【摘要】 建立了一个基于二维的元胞自动机-格子Boltzmann方法(cellular automaton-lattice Boltzmann method,CA-LBM)的耦合模型,对自然对流作用下枝晶的生长行为进行模拟研究.本模型采用CA方法模拟枝晶的生长,采用LBM对自然对流及由对流和扩散控制的溶质和热传输进行数值计算.通过计算方腔自然对流问题对模拟自然对流、溶质和热传输的LB模型进行了验证.应用所建立的CA-LBM耦合模型模拟研究了合金中单枝晶和多枝晶在自然对流作用下的生长规律,并将单枝晶上游尖端的稳态生长模拟数据与解析模型的预测结果进行了比较.结果表明,模拟结果与理论预测值吻合良好,自然对流会对枝晶的生长产生重要影响.更多还原

【Abstract】 A two-dimensional (2-D) model coupling cellular automaton-lattice Boltzmann method (CA-LBM) was developed for the simulation of dendritic growth in the presence of natu- ral convection.The present model adopts the CA approach for the simulation of dendritic growth and the LBM for the numerical solution of flow dynamics as well as the species and heat transports controlled by both diffusion and convection.The validation of the LBM was performed by testing the calculated natural convection in a square cavity.The CA-LBM model was applied to simulate single and multi-dendritic growth in alloys under natural convection.The simulated single dendritic steady-state growth data of the upstream tip can be compared well with the analytical predictions.It is found that the dendritic growth is obviously influenced by natural convection.更多还原