Enhanced impingement characteristics of supersonic oxygen jets on molten bath using a multi-nozzle oxygen lance in a converter

Abstract

In the context of supersonic oxygen jets impinging on the bath surface, understanding the gas-bath interaction mechanism is of paramount importance for optimizing lance design in the converter for steelmaking process. This study employs a coupled VOF model and realizable k-ε turbulence model to simulate the gas/metal/slag turbulent flow in a 180t converter for exploring the essential aspects such as cavity, stirring dead zone, slag-metal splash, and kinetic energy distribution. To validate the model reliability, the numerical results are compared with experimental measurement. The results indicate that: the shear stress from the deflected oxygen jet induces surface waves in the cavity, propagating from its edge to the converter wall. The total splashing volume of the metal and the slag is minimal at a nozzle inclination angle of 14°, while the mass ratio of entrained molten iron in the splash is lowest at an inclination angle of 18°. The slag kinetic energy typically accounts for approximately 30% of the total kinetic energy of the bath. Remarkably, the slag layer, equipped with 4 nozzles and an inclination angle of 14°, demonstrates the most efficient utilization of the molten bath stirring energy, constituting an impressive 34.03% of the total kinetic energy. Moreover, a larger characteristic cavity depth expedites local circulation motion while diminishing the overall stirring performance in the bath. These findings provide valuable insights into the behavior of multiple supersonic oxygen jets in the converter, furnishing essential information for process optimization and design in the steelmaking industry.