UDV flow measurements in a model of the Czochralski crystal growth process


UDV flow measurements in a model of the Czochralski crystal growth process

Franke, S.; Pal, J.; Eckert, S.

This contribution describes a model experiment for the Czochralski crystal growth process. Low melting point liquid metals as GaInSn are an important tool to investigate the flow structure for such industrial processes. UDV flow measurements were conducted in a cylindrical Rayleigh-Bénard (RB) setup with modified thermal boundary conditions with and without the influence of an external rotating magnetic field. The topology of the prevailing thermally-driven convection might be very complex and is mainly determined by the aspect ratio of the liquid volume and the strength of the convection described by the characteristic dimensionless Grashof number. Two kinds of techniques were used to investigate the flow. Firstly, by means of single UDV transducers measurements of the radial velocity component were carried out shortly below the melt surface across the entire diameter of the cylindrical liquid column at various azimuthal angles. Secondly, a vertically arranged UDV array was applied at the side of the cylinder to obtain detailed information about the radial velocities in the covered meridional plane. The results reveal the complex flow structure of natural convection in a Czochralski crucible which gains in complexity with applied rotating magnetic field (RMF).

Keywords: Czochralski crystal growth; Rayleigh-Bénard convection; Ultrasound Doppler velocimetry; Flow measurements; Electromagnetic stirring

  • Lecture (Conference)
    11th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, 05.-07.09.2018, Berlin, Germany
  • Contribution to external collection
    in: Proceedings of the 11th International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, Berlin: Eigenverlag, 2018

Permalink: https://www.hzdr.de/publications/Publ-27844
Publ.-Id: 27844