A physics-based model of thermodynamically varying fuel moisture content for fire behavior prediction.

Fuel moisture content (FMC) is a critical parameter in fire and plume behaviors, showing diurnal and spatial variations influenced by local meteorological conditions, soil characteristics, and fuel properties. In low-intensity fires, small-scale FMC variations intensify, leading to an amplification of their effects on fire physics. In an effort to capture these variations, this paper presents the development of a physics-based model that couples a thermodynamic-based FMC prediction model for dead fuels with the Fire Dynamics Simulator of the National Institute of Standards and Technology. The model accuracy is validated against several existing experimental data, showing improvements over the baseline model which uses the kinetic-based Arrhenius drying approach. A case study of flame propagation in a small fuel bed is also presented, indicating the improved performance of the new model and its novel capabilities in capturing complex processes of fuel drying and moisture flux exchanges between the fuel and ambient atmosphere. • Fuel moisture is an important factor in shaping fire behavior and plume dynamics. • A detailed fuel moisture model is integrated into a fire-atmosphere interaction model. • The model is physics-based, based on dead-fuel energy-water balance analysis. • The model is integrated into the Fire Dynamics Simulator (FDS) of NIST. • It improves fire behavior prediction, capturing the complex fuel drying dynamics. [ABSTRACT FROM AUTHOR]