Use of cold liquid metal models for investigations of the fluid flow in the continuous casting process

Model experiments with low melting point liquid metals are an important tool to investigate the flow structure and related transport processes in melt flows relevant for metallurgical applications. Water model experiments are of limited value, particularly in the cases of strong temperature gradients, two-phase flows or flows exposed to electromagnetic fields. We present the new experimental facility LIMMCAST for modelling the continuous casting process of steel using the alloy SnBi at temperatures of 200-400°C. The parameters of the facility and the dimensions of the test sections will be given, and the possibilities for flow investigations in tundish, submerged entry nozzle and mould will be discussed. In addition, the smaller set-up mini-LIMMCAST will be presented, which works with the room-temperature liquid alloy GaInSn. The main value of cold metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial and temporal resolution. New ultrasonic and electromagnetic techniques for measuring the velocity in liquid metal flows came up during the last decade allowing for a satisfying characterisation of flow quantities in the considered temperature range up to 400°C. A selection of results from LIMMCAST and mini-LIMMCAST will be presented in this paper covering various phenomena occurring in single-phase and two-phase flows.
Main emphasis of the experimental programme is put on the effect of diverse magnetic fields on the fluid flow in the mould. Although magnetic fields have already been adopted for industrial use since more than 20 years, the impact of electromagnetic brakes or stirrers on complex and highly turbulent flows appears to be very complex and has not been fully understood until now. The flow measurements performed at the liquid metal model experiments deliver a valuable experimental data base being suitable for validation of numerical simulations.