垂直缝隙式浇注系统充型特性的理论分析及模拟研究

Theoretical Analysis and Simulation Study on Filling Behavior of Vertical Slot-type Pouring System

基于相似理论建立了垂直缝隙式浇注系统充型过程的流体力学模型,并对低压铸造条件下利用此类浇注系统生产圆筒铸件时的充型状态进行了水模拟和数值模拟研究。结果表明,垂直缝隙式浇注系统难以实现平稳的逐层顺序充填效果,在充型初期液体首先沿立筒上升一段距离,并以类似顶注的方式进入铸型,容易导致液面翻腾和气体卷入,并在型腔中产生环流现象,造成铸型局部过热使得凝固温度场分布不合理,从而严重恶化铸件质量。

The hydrodynamic model for filling process of vertical slot-type pouring system was established firstly based on similarity theory. Then the water simulation and numerical simulation were applied to investigate the filling behaviors of sleeve casting with such pouring system in low pressure casting process. The results show that, at the start of the filling stage, it is difficult to achieve a smooth and layer-by-layer filling pattern and the liquid fills into the mould in a pattern similar to the top-pouring mode after rising a distance in the vertical cylinders. This kind of filling pattern results in the turbulence, air entrapment and circular flow in the mould, which will lead to a local overheating of mould and an unreasonable temperature distribution at solidification stage, consequently the serious deterioration of casting quality.