The process of high-pressure water penetration in water-assisted injection molding (WAIM) was simulated based on the volume of fluid method

and the filling behavior of polymer melt as well as the elongation and shear fields were studied and analyzed.The simulated results showed that the process of melt filling propelled by high-pressure water was divided into three stages

namely

initial filling

fast filling

and terminal filling stages.Remarkable elongational rate was only present in the regions near both water and melt fronts.Widely-distributed and high shear rate was present in the region near the water front

whereas water had little shear effect on the melt in the water-penetrated zone.The simulated penetration length and hollow rate of the WAIM part matched well with the experimentally determined ones.