Study On The Optimization Simulation Of Submerged Entry Nozzle In Mold During Bloom Continuous Casting

Mold is not only the first step of producing solid steel,but also the key step of removing inclusions and improving the quality of steel.A reasonable mold flow field is favorable for the inclusion to float up.The protective slag is well heated and the slag formed acts as a lubricant.Or meniscus fluctuation in a reasonable range,reduce the possibility of slag rolling,on the contrary,these will lead to all kinds of defects in continuous casting billets.Therefore,improving mold flow field is of great significance to continuous casting process.Based on the optimization of mold nozzle,physical simulation and numerical simulation were used to study the flow field of 280 mm×380 mm large-slab mold.In the physical simulation study,a 1:1 mold water simulation experiment device was constructed to realize the continuous casting flow process under different submerged entry nozzle,different drawing speed and different liquid level.In the study of physical simulation,using PIV on mold flow speed,carried out four different nozzle was studied under different drawing speed,the characteristics of flow field under different liquid level depth study showed that four-hole nozzle opening angle downward,the working condition of the high level,low speed of flow is relatively uniform,influence on liquid surface fluctuation is small,speed of liquid level within a reasonable range.Based on the above physical simulation objects and simulation process,the numerical simulation research is carried out and expanded.Numerical simulation by using Fluent software to further study the submerged entry nozzle opening angle,hole number,installation angle changes in parameters such as the velocity field of the flow field in the mold and the influence of liquid surface wave,research shows that the double-hole nozzle down 15 °,the insert depth of 120 mm to 130 mm,the mold to form a good circulation,the liquid level fluctuation is small.When the double-hole nozzle is changed into four-hole,the disturbance range of the flow field inside the mold increases,which is more conducive to heat transfer at the lower part of the mold.When the installation angle is diagonal,the internal flow field is rotating flow,the flow state is more stable,and the flow at the corner of the mold is strengthened.To sum up,in order to better improve the flow field of this type of large-blank continuous casting mold,this thesis carried out optimization research on submerged entry nozzle.The conclusions of physical simulation and numerical simulation were consistent,and the four-hole nozzle was preferred,the opening angle was 15 ° downward,and the nozzle was installed diagonally.The research results can be used in the actual production process of this type of large blank,provide reliable basis for it,and play a guiding role in production practice.