电弧炉内长电弧等离子体的数值模拟

Numerical simulation of a long arc plasma in an electric arc furnace

全废钢连续加料电弧炉内长电弧作为炉内主要的能量来源,对废钢熔化及钢液升温至关重要.采用磁矢量势的磁流体动力学方法建立了电弧炉内电弧的数值模型,并基于该数值模型对电弧炉内电磁场、温度场和流场进行耦合求解,研究了电流大小、弧长对电弧炉内电弧的温度、速度、压力及气体剪切力特性的影响.结果表明,全废钢连续加料电弧炉内电弧等离子体呈“长钟型”分布,电弧柱较细长;随着电流增大,电弧有效作用范围增大,阳极表面电弧压力和气体剪切力增大;随着弧长增加,电弧有效作用范围减小,阳极表面的电弧压力和气体剪切力减小.短弧操作对熔池冲击剧烈,长弧操作熔池较为平稳,合理控制电流和弧长能有效提高电弧热效率.

The continuous scrap electric arc furnace adopts a long arc operation for a longer arc length and a larger discharge power.Although the long arc differs from the traditional welding short arc,few reports on long arc simulation research in the field of the electric arc furnace are available.As the main energy source in the electric arc furnace,the long arc is very important for the melting of scrap and heating of molten steel.Due to the complicated physical phenomena in the electric arc furnace,it is difficult to accurately obtain the distribution of various physical fields in the furnace.Therefore,numerical simulation is a frequently used method for studying the arc plasma in the electric arc furnace.In this paper,the magnetohydrodynamic method of the magnetic vector potential was used to establish the numerical model of an arc.Based on this numerical model,the electromagnetic field,temperature field,and flow field were coupled and solved.The effects of current and arc length on the temperature distribution,velocity distribution,arc force,and shear stress of the arc in the electric arc furnace were studied.The results show that the arc plasma in the electric arc furnace is distributed in a long bell shape,and the arc column is slender.As the current increases,the effective arc action range increases,and the arc pressure and shear stress on the anode surface increase.As the arc length increases,the effective arc action range decreases,and the arc pressure and shear stress on the anode surface decrease.The short arc operation has a strong effect on the molten pool,and the long arc operation is relatively stable.A reasonable control of the current and arc length effectively improves the thermal efficiency of the arc.