Numerical simulation of the jet characteristics of a six-hole dual-mach-number oxygen lance for a 120 t converter

To further address the practical issues of enhancing steelmaking efficiency, improving the slag melting rate, and reducing molten steel splashing in Chinese steel enterprises, this study proposed a six-hole dual-Mach-number oxygen lance (DMNOL) nozzle and investigated the effect of the dual-Mach-number design on the jet characteristics of the oxygen lance through numerical simulation. The results show that, compared with the original enterprise nozzle (Ma = 2.0), the coalescence distance of the DMNOL jet was significantly increased, effectively delaying jet velocity decay. The optimal dual-Mach-number nozzle was the one with Ma = 2.0 and 2.05. Compared with the original enterprise nozzle, the optimal dual-Mach-number nozzle exhibited an 11.06% increase in the supersonic region length of the jet and a 36.22% extension in the jet coalescence distance. At the optimal steelmaking lance height of 1.2 m, the optimal nozzle achieved a 9.26% increase in the effective impact area and an approximately 3.23% decrease in impact depth, improving steelmaking efficiency while reducing molten steel splashing. At the optimal slag melting lance height of 1.8 m, the optimal nozzle achieved a 33.33% increase in the slag melting impact area and a 3.69% increase in impact depth, enhancing the slag melting rate while promoting bath stirring.