Numerical and experimental modelling of VGF-type buoyant flow under the influence of travelling and rotating magnetic fields


Numerical and experimental modelling of VGF-type buoyant flow under the influence of travelling and rotating magnetic fields

Galindo, V.; Niemietz, K.; Pätzold, O.; Gerbeth, G.

Numerical and experimental modelling of a VGF-type (VGF - Vertical Gradient Freeze) buoyant flow under the influence of both travelling and rotating magnetic fields (TMF and RMF, respectively) is presented. Low-temperature flow experiments were carried out using a GaInSn alloy as model fluid. Radial heating and cooling of the melt leading to a meridional double vortex flow like in typical VGF growth, was introduced using a double-walled melt container. The flow was found to be significantly influenced by the mutual interaction of buoyant and electromagnetically driven forces. With increasing axial temperature difference, the buoyant flow becomes more concentrated in the upper and lower part of the melt leaving an extended melt zone with low flow velocity around the mid-height. Furthermore, VGF-type buoyancy is found to stabilize TMF- and RMF-induced melt flows. Besides, the time evolution of the flow just above the stability threshold is studied. In the case of combined VGF-type/RMF flow complex fluctuation patterns are observed, which depends sensitively on the applied thermal field.

Keywords: Fluid flows; Magnetic fields; Vertical gradient freeze technique; numerical simulation

  • Lecture (Conference)
    5th International Workshop on Crystal Growth Technology, 26.-30.06.2011, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-16664
Publ.-Id: 16664