铝电解槽磁流体稳定性有限元分析

Finite element analysis for magnetohydrodynamic stability of an aluminum reduction cell

本文采用有限元法求解分层磁流体小扰动方程系统特征值 ,研究铝电解槽稳定性。研究结果表明 ,在没有电磁力时 ,铝液表面波动 (内波 )是稳定的。存在电磁力时 ,它会激发铝液表面波动的某些低频长波分量不稳定性 ,高频短波不受影响。被激发的不稳定波动频率和扰动增长率与电流密度、磁感应强度垂直分量 ,铝电解槽长宽比、电解质和铝液的密度差、厚度等因素密切相关。减少电流密度、磁感应强度、增加电极距离和铝液厚度可以提高铝电解槽的稳定性。

This paper employs the finite element method to solve the eigenvalue problem on the stability of a perturbed 2D magnetohydrodynamics (MHD) model of an aluminum reduction cell. Numerical results indicate that the interface waves of molten electrolyte and aluminum liquid of a reduction cells are stable in cases without electromagnetic forces. In practice elctromagnetic force always induces instability of a few long-wave components of surface oscillations of aluminum liquid. The natural frequencies and the growth rates of the induced unstable modes strongly depend on current density, magnetic fields, density difference of electrolyte and aluminum liquid, the ratio of length and width of a reduction cell and the thickness of liquid layer. It is confirmed that the stability of a reductioin cell can be enhanced by increasing the anode/cathode distance (ACD) and the thickness of aluminum liquid.