Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Fluid flow in the mould cavity of the continuous casting process can be controlled by the application of magnetic fields. Experiments have been performed at room temperature using a small-scale experimental set-up with the eutectic alloy GaInSn. The ultrasound Doppler method was applied for measuring the fluid velocity in the mould. An arrangement of 10 transducers was used to determine a two-dimensional distribution of the horizontal velocity component. According to the concept of the electromagnetic brake the impact of a DC magnetic field on the outlet flow from the submerged entry nozzle (SEN) has been studied. Our measurements deliver an authentic reproduction of the location and extension of the emergent jet and disclose the temporal behaviour of the flow inside the jet as well as in the recirculating zones. An important result of our study was the feature that a static magnetic field may give rise to non-steady, non-isotropic large-scale flow perturbations. Likewise, the flow measurements presented here did not confirm the expectation of a smooth reduction of the velocity fluctuations at the nozzle outlet due to the magnetic field. This problem requires further investigation, because the concept of an EMBR in the continuous casting process relies on a reliable damping effect of the applied magnetic field. The combination of liquid metal cold models and the ultrasound Doppler method as a powerful flow measuring technique in liquid metals appears as an important tool for an experimental investigation of such open questions and provides valuable experimental data for the validation of numerical flow simulations.