Optimization Of Continuous Casting Mold With Argon Blowing And Study Of Nozzle Clogging On Mold Powder Entrapment

In this paper, according to the characteristics of multiphase flow in the castingmold, we build a three-phase flow mathematical model, which could simulate the stateof fluctuation in the steel-slag interface with VOF model and trace the trajectories ofargon bubble with DPM model through CFD numerical simulation software. The liquidlevel fluctuation is large and high risk in slag during the process of pouring incontinuous casting mold in a steelmaking plant. This paper take the850mm×230mmand1300mm×230mm section mould as the research object, using the VOF+DPMmathematical model to optimize the parameters of nozzle structure (nozzle angle,expanding angle) and pouring process, and build a1:2physical model to verify theresults. In addition, we use the VOF+DPM mathematical model to study the differentdegrees of nodulation of the unilateral of submerged nozzle side hole influents on thesteel flow and argon bubble movement in the mold. The results show that:(1) The results of using the VOF+DPM mathematical model to simulate the flowfield in mold can clearly reflect different operating parameters on mold powderentrapment, which is in good agreement with the water model.(2) The flow field changes greatly after blowing argon, the upper reflux beingsuppressed, and the centroid shift to narrow side or even disappear. Steel-slag interfacemorphology changes greatly, and the peak of wave may not appear in the meniscussurface, so the interface fluctuations has no obvious regularity.(3) The best parameters of850mm×230mm section are as follows: nozzle angle15°, expanding angle0°, immersion depth150mm, argon blowing rate15l/min, Thebest parameters of1300mm×230mm section are as follows: nozzle angle20°, angleof expansion9°, immersion depth150mm, argon blowing rate15l/min. After Optimized,the interface fluctuation is relatively uniform, the interfacial average speed is smaller,the average turbulent kinetic energy of upper reflux is also smaller, argon bubblefloatation area is larger, less influence on the interface, which helps to reduce the incidence rate of slag and promote impurity floatation.(4) After the nozzle clogging, the flow field shows obvious asymmetry in the mold,and the speed of steel in non-clogging side is greater than the clogging side, which leadsto the interface fluctuates strongly of the non-clogging side. When the nozzle cloggingrate increases, the asymmetry degree of steel flow in the mold increases, leading to forma vortex near the nozzle and greatly increase the interface fluctuation, which increasesthe powder entrapment incidence of the non-clogging side and deteriorates castingconditions.