【摘要】 建立了电磁离心凝固过程熔体动量传递、传热和传质耦合数学模型,模拟计算了熔体在不同感应强度下的流动速度.计算结果表明,熔体在电磁力的作用下产生与铸模转动方向相反的流动,流动速度呈周期性分布,并且在凝固前沿达到最大.随着磁感应强度的增加,熔体流动速度达到的最大值也愈大.使用有限元软件ANSYS,把熔体流动计算结果作为参数,计算了枝晶的受力状态.通过计算表明,熔体流过枝晶会在枝晶周围产生很大的速度变化,流体对枝晶的冲刷可使枝晶产生机械折断.电磁搅拌通过增加断裂枝晶数量促进柱状晶-等轴晶转变.更多还原

【Abstract】 A fully coupled fluid flow, heat and solute transport model is developed to predict velocity of melt flow during electromagnetic centrifugal casting. As a result, melt flow can be yielded in the opposite direction of rotating mold owing to an electromagnetic force. The velocity of melt flow displays periodicity and reaches the maximum at the solidifying front. The stronger the magnetic flux densities, the larger the maximum of melt flows. Based on FEM software ANSYS, the dendrites stress states are computed using the results of the melt flow as computing parameters. It is found that the melt flow is largely changed when melt flows around the dendrite, the dendrites can be fractured by the melt flow. So the electromagnetic stirring contributes to the columnar-to-equiaxed transition because of increasing the number of fractured dendrites.更多还原