Shape and stability of the slag/melt interface in a small dc ESR process
Shape and stability of the slag/melt interface in a small dc ESR process
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DOI：
10.1016/j.msea.2005.08.212
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发表时间：
2005-12
期刊：
影响因子：
6.4
通讯作者：
A. Kharicha;A. Ludwig;Menghuai Wu
中科院分区：
文献类型：
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作者：
A. Kharicha;A. Ludwig;Menghuai Wu
电渣重熔（ESR）工艺已被有效地用于生产基于可实现的受控凝固的高质量大型铸锭。尽管进行了大量的模拟，但预测工艺的重要操作细节仍然具有挑战性，例如电极浸入的影响，更重要的是，熔化系统（电极，炉渣，池）中不稳定的结果。为了有一个更好的理解的过程中，目前的工作旨在验证的有效性，这是广泛使用的在以前的模拟两个假设。首先是炉渣/钢界面的平坦度，其次是整个区域上电流密度的垂直度和稳定性。在本文中，磁流体动力学（MHD）现象发生在ESR的数学模型，更严格地模拟电流在模具的关闭。在现阶段，该模型不包括任何浮力或固化效应。采用VOF模型解决了该问题的多相问题，将该区域划分为由自由界面分隔的两个子域（钢和渣）。研究了外加直流电流和结晶器直径对初始界面的影响。我们表明，除了如果模具是绝缘的，接口是从来没有平坦的。在某些情况下，界面甚至变得不稳定，导致电短路。
The electro-slag remelting (ESR) process has been used effectively to produce large ingots of high quality based on the controlled solidification that can be achieved. Despite numerous simulations, it is still challenging to predict important operating details of the process, such as the effect of the electrode immersion and, more importantly, the results of instabilities in the melting system (electrode, slag, pool). In order to have a better understanding of the process, the present work aims to verify the validity of two assumptions which were widely used in previous simulations. First is the flatness of the slag/steel interface, and second concerns the verticality and the stationarity of the density of the electric current over the entire domain. In the present paper, a mathematical model of the magneto-hydrodynamic (MHD) phenomena occurring during ESR, modelling more rigorously the closure of the electric current at the mould is presented. At the present stage, the model does not include any buoyancy or solidification effects. The multiphase aspect of the problem is solved by using a VOF model, the domain is divided in two sub-domains (steel and slag) separated by a free interface. The effect of the imposed dc current and the mould diameter on the initial interface was investigated. We show that except if the mould is insulating, the interface is never flat. In some cases the interface even becomes unstable leading to an electric shortcut.