大型铝电解槽电解质流场涡结构的数值模拟

针对铝电解槽内熔体旋转流动的特点,提出使用涡量和旋转强度来对其涡结构进行定量解析,并以某300kA槽电解质流场为研究对象,使用CFX12软件平台进行数值模拟。结果表明:极间水平截面和阳极间缝垂直截面的旋转强度最大值分别为1.611和1.961 s 1,其绝对涡量最大值分别为4.002和3.391 s 1;阳极气泡的搅动使阳极周围电解质中成对出现反向对称小涡;而电磁力的不均匀性导致部分阳极底部出现不对称大涡;阳极中缝和间缝相交位置的绝对涡量超过4 s 1,在该位置布置下料点有利于氧化铝的分散。故运用涡分析法能得到更为丰富和精确的流场信息,为槽结构的设计提供理论指导。

Numerical simulation on vortical structures of electrolyte flow field in large aluminium reduction cells

In view of the characteristics of the rotation flow of the melt in aluminum reduction cells,the methods of vorticity and swirling strength were introduced to analyze the vortical structures of aluminum reduction cells quantitatively.Based on the software CFX12,the electrolyte flow field in a 300 kA cell was numerically simulated.The results show that the maximum swirling strengths on the interpolar horizontal plane and the vertical cross-section plane of the anode gap are 1.611 and 1.961 s-1 respectively,and the maximum absolute vorticities are 4.002 and 3.391 s-1,respectively.Small vortexes occur as reverse symmetrical pairs around the anode because of the stirring of anode gas,while large asymmetric vortexes are caused under some anodes by the nonuniformity of electromagnetic forces(EMFs).The alumina feeding points should be set at the intersection position of center channel and anode slots to achieve the best mixing effect of alumina,where the absolute vorticity is greater than 4 s-1.Thus,the above method can provide more flow field information with higher precision and theoretical guidance for the structural design of the cell.