A NOVEL HYBRID NUMERICAL TECHNIQUE TO MODEL 3-D FOUNTAIN FLOW IN INJECTION-MOLDING PROCESSES

A novel hybrid two-dimensional (2-D)/three-dimensional (3-D) numerical technique is presented to model 3-D fountain flows in thin cavities a s encountered in injection molding processes. At the fountain flow reg ion. where all three velocity components are significant, the governin g 3-D fluid flow equations are solved by using a pressure Poisson form ulation. Behind the flow front, where out of plane flows are negligibl e, the 2-D Hele-Shaw formulation is employed, largely reducing the num ber of unknowns in comparison to a fully-three-dimensional formulation . Boundary fitted coordinate systems (BFCS) together with the finite d ifference method (FDM) are used to solve the governing equations on a non-staggered grid. The formulation is capable of handling non-lineari ties in the material behavior due to the shear-thinning characteristic s of typical resin systems. Results are presented for isothermal flow of Newtonian and shear-thinning fluids through diverging and convergin g flow sections.