Numerical Simulation of Droplet Splashing Behavior in Steelmaking Converter Based on VOF-to-DPM Hybrid Model and AMR Technique

Droplet splashing behavior caused by the top blowing supersonic jets impacting the liquid metal surface significantly affects the decarburization efficiency and refractory erosion during the basic oxygen furnace (BOF) steelmaking process. However, simulating the mass and size of splashing droplets is challenging because the droplet size differs by multiple orders of magnitude from the molten bath. Herein, a hybrid model (VOF-to-DPM) coupling the volume of fluid model (VOF) and discrete phase model (DPM) was combined with the adaptive mesh refinement (AMR) technique to successfully achieve high-resolution and quantitative capture of splashing droplets. The simulation results are in good agreement with the droplet splashing rate calculated by the theoretical formula based on the Blowing number (N_B) within the allowable error range. The generation mechanisms of splashing droplets caused by single-hole and multiple-hole jets impacting the liquid surface were clarified. Furthermore, the effects of oxygen lance height and top blowing flow rate on the total droplet mass, mass and percentage of droplets sprayed on the furnace wall, and the droplet size were also investigated. It was revealed that with the decrease of the oxygen lance height, the total droplet mass increases and then decreases, and the droplet size increases. As the top blowing flow rate increases, the total mass and size of droplets both tend to increase. The proportion of droplets sprayed on the furnace wall increases sequentially when the impact cavities are in the penetrating mode, splashing mode, and quasi-dimpling mode. Moreover, the relationship between the cavity morphology and the droplet splashing was quantitatively characterized. As the modified cavity shape index (I_cm) increases, the droplet splashing mass increases then decreases and finally increases. The change in cavity mode is the main factor affecting the droplet splashing behavior.