消失模珠粒射料充填过程的数值模拟

为了解消失模珠粒射料充填过程,采用Eulerian-Lagrangian方法建立了数学模型,并进行了数值模拟。在该模型中把空气处理成连续介质,采用SIMPLE方法在Euler网格中求解气相连续方程和动量方程;珠粒为离散颗粒,其运动遵循Newton运动定律。采用自行设计的模具进行了实验验证,用数码摄像机记录了珠粒充填过程。数值模拟和实验结果显示:在珠粒充填前期,模具底部空气流动速度快,携带能力强,到达模具底部的珠粒都被带到顶部堆积。珠粒充填超过2/3以后,珠粒才开始在底部堆积,最后形成一个椭圆形漩涡并逐步消失。数值模拟和实验结果符合较好。

Numerical simulation of the injection of expanded beads in lost foam casting

An Eulerian-Lagrangian numerical simulation scheme was used to model the injection of beads in lost foam casting to analyze the injection process. The gas phase continuity and momentum equations were solved using the SIMPLE algorithm, with the bead motion predicted using Newton's law. The calculated results were validated by filming the injection of expanded beads in an experimental system. In the beginning of the injection process, the large air velocity carried the beads from the mould bottom to the top where they accumulated. The beads began to also be deposited at the bottom after about 2/3 of the injection time as an elliptical vortex formed. The vortex became smaller and disappeared as the filling process finished. The numerical results are in good agreement with the experimental results.