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The Phenomenon of filling flow in injection molding can be
describedin terms of an one dimensional fully-de- veloped main
flow and a complex two dimensional flow near the advancing
front, termed the" fountain flow ".In the early analysis of
filling stage,different models have been proposed to describe
the molding cycle with varying degrees of approximation. these
models, however , have generally neglected the melt front
region ,i.e.,the fountain effect and the transientand interial
terms. Especally,the fountain effect is responsible for the
highly oriented surface layer and will influence the degree of
crystallinity as well as the quality of welding line.Due to the
signficant implication for microstructure ,the fountain effect
is explicitly taken into considera- tion in the simulation. A
computer program based on MAC method has been developed or the
numerical simulation of two dimensional viscous fluid flow.
Especially,Weighting Function Scheme is employed to describe
the governing equation which is solved by SIMPLER algorithm.For
particle tracking,the phenomenon of steady ,unsteady fluid flow
with a free surface flow can be described by numerical analysis
. In this research,we observe "fountain effect" obviously in
the early stage of filling process,via the rearrangement of the
velocity profile in the vincinity of melt front. As the time
going,front type changes and will not allow the steady
interfacial type that corresponding to the predition in
experimental observation.
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