An Investigation towards Coupling Molecular Dynamics with Computational Fluid Dynamics for Modelling Polymer...

Area of Science:

• Materials Science
• Chemical Engineering
• Fire Safety Engineering

Background:

• Polymer composites in building materials contribute significantly to severe fires, as seen in the Grenfell Tower incident.
• Understanding polymer pyrolysis is crucial for mitigating fire risks in the built environment.

Purpose of the Study:

• To develop a multi-scale modeling framework for simulating the fire behavior of polymer composites.
• To predict toxic gas, charring, and smoke particulate formation during polymer pyrolysis and combustion.

Main Methods:

• Applied kinetics parameters and pyrolysis gas volatiles from Molecular Dynamics (MD) models to a Computational Fluid Dynamics (CFD) fire model.
• Utilized a detailed chemical kinetics combustion model with identified gas volatiles as parent fuel.
• Tested the framework on pure and flame-retardant polyethylene systems.

Main Results:

• The model successfully predicted the chemical distribution of decomposed compounds for selected polymers.
• Enhanced predictions of toxic gas, charring, and smoke particulates were achieved.
• The framework demonstrated the chemical distribution of fully decomposed compounds.

Conclusions:

• The developed multi-scale model offers a viable approach to simulate polymer material fire behavior.
• This method reduces the need for costly experimental data on thermal degradation properties.
• The framework has potential applications for various polymer materials in fire safety assessments.