Sensitivity of Smoldering Combustion to Cellulose and Hemicellulose Content

摘要

Smoldering combustion of forest duff can persist for long periods of time and cause damage to ecosystems by destroying the duff layer or by transitioning to flaming combustion. Smoldering combustion of specific fuels, such as peat and cotton, have been studied in detail but the sensitivity of smoldering combustion to individual fuel constituents (e.g., cellulose, hemicellulose) is largely unknown. This knowledge is needed to help validate numerical models, understand how to extend findings to different fuels, and identify the role of fuel chemistry in controlling smoldering combustion. With this motivation, the objective of this study is to identify the effects of the concentration of cellulose and hemicellulose on surface propagation velocity and temperature distribution for smoldering combustion. This is achieved by systematically varying the fuel composition from 100% cellulose to 100% hemicellulose and identifying changes in the propagation velocity and temperature gradients. Type-K thermocouples were used to measure temperature gradients and surface propagation velocity. Infrared and visual cameras were also used to determine the surface propagation velocity. Fuels with greater cellulose content propagate faster than fuels with less cellulose and more hemicellulose. A roughly linear dependence of the propagation velocity on the concentration of cellulose was identified.