Numerical Simulation Of Flow Field And Surface Fluctuation Of Molten Steel In Mold Of Slab Continuous Caster

Mold, as the most crucial part in the continuous casting machine and called the heart of it, plays an important role in improving the quantity and quality of the steel. Flow pattern and surface fluctuation of molten steel in the mold directly influence the continuous casting production and billet quality. Most of billet surface defects originate from the continuous casting mold. At the same time, the billet quality increases with a higher casting speed. But the higher speed makes flow field and surface fluctuation of molten steel fluctuating drastically, which brings the new problem to billet quality for a continuously cast strand. So, it is obviously significant to analyses and study the flow field and surface fluctuation of molten steel in the mold of slab continuous caster.Flow field in the continuous casting mold is an extremely complicated physical-chemical process at high temperature, which is hard to measure directly. In the condition, using numerical simulation is a high effective approach to study the flow state and free surface fluctuation.For a long time flow action of molten steel in the mold is simplified to steady state and meniscus by interfacial tension is ignored because it is difficult to deal with the unsteady interface of free surface. The multiphase flow coupled with the standard k-εturbulence model is carried out to know flow field and surface action and then to provide a basis for optimize cast process.Numerical simulation on flow field and free surface fluctuation of the mold with the billet section is 1280mm×180mm,was carried out by commercial software FLUENT. It has been proved that the different side-hole angle, immersed depth of the submerged entry nozzles and the casting speed have a remarkable influence on the flow field and free surface fluctuation in the mold. The free surface keeps little period of fluctuation in the steady casting process. As casting speed is increasing, the mold liquid steel flowing speed is more and surface fluctuation of molten steel fluctuates more drastically; with side-hole down angle larger and with immersed depth of the submerged entry nozzles deeper, surface fluctuation of molten steel fluctuates less drastically, but the liquid steel flow impact point to the mold narrow face gradually becomes low, which is not good for inclusion to float. So in the process of the technological design , different parameters should be optimized.