| Blowing in argon is the driving force of the RH molten steel circular flow, the argon blowing conditions, including the amount of argon blowing, the number of argon nozzles and inner diameters and distribution of the argon nozzle, not only determine the size and distribution in the molten steel of the argon bubbles blown in, but also are related to the circulation flow rate of molten steel and the structure of the flow field in the vacuum chamber and ladle. So argon blowing conditions are the key factors that determine the efficiency and effectiveness of vacuum refining. In this paper, according to the water model experimental equipment of a RH vacuum refining device of water model experiment equipment, considering the flow behavior of the turbulence in the flow process, starting with the basic phenomena of driving circulation flow (i.e., blowing in argon into upward pipe), using the CFD software-ANSYS FLUENT as the numerical computation and analysis platform, the law of the effects of different argon blowing conditions on circular flow. Numerical simulation not only can capture the distribution characteristics of argon bubble and the details of liquid flow field in the RH cyclic process, but also can provide an important reference for studying the effects of argon blowing parameters on circular flow and circulation flow rate in the process of RH refining and for the process design and optimization of RH refining process.The main research work is as follows:(1) On the base of the review of RH vacuum refining and numerical simulation of it, the limitations of current adopted mathematical model of numerical simulation are analyzed and the simulation strategies of gas-liquid two-phase flow are determined.(2) The three-dimensional model of the RH vacuum refining equipment (a vacuum chamber, a ladle and two circulation pipes) is created and meshed with the software-ANSYS Workbench. The mathematical model and boundary conditions are determined(3) The gas-liquid two-phase flow in the water model experiment equipment of a RH vacuum degasser has been simulated with the software-ANSYS FLUENT and numerical simulation results are compared with the measured data of experiment equipment. The effects of lifting gas flow rates, the number, inner diameters and locations of gas nozzles and other factors on the circular flow of refining equipment are analyzed and discussed.The research work shows that:Among all of the argon blowing conditions, the effects of lifting gas flow rates on circular flow is the most obvious. Increasing the lifting gas flow rate can effectively improve the gas holdup and the velocity of gas rising in the center area of upward pipe of the RH equipment, the flow speed of liquid phase and the circulation flow rate of the RH equipment. In the specific conditions of argon blowing, there exists an optimal number of gas nozzles which make gas rise fastest; The number and inner diameters of gas nozzles have an inverse relationship with the circulation flow rate. Both of staggering the gas nozzles hierarchically and lowering the position of the gas nozzles are beneficial to improve the speed of gas rising and increasing the circulation flow rate. |
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