62
kg·m-3
Bubble viscosity
2.125 × 10-5
Pa·s
Bubble diameter
10, 12, 14, 16
mm
Slag density
2000, 3000, 4000, 5000
kg·m-3
Slag viscosity
0.05, 0.5, 1, 2
Pa·s
Slag-metal interfacial tension
0.65, 0.8, 0.95, 1.1
N·m-1
Table 2 Physical parameters of the fluids for numerical simulations[27]
Fig.4 Variations of bubble entrainment in different oil-water systems
Fig.5 Comparisons between the mathematical (a) and experimental (b) results of bubble rising process
Fig.6 Comparison between the mathmatical and experimental results of bubble entrainment
Fig.7 Variations of entrainment volume of molten steel as a function of time
Fig.8 Influences of bubble diameter (a), slag density (b), slag viscosity (c), and slag-metal interfacial tension (d) on the entrainment volume of molten steel
Fig.9 Variations of slag-metal interfacial area as a fun-ction of time
Fig.10 Influences of bubble size (a), slag density (b), slag viscosity (c), and slag-metal interfacial tension (d) on the interfacial area
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