FUEL MAPPING AND FIRE PHYSICS

Abstract: The current study presents a series of experiments investigating the smoldering behavior of woody fuel arrays at various porosities under the influence of wind. Wildland fuels are simulated using wooden cribs burned inside a bench scale wind tunnel. Smoldering behavior was characterized using measurements of both mass loss and emissions. Results showed that the mean burning rate increased with wind speed for all cases. In high porosity cases, increases in burning rate between 18% and 54% were observed as wind speed increased. For low poros- ity cases an increase of about 170% in burning rate was observed between 0.5 and 0.75 m/s. The ratio of CO/CO2 emissions decreased with wind speed. Thus, wind likely served to promote smoldering combustion as indicated by the decrease of CO/CO2 which is a marker of combustion efficiency. A theoretical analysis was con- ducted to assess the exponential decay behavior in the time- resolved mass loss data. Mass and heat transfer models were applied to assess whether oxygen supply or heat losses can solely explain the observed exponential decay. The analysis showed that neither mass transfer nor heat transfer alone can explain the exponential decay, but likely a combination thereof is needed.