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An Experimental Investigation into the Wildland Fire Burning Characteristics of Loblolly Pine Straw




Stubbs, Daniel

Type of Degree

Master's Thesis


Aerospace Engineering


Wildland fires present a threat to both the environment and to homes and businesses in the wildland urban interface. Understanding the behavior of wildland fires is crucial for developing informed risk management techniques, such as prescribed burning, to prevent uncontrolled fires, which devastate communities globally. In this work, an optically accessible facility was developed combining traditional and optical diagnostic techniques to study the combustion of wildland fuels. The developed testing facility was then used to measure the burning characteristics of loblolly pine (\textit{Pinus taeda}) straw. Mass loss rate, flame temperature, propagation rate, flame geometry, chemiluminescent flame intensity, and pollutant emissions from the fire were measured for fuel loadings of 0.98, 1.31, and 1.63~\si{kg/m^2}. Mass loss rate was found to increase with fuel loading. The flame propagation rate was found to increase slightly while approaching an asymptotic value. The flame height increased more significantly with fuel loading, but also approached an asymptotic value. Flame length was found to increase slightly with fuel loading, and throughout the duration of the test. Flame surface area was found to increase linearly with fuel loading, indicating that the flame length may be increasing in a way that compensates for the asymptotic nature of the flame height. The flame intensity and flame temperatures did not change significantly, suggesting they are driven by the chemical kinetics of the pine straw combustion rather than the physical arrangement of the fuel bed. Carbon monoxide emissions were found to increase significantly with fuel loading, while sulfur dioxide increased only slightly, and nitrogen oxides remained near zero. It was concluded that most mass loss is due to flaming combustion in the leading flame front. The results presented here can be used to inform prescribed burning practices to reduce the risk of uncontrolled fire, manage ecosystem health, and as useful validation data for wildland fire modeling codes currently under development.