Characteristics of the Flying of Forest Combustible Materials Upstream of a Fire Barrage Under the Action of an Air Flow

Results of experiments on determination of the temperature, velocity, and mechanical trajectory of fragments of forest combustible materials subjected to pyrolysis, flying away under the action of high-velocity air flow, are presented. The effect of flying of such fragments over a fire barrage was mainly investigated. The experiments were performed with conifer needles and leaves, representing typical combustible materials in ground forest fires. On the basis of the experimentally determined effect of inclination of a flame over a fire barrage formed of moistened forest materials, physical and mathematical models of flying of fragments of forest combustible materials subjected to pyrolysis upstream of such a fire barrage have been developed. With the use of these models, the characteristic length of the zone of flame combustion of a forest material, the height of the flame in this zone, and the geometric dimensions of the fire barrage necessary and sufficient for reliable localization of the flame combustion and thermal decomposition of forest combustible material were determined.