The study on the fluid flow, meniscus oscillation, slag entrapment in continuous casting mould was conducted mathematically and experimentally. The results show that the injection of argon into submerged nozzle enhan...The study on the fluid flow, meniscus oscillation, slag entrapment in continuous casting mould was conducted mathematically and experimentally. The results show that the injection of argon into submerged nozzle enhances the meniscus oscillation, thus increases the probability of slag entrapment, and the critical argon blowing flow rate, which will give rise to slag entrapment, is around 10l/min. The trajectory of bubble is affected by the bubble diameter and the molten steel flow, and the bubble diameter is dominant. The bubble with diameter 1.4mm floats fastest with 0.47m/s terminal velocity.展开更多
Bubbling to Jetting Transition is of the outmost importance in metallurgical processes given that the flow regime influences the refining rates, the refractory erosion, and the blockage of injection nozzles. Bubbling ...Bubbling to Jetting Transition is of the outmost importance in metallurgical processes given that the flow regime influences the refining rates, the refractory erosion, and the blockage of injection nozzles. Bubbling to jetting transition during subsonic bottom injection of argon in molten steel is studied here. The effect of the molten steel height, the injection velocity, the nozzle diameter, and the molten steel viscosity on the jet height and the bubbling to jetting transition is numerically analyzed using Computational Fluid Dynamics. Five subsonic argon injection velocities are considered: 5, 25, 50, 100 and 150 m/s. Three values of the metal height are taken into account, namely 1.5 m, 2 m and 2.5 m. Besides, three values of the nozzle diameters are considered: 0.001 m, 0.005 m and 0.01 m. Finally, three values of the molten steel viscosity are supposed: 0.0067, 0.1 and 1 kg/(m<span style="font-family:Verdana;"><span style="white-space:nowrap;">·</span></span><span style="font-family:Verdana;">s). It is observed that for the argon-molten steel system</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> the bubbling to jetting transition occurs for an injection velocity less than 25 m/s and that for the range of viscosities considered, the molten steel viscosity does not exert significant influence on the jet height and the bubbling to jetting transition. Due to the jet instability at subsonic velocities</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> a second transition, namely jetting to bubbling, is appreciated</span><span style="font-family:Verdana;">.</span>展开更多
The stirring of a molten steel ladle with argon injection through a top submerged lance and a bottom nozzle is numerically studied here through Computational Fluid Dynamics (CFD) simulations. Three lance submergence d...The stirring of a molten steel ladle with argon injection through a top submerged lance and a bottom nozzle is numerically studied here through Computational Fluid Dynamics (CFD) simulations. Three lance submergence depths and three injection velocities are considered in the CFD numerical experiments. The turbulent dissipation rate is employed to characterize the stirring phenomenon. The mixing times are determined from the gas flow rate, ladle geometry and bath depth using an empirical correlation.展开更多
To investigate the transient transport and entrapment of argon bubbles and inclusions simultaneously during continuous casting,a 3D large eddy simulation model coupling molten steel flow,solidification and particle mo...To investigate the transient transport and entrapment of argon bubbles and inclusions simultaneously during continuous casting,a 3D large eddy simulation model coupling molten steel flow,solidification and particle motion was constructed.In this model,momentum transfer between molten steel and argon bubbles was performed by two-way coupling.The predicted results indicate that argon bubble injection changed the flow pattern of molten steel and the inclusion motion in the liquid pool.Consequently,the inclusion capture near the solidifying front was changed.In addition,measurements of bubbles and inclusions in the obtained samples were performed by methods of optical microscope examination and galvanostatic electrolysis.The results show a favorable agreement between the model predictions and the measured results,which validate the mathematical model.Furthermore,the predicted results of the inclusion entrapment in the case with argon bubble injection are more compatible with the measurements than those in the case without argon bubble injection.展开更多
文摘The study on the fluid flow, meniscus oscillation, slag entrapment in continuous casting mould was conducted mathematically and experimentally. The results show that the injection of argon into submerged nozzle enhances the meniscus oscillation, thus increases the probability of slag entrapment, and the critical argon blowing flow rate, which will give rise to slag entrapment, is around 10l/min. The trajectory of bubble is affected by the bubble diameter and the molten steel flow, and the bubble diameter is dominant. The bubble with diameter 1.4mm floats fastest with 0.47m/s terminal velocity.
文摘Bubbling to Jetting Transition is of the outmost importance in metallurgical processes given that the flow regime influences the refining rates, the refractory erosion, and the blockage of injection nozzles. Bubbling to jetting transition during subsonic bottom injection of argon in molten steel is studied here. The effect of the molten steel height, the injection velocity, the nozzle diameter, and the molten steel viscosity on the jet height and the bubbling to jetting transition is numerically analyzed using Computational Fluid Dynamics. Five subsonic argon injection velocities are considered: 5, 25, 50, 100 and 150 m/s. Three values of the metal height are taken into account, namely 1.5 m, 2 m and 2.5 m. Besides, three values of the nozzle diameters are considered: 0.001 m, 0.005 m and 0.01 m. Finally, three values of the molten steel viscosity are supposed: 0.0067, 0.1 and 1 kg/(m<span style="font-family:Verdana;"><span style="white-space:nowrap;">·</span></span><span style="font-family:Verdana;">s). It is observed that for the argon-molten steel system</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> the bubbling to jetting transition occurs for an injection velocity less than 25 m/s and that for the range of viscosities considered, the molten steel viscosity does not exert significant influence on the jet height and the bubbling to jetting transition. Due to the jet instability at subsonic velocities</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> a second transition, namely jetting to bubbling, is appreciated</span><span style="font-family:Verdana;">.</span>
文摘The stirring of a molten steel ladle with argon injection through a top submerged lance and a bottom nozzle is numerically studied here through Computational Fluid Dynamics (CFD) simulations. Three lance submergence depths and three injection velocities are considered in the CFD numerical experiments. The turbulent dissipation rate is employed to characterize the stirring phenomenon. The mixing times are determined from the gas flow rate, ladle geometry and bath depth using an empirical correlation.
基金The authors gratefully express their appreciation to the National Natural Science Foundation of China(51834002)Fundamental Research Funds for the Central Universities(FRF-AT-20-05)for sponsoring this work.
文摘To investigate the transient transport and entrapment of argon bubbles and inclusions simultaneously during continuous casting,a 3D large eddy simulation model coupling molten steel flow,solidification and particle motion was constructed.In this model,momentum transfer between molten steel and argon bubbles was performed by two-way coupling.The predicted results indicate that argon bubble injection changed the flow pattern of molten steel and the inclusion motion in the liquid pool.Consequently,the inclusion capture near the solidifying front was changed.In addition,measurements of bubbles and inclusions in the obtained samples were performed by methods of optical microscope examination and galvanostatic electrolysis.The results show a favorable agreement between the model predictions and the measured results,which validate the mathematical model.Furthermore,the predicted results of the inclusion entrapment in the case with argon bubble injection are more compatible with the measurements than those in the case without argon bubble injection.
