Numerical Simulation of Alumina-Mixing Process with a Multicomponent Flow Model Coupled with Electromagnetic Forces in Aluminum Reduction Cells

An extended computational fluid dynamics model combined with the driving forces of anode gas bubbles and electromagnetic forces (EMFs) was developed for the alumina-mixing process in aluminum reduction cells. A practical feeding scheme and the consuming rate of alumina depending on the local current intensity of the bath-metal interface were considered in the simulation. A comparative numerical study was carried out using the models with and without considering the EMFs. The results show that considering different driving forces in modeling can lead to different results for alumina mixing in the cell. The existence of the bubble movement makes alumina disperse more quickly in local areas, and it greatly contributes to the vertical dispersion in the early stage of mixing. The EMF plays a more important role in the long-range transportation of alumina in the cell. Both forces should be taken into consideration in the modeling because they have a positive influence on distribution uniformity and the dispersion rate of alumina.