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基于耦合流场和热噪声的相场模型及合理高效的三维动态求解域加速算法,定量模拟了在受迫流动下枝晶的非对称生长及流速对迎流、背流两侧的温度分布和层流层分布的影响.计算结果表明,受迫流动使迎流、背流两侧温度的分布与层流层分布呈现不对称状态,导致迎流侧与背流侧的过冷度不同,而熔体施加于枝晶界面前沿迎流侧的力还不足以抑制过冷度的作用,结果造成枝晶迎流方向优先生长,从而产生倾向于散热方向的倾斜;同时,由于迎流侧的实际过冷度大于背流侧,有利于促进迎流一侧枝晶生长速度以及稳定侧向分枝生长,从而导致了侧向分枝的非对称生长.随着流速的增加,枝晶倾斜程度越大,枝晶的不对称性越明显。
Based on the phase field model of coupled flow field and thermal noise and the reasonable and efficient three-dimensional dynamic solution domain acceleration algorithm, the asymmetric growth of dendrites and the effect of flow rate on the temperature distribution and layer The results show that the forced flow causes the temperature distribution on both sides of the backflow to be asymmetric with the distribution of the troposphere, resulting in different degrees of undercooling on the onstream and backflow sides, whereas the melting The force exerted on the frontal flow of the dendrite interface by the body is not enough to suppress the effect of undercooling, resulting in preferential growth of the dendrite in the flow direction, resulting in a tilt that tends to dissipate the heat. At the same time, due to the actual The cold degree is greater than the backflow side, which is conducive to promoting the growth rate of dendrite on the side of the oncoming flow and stabilizing the lateral branch growth, resulting in the asymmetric growth of the lateral branches.With the increase of the flow rate, Dendrite asymmetry more obvious.