Experimental investigation of liquid metal two-phase flows in a continuous casting model

We present an experimental study concerned with the two-phase flow in a mockup of the continuous casting process of steel. A specific experimental facility was designed and constructed at HZDR for visualizing two-phase flows in the mould and the SEN by means of X-ray radioscopy. This setup utilizes the low melting, eutectic alloy GaInSn as model liquid. The argon gas is injected through the tip of the stopper rod into the liquid metal flow. The system operates continuously under isothermal conditions. First results about the two-phase flow will be presented here accompanied by a discussion of the advantages and limitations of the X-ray method.
The position of the X-ray observation window can be changed, which allows the inspection of regions around the gas injection point at the tip of the stopper rod or the development of the bubbly flow in the mould. The X-ray images reveal complex flow situations, for instance, argon bubbles might be attracted by the wall of the SEN near the inlet forming huge bubbles there. Smaller bubbles are generated at the bottom of the SEN, where high shear flows exist. The bubbles in the mould are entrapped by the liquid metal jet. The tendency to rise towards the mould level increases with growing bubble size.