Models for magnetohydrodynamics of alumi

The electric current and the associated magnetic field in aluminium electrolysis cells create effects limiting the cell productivity and possibly cause instabilities such as surface waving, 'anode effects', erosion of pot lining, and feed material sedimentation. This study presents an instructive analysis through the step-by-step inclusion of various physical coupling factors affecting the magnetic field, electric current, velocity, and wave development in the electrolysis cells. A full time-dependent model is established that couples nonlinear turbulent fluid dynamics with the extended electromagnetic field in the cell and the entire bus bar circuit, incorporating ferromagnetic effects. The methodology is illustrated using animated examples for high amperage cells. Additionally, the theory and numerical model of the electrolysis cell include variations in the cell bottom of the aluminium layer and the electrolyte thickness due to the anode non-uniform burn-out process and the presence of anode channels. The results validate the importance of these channels and indicate a need to reconsider previous magnetohydrodynamic instability theories and dynamic wave development models, revealing significant 'sloshing' MHD wave patterns in aluminium production cells.