Development of molten metal holder of Faraday type

法拉第型熔融金属保持器的研制

• 批准号: 02555038
• 负责人: YAMANE Ryuichiro
• 金额: $ 2.69万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02555038/
• 关键词: Fluid Mechanics; Magnetohydrodynamics; Continuous Casting; DC Magnetic Field; DC Current; Shape-Control; 電磁力; 溶融金属; 冶金学; 鉄と鋼; 曲面創成; 波動

This study was conducted for the development of a molten metal holder. The molten metal is held without contact by the electromagnetic force which is induced by the interaction between DC current and DC magnetic field. We determined the the shape of the free surface under various conditions. Transient response and frequency characteristics were also determined with relation to the feedback control. From the analysis and the experiments with mercury, following results were obtained.(1) Stable holding of the molten metal without contact can be realized by using an electromagnetic force.(2) When the electromagnetic force is irrotational, no flow is induced in the fluid. In case that the horizontal DC electric current and nonuniform vertical DC magnetic field which cross each other in right angle are applied to the molten metal, stable concave or convex surface is formed.(3) In case of the electromagnetic force with a rotational part, a recirculating flow is induced in the fluid ; however, the flow becomes weak as the magnetic field becomes strong. Various shapes of the free surface can be realized by changing both the position of the electrode and the distribution of the magnetic field.(4) When the electromagnetic force is suddenly applied, surface waves are generated. These waves disappear as the magnetic field becomes strong. There exists a suitable magnetic field strength to reduce the time required for the stationary surface to a minimum.(5) The AC part of the electric current make the surface unstable. Unsteady electromagnetic force causes the vertical or horizontal sloshing of the liquid metal. An increase of the Reynolds number or of the Weber number will make the system unstable but an increase of the Stuart number will make the system stable.

本研究是为了开发一种熔融金属保持器而进行的。通过直流电流和直流磁场之间的相互作用而感应出的电磁力，使熔融金属保持不接触。确定了各种条件下的自由面形状。瞬态响应和频率特性也确定与反馈控制。从分析和汞的实验中，得到以下结果。(1)通过使用电磁力，可以实现熔融金属的稳定保持而不接触。(2)当电磁力是无旋的时，在流体中不引起流动。在向熔融金属施加彼此成直角交叉的水平直流电流和不均匀的垂直直流磁场的情况下，形成稳定的凹或凸表面。(3)在具有旋转部件的电磁力的情况下，在流体中诱导再循环流动;然而，随着磁场变强，流动变弱。通过改变电极的位置和磁场的分布，可以实现各种形状的自由表面。(4)当电磁力突然施加时，就会产生表面波。当磁场变强时，这些波就会消失。存在合适的磁场强度以将静止表面所需的时间减少到最小。(5)电流的交流部分使表面不稳定。不稳定的电磁力会引起液态金属的垂直或水平晃动。雷诺数或韦伯数的增加将使系统不稳定，但斯图尔特数的增加将使系统稳定。