Technische Universitaet Dresden

Helmholtz-zentrum Dresden-rossendorf E.v.

Dirk Raebiger

Gunter Gerbeth

Sven Eckert

Bernd Willers

Petr A Nikrityuk

Kerstin Eckert

Roger Grundmann

The invention relates to a method and to a device for the electromagnetic stirring of electrically conductive fluids in the liquid state and/or in the state of onsetting solidification of the fluid, using a rotating magnetic field that is produced in the horizontal plane of a Lorentz force. The aim is to achieve an intensive three-dimensional flow on the inside of the fluid for mixing in the liquid state up to the direct vicinity of solidifying fronts, and to simultaneously ensure an undisturbed, free surface of the fluid. The solution is to change the direction of rotation of the magnetic field rotating in the horizontal plane at regular time intervals in the form of a period duration, wherein the frequency of the directional change of movement of the magnetic field vector is adjusted such that in the state of mixing the liquid fluid a period duration is adjusted between two directional changes of the magnetic field during a time interval as a function of the adjustment time with the condition (I) 0.5&#xb7;t&#x3c;T&#x3c;1.5&#xb7;tand such that, at the beginning of the state of onsetting solidification of the fluid, a period duration is set between two directional changes of the magnetic field in a time interval as a function of the adjustment time with the condition (II) 0.8&#xb7;t&#x3c;T&#x3c;4&#xb7;t, wherein the adjustment time; is specified by the equation (III) in which after an activation of the rotating magnetic field in a fluid in the resting state the double vortex of the meridional secondary flow forms, and in which &#x3c3; is defined as the electric conductivity, &#x3c1; as the density of the fluid, &#x3c9; as the frequency, Bas the amplitude of the magnetic field, and Cas the constant for the influence of the size and shape of the volume of the fluid.

Method and device for the electromagnetic stirring of electrically conductive fluids

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Dresden, Germany

Dirk Raebiger