浇注速度对铸件充型过程流场影响的数值模拟

Numerical Simulation on Influence of Pouring Velocity on Flow Field of Casting During Mold-Filling

基于ANSYS软件的CFD模块,利用不可压缩流体的流动控制方程和标准的K-ε模型,以1623K的HT150金属液为对象,对不耦合温度场时铸件充型过程的二维流场进行数值模拟,考察了浇注速度的影响。结果表明,浇注速度对流场的影响显著。当浇注速度较低(0.7m/s)时,金属液充型平稳,基本上不存在卷气现象,自由表面几乎一直保持水平状态直到充型结束,但在充型开始到整个直浇道被金属液填满的过程中发生多次流体分离现象。随浇注速度的提高,流体分离现象显著降低甚至消失,金属液与型壁碰撞加强,卷气的倾向增强。当浇注速度为1.3m/s,金属液与型壁撞击强烈,卷气明显,充型过程极不平稳,自由表面波动剧烈。综合比较的结果表明较为合适的浇注速度为1.0m/s。

Based on CFD module of ANSYS software, two-dimension flow field of a HT150 melt at 1 623 K temperature during filling into a quadrate mold, without coupling temperature field, was numerically simulated, using the governing equations of the incompressible viscosity fluid and the standard K-ε model. Influence of pouring velocity on flow field was investigated in this paper. When the pouring velocity was 0.7 m/s, the filling process was windless, and the melt did not engulf the air, and the free surface was keeping smooth all the while, but the melt separated into drops a few times before the sprue was filled completely. With increase in the pouring velocity, the phenomenon of the melt separating into drops alleviated, even disappeared, and both of the intensity of the melt impinging against the mold and the tendency of the melt engulfing the air increased. When the pouring velocity was 1.3 m/s, the melt impinged against the mold fiercely and engulfed the air severely, and the free surface was wavy insurgently. The simulation results indicated that the pouring velocity had a remarkable influence on the flow field and suggested a pouring velocity of 1.0 m/s is suitable.