Modeling Injection Molding of High-Density Polyethylene with Crystallization in Open-Source Software.

Area of Science:

• Polymer science
• Computational fluid dynamics
• Materials modeling

Background:

• Accurate crystallization modeling is crucial for predicting polymer processing behavior.
• Existing models often lack comprehensive inclusion of coupled physical phenomena.
• High-density polyethylene (HDPE) processing requires detailed understanding of its crystallization kinetics.

Purpose of the Study:

• To develop and validate an enhanced crystallization model for HDPE within OpenFOAM.
• To incorporate key physical interdependencies affecting crystallization and thermomechanical behavior.
• To provide an open-source tool for further research in polymer crystallization modeling.

Main Methods:

• Modification of the open-source computational fluid dynamics code OpenFOAM.
• Implementation of HDPE crystallization kinetics based on literature data.
• Inclusion of pressure- and temperature-dependent material properties (thermal conductivity, specific heat).
• Modeling of deformable cavity and pressure-dependent heat transfer coefficient.
• Simulation of latent heat release and deviatoric elastic stress evolution.

Main Results:

• The model successfully predicts cavity pressure evolution, a key indicator of solution quality.
• Through-thickness plots reveal insights into pressure, temperature, and cooling rate at various crystallinity levels.
• The simulation provides a comprehensive understanding of thermomechanical conditions during HDPE crystallization.
• The developed code and simulation setup are made openly available.

Conclusions:

• The modified OpenFOAM code provides a robust framework for advanced crystallization modeling.
• Accurate prediction of thermomechanical conditions is achieved by incorporating coupled physical phenomena.
• The open availability of the code and setup will facilitate future research and development in polymer processing.