MATHEMATICAL MODEL OF CALCULATION OF THE SURFACE INTENSITY OF FEED OF A COOLANT IN AVIATION EXTINGUISHING OF GROUND FOREST FIRES

Results of mathematical modeling of the water concentration of the underlying surface during the aviation extinguishing of ground forest fi res of varying intensity have been given. In extinguishing a high-intensity ground fi re, droplets entering the zone of combustion evaporate in the fl ame. Therefore, no wetting of the underlying surface occurs in the combustion zone. With increase in the initial velocity of the droplets, the left boundary of the zone of wetting shifts to the seat of fi re, thus raising the effi ciency of the use of water in the process of fi re extinguishing. In extinguishing a moderate-intensity ground fi re, two coverage zones are formed on the windward and leeward sides of the seat of fi re, and also the region of intense evaporation between them. Boundaries between these regions are only determined by the intensity of the fi re and by the geometric characteristics of the combustion zone. Investigation of the infl uence of conditions for the formation of a gas–droplet cloud on the process of extinguishing a low-intensity ground fi re shows that at a small dropping height, a single continuous coverage zone is formed. In this case its length is determined mainly by the length of the primary cloud and to a lesser extent by the initial droplet velocity and the distribution of the wind velocity in the atmosphere.
Results of mathematical modeling of the water concentration of the underlying surface during the aviation extinguishing of ground forest fi res of varying intensity have been given. In extinguishing a high-intensity ground fi re, droplets entering the zone of combustion evaporate in the fl ame. Therefore, no wetting of the underlying surface occurs in the combustion zone. With increase in the initial velocity of the droplets, the left boundary of the zone of wetting shifts to the seat of fi re, thus raising the effi ciency of the use of water in the process of fi re extinguishing. In extinguishing a moderate-intensity ground fi re, two coverage zones are formed on the windward and leeward sides of the seat of fi re, and also the region of intense evaporation between them. Boundaries between these regions are only determined by the intensity of the fi re and by the geometric characteristics of the combustion zone. Investigation of the infl uence of conditions for the formation of a gas–droplet cloud on the process of extinguishing a low-intensity ground fi re shows that at a small dropping height, a single continuous coverage zone is formed. In this case its length is determined mainly by the length of the primary cloud and to a lesser extent by the initial droplet velocity and the distribution of the wind velocity in the atmosphere.
Author:  O. V. Matvienko, V. A. Arkhipov, O. I. Daneiko, A. S. Usanina, S. A. Basalaev, A. M. Bulavk
Keywords:  aviation fi re extinguishing, liquid–droplet cloud, gravity sedimentation, high-temperature medium, natural fi re, breakup and evaporation of droplets, mathematical modeling.
Page:  973-984