基于不同数值模型的铸锭凝固过程研究

Numerical simulation of ingot solidification process based on different models

基于金属凝固理论和欧拉多相流体方法,深入分析了连续介质模型和体积平均模型之间的差异与联系,并对铸锭凝固过程中的固-液界面形态和组织演化规律进行理论预测和模拟计算。就达到相同的宏观描述目的而言,连续介质模型仅可以模糊的描述凝固状态的转变规律,而体积平均模型却可以清晰地显示柱状晶-等轴晶转变和晶粒特征;体积平均模型的数值计算工作量过大且十分繁琐,因此,其计算速度要远慢于连续介质模型;模拟结果与实验铸锭吻合良好,证明了本文算法的可行性。

The comparison of continuous model and volume-averaged model was studied based on the principles of metal solidification and Eulerian multiphase algorithm,and the liquid-solid interfacial morphology and structure evolutional law of the microstructure were predicted by the two models during solidification. The simulation results show that only the variation of volume fraction of liquid phase(or solid phase) during solidification is able to be exhibited by the continuous model,and the description for the ingot solidification is fuzzy; however,as to the volume-averaged model,the microstructure evolution,especially the columnar-to-equiaxed grain transition can be exhibited clearly,although the calculation load is heavy and its time costing is large; Further more,the simulation results are acceptably coincidence with the experimental ones,proving the feasibility of our algorithm.