Pyrolysis and autoignition behaviors of oriented strand board under power-law radiation

Abstract

This contribution addresses a multi-component high order parallel reaction scheme developed for pyrolysis of Oriented Strand Board (OSB), a typical engineered wood product, and its application in estimating autoignition behaviors under power-law heat flux (HF). Thermogravimetric analysis tests were conducted first to parameterize the pyrolysis model by model fitting method. Subsequently, gram-scale autoignition experiments, using five power-law HFs, were implemented in a newly designed apparatus. Thermodynamics of OSB were determined by inverse modelling combining an improved numerical model and the measured surface temperatures and mass loss rates under a moderate HF. The extrapolation capability of the developed model was verified by simulating the remaining experimental measurements at alternative heating scenarios. Both critical temperature and critical mass flux were employed in predicting autoignition times. The results show that the developed pyrolysis model accurately captures the measured mass and mass loss rate collected in TGA tests. Meanwhile, relatively good agreement was found between the simulated and measured surface temperatures and mass loss rates in bench-scale tests despite some minor divergence due to the observed cracks of generated char layer. Furthermore, the uncertainties of the attained kinetic and thermodynamic parameters were quantitatively evaluated by parametric study.