Demystifying Underlying Fluid Mechanics of Gas Stirred Ladle Systems with Top Slag Layer Using Physical Modeling and Mathematical Modeling

Effects of slag layer thickness on the fluid dynamics of liquid steel in gas-stirred ladles by bottom injection of argon was studied through water modeling experiments and numerical simulations. Mixing times increase considerably with thicker slag layers and decrease of gas flow rates. The physical properties of the system have a smaller influence on mixing time. Slag Eye Opening (SEO) area is increased under thin slag layers, increase of gas flow rates, and denser and less viscous slags. The planes close to the metal-slag interface, under the presence of thick slag layers for a given gas flow rate, are split in subregions of small velocities with different orientations making the lower fluid to come close to a stagnant condition. The presence of, either, thick or thin slag layers does not influence the axial velocity along the plume height for a fixed flow rate of gas. The SEO area follows a linear relationship with the square root of the densiometric Froude number based on the slag layer thickness.