【作者】 姜艳丽；

【导师】 崔建忠； 冯乃祥；

【作者基本信息】 东北大学 ， 材料加工工程， 2009， 博士

【摘要】 铝电解槽的物理场对铝电解槽的电流效率和槽寿命等技术指标影响显著,因此,铝电解槽多物理场的模拟研究对铝电解槽物理场的优化设计和新槽型的开发都具有十分重要的意义,本论文采用计算机仿真技术,以大型有限元软件ANSYS为平台,以160kA原阴极铝电解槽和东北大学冯乃祥所研发的新型阴极结构铝电解槽为研究对象,对原阴极铝电解槽和新型阴极结构铝电解槽的多物理场进行模拟计算。原阴极铝电解槽和新型阴极结构铝电解槽三维电场和磁场的计算结果表明：新型阴极结构铝电解槽与原阴极铝电解槽铝液和电解质中的电流分布规律基本相似,不同的是,新型阴极结构铝电解槽中铝液Z向垂直电流减小,阴极凸台表面上部的铝液中X向(长轴)水平电流增加,此外,新型阴极结构铝电解槽的电解质电压降比原阴极铝电解槽的电解质电压降降低0.38V,说明新型阴极结构铝电解槽更加节能；新型阴极结构铝电解槽和原阴极铝电解槽铝液与电解质中磁场分布规律相似,磁场值相差也不大,其磁力线基本上可以看做一个绕Z轴顺时针的大旋涡,其计算结果与测量结果基本吻合；新型阴极结构铝电解槽与原阴极铝电解槽铝液和电解质中的电磁力分布趋势不同,但其值大小差别不大,原阴极铝电解槽铝液中的总电磁力离阴极上表面越近其值越大,而新型阴极结构铝电解槽的总电磁力矢量和则是先减小,至阴极凹槽内升高,原阴极铝电解槽电解质中的总电磁力离阴极上表面越远其值越大,至阳极问隙时达到最高,而新型阴极结构铝电解槽的总电磁力在阳极底掌下变化不大,分布均匀,至阳极间隙时降低。原阴极铝电解槽和新型阴极结构铝电解槽三维流场的计算结果表明：新型阴极结构铝电解槽铝液与电解质的速度都要小于原阴极铝电解槽铝液与电解质的速度,且存在更大面积的零速度区域,在铝液与电解质交界面上,铝液与电解质的Z向垂直速度低于原阴极铝电解槽铝液与电解质的Z向垂直速度,且具有较多的小峰值,取代了原阴极铝电解槽铝液与电解质交界面上稀疏的高峰值,从而可以推断在铝液与电解质交界面上,新型阴极结构铝电解槽的波动幅度小而光滑,因此将比原阴极铝电解槽更为稳定。原阴极铝电解槽和新型阴极结构铝电解槽三维温度场的计算结果表明：其计算结果与测量结果基本吻合,采用新型阴极结构后,底部保温不足,导致新型阴极结构铝电解槽过冷,重新设计后整个新型阴极结构铝电解槽的底部保温效果良好,符合电解槽热设计原则。原阴极铝电解槽和新型阴极结构铝电解槽三维热应力场的计算结果表明：新型阴极的应力集中区出现阴极凸起与阴极表面的连接处,原阴极的应力集中区出现在长轴两端,新型阴极与原阴极相比,其正应力最大值差别不大,XZ面的应力集中虽然有所增强,但缓解了XY面与YZ面的应力集中。综上所述,本研究为新型阴极结构铝电解槽各物理场提供了有效的分析手段,从而为大型新型阴极结构铝电解槽的物理场优化设计以及对工业生产槽的工程分析与诊断都将有重要的参考价值。更多还原

【Abstract】 The multi-fields of aluminum reduction cell have significant influenced on the current efficiency and the cell life, so the numerical simulation of the multi-fields in aluminum reduction cells is very important to optimize the conventional cells and the design the new model cells. The mathematical model of electromagnetic field, flow field, temperature field and thermal-stress field was established in the paper. The multi-field of the 160kA conventional and new model cathode (invented by Feng Naixiang of Northeast University) cells was numerically calculated with commercial software ANSYS.The calculated results of the 3D electromagnetic field show that:the current distribution of the conventional cells is similar to those of the new model cathode cells, but in aluminum of the new model cathode cells, the Z Current density decreased, while the X (long axes) Current density of aluminum that is up from the surface of convex cathode increased, in additional, the voltage drop in electrolyte of the new model cathode cells reduces 0.38V, which proves that the new model cathode cells is advantageous in energy conservation;The magnetic distribution of the conventional cells and new model cathode cells is similar, the magnetic line forms a clockwise swirl, and the measured data was consistent with the simulated results.The Lorentz force distribution of the conventional cells and new model cathode cells is differ, but the value is similar, the Lorentz force in aluminum of the conventional cell become higher near the surface of the cathode, while the Lorentz force in aluminum of the new model cathode cells decreased at first, then increased at the concave of cathode, the Lorentz force in electrolyte of the conventional cell become higher away from the surface of the cathode, while the Lorentz force in electrolyte under the anode bottom of the new model cathode cells is evenly distributed, then decreased in gap of the anode.The calculated results of the 3D flow field show that:in the new model cathode cells, the velocity of the aluminum and electrolyte is smaller than the one of the conventional cell, and there is wider zero velocity region; at the interface of aluminum and electrolyte of the new model cathode cells, the peak of Z velocity is smaller and denser, replace the larger and sparser peak of Z velocity at the interface of aluminum and electrolyte of the conventional cells, so it can conclude that the fluctuation of the new model cathode cells is smoother, therefore, the new model cathode cells is steadier.The calculated results of the 3D temperature field show that:the measured data was consistent with the simulated results, the new model cathode cells is cooler because of the bad insulation work of the bottom carbon block, and after designed, the bottom temperature of the new model cathode cells is hearth.The calculated results of the 3D thermal-stress field show that:the stress concentration is at the joints of the convex and the surface of cathode in the new model cathode cells, while the stress concentration is at the ends of long axis of cathode in the conventional cells; in the new model cathode cells, the XZ shear stress concentration is enhanced, but the XY and YZ shear stress concentration is released.In conclusion, the numerical simulations provide an exact and high efficiency method for the multi-field of the new model cathode cells, and have the important references values for project analysis and diagnose.更多还原