Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

This paper presents numerical and experimental investigations with respect to the fluid flow in the continuous casting process under the influence of an external DC magnetic field. According to the concept of the electromagnetic brake (EMBR) the impact of a DC magnetic field on the outlet flow from the submerged entry nozzle (SEN) has been studied up to Hartmann numbers of about 400. Numerical calculations were performed by means of the software package CFX with an implemented RANS-SST turbulence model. The non-isotropic nature of the MHD turbulence was taken into account by specific modifications of the turbulence model. The numerical results were validated by flow measurements carried out in a small-scale mockup using the eutectic alloy GaInSn. The comparison between our numerical calculations and the experimental results displays a very well agreement. The magnetic field causes a deflection of the jet and decreases its exit angle from the nozzle ports. An elongation of the jet cross section can be observed along the magnetic field direction. A significant return flow occurs in the adjacent regions of the jet. Specific vortices are formed with axes being aligned with the magnetic field direction, which is typical for quasi-two-dimensional magneto-hydrodynamic flows. Likewise, the results did not confirm the expectation that the use of the DC magnetic field induces a general reduction of the velocity fluctuations all over the mould region. Actually, under certain conditions the application of a horizontal magnetic field may cause intense, non-steady and non-isotropic flow structures. Another important result of our study is the feature that the electrical boundary conditions have a serious influence on the mould flow just as it is exposed to an external magnetic field.