Numerical Simulation Of Flow Field And Surface Fluctuation Of Molten Steel In The Mould For Wide And Thick Slab

These years, with the developing of continuous casting technology and increasinglydemand for high-quality steel. Mould as the heart of continuous caster, is the last stagewhich makes steel clean in the process of continuous casting and by more and morepeople’s attention. In recent years, with the rapid development of shipbuilding, nuclearenergy, defense, major equipment, large equipment manufacturing and other industries, sothat the increasing demand for wide and thick slab. In the wide and thick slab production,the flow fluid has a great impact on not only inclusions floatation and slag entrapment, butalso closely related to the slab surface defects and segregation. Thus, study and optimizethe flow filed have a great influence on improving the surface quality of casting slab andefficient production.Due to the continuous casting process involves high temperatures and complexheterogeneous reactions, there is still no accurate field data test, using numericalsimulation method has become an important means of studying the mould flow field.Taking the mould of wide and thick slab continuous casting (cross section size is2300×250)as an object， using FLUENT commercial software and by coupled k-eturbulence model and VOF model to calculate three-dimensional numerical simulation onflow field and free surface fluctuation of the mould. It tends to research the casting speed,immerging depth of the submerged entry nozzle and angle of the nozzle port of the effecton the flow field and free surface fluctuation in the mould. The result shows that:（1）The basic characteristics of the molten steel flow field: the bigger velocity of steelfrom the nozzle port, and divide into two streams, forming upper recirculation zone andlower recirculation zone.（2）The VOF model could accurately simulate the free surface fluctuation. The mouldcasting process belongs to the unsteady state process, at this time the free surfacefluctuation by a big margin. After some time, the free surface is no significant fluctuation,can be considered to reach a stable casting. (3) By the casting rising up, the speed of steel and the free surface fluctuation alsoincrease. As immersed depth of the submerged entry nozzle deeper and side-hole downangle larger, this is favorable to decrease the velocity and fluctuation of molten steelsurface, and the probability of slag entrapment, whereas increase the impact depth ofmolten steel flow, which is unfavorable for the shell growth and the removed of impurityand bubble.