基于LBM算法的强迫对流合金枝晶生长相场法模拟  

Phase-field simulation of alloy dendritic growth based on LBM algorithm in force flow

作　　者：王智平[1,2] 王喜君[1] 冯力[1] 朱昶胜[1,3] 路阳[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料重点实验室,甘肃兰州730050 [2]兰州理工大学甘肃省有色金属及复合材料工程研究中心,甘肃兰州730050 [3]兰州理工大学CAD中心,甘肃兰州730050

出　　处：《兰州理工大学学报》2014年第2期18-22,共5页Journal of Lanzhou University of Technology

基　　金：国家自然科学基金(51161011;11364024);甘肃省自然科学基金(1108ZSB096);甘肃省科技支撑计划(1204GKCA065);甘肃省工信委项目(1101ZSB149)

摘　　要：将二元合金枝晶生长的相场模型与模拟流场的Lattice Boltzmann(LBM)模型相藕合,建立模拟在强迫对流状态下枝晶生长的二维相场-LBM模型(PF-LBM),模拟Al-4.5%Cu(质量分数)二元合金在强迫对流环境下凝固过程中枝晶生长,实现过冷熔体流动场与相场耦合.结果表明:计算流场的LBM算法对树枝晶生长模拟效率高,数值稳定性好.在纯溶质扩散时,枝晶周围的溶质分布均匀,各方向枝晶尖端生长速度一样,枝晶的生长形貌呈现对称.有强迫对流情况时,熔体的流动改变了枝晶周围的溶质分布,上游的溶质被冲刷到下游,致使上游成分过冷度大,下游成分过冷度小,枝晶的尖端生长在迎游方向的速度大于纯扩散时的速度,而在下游方向枝晶生长受到抑制,形成与纯溶质扩散时不一样的非对称的枝晶生长形貌.The Lattice Boltzmann Method （LBM） was coupled with a phase-field model to simulate den- drite growth of Al-4. 5%Cu （mass percent） binary alloy with fluid flow during solidification, thereby, phase field-LBM model （PF-LBM） was established to simulate the dendritic growth of undercooled melt in a forced laminar flow state. The results show that the model have high computational efficiency and good numerical stability in simulating dendritic growth by combining the LBM. The dendrite shapes are symmetrical when the pure solute diffused, the dendrites evenly distribute around the solute, and the dendrite tip growth rate is the same. However, the melt flow change solute distribution around the dendrite when the situation is with forced convection, the solute is washed from upstream to downstream, resulting an large components undercooling in the upstream and an small undercooling in the downstream, as a result, the growth velocity of upstream dendritic tip is higher than that when the pure solute diffuse, but the downstream dendritic tip is inhibited and the dendrite shapes are unsymmetrical as same as that when the pure solute diffuse.

关 键 词：相场 枝晶生长 LATTICE BOLTZMANN方法 

分 类 号：TG248[金属学及工艺—铸造] TG244