铝电解槽中局部阴极电流增大对电解质-铝液两相流场的影响  

Effect of Local Cathode Current Increasing on Bath-Metal Two-Phase Flow Field in Aluminum Reduction Cells

作　　者：王富强 刘伟[2] 王兆文[1] WANG Fuqiang;LIU Wei;WANG Zhaowen(School of Metallurgy,Northeastern University,Shenyang 110819,China;Shenyang Aluminum and Magnesium Engineering and Research Institute Co.,Ltd.,Shenyang 110001,China)

机构地区：[1]东北大学冶金学院,沈阳110819 [2]沈阳铝镁设计研究院有限公司,沈阳110001

出　　处：《金属学报》2020年第7期1047-1056,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.51434005和51529401。

摘　　要：采用数值模拟方法建立了三维非稳态电解质-铝液两相流500 kA全槽模型,并通过铝液流速和电解质/铝液的界面变形测试数据验证了模型的准确性。在此基础上模拟并定量评估了6种实际电解生产中存在的局部阴极电流增大60%对铝液流场和界面变形产生的影响程度。结果表明,局部阴极电流增大并不能改变全槽的铝液流场和界面变形的整体趋势,只是局部位置的铝液流速和界面变形幅度略有差异,其中A2A3阴极电流增大有利于抑制B侧中部的界面隆起,极距平均改善幅度为3.0%。分别通过增大电解槽两端部,中部和A、B两侧的部分阴极电流比例对比分析了两相流场变化规律。结果表明,适当增加电解槽两端部的阴极电流有利于抑制界面变形,尤其是A1~A4和A21~A34阴极电流增加28%可将界面隆起最大值降低2.4 mm,B7~B18的极距平均拉高9.5%。该研究为母线优化和改善电解槽磁流体稳定性提供了一条新思路。The stability of the magnetohydrodynamics(MHD)of aluminum reduction cell is determined by the bath-metal two-phase flow field.So,konwing how to optimize the metal flow field and restrain the bath/metal interface deformation is the key to maintain the stable and efficient operation of cell.Many previous works on the bath-metal flow field are based on the static electromagnetic force stirring the melt,however,it should be have some deviation from the actual cell state.A three dimensional bath-metal two-phase quasi-steady flow model(based on transient electromagnetic force)for full 500 kA aluminum reduction cell was built by means of numerical simulation in this work,and validated by metal velocity and bath/metal interface deformation measurement in industrial cells.The effects of 60%increase of local cathode current on melt flow distribution and interface deformation were simulated and evaluated according to abnormal 6 cases in realistic electrolytic process.It was found that the increase of local cathode current has little effects on the general pattern of flow field and interface deformation in cell,but the amplitude of local metal velocity and interface deformation would be changed in certain extent.The increase of local cathode current in A2~A3 could decrease the interface height in middle cell of downstream side(side B),with anode cathode distance(ACD)increasing by 3.0%.But the other 5 cases could deteriorate the low ACD zone further in side B,especially the increase of local cathode current in A10A11,with average ACD decreasing by 4.6%in B12~B20.The solution is to cut cathode flexes partially in abnormal position to decrease the effect on the bath-metal two-phase flow.According to the evaluation results,it is found that the uneven distribution of cathode current may be helpful to decrease the interface deformation and improve the MHD stability of cell.Based on this finding,the bath-metal two-phase flow field was changed by increasing the proportion of cathode current at the two ends of cell,the middle part of

关 键 词：铝电解槽 两相流场 局部阴极电流增大 界面变形 数值模拟 优化 

分 类 号：TF821[冶金工程—有色金属冶金] O441.4[理学—电磁学]