Simulation Of Electromagnetic Field And Interface Wave Of Electrolyte/Aluminum In Aluminum Reduction Cell With Novel Cathode Structure

The magnetic field distribution which generated by strong current in aluminum reduction cell would affects the melt aluminum flow directly in electrolytic process, in particular, the interface wave of electrolyte/liquid aluminum, it will make the great affect on the technical and economic indicators of the aluminum reduction cell, such as production operation of the aluminum reduction cell, power consumption, current efficiency and the life of aluminum reduction cell. Therefore, it is important to study the magnetic field and movement of the melt aluminum flow for aluminum industry on saving energy consumption and improving the current efficiency.This research which is based on Maxwell equation and combined N-S equation utilizes Edge-based Method and Finite Volume Method to solve electromagnetic field and fluctuate of molten aluminum in aluminum reduction cell with novel cathode structure which is proposed by Pro. Naixiang Feng. Moreover, the change of current, magnetic field, flow field and the interface wave of electrolyte/aluminum is be compared.The aluminum reduction cell’s structure is very complex, and the size of medium in aluminum reduction cell is different. For the reasons given above, divide mesh and apply boundary condition is difficult to go on. The structure mesh is taken when apply the mesh on component which size change sharply so that the accuracy of the simulation can be ensured. The air that locate outer layer is divided by structure mesh and unstructured mesh is used on inner layer. Therefore, the mesh quantity and the computing time is decrease.The study in this dissertation is the influence of the electric field and magnetic field distribution in aluminum reduction cell with different cathode structure carbon bricks, and analyses the result. The result show that the current density increase in the novel cathode structure aluminum reduction cell and the current distribution became more uniform compared with traditional aluminum reduction cell. The other hand, weak horizontal current appears on the convex surface, and weakened the longitudinal waves of molten aluminum indirectly. The voltage drop of the entirely novel aluminum reduction cell has reduced, the maximum value is178mV. Besides, the magnetic field distribution of molten aluminum also become more uniform and flat in the novel aluminum reduction cell. Moreover, the total magnetic flux density decreases in the novel aluminum reduction cell.In this paper, the electromagnetic force is the only power source of the fluid, and study the melt state of motion in novel cathode structure aluminum reduction cell with homogeneous model and N-S turbulence equations. A comparative analysis of the different flow fields influenced by the structure of carbon brick is presented. It turns out that the horizontal movement of molten aluminum dominates only affected by the electromagnetic force and two reverse eddies arise in flow field of molten aluminum. The velocity of molten aluminum and the amplitude of molten aluminum surface reduce in the novel aluminum reduction cell. The maximum decreasing of the average velocity is0.0582m-s-1and the amplitude is0.83cm.According to the calculating result, there are some characteristics in the novel aluminum reduction cell, such as the magnetic field distribution is more uniform and flat, the voltage drop of the entirely aluminum reduction cell is lower and the amplitude of molten aluminum surface is smaller than the tradition aluminum reduction cell and so on. It can be concluded that the current efficiency would be enhanced in the novel aluminum reduction cell, so it will save the electrical energy greatly.