Study on the Fluid Flow Characteristics of Coherent Jets with CO₂ and O₂ Mixed Injection in Electric Arc Furnace Steelmaking Processes

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO₂ and O₂ mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO₂ significantly weakened the shrouding combustion reactions of CH₄ and the relative importance of the chemical effect of CO₂ increases with CO₂ concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO₂ increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.