LARGE GAS BUBBLES UNDER THE ANODES OF ALUMINUM ELECTROLYSIS CELLS

摘要

The gas bubble laden layer under the anodes during thernelectrolysis of alumina plays an important role in thernhydrodynamics and the voltage balance of the reduction cells.rnUnder certain geometrical and operational conditions, very largerngas pockets, in the order of hundred cubic centimeters can bernformed. The particular shape of these large gas bubbles was firstrndescribed by Fortin et al in 1984 [1]. In the present paper thernresults of a combined experimental and numerical approach arerndescribed. In the experiments, the shape and the kinematics of thernFortin bubbles were analyzed by videography and Particle ImagernVelocimetry (PIV). A finite element method (FEM) combinedrnwith a Volume of Fluid (VOF) method was used to reproduce thernexperimentally observed phenomena, with particular attention tornthe reduction of the numerical diffusion of the liquid-gasrninterfaces. The morphology of the large bubbles and theirrnmovement including the velocity field around them are described.