Simulation of Polymer Melt Injection Molding Filling Flow Based on an Improved SPH Method with Modified Low-Dissipation Riemann Solver

Simulations are performed for the polymer melt injection molding filling flow using an improved SPH (smoothed particle hydrodynamics) method. For improving the numerical stability of the high-pressure and high-viscosity injection molding filling simulation, a modified low-dissipation Riemann solver is proposed, and the Tait equation of state and several improvements are adopted in the improved SPH method. Simulations with three cavities are performed for verification of the SPH method, including a simple long rectangular cavity and two relatively complex cavities for study of injection flow balancing. For each cavity, the pressure and velocity results of the injection molding filling simulation are demonstrated, discussed, and compared with the results of the corresponding Moldflow simulation. Furthermore, results of particle motion tracking are also analyzed for an insight into the fountain flow effect. The SPH simulation results indicate that the improved SPH method can well weaken the non-physical pressure oscillation with reasonable pressure results and controlled melt compressibility, and the SPH results are in good agreement with the Moldflow results.