(116i) Study On Three-Phase Flow Behavior Under Electromagnetic Field

Abstract: With the development of powerful CFD solver and faster and cheaper computers, multiphase flow models have been improved significantly during the last decade, and some complex multiphase flow behaviors also can be predicted by numerical simulation. In this paper, the three-phase flow behaviors under the electromagnetic field will be investigated by CFD simulation and PIV measurement. These complex transport phenomena frequently take place in the metallurgical processes. For example, in the electrolysis process of the molten magnesium salt, magnesium is produced from cathode as droplets, while the by-product chlorine gas is produced from anode as bubbles, both trying to rise the surface of the electrolyte as a result of the density difference with the electrolyte, so a three-phase flow under the stronger electromagnetic field will be formed in the electrolytic cell. In this work, we focus the research on the three-phase flow behavior in the advanced diaphragmless electrolytic cell, where the cell with the dimension 2.91x1.87x1.40m, 8 anodes with dimension 0.95x1.14x0.15m, 9 cathodes with dimension 0.95x1.05x0.05m, and the anode and cathode distance as 0.07m. Firstly, the numerical simulations on the electric field and the magnetic field are done, respectively, where the order coupling method to calculate the coupled field is adopted and the current distribution is regarded as the input of the magnetic field distribution. Ansys 11.0 software is used in the simulation. Furthermore, the numerical simulation on the flow field considering the effect of electromagnetic field is done. The governing equation of the internal flow field in the electrolytic cell is established, the standard k-e turbulence model and the VOF multiphase flow model are selected for a comprehensive description of the flow characteristics of multiphase flow in the electrolytic cell, Lorentz force is added as the momentum source term in order to combine the effects of magnetic field on the flow field. FLUENT6.3 software is used in the simulation. Figure 1,2 and 3 show the typical simulation results of the magnetic field, the Lorentz force distribution and the three-phase flow field. The effect of electromagnetic field on three-phase flow behaviors are analyzed by the numerical simulation in this paper. Moreover, based on the similarity principles of geometric, dynamic, kinematics, and chemical reaction, using dimensional analysis to keep the same Reynolds number, Galileo number and Weber number between the cold model experiment and the electrolysis process of the molten magnesium salt, a full-scale cold model experimental equipment is built up. The three phase compounds in the cold model experiment are 10% sodium nitrate solution, silicon oil and argon gas. The flow field is measured by PIV technology, as shown in Figure 4. The experimental results test against the numerical simulation results of three-phase flow without electromagnetic field.