Reza Ziazi, Abhinandan Singh, Ahmed O. Said, Weixuan Gong, Bruno Schardong, Matthew Patterson, Nicholas S. Skowronski, Albert Simeoni

Wind, moisture content, and density of fuel are three environmental factors that affect the rate of fire spread in wildland fires by changing the rate of convection, radiation, and conduction heat transfer from the flames and burned fuels to the unburned fuel. These effects have been experimentally investigated in the current study to further understand the complex phenomena of wildland fire spread. In this study, wind tunnel experiments have been carried out using three different wind velocities across a fuel bed comprised of pine needles heterogeneously distributed to cover an area of 1.2x3 m2. The surface temperature of the vegetative fuel (or pine needle) has been measured using thermocouples to study the temperature variations over the fuel bed to probe the effect of upstream wind over the fuel bed. Moreover, the fuel consumption has been evaluated for a select area of 0.5x0.6m2 using a load cell to investigate the mass loss rate of the fuel during pyrolysis, flaming, and smoldering combustion. The rate of flame spread is estimated by analyzing the temperature of the fuel bed, which was synchronized with the images captured from the flame front. The mass loss rate is seen to increase with the wind velocity. The spread rate shows a constant increase with the increased velocity, which has also influenced the variation of heat flux and temperature over the bed.