Numerical Simulation of Solidification Process of Molten Polymer Flowing in a Two-Dimensional Flat Channel

Solidification process of molten polymer was simulated with a numerical simulation program developed by considering non-Newtonian flow and crystallization simultaneously. In our crystallization model, effects of non-isothermal and stress-induced crystallization kinetics were taken into account. The simulation model was applied to the solidification process of molten polypropylene, a crystalline plastic, flowing in a two-dimensional flat channel with both cooled walls. Various cooling wall temperature, polymer mass velocity, and the thickness of the test channel were investigated numerically. As the cooling wall temperature decreased, the thickness of the skin layer increased and the thin layer of low crystallinity was found near the cooling wall surface. Furthermore, the greater the mass velocity, the earlier the starting and saturating times of the growth of the skin layer. It was also found that the thickness of the non-dimensional skin layer bacame thicker with a decrease in the thickness of the test channel.