Effect of magnetic forces on bubble transport and MHD stability of aluminium electrolysis cells

V. Bojarevics - A. Roy

University of Greenwich, Park Row, London, SE10 9LS, UK

Abstract
The effect of electro-magnetophoretic force on gas bubbles due to the additional magnetic pressure distribution in the electrolyte is analyzed and a mathematical model is derived. According to the results, the integral force on an individual bubble is of similar order as the typical drag force associated with the electrolyte flow, opposing the motion of bubbles along the slightly inclined base of the anode. This could explain certain features of the anode effect onset. It is demonstrated that the presence of electrolyte channels, where the bubbles escape, has a crucial effect on the shape and size of the metal-bath interface deformation. A shallow layer flow model accounting for the channels is derived. Results on the interface stationary shape and MHD wave stability are presented. Figs 9, Refs 16.