The effect of magnetic field on the continuous steel casting process

这是本研究的最后一年，对四年来的研究成果进行了总结。将磁场应用于连铸过程中，保证了钢水的安全凝固。本文采用连续性方程、x、y、z三个方向的动量方程和能量方程来模拟钢水的对流。在此基础上，考虑了欧姆定律、电守恒定律和毕奥-萨伐尔定律。和o.1？lx0.1？将喷嘴伸入钢水中，最高温度可达0.5℃。钢水从喷嘴底部吹出。四周四面侧壁等温冷却，上下平面隔热。考虑了三种情况，即一个线圈绕矩形封闭空间，两个线圈在x方向的末端，两个线圈在y方向的末端。模型方程用有限差分方程组逼近，用HSMAC格式求解。计算区域被划分为50^3个非均匀交错网格。数值条件为Re=10^4，Re&lt；In=10^3，Gr=10^7，Pr=0.025，Ha=0,100,200和500。在一个线圈的情况下，在Ha=100和200时形成大的滚动室，但在Ha=500时减少。然而，连铸钢过程还包括许多其他因素，还需要进一步的研究。

This is the final year of the research and research results are summarized for four years. Magnetic field is applied to the continuous steel casting process to solidify the molten steel safely. In this work, the convection of molten steel was modeled by the equation of continuity, momentum equations in the x-, y-, and z-directions and energy equation. Further more Ohm's law, conservation of electricity and Bio-Savart's law were considered.The system is composed of a rectangular box of ?x?lx2? and O.1?lx0.1? nozzle is extended into the molten steel up to 0.5?.Molten steel is blown out through the bottom of a nozzle. Four surrounding side walls are cooled isothermally and top and bottom plane is thermally insulated. Three cases of magnetic field were considered, i. e., one coil around a rectangular enclosure, two coils at the end of x-direction and two coils at the end of y-direction. Model equations were approximated by finite difference equations and solved by a HSMAC scheme. Computational region was divided into 50^3 meshes with nonuniform staggered meshes. Numerical conditions are Re= 10^4, Re_<in> = 10^3, Gr=10^7, Pr=0.025 and Ha=0, 100, 200 and 500.When there is no magnetic field, the jet fluid from nozzles hit the solidifying side walls and constitute four rolls. In the case of one electric coil, large roll cells were constituted at Ha = 100 and 200 but they were decreased at Ha = 500. In the case of x-directional two coils, at Ha = 100 and 200 the convection cells were similar to that at Ha = 0 but at Ha= 500, roll cells were limited to the upper part and the jet flow from nozzles did not reach the side walls. In the case of y-directional two coils, even at Ha = 500, jet flow from nozzle remained and reached to the side walls.From these results, a coil around an enclosure appears to be best and the x-directional two coils system is the next. However, continuous steel casting process includes many factors other than this and further study is required.