Investigations of unstable flows in magnetic fields relevant for industrial applications


Investigations of unstable flows in magnetic fields relevant for industrial applications

Eckert, S.; Gerbeth, G.; Pal, J.; Räbiger, D.; Shevchenko, N.; Timmel, K.; Vogt, T.

Various types of magnetic fields are applied for electromagnetic flow control in many industrial applications such as metallurgy, casting, crystal growth or electrochemistry. The first part of this paper considers the electromagnetic damping of instabilities by DC magnetic fields (so-called “Electromagnetic Brakes”), which are exploited for casting of steel or aluminum. The magnetic field tends to damp 3D flow perturbations leading to the development of 2D flow structures aligned with the magnetic field direction. However, this effect is not equivalent to a complete damping of turbulent fluctuations as it might be expected at a first glance. The magnetic field application may even enhance local velocity fluctuations in the continuous casting process. This feature that a DC magnetic field may give rise to non-steady, non-isotropic flow structures has to be taking into account for designing of tailored magnetic fields in the continuous casting process.
AC magnetic fields are used in metallurgy and crystal growth for melt stirring or the suppression of instabilities, respectively. The second part of this contribution provides a brief insight into flow phenomena in a liquid metal column resulting from the application of diverse AC magnetic fields, for instance time-modulated or superposed fields.

Keywords: Liquid metal; flow instability; electromagnetic fields; electromagnetic flow control

  • Invited lecture (Conferences)
    European GDR Dynamo & MHD Days 2012, 01.-04.10.2012, Nice, France

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Publ.-Id: 17865