坯壳导电性对电磁制动结晶器多物理场的影响  

Effect of conductivity of shell on multiphysics in continuous casting mold under electromagnetic braking

作　　者：吴颖东 刘中秋 李宝宽 WU Ying-dong;LIU Zhong-qiu;LI Bao-kuan(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819

出　　处：《连铸》2020年第6期1-8,共8页Continuous Casting

基　　金：国家自然科学基金资助项目(51974071);中央高校基本科研业务资助项目(N182505039,N2025020)。

摘　　要：采用雷诺时均方法,标准k-ε模型研究电磁制动下凝固坯壳导电性对板坯连铸结晶器内流场和电磁场的影响。计算了3种不同工况,1—忽略凝固坯壳导电性,2—凝固坯壳电导率取定值,该值等于钢液电导率,3—凝固坯壳电导率随温度变化,并对比了3种工况下感应电流、洛伦兹力、焦耳热及速度分布。结果表明,相较于凝固坯壳绝缘的情况,坯壳导电时,上环流减弱,下环流增强,环流涡心区域扩大;洛伦兹力、感应电流密度、焦耳热最大值出现在水口和射流区域,在制动区域内数值较高,随着远离制动区域而迅速衰减;坯壳导电时,数值和分布范围较坯壳绝缘时均有明显提高;电磁制动下坯壳导电性影响显著,因此模拟计算时凝固坏壳的导电性不应被忽略;由于凝固坯壳电导率接近钢液,因此工况2、3差异微小,由凝固坯壳导电引起的流场、感应电流密度分布和焦耳热分布的变化在工况2下变化幅度略大于工况3。Reynolds-Averaged-Navier-Stokes(RANS)method with standard k-εmodel has been adopted to study the effect of the conductivity of the solidified shell on the flow field and electromagnetic field in the slab continuous casting mold under electromagnetic braking.Three different cases were simulated,1—neglecting the conductivity of the solidified shell being,2—setting the value of conductivity of solidified shell equal to that of the molten steel,3—the conductivity of the solidified shell varying with temperature.The distributions of induced current density,Lorentz force,Joule heat and flow velocity were compared.The results show that,when the solidified shell is conductive,the upper recirculation is weaker while the lower recirculation is stronger,both vortex regions of upper and lower circulation become larger compared with when the insulating shell situation.The maximum value of induced current density,Joule heat and Lorentz force occur within the nozzle and jet region,having a larger value within the braking region and decreasing steeply with the distance from braking region.The numerical value and distribution range of the shell are obviously increased when the shell is conductive compared with when the shell is insulated.Under electromagnetic braking,the conductivity of solidified shell has a great effect on the flow pattern hence has to be considered in simulation.As the conductivity of solidified shell is so close to molten steel,thus leaving a little difference between case 2 and 3.Still,it can be seen that the differences induced by electrically conducting wall are slightly more distinct in the case 2 than case 3 for the flow field,the induced current density and the Joule heat.

关 键 词：连铸结晶器 电磁制动 导电性 凝固坯壳 数值模拟 

分 类 号：TF777[冶金工程—钢铁冶金]