无接触熔炼铜坩埚内部磁场分布规律及其影响因素

Distribution and Affecting Factors of the Axial Magnetic Fields in the Cold Crucible for Non-contact Melting

利用磁探针测量了无接触熔炼铜坩埚内部的轴向磁场,得到了在相同半径、不同方位以及不同半径、同一方位上的轴向磁场的分布规律;并考察了励磁电流、电源频率以及励磁线圈与铜坩埚的相对位置对轴向磁场的影响。结果表明,轴向磁场在励磁线圈所在范围内较强,随着与励磁线圈中垂面轴向距离的增加而减弱,并表现出关于励磁线圈中垂面的非对称的分布规律;轴向磁场强度基本不随半径改变,且表现出关于中心轴线对称的分布规律;铜坩埚起到了使磁场均匀化的作用。另外还发现,轴向磁场随励磁线圈与铜坩埚底部距离的增大而减弱,随励磁电流的增大而增强,随电源频率的上升而减弱。

Based on the Faraday's Law of electromagnetic induction,the axial magnetic fields at different radiuses and positions along the axis of the cold crucible made of copper were measured with a magnetic probe.Several factors influencing the magnetic fields were investigated such as the exciting current,the frequency and distance between the magnetic-exciting coils and the bottom of the crucible.The experimental results show that:the strong axial magnetic fields are induced within the coils,and the magnetic fields are decreased with the increase of the distance between the coils and measuring positions,which exhibits distribution asymmetrically to the central vertical plane.With the increase of the radius,the axial magnetic fields are increased slightly,and it is distributed symmetrically to the center axis.In addition,the copper crucible can make the fields distribute uniformly.The increase of the exciting current,the decrease of the frequency and the distance between the coils and the bottom of the crucible will also make a contribution to the enhancement of the axial magnetic fields.