X-ray radioscopy as a powerful tool for visualization of liquid metal bubbly flows

Many technical applications in metallurgy and the quality of continuous casting rely on liquid metal two-phase flows. Injection of the Argon gas became an integral part of continuous casting since it prevents clogging of the casting nozzle and also separates alumina particles from the melt. On the other hand, injection of gas has many side effects as for example induction of highly turbulent complex two-phase flows. There exist many numerical simulations and water models, but due to large differences in physical properties between water and liquid metals water models and experiments cannot be fully extended to liquid metals. Therefore, direct investigation and understanding of liquid metal two-phase flows became critical. In the present work we demonstrate that X-ray radiography can be used as a powerful tool for the visualization of liquid metal two-phase flows. Here we present an experimental study of ascending bubble chains over a wide range of gas flow rates in GaInSn alloy at room temperature. We report on differences in bubble release frequency, shape, size, velocity etc. and additionally compare with experiments in water. The efficiency of the corresponding measurement technique is primarily validated in water experiments.

* The research is supported by the German Helmholtz Association in form of the Helmholtz-Alliance “LIMTECH”.