Bubble breakup inside a bubble chain


Bubble breakup inside a bubble chain

Keplinger, O.; Shevchenko, N.; Eckert, S.

Liquid metal two-phase flows are widely used in metallurgy and continuous casting. For example Argon gas is injected during metal casting to enhance mixing of the melt and for the floatation process in which Argon gas bubbles separate undesired inclusions from the melt by transporting them towards the slag layer at the free surface improving the melt cleanliness. The floatation process is highly dependent not only on the properties of the inclusions but also on the size and surface characteristics of the dispersed gas phase. The bubble size distribution and interfacial area inside the melt are strongly influenced by the bubble coalescence and breakup. Despite a considerable number of numerical studies on bubble coalescence and breakup in liquid metals only few experimental data exists. Therefore, direct investigation of bubble coalescence and breakup in liquid metals becomes crucial.
Bubble breakup processes in a bubble chain ascending in non-transparent liquid metal were examined by X-ray radiography through high-speed video imaging. The Argon gas bubbles were injected through a single bevel-shaped nozzle positioned in the middle at the bottom of a flat Plexiglas vessel filled with eutectic GaInSn alloy at isothermal conditions. The bubble breakup mechanisms observed in the chosen experimental geometry were mainly initiated by bubble collisions or by the interaction of the bubbles with the flow pattern developed in the vessel due to viscous shear forces influencing the bubble interface. We present experimental results accompanied by statistical analysis of the bubble breakup frequency, number of daughter bubbles and their size distribution, bubble velocities before and after the breakup process, etc. for a broad range of Argon gas flow rates.

Keywords: Bubble breakup; bubble chain; two-phase flow; liquid metal; GaInSn

  • Poster
    15th Multiphase Flow Conference & Short Course, 15.-17.11.2017, Helmholtz-Zentrum Dresden-Rossendorf, Germany

Permalink: https://www.hzdr.de/publications/Publ-26264
Publ.-Id: 26264