Abstract: In order to investigate waterassisted injection molding process numerically, a twodimension, transient, kω turbulence flow model was formulated. Volume of Fluid (VOF) method was used to trace the moving interfaces. The influence of water injection speed, water temperature, and water injection delay time on water penetration was studied by numerical simulation using powerlaw viscosity for the melt. The simulation showed that increasing water injection speed increased the water penetration length and reduced the residual wall thickness. Water temperature had little influence on the water penetration length and residual wall thickness. Increasing waterinjection delay time increased both water penetration length and residual wall thickness.

Key words: waterassisted injection molding, turbulence flow, numerical simulation