Numerical Study of Surface Regression of a Flame Retarded Expandable Polystrene

Abstract

In this article, a new numerical model to trace the solid fraction within the porous media flame retarded expandable polystyrene (FR-EPS) has been developed. The model uniquely embraces both the properties of the solid and fluid mixture, where the ratio between solid/fluid is governed by a newly defined solid fraction term determined by a transport equation. To establish the solid decomposition kinetics of FR-EPS, thermal gravimetric analysis (TGA) tests were carried out with three different increment temperature rates. With the application of the Kissinger’s method followed by a curve-fitting approach, a theoretical prediction of the decomposition kinetics was obtained in the form of Arrhenius expression. The extracted kinetics was then imported into the novel porous media model, in associated with the large-eddy-simulation (LES) based computational fluid dynamics (CFD) framework. A three-dimensional cone calorimeter configuration was constructed numerically and the flame profile was visualised with the application of temperature contours. This model has demonstrated the capability to produce a realistic flaming profile and provides a detailed description of the solid region surface regression controlled by pyrolysis kinetics.