The present study proposed, for the first time, an evaluation method to predict the generation rate of aluminum dross in melting or holding furnaces during mechanical stirring of molten aluminum through water model experiments and numerical simulation. In the experiments, a gas–liquid interface reaction between CO 2 gas and NaOH solution was exploited as a model reaction between the aluminum melt and air moisture, and perlite particles were used to model dross layer on the free surface of liquid aluminum. The results reveal that the reaction rate is increased with the impeller rotation speed. Besides, the reaction rate depends on the impeller rotation direction, but this dependence is different for the cases of presence and absence of particles on the liquid surface. In the first case, the reaction rate at the counter-clock rotation was higher than that at the clock-wise rotation. On the other hand, in the second case, the clock-wise impeller rotation yielded a higher reaction rate compared to the counter-clock rotation case. These phenomena can be explained by the mass transfer across the gas–liquid interface at the particle-free area.

中文翻译：

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铝机械搅拌过程中铝渣生成率的模型试验与数值模拟评价

本研究首次提出了一种通过水模型实验和数值模拟来预测熔融铝机械搅拌过程中熔化或保温炉中铝渣生成率的评价方法。在实验中，CO 2 气体和NaOH 溶液之间的气液界面反应被用作铝熔体和空气水分之间的模型反应，珍珠岩颗粒被用来模拟液态铝自由表面上的浮渣层。结果表明，反应速率随着叶轮转速的增加而增加。此外，反应速率取决于叶轮旋转方向，但这种依赖性对于液体表面上有无颗粒的情况是不同的。在第一种情况下，逆时针旋转时的反应速率高于顺时针旋转时的反应速率。另一方面，在第二种情况下，与逆时针旋转的情况相比，顺时针叶轮旋转产生了更高的反应速率。这些现象可以通过无颗粒区域气液界面的传质来解释。