Numerical Simulation of Casting Filling Process of Composites Reinforced with Nano SiC Based on Smoothed Particle Hydrodynamics

摘要

The actual casting filling process can be deemed as the coupled flow of air, molten metal and solid-phase particles (such as slag) inside the cavity, which may cause air entrapment, slag inclusion and other casting defects, and affect the quality of casting. Through computation simulation of the casting filling process on the basis of smoothed particle hydrodynamics (SPH) method, it can not only precisely track the motion trajectories of air, molten metal and slag particles, but also precisely predict air entrapment, slag inclusion and other casting defects. This paper established a mathematical model of gas-liquid-solid three-phase flow for the SPH-based casting filling process. The model eliminated the instability of gas-liquid interface pressure by introducing the corrected gas-liquid two-phase momentum equation, and maintained a clear interface between air and molten metal by introducing the surface tension model. In addition, it introduced the motion model of rigid body to deal with the coupled flow process of slag, air and molten metal. The mathematical model established in this paper was used to calculate the bubble floating and the flowing process of the gas-liquid two-phase during mold filling through the bottom side of the injection cavity and of the gas-liquid-solid three-phase flow during mold filling for casting of plate (the plate was composite reinforced with nano SiC, and the viscosity of the composite melt was calculated from the viscosity formula of the composite melt). The calculated results were compared with the experimental results to verify the accuracy and validity of the mathematical model established.