Study On Numerical Simulation Of The Electrolyte Flow Field In Aluminum Reduction Cells

The electrolyte flow has significant influences on heat and mass transfer processes in aluminum reduction cells. The researches into the electrolyte flow are very important either for proper operation of the conventional cells or for the design of the drained cells.As a sub-project, the basic design and research of drained aluminum reduction cells (G1999064903), the electrolyte flow field in the 156kA aluminum reduction cells with two end anode risers was studied in this paper. Firstly, the electrolyte flow in aluminum reduction cells was analyzed in detail. Three-dimension physical and numerical models of the electrolyte flow were established by means of appropriate simplification. Secondly, based on the commercial CFD software CFX-4.3, the electrolyte flow field in the conventional cells was numerically calculated in three cases, i.e. the flow induced by electromagnetic force, the flow driven by anode gas, and the flow driven simultaneously by the above two forces, respectively. The calculated results were analyzed and validated by the results of water model experiment and related literatures. At last, the electrolyte flow field in the drained cells with advanced structure was simulated by use of the validated model. The influences of cathode drained slope and anode cathode distance (ACD) on the electrolyte flow were also been investigated quantitatively.The main innovations and conclusions of the paper are as follows:(1) In this paper, all the electrolyte flow domains were considered, which made the research range wider. The multi-fluid model was used to describe the electrolyte flow at first time. The distortion of the anode bubbles was also taken into account, which was close to the practical condition.(2) In the conventional cells, the electrolyte flow induced by electromagnetic force produces a large eddy pattern predominately in the horizontal direction. The electrolyte flow driven by anode gas is a local circulation around each anode. The electrolyte flow driven by the combination of the above two forces is similar to the solely anode gas driven case, which indicates that the electrolyte flow field is mainly determined by the anode gas.(3) The electrolyte flow in the drained cells is more even than in the conventional cells. Corresponding to present center point feeding, the electrolyte flow in the drained cells is more advantageous to the release of anode gas, the dissolution and diffusion of alumina, and the gradient reduction of the electrolyte density and temperature.(4)The cathode drained slope and anode cathode distance have some effects on the electrolyte flow. The research will provide theoretical reference for the structure optimization of the drained cells.