Combustion of irradiated dry and wet oak

Abstract

Combustion of dry oak and wet oak with 50 wt% water content at a fire level surface heat flux of 2 cal/cm 2 sec was experimentally investigated. Experimental measurements included thermal-physical properties, mass loss rate, surface regression rate, solid density, temperature, pressure, and gas composition. Effects of absorbed water on wood pyrolysis and combustion are examined from these measurements. It is found that the absorbed water mainly delays the temperature rise in the wet wood and the vaporized water convectively cools the pyrolyzing wood. The pyrolysis process is thus delayed in the wet wood and the volatile combustible gases are diluted by the water vapor. Decomposition of water and reaction between water and wood char (carbon) do not appear to occur significantly. At steady-state burning, surface regression rates are the same for both dry and wet wood, apparently because the regression rate is primarily governed by the oxygen supply to the char surface.