Numerical Simulation And Flow Law Of Chaotic Flow Of Aluminum-rare Earth Multiphase Melt

The solidification process of aluminum alloy involves a series of complex physical changes,which includes energy transfer,mass transference,phase transformation and so on.Because of its capability of stirring molten metal and improving the performance of metal,electromagnetic stirring technology is been widely used in smelting industry.Electromagnetic stirring machine can generate induced current which is good for mass and heat transfer in the melt by using changeable electromagnetic field,and it is different from general mechanical stirring and has some advantages,such as non-contacting,easy controlling and high efficiency energy saving etc.Based on simulation of magnetic field and flow field in the electromagnetic stirring machine made by waste motor and analysis of simulation results through chaos theory,the effect of electromagnetic stirring time and frequency on melt flow and distribution of La among melt was explored.The electromagnetic field of self-made electromagnetic stirring machine was simulated by using finite element software-Maxwell and the effect of different frequency on induced magnetic field in it were calculated.The electromagnetic force which was gained by Maxwell was applied in Fluent software,then the melt of stirring machine was analyzed by Fluent software.At last,the distribution cloud picture of La in the stirring machine under different stirring parameters were obtained.The related chaos parameters of flow field and chaotic state of melt movement in the stirrer were discussed by self-coupling program through Matlab software.Analysis results indicates that with stirring time and electromagnetic frequency increasing,the electromagnetic force that melt was received in the stirrer and chaotic degree of its flow movement were improved;Variable frequency stirring became more effective to stir and mix for aluminum-rare earth multiphase melt than a certain frequency stirring and flow chaotic extent of melt was higher.The microstructure of rare earth-aluminum alloy sample was investigated under the condition of without stirring,10Hz?20Hz?30Hz of stirring frequency and variable frequency.Improvement of stirring frequency could improve metallurgical microstructure of samples in a certain frequency by the comparison of different metallurgical microstructure picture,but the improving effect did not exist any more when frequency reached a certain state.The effect of variable frequency stirring was better than a signal frequency stirring.