Abstract: Jet characteristic of oxygen lance directly affects the metallurgical performance of converter. To solve the problems of long blowing time and high oxygen consumption of a 120 t converter, oxygen lance nozzle optimization was carried out, then the jet characteristics was studied based on numerical simulation. In this paper, the features of high temperature and high CO concentration in steelmaking environment were fully considered, and the gas phase combustion mechanism was creatively introduced into the simulation. Firstly, the differences of temperature field and velocity field in the computational domain between the case without considering combustion and the case considering combustion were analyzed. The results show that combustion reaction between oxygen jet and CO will occur, and the combustion flame is mainly concentrated in the region between multiple jets. Gas phase combustion helps to suppress the attenuation of jet velocity and the coalescence of multiple jets. Simulation results of old lance and new lance indicate that the jet length and strand diameter of new oxygen lance are larger and have stronger impact ability. The new oxygen lance was applied at the steel plant, oxygen blowing time was shortened by 50 s, oxygen consumption was reduced by 1.37 m³/t, slagging was improved, lance sticking and slag slopping were decreased. Overall, the metallurgical indexes were improved comprehensively after applying the new lance.

Key words: oxygen lance, oxygen jet, gas combustion, numerical simulation, steelmaking environment