INTERACTION OF TYPICAL FIRE-EXTINGUISHING LIQUIDS WITH THE FOREST FUEL COMBUSTION FRONT

The paper presents the results obtained in experimental studies of the processes of localizing the combustion of typical forest fuel materials (needles, foliage, and their mixtures with twigs) using a control line (firebreak) of a wetted layer of such materials formed before the fronts of their thermal decomposition and combustion. Water, bischofite solution, OS-5 solution, bentonite suspension and a foaming agent emulsion were used as fire-extinguishing agents. Relative mass and volume concentrations of water impurities were selected in accordance with ranges that are typical of modern fire-extinguishing systems. The possibility is shown for localizing the combustion of the said materials by reducing their temperature through heat accumulation by water, which has a high heat capacity and undergoes endothermic phase transformations, and blocking the access for the oxidizer and pyrolysis products to the flame combustion zone by forming a buffer zone from relatively cold water vapors and reducing the concentration of the products of materials' thermal decomposition as a result of the fire-extinguishing agent spreading on their surface and pores. The conditions are determined for guaranteed localization of the burning of a forest area by supplying its control line with a liquid composition in the form of a massive water drop, a jet and aerosol. It is shown that the supply of an aerosol cloud to the control line is the most efficient method in terms of minimal liquid consumption and guaranteed combustion localization.