导流槽燃气预热过程中阴极炭块类型对其热应力的影响

Influence of different kinds of cathodes on thermal stress distribution of drained cell in gas preheating process

以有限元分析软件ANSYS为平台,建立导流槽半槽有限元模型,对普通炭块、半石墨质、半石墨化和石墨化4种阴极炭块在燃气预热过程中的温度、位移与热应力分布进行数值模拟研究。研究结果表明:炭块表面的高温区位于燃气的射流区域;炭块两侧的位移都呈对称分布,x,y和z方向位移较大的区域分别位于边部聚铝沟、中部聚铝沟及烟道端聚铝沟附近;热应力集中的区域位于中央聚铝沟下方的阴极炭块与钢棒接触处。随着石墨含量的增加,不同炭块表面的最高温度相差不大,但下表面的平均温度升高,预热效果变好;炭块的位移增大,而炭块内的最大热应力有不同程度的降低。与普通炭块相比,石墨化炭块下表面的平均温度增加19.44%,总位移增加17.04%,而最大热应力降低24.06%;增加炭块中的石墨含量,可减小炭块破损的可能性。

A finite element model of half drained aluminum reduction cell in gas preheating process was developed by software ANSYS. The numerical simulation on four kinds of cathodes （amorphous, semi-graphitic, semi-graphitized and graphitized） under the same preheating conditions was carried out. The results show that the area of high temperature is located at the jet region. The displacement of cathodes is symmetrical and the large displacements in x, y and z directions are located in the side grooves, central groove and duct end groove, respectively. And the region of large thermal stress locates at the interface between cathode block and collector bar. With the increase of graphite, the maximum temperature difference between different cathodes is small, while the average temperature of bottom surface is enlarged. The displacement of different cathodes increases, and the maximal thermal stress decreases. Compared with amorphous cathode, the average temperature at bottom surface and displacement of graphitized cathode increase by 19.44% and 17.04%, respectively, and the maximal thermal stress decreases by 24.06%. The possibility of cathode failure can be reduced with the increase of graphite content in cathode.