On the Fluid Flow and Mixing Phenomena in Ladles Equipped with Impeller and Gas Purging for Degassing of Al-Based Alloys

In this work a fundamental Eulerian mathematical model is developed to simulate fluid flow and mixing phenomena in aluminum ladles equipped with an impeller for dehydrogenization treatment. The effect of rotating speed and type of impeller, depth of immersion, and gas flow rate, on the mixing behavior and vortex formation is analyzed with this model. The model simulates operation with and without gas injection and it is developed in the commercial PHOENICS 3.4 CFD code in order to solve all conservation equations governing the process, i.e., continuity, 3D turbulent Navier-Stokes and k-ε turbulence model for a two-phase fluid flow problem using the Inter Phase Slip Algorithm. In order to realistically represent the process, the shape of the furnace and the impellers are modeled by employing Body Fitted Coordinates. It is concluded that the mixing behavior is highly dependent on the rotation speed and impeller type. Mixing time is improved when: the impeller is located at a depth of 0.229 m into the aluminum bath, and by using high rotation speeds, ladles with a high ratio of diameter to height, and impellers with notches.