A physics-based ignition model with detailed chemical kinetics for live fuel burning studies

Abstract

This work presents a computationally inexpensive framework for modeling combined pyrolysis and gas-phase combustion of general vegetative fuels, which improves on existing solvers by incorporating detailed chemical kinetics and predicts the ignition behavior. The main motivation for this work is capturing the burning behavior of live wildland fuels, which can differ from those of dead fuels. Existing models are unable to accurately predict the ignition time and temperature variations for the live fuel cases. The kinetics model used here accounts for the non-primary constituents of fuels, or “extractives”, which are expected to play a role in this distinct behavior. Validation studies show that the developed model is a promising tool for understanding the effects of fuel chemistry and spatial variation on ignition and fuel burning behavior. Case studies using the tool suggest that variations in ignition time can be explained by combined effects of variables such as moisture content, initial composition, and density.