Cataloging Information
Fire Prediction
Weather
Wood cribs are often used as ignition sources for room fire tests. A wood crib may also apply to studies of burning rate in wildland fires, because wildland fuel beds are porous and three dimensional. A unique aspect of wildland fires is the ubiquitous presence of wind. However, very little is known about what effect the increased ventilation has on the burning rate of cribs in either the densely- or loosely-packed regime. Experiments were performed with seven cribs designs with a range of porosities and two fuel element sizes: 0.64 cm and 1.27 cm. These cribs were burned in a wind tunnel with wind speeds ranging from 0 m/s to 0.7 m/s. Changes in the observed flame structure and burning patterns with wind are noted and discussed. The effect of wind on the burning rate was seen to depend on the fuel thickness. At the highest wind speed tested, cribs built with the 1.27 cm sticks showed a 6.5% to 61.5% increase in burning rate depending on porosity. Cribs built with the 0.64 cm sticks showed a decrease of 36.7% to 60.6% that was relatively constant with wind speed. Possible mechanisms of these changes are discussed. Future work will include further testing to clarify the causes of these trends.
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