Fully-Coupled Electric-Thermal-Flow Modeling and Investigation of Dynamic Thermal-Ledge Behavior in Aluminum Electrolysis Cell

Aluminum electrolysis cells (AECs) require effective thermal regulation to operate flexibly alongside renewable energy sources. Prior to implementing thermal regulation strategies, it is essential to predict the dynamic variations in the thermal field and ledge characteristics of a full-scale cell. This study introduces a transient electro-thermal-flow coupling model for a full-scale AEC, aimed at investigating the interactions between ledge distribution and various operational fields, including thermal, electric, and flow fields. The model facilitates the calculation and assessment of the dynamic properties of the ledge and thermal balance under ±15% flexible current variations. Results indicate that during a current increase, ledge melting predominantly occurs in the electrolyte layer, while ledge solidification is primarily observed in the metal layer during a current reduction. Regions with a thicker ledge and faster velocity tend to melt more during current increases and are less likely to return to their original shape and thickness during current reductions, complicating the rapid restoration of thermal equilibrium. To achieve uniform ledge distribution and real-time adaptation to flexible current variations, it is recommended to install distributed cooling devices on the sides of the AEC to enable differential ledge regulation at various locations.