Abstract: In order to further speed up the scrap heating rate and shorten the smelting cycle, a numerical simulation model of coherent oxygen-fuel mixed jet was established for the short process full scrap EAF steelmaking process. The effects of different oxygen-fuel ratio and different oxygen-fuel flow rate on the dynamic characteristics of mixed gas injection, the length of combustion zone and the position of combustion zone were analyzed. The results show that in the medium and high-grade burner modes, as the oxygen-fuel ratio increases, the outlet velocity and the length of the core section of the potential flow gradually increase, and the position of the beginning of the combustion reaction is delayed. When the oxygen-fuel ratio is 2.2, the length of the combustion reaction zone is the longest, which is conducive to the full mixing combustion of natural gas and oxygen. The gas-phase jet in the low-grade burner mode does not form a potential flow core, which means that the heat released by the combustion process may not be effectively concentrated on the scrap melting. Based on the numerical simulation results, the injection parameters and time of the oxygen-fuel lance were adjusted, the oxygen-fuel ratio was increased from 2.0 to 2.2, and the service time of the low-grade burner was shortened. The smelting data of a complete campaign was statistically analyzed, the power supply time was shortened by 0.7 min, and the natural gas consumption was reduced by 0.29 m³/t. 

Key words: electric furnace steelmaking, oxygen-fuel mixed injection, numerical simulation, scrap melting