Numerical Simulation Of Magneto Hydrodynamics In Round Billet Continuous Casting Molds

Continuous casting mold with electromagnetic stirring (M-EMS) is becoming an effective method to control the process of solidification, improve the solidification structure and increase the quality of products. So, it is of great significance to understand the process in round billet with EMS, for specific continuous casting conditions.Firstly, a mathematical model to describe the three-dimensional electromagnetic field in the round billet mold with M-EMS was set up according to the specific continuous casting process. The finite element analytical software ANSYS was used to perform the numerical simulation, and the characteristics of the electromagnetic field distribution in the mild, and the effects of exciting current intensity and frequency on electromagnetic field were investigated. The research shows that:The values of magnetic induction reach its maximum at the middle plane of the stirrer and become smaller towards the two ends of the round billet gradually, and magnetic field distribution is more uniform in horizontal plane. Electromagnetic force distributes circumferentially at horizontal plane, and tangential electromagnetic force is proportional to the distance to the round billet center. The values of tangential electromagnetic force reach its maximum at the center of the stirrer along drawing direction. Both magnetic induction and electromagnetic force increase with the exciting current intensity. With the increase in frequency, magnetic induction in the mold decreases, and electromagnetic force increases first and then decreases,4.0Hz at a maximum.On the basis of the electromagnetic field solution, and combing the coupled theory of the electromagnetic field and the flow field, a three-dimensional finite mathematic module to describe the molten steel flow in the round billet mold during M-EMS process. The numerical simulation was performed by using software, and the characteristics of the molten steel flow field distribution in the round billet mold, and the effects of exciting current intensity current intensity and frequency as well as casting speed on molten steel flow field were researched. Simulation shows that, without electromagnetic stirring, molten steel spits out from submerged entry nozzle (SEN), and penetrates deep down the liquid point, and then returns upward along the side of solidification to form a single loop. And electromagnetic stirring, the molten steel out from SEN shifts from vertical downward to horizontal rotary in an effective zone of electromagnetic stirring, forming a rotary movement of the main stream district..This can be used for analyzing the flow field of the molten steel in the round billet mold for the certain operating conditions and operation parameters by using the mathematical model and the simulation results which proposed in this thesis. It also provides the theoretical basis for selecting reasonable electromagnetic stirring parameters, and guiding the actual production of continuous casting process.