| Applying electromagnetic brake technology in continuous casting process based on conventional continuous casting is a new technology which had great value. The technology used the interaction between static magnetic field generated by direct current and the liquid metal flow, and then the Lorentz force which was in the opposite direction of the liquid generated in the liquid metal flow, and the liquid metal flow was under braking. The technology could inhibit the impact of molten steel striking on the narrow face of the mould, prevent leakage, reduce the impulsion depth of molten steel, and help inclusion floating. The practice has proved that the technology can improve the surface quality of the billet substantially, and provide technical support for the production of non-defective slab and create conditions for high-speed continuous casting and continuous casting rolling.Commercial software ANSYS is a powerful and flexible design simulation software, as well as FLUENT. In this paper, I established a three-dimensional electromagnetic field model including the molten steel, mould, braking equipment and air under the process of new type of electromagnetic brake by ANSYS software, and then solved it, and researched the distribution characteristics and laws of magnetic flux density which was generated by the new type of electromagnetic brake. Solved the three-dimensional mathematical model of molten steel flow in continuous casting mould whether using of the new type of electromagnetic brake by FLUENT software, and researched the effect of the flow field of steel under different technical parameters (magnetic induction intensity, casting speed, nozzle immersion depth), providing a reasonable basis on optimization of the magnetic field and flow field of liquid steel in the mould, improvements and design of the electromagnetic brake.The study has been divided into three parts. Firstly, establishing the mathematical model of electromagnetic field which simulated the process of electromagnetic braking, then solved it and analyzed it. Secondly, establishing the mathematical model of steel flow field in the conventional slab continuous casting mould when there was not applied electromagnetic brake, then solved it and analyzed it. Finally, establishing the mathematical model of steel flow field which simulated the process under new electromagnetic braking in the mould, then solved and analyze.This simulation results in this paper are shown as bellow. After applying the new type of the electromagnetic brake, the magnetic flux density within the steel liquid where was covered by the poles was larger, other areas of liquid steel was smaller. The distribution of magnetic flux density in liquid steel where was covered by the poles was uniform along the thickness and height direction of the mould, and the distribution of magnetic flux density was generally uniform along the width direction of the mould. The magnetic field which was produced by the new electromagnetic brake could meet the requirements in continuous casting process. When0.3T of magnetic flux density applied in liquid steel, the effect of electromagnetic force in fluid by braking was obvious, and flow velocity and turbulent kinetic energy on free surface decreased, which will help to prevent slag. Vertical velocity and turbulent kinetic energy of narrow face decreased, then the velocity of the steel flow striking the narrow face reduced, and the impact was weakening, which helped preventing leakage and the inclusions floating and separating. When applied the smaller magnetic flux density (0.1T,0.2T), the effect to flow field of steel was a little, but with the increasing of magnetic flux density (0.3T≦B≦0.5T), The overall flow velocity and turbulent kinetic energy of liquid steel on free surface in mould and vertical velocity of narrow surface reduced significantly. The new type of electromagnetic brake can meet the continuous casting process under circumstances of different casting speed, reduce meniscus fluctuations, slag, steel leakage and non-metallic inclusions sinking which was difficultly separating, the shortcomings above were due to increasing casting speed in conventional continuous casting. The new electromagnetic brake can also meet the continuous casting process under different circumstances of nozzle immersion depth, and inhibit the increasing of flow velocity and turbulent kinetic energy on free surface of molten steel when the immersion depth was smaller (200mm). In a word, the new type of electromagnetic brake can control the flow of molten steel in mould better, and reduce defects which were not conducive in continuous casting process, and improve the quality of the slab. |
