Numerical Simulation Of 3D Coupling Of Multi-physics In Preparing Semi-solid Slurry By Electromagnetic Stirring

Semisolid metal forming (SSM or SSF) is considered to be a great potential in the short process, near net shape forming technology and has a huge market application in the future. The electromagnetic stirring has been used in the preparation of semisolid slurry which hold that a key technology. It is a complicated time-variation procedure which relates to electromagnetic field,flow field and temperature field. It's difficult to measure the processing parameter on the spot. The analysis of electromagnetic stirring applied the finite element software to provides an effective means to adjust the parameters of electromagnetic stirring.In this paper, the electromagnetic field, flow field and heat transfer process during electromagnetic stirring for low frequency rotating electromagnetic stirrer were calculated based on ANSYS finite element software. The distribution of electromagnetic field, the dependence of the stirrer parameters on magnetic flux intensity and the Lorentz were analyzed according to the simulated results. The magnetic flux intensity and Lorentz, velocity field of the stirred slurry and temperature field under different cooling conditions were gained.The results show that magnetic induction intensity and electromagnetic force in semisolid slurry takes on three-dimension distribution. And they increased with the enhancement of current strength at the same current frequency . The higher magnetic flux intensity results in enlargement of stirring power which promote the flowing stir for the semisolid slurry.For the same current intensity, the Lorentz is increased with the increasement of frequency, whereas the magnetic flux intensity is decreased with the increasement of frequency.The velocity field of semisolid slurry under electromagnetic stirring is studied by computer simulation. It also showed the electromagnetic force divided into radial and tangential, of which the tangential contribute towards the main reason for the electromagnetic stirring. The stirred semisolid metal slurry endures shear force as the Lorentz has a spatial distribution.The stirring time is too long to good. As the temperature decreased, it will reduce beyond the semi-solid temperature which does not suitable for stirring. We can know that the two parameters of temperature and the stirring time are interacted. It is concluded that current intensity and frequency can promote the stirring.The velocity field of semisolid slurry under electromagnetic stirring is studied by computer simulation.Under the electromagnetic stirring, the flow of melt would become intense and make the superheat disappear. It is shown that the slurry temperature distribution was changed by electromagnetic stirring. As a result, the crystal nucleus condition is changed which leads to the formation of equiaxed grains.