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在有限体积软件FLUENT的基础上建立了包晶合金定向凝固的多场耦合模型,并计算了Sn-Cd包晶合金定向凝固时的温度场、流场、溶质场以及固液界面形态等特征。研究表明,试样直径是决定自然对流强度的主要因素,随着试样直径的增大,固液界面前沿熔体流速增大,径向溶质偏析程度先增强后减弱;抽拉速率增大时,自然对流强度变化较小,固液界面前沿的环流区域减小,溶质径向偏析程度减弱;试样直径越小,抽拉速率越大,试样初始过渡区长度越短。
Based on the finite volume software FLUENT, a multi-field coupling model of directional solidification of peritectic alloy was established and the characteristics of temperature field, flow field, solute field and morphology of solid-liquid interface during directional solidification of Sn-Cd peritectic alloy were calculated. The results show that the diameter of the sample is the main factor that determines the natural convection strength. As the diameter of the sample increases, the melt flow rate at the front of the solid-liquid interface increases and the radial solute segregation first increases and then decreases. When the drawing rate increases , The change of natural convection intensity is small, the circulation area at the front of solid-liquid interface decreases and the degree of solute radial segregation decreases. The smaller the sample diameter, the larger the extraction rate, the shorter the initial transition zone length.