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以欧拉方法和体积元平均技术为基础,建立考虑固相移动的大尺寸钢锭宏观偏析数学模型.研究了纯自然对流和包含固相移动两种情况下宏观偏析形成的模式,分析了临界固相分数和固相密度变化对宏观偏析形成的影响.计算结果表明:无论是否考虑固相移动,A型偏析形成机理是侧壁形成的固相与底部形成的固相之间形成狭窄的补缩通道,此通道内溶质富集且流动不顺畅,最后形成了高成分区域.增大临界固相分数会导致A型偏析带和底部负偏析的加剧.固相密度的增加会引起底部负偏析和顶部正偏析的偏析程度增大,但A型偏析带的长度不随固相密度的增加而增长.将模拟结果和实验结果进行对照,验证了模型的准确性.
Based on the Eulerian method and the volume element average technique, a macrosegregation mathematical model of large ingot ingot considering solid phase movement is established. The modes of macroscopic segregation under pure natural convection and solid phase movement are studied. The influence of phase fraction and solid density on macrosegregation formation is analyzed.The results show that the formation mechanism of type A segregation is whether the solid phase formed by the side wall and the solid phase formed at the bottom form a narrow constriction Channel, this channel solute enrichment and the flow is not smooth, and finally formed a high-component area. Increasing the critical solid fraction will lead to aggravating A segregation zone and the bottom of the negative segregation increased solid density will cause the bottom of the negative segregation and The segregation degree of positive segregation increases at the top, but the length of type A segregation zone does not increase with the increase of solid density. The simulation results and the experimental results are compared to verify the accuracy of the model.