Numerical investigation of bubble dynamics in aluminium electrolytic cells

Abstract

Gas generated beneath anodes in aluminum electrolytic cells play an important role for the circulation of the bath, alumina mixing, and heat balance. Those bubbles cause an extra voltage drop, which is strongly affected by the amount and shape of the bubbles beneath anodes. Consequently, understanding the dynamic behavior of bubbles in aluminum electrolytic cells has been a major research focus worldwide in recent decades. This paper presents a numerical investigation of the motion of a single bubble beneath an anode. Using a 2-dimensional geometry of part of a real cell, the motion of different sized bubbles has been simulated. It was found that the bubble size affects bubbling dynamics significantly as is measured by bubble shape, sliding velocity beneath anodes and bubble induced turbulence. Simulations have been also conducted using an air-water system to check its relevance to the CO2-cryolite system.