导流槽阴极热应力分布计算和结构优化

Calculation of Thermal Stress Distribution in Drained AluminumReduction Cell Cathode and Its Structural Optimization

使用ANSYS有限元计算软件建立了75kA导流型铝电解槽热应力分布的计算模型,对聚铝沟位于槽中部导流型铝电解槽阴极内部的热应力分布进行了计算研究,为了减小阴极内部应力的集中,对电解槽结构进行优化。研究结果表明:采用典型的截面为矩形的聚铝沟和普通方钢作为阴极钢棒时,在聚铝沟处的阴极炭块和涂层以及阴极炭块内部炭糊与阴极钢棒端部接触之处存在较大的应力集中,从而可能造成阴极炭块开裂以及涂层与阴极炭块分离;采用半圆形截面聚铝沟能缓解角部的应力集中,但在聚铝沟圆弧底部的炭块和涂层中各存在1个x方向的正应力集中,最大值分别为-6.65×107Pa和-4.97×107Pa;采用小直径圆弧角的聚铝沟要比采用半圆形或矩形截面的聚铝沟更能改善此处涂层和炭块中的应力分布,而采用端部为半球形的阴极钢棒能有效地减小阴极炭块内部由于阴极钢棒热膨胀产生的应力集中。

A thermo-stress calculating model of 75 kA drained style aluminum reduction cell was developed with finite element software package ANSYS to calculate thermal stress distribution in the cathode. The results show that when the right angled sump and currently used cathode collector bar were applied, the great stress intensity exists in TiB_2 coating layer and the carbon is around the sump. This great stress intensity in the carbon cathode and coating layer are harmful to the integrity of the drained cathode. To decrease the stress intensity in the cathode, cathode structural optimization was put forward, the results show that half circled sump could reduce the stress intensity at the corners of the sump, however there was still anther stress intensity at the bottom of the sump, the maximum value of which -6.65×10~7 Pa and -4.97×10~7 Pa in the coating layer and cathode carbon respectively. The sump with the corners rounded serves more effectively to improve the stress distribution in the coating layer and cathode carbon around the sump than that with the right angled corner, and the end rounded cathode bus-bar largely reduces the stress intensity caused by the thermo-expand and deformation.