NUMERICAL ANALYSIS OF MULTIPHASE FLOW AND MIXING IN LADLES: LANCE, PLUG AND COMBINED INJECTION

This research leverages a three-dimensional computational fluid dynamics (CFD) model to investigate the intricate multiphase flow and mixing phenomena within an industrial gas-stirred ladle. By coupling the Discrete Phase Model (DPM) and Volume of Fluid (VOF) methods, the model simulates the complex interactions between the gas, liquid steel, and slag phases. The study focuses on evaluating the mixing efficiency of various gas injection configurations: lance injection, bottom plug injection, and a combination of both. To conduct the simulations, a three-dimensional geometry, based on Cleveland Cliffs specifications, was employed. Two gas flow rate combinations, 8 SCFM and 16 SCFM, were considered in the unsteady, isothermal CFD model. Initial flow analyses were performed to assess the overall fluid flow patterns, velocity distribution, and slag eye formation. Subsequently, a detailed mixing study was conducted to evaluate the impact of different injection configurations on mixing efficiency. The slag eye diameter was found to vary depending on the flow rate and injection configuration. Higher flow rates generally led to larger slag eye diameters. The Plug 16 SCFM configuration achieved the fastest mixing time at 156 seconds, 35.3% faster than Plug 8 SCFM (241 seconds). Lance (3 ports) was slowest at >800 seconds, 412.8% slower than Plug 16 SCFM. Slag eye diameter increased 2.0% from Plug 16 SCFM (1.52 m) to Lance (3 ports) + Plug (1.55 m), while Lance (9 ports) and Lance (3 ports) reduced by 14.2% (1.33 m) and 41.9% (0.90 m), respectively. Increasing gas flow from 8 to 16 SCFM in plug injection reduced mixing time by 35.3% and increased slag eye size by 2.0%. The Lance (3 ports) + Plug configuration optimized turbulence, minimized dead zones, and enhanced steel homogeneity, critical for efficient ladle refining.