Study on the Regulation of Electromagnetic Stirring of Liquid Metal.

高频感应加热炉常用于金属熔体的基础研究，但在恒温下不可能大幅度改变搅拌强度。这一局限性阻碍了冶金动力学研究的发展。本研究在传统感应电炉的基础上，提出了两种调节气流强度的方法。对流量调节特性进行了实验和理论验证。导电环流量调节(1)方法：在坩埚和加热线圈之间放置一个由石墨或钼制成的环，以吸收穿透到铁液中的部分磁通并产生搅拌力。吸收的比例可以通过视电阻率来调节，视电阻率随环的形状而变化。(2)实验：炉内磁通密度的测量和…的溶解实验更多的是在铁水中制造石墨棒。发现磁通密度和局部传质系数的分布随着环的电阻率的变化而变化很大。从这些结果可以得出结论，环网的使用使流量调节成为可能。然而，为了更方便地操作，似乎很难将环连接到可变电阻上。二次线圈流量调节(1)方法：水冷铜线圈(二次线圈)连接到外部线圈，可变匝数，位于靠近铁液自由表面的坩埚外。通过改变外线圈的匝数来改变二次线圈附近的磁通。(2)实验：进行了与上述相同的实验，实现了通过改变连接到二次线圈的外线圈的匝数来调节流量。理论研究将互感模型应用于电炉内的电磁场。磁通密度的计算结果与观测值吻合较好。基于N-S方程和铁液中碳的守恒方程，对铁液中的流体流动和传质进行了数值分析。计算结果证明了二次线圈方法的可行性。较少

The high frequency induction furnace is often used for fundamental studies concerning the molten metals, but it is impossible to change the stirring intensity widely under a constant temperature. This limitation prevents the advancement of the metallurgical kinetic studies. The present study proposes two methods to provide a means of regulating the flow intensity widely based on a conventional induction furnace. The characteristics of the flow regulation have been checked experimentally and theoretically.1. Flow Regulation by Electrically Conductive Rings(1) Method : A ring made from graphite or molybdenum is located between a crucible and a heating coil to absorb a part of the magnetic fluxes which penetrate in a liquid iron and generate the stirring forces. The fraction of absorption can be regulated by the apparent resistivity which is changed by the shape of the ring.(2) Experiments : The measurements of the magnetic flux densities in the furnace and the experiment on dissolution o … More f a graphite rod in a liquid iron have been made. The distributions of the magnetic flux densities and local mass transfer coefficients have been found to change extremely with the change in the resistivity of the ring. From these results, it is concluded that the flow regulation is enabled by using the ring. However it seems difficult to connect the ring to a variable resistance for more convenient operation.2. Flow Regulation by a Secondary Coil(1) Method : A water cooled copper coil (secondary coil) which is connected to an external coil, variable turn numbers, is located out of a crucible near the free surface of liquid iron. The magnetic fluxes near the secondary coil can be changed by changing the turn numbers of the external coil.(2) Experiments : The same experiments as the above ones have been made and the flow regulation by changing the turn numbers of the external coil connected to the secondary coil has been realized experimentally.3. Theoretical StudyThe mutual inductance model is applied to the electromagnetic field in the furnace. The computed results on the magnetic flux densities agree well with the observed ones. The fluid flow and mass transfer in liquid iron have been analyzed numerically on the basis of the Navier-Stokes equation and the conservation equation of carbon in liquid iron. The computed results have supported the capability of the secondary coil methods. Less