利用超重力分离铝熔体中的夹杂颗粒

Separation of inclusion particles from aluminum melt by super gravity

利用Al-17%Si-4.5%Cu熔体中密度较小的初生硅颗粒模拟金属熔体内部的夹杂物,并采用超重力场分离熔体中的夹杂颗粒,研究了不同重力系数条件下,金属熔体中夹杂物的分离规律.实验结果表明：经过超重力处理后,初生硅颗粒在试样上部区域发生明显的偏聚现象,试样内部出现无初生硅颗粒区域,且随着重力系数的增加,无初生硅颗粒的区域面积逐渐增大,说明重力系数越大,硅颗粒在试样上部区域的聚集程度越好.随着重力系数的增大,试样的净化效率逐渐升高,当重力系数（G）为500时,试样的净化率达到了84.98%.利用DPM离散相模型对超重力场下熔体内部硅颗粒的具体受力情况进行分析,并模拟研究铝熔体内部硅颗粒在不同重力场中的分离行为.数值模拟结果证明了夹杂颗粒在沿着超重力方向上的运动行为近似符合Stokes运动定律.这表明超重力场可以有效分离金属熔体中的夹杂物.

The increasing demand for high-quality aluminum alloys in the automobile industry and other manufacturing fields has motivated manufacturers to produce cleaner aluminum alloys. However,conventional methods can barely meet the cleanliness requirements of many applications due to their low removal efficiencies. To develop an innovative and highly efficient method for separating inclusions from aluminum melt,this study investigated the separation behavior of silicon particles by super gravity under different gravity fields using the primary silicon particles of Al-17% Si-4. 5% Cu melt to simulate the inclusions in molten metal. The experimental results show that primary silicon particles accumulate in the upper region of samples obtained by super gravity,while the area in which there are no primary particle appears in the sample. The accumulation effect of the silicon particles improves as the gravity coefficients increase. In addition,the purification efficiency of samples obtained by super gravity increases as the gravity coefficient increases. This paper found the purification efficiency of samples to reach 84. 98% at a gravity coefficient of G = 500. Using the discrete phase model（DPM）,the paper also analyzed the forces acting on the particles in the melt and simulated the separation behavior of silicon particles in the melt under various gravity fields. The simulation results indicate that the movement of silicon particles along the direction of super gravity approximately obeys Stokes＇ law. There results demonstrate that inclusion particles in aluminum melt can be separated effectively by super gravity.