建立了耦合流场、浓度场、温度场的CA-LBM模型,采用该模型再现了合金在自然对流条件下柱状晶向等轴晶的转变过程,并与无对流条件下的凝固组织作对比,研究了自然对流对温度场和CET转变的影响。结果表明:自然对流促进了热的输运,加速了凝固进程,使柱状晶向等轴晶的转变提前,有细化晶粒的作用。 A coupled CA-LBM model of flow field, concentration field and temperature field was established. The model was used to reproduce the transformation process of columnar grains to equiaxed grains under natural convection. Compared with the solidification structure under no-convection conditions, The effect of natural convection on temperature field and CET transition was studied. The results show that natural convection promotes the transport of heat, accelerates the solidification process, advances the transformation of columnar grains into equiaxed grains, and has the function of grain refinement.