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基于Tong和Beckermann等提出的耦合流场的相场模型,采用有限差分法对纯金属凝固过程进行二维模拟计算,研究了不同对流速度对金属枝晶生长的影响.结果表明:在有对流情况下,上游及下游枝晶呈现不对称形貌,上游枝晶生长速度明显比下游方向生长速度快.随着对流速度的增大,上游尖端过冷度也增大,枝晶生长也越快.这是由于流体速度越大,对上游枝晶冲刷越强,上游枝晶尖端实际过冷度越大,枝晶生长越迅速.
Based on the phase field model of coupling flow field proposed by Tong and Beckermann et al., The finite difference method is used to simulate the solidification process of pure metal and the effects of different convection velocities on the growth of metal dendrites are studied. The results show that in the case of convection The upper and lower dendrites show an asymmetric morphology, and the growth rate of the upper dendrites is obviously faster than that of the lower ones.With the increase of the convection velocity, the undercooling of the upstream tip also increases and the dendrite grows faster. This is because the greater the fluid speed, the stronger the upstream dendritic scouring, the higher the actual undercooling of the upper dendrite tip, the faster the dendrite grows.