Title :
Electromagnetic separation techniques in metal casting. II. Separation with superconducting coils
Author :
Markarov, S. ; Ludwig, Reinhold ; Apelian, Diran
Author_Institution :
Dept. of Metal Processing Inst., Worcester Polytech. Inst., MA, USA
fDate :
3/1/2001 12:00:00 AM
Abstract :
The second part of this paper is devoted to the use of dc superconducting coils for electromagnetic separation of small nonconducting inclusions in metal casting. We theoretically analyze two methods: 1) magnetohydrodynamic separation with an electric current induced by a mean flow (conical separator) and 2) electromagnetic separation with an externally injected electric current (helical separator). First, the paper develops a model of the conical separator proposed by Gillon and Pillin in 1998 and compares it with experiments. It states that the main reason for poor separation efficiency can be flow inhomogeneity and turbulence in the separation channel. Second, the paper introduces a model of the electromagnetic separator with an injected current. Such a model has a number of advantages including better performance and higher flow homogeneity. It is capable of separating of nonconducting inclusions on the order of 10 μm in size in a magnetic field of 8 T with a flow rate of 1 kg/s. Power efficiency of the electromagnetic separation is studied with respect to the accompanying Joule´s heating of molten metal. It is found that the electromagnetic separator with a superconducting coil and an injected current has the highest power coefficient, at least 100 times greater than the efficiency of conventional separation devices
Keywords :
casting; electromagnetic forces; magnetic separation; magnetohydrodynamics; superconducting coils; 10 micron; 8 T; Joule´s heating; conical separator; electromagnetic separation techniques; externally injected electric current; flow homogeneity; flow inhomogeneity; flow rate; helical separator; injected current; magnetohydrodynamic separation; metal casting; nonconducting inclusions; power efficiency; separation efficiency; superconducting coils; Casting; Current; Electromagnetic analysis; Electromagnetic heating; Electromagnetic modeling; Magnetic analysis; Magnetic fields; Magnetohydrodynamic power generation; Particle separators; Superconducting coils;
Journal_Title :
Magnetics, IEEE Transactions on