Modeling Argon Gas Behavior in Continuous Casting of Steel

In the continuous casting of steel, argon gas injection through the upper tundish nozzle wall or stopper tip is known to decrease clogging and remove inclusions. In addition to this intended gas injection, gas may be passively aspirated into the flow system by negative pressure developed inside of the nozzle. The injected gas forms gas pockets and bubbles through complex redistribution processes that greatly affect flow in the mold, leading to defects in the final product. Estimating the number and size distribution of bubbles is crucial to optimize multiphase flow in this important manufacturing process. This article introduces an integrated methodology to investigate these phenomena and provides examples to validate the approach. The system features models to predict: gas leakage, pressure distribution in the entire system, gas pockets and the size distribution and trajectories of bubbles using a new hybrid method, and multiphase flow in the nozzle and mold.