Abstract The transient flow behavior of the semi-solid slurries for Sn-15Pb and 357.0 alloys during die casting process is investigated by experimental and numerical methods. A model for the transient-state three-dimensional multiphase flow based on the kinetic theory of granular flow is developed. This model is applied to investigate the distribution of solid concentration, flow state, pressure variation of the semi-solid slurry in the die casting process. The three important aspects of the multiphase flow, flow regime, particle-particle interaction and particle-liquid interaction, are interpreted according to the characteristic of the system. The model is verified by partial filling and in-situ observation experiments. Then it is applied for the phase segregation study of an elbow cavity encountered in practice. Results indicate that the 3D multiphase model can depict the flow characteristics of the semi-solid slurry very well. The inner arc side of the elbow cavity is easier to have liquid phase segregation than the outer arc side for the lower velocity gradients of the solid and liquid phases.

中文翻译：

---

半固态压铸过程中 Sn-15Pb 和 357.0 合金瞬态流动的多相建模

摘要 通过实验和数值方法研究了压铸过程中Sn-15Pb 和357.0 合金半固态浆料的瞬态流动行为。建立了基于颗粒流动力学理论的瞬态三维多相流模型。该模型用于研究压铸过程中半固态浆料的固体浓度分布、流动状态、压力变化。多相流的三个重要方面，流态，颗粒-颗粒相互作用和颗粒-液体相互作用，根据系统的特性进行解释。该模型通过部分填充和原位观测实验验证。然后将其应用于实践中遇到的弯头空腔的相分离研究。结果表明，3D 多相模型可以很好地描述半固体浆料的流动特性。由于固液相的速度梯度较低，弯管内弧侧比外弧侧更容易发生液相偏析。