活塞式压缩机缸体充型凝固过程数值模拟研究

Study on Cylinder of Compressor Numerical Simulation of Mold Filling and Solidification in Casting Process

通过对活塞式压缩机缸体底注方式和顶注雨淋两种工艺方案的充型和凝固过程的数值模拟,揭示了缸体的液相分布和温度场分布及凝固顺序和冷铁的特殊作用,冷铁使顶注雨淋方式的下低上高的温度场分布趋势得到明显的加强,改善了缸体在凝固过程中的液相分布,改变了先中间后两头的凝固顺序,缸体从总体上形成了从下往上的有利于补缩的凝固顺序。从而得出了压缩机缸体的最佳铸造工艺方案是顶注雨淋浇注系统+顶部压力冒口+底部冷铁+阀孔冷铁+缸径冷铁(下部),并预测了压缩机缸体缩孔缩松产生的部位和大小。实际生产验证了模拟结果的正确性。

Through the numerical simulation of mold filling and solidification about the cylinder of compressor about the bottom gating system and the top - shower gating system, the results indicate the distribution of liquid field and the distribution of temperature field and the solidification direction, and the special efficenent of cold iron, By the use of cold iron, the distribution of temperature gradient changes more stronger in the top - shower gating system, which improves the distribution of liquid field and change the solidification direction from middle earlier to two ends later of cylinder into from down earlier to up later, the changed solidification direction is of great use for feeding, so the best process schema was obtained, it is top - shower gating system ＋ bottom cold iron ＋ valve orifice cold iron ＋ cylinder diameter cold iron（ down）, and the position and measurement of shrinkage cavity and porosity in the cylinder of compressor are forecasted, it is testified that the results of numerical simulation is correct by the results of practice.