Bubbly Mold Flow in Continuous Casting: Comparison of Numerical Flow Simulations with Water Model Measurements

The impact on the mold flow of inert gas bubbles originating from a gas injection at the top of the submerged entry nozzle is investigated. Results from a physical model using water and air are compared with corresponding numerical flow simulation results. In numerical models, the bubble velocities are determined by calculating the force equilibrium between buoyancy, drag force, and other forces acting on the bubbles. For the observed bubble size in the physical model, the so‐determined rising velocity of the bubbles is significantly too high in comparison to the water model experiment. Various effects can influence the rising velocity of bubbles. One of them is that the presence of turbulence obviously reduces the rising velocity. The influence of turbulence models and of a turbulence‐induced bubble drag modification is analyzed in numerical flow simulations and compared to water model results.