Effect of Main Gas Composition on Flow Field Characteristics of Supersonic Coherent Jets with CO₂ and O₂ Mixed Injection (COMI) at Steelmaking Temperature

摘要

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 supersonic coherent jets with CO_(2) and O_(2) mixed injection (COMI) was proposed and through industrial experiments, it can be found that the supersonic coherent jets with COMI showed remarkable advantages in reducing the dust production during EAF steelmaking. In this study, based on the eddy dissipation concept (EDC) model with the detailed chemical kinetic mechanisms (GRI-Mech 3.0), a computational fluid dynamics (CFD) model of supersonic coherent jets with COMI was built. 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 supersonic coherent jets with COMI at steelmaking temperature 1700 K was studied and the results show that the chemical effect of CO_(2) significantly weakens the shrouding combustion reactions of CH_(4) and the relative importance of the chemical effect of CO_(2) increases with CO_(2) concentration increasing. The potential core length of supersonic coherent jets decreases with the volume fraction of CO_(2) increasing. Moreover, it also can be found that the potential core length of supersonic coherent jets can be prolonged with higher ambient temperature.