The research led by Prof. Geniy Kuznetsov is supported by a grant from the Russian Science Foundation. The research findings are published in the Fire (Q1; IF: 2,726).
One of the most promising ways to combat forest fires is to create a control line ahead of the fire front by wetting a layer of forest fuels to a certain depth with water or specialized water-based compositions. This line can be made by spraying water from aircraft or by using ground equipment. The combustion front, having reached this control line, stops until the wetted part of the forest fuel gets completely dry, and then continues moving with a lower velocity. This velocity depends on the wetting depth, moisture concentration in the forest fuel and the width of the control line. Mathematical modeling in this case can be an effective tool for analyzing the conditions and characteristics of forest fire containment.
Scientists from the Butakov Research Center and the Research School of High-Energy Physics at Tomsk Polytechnic University have proposed a fundamentally new approach to mathematical modeling for predicting the physical and chemical processes of forest fire propagation. They described a set of key physical and chemical processes that occur in the wetted layer of forest fuel under rapid heating. The analysis was based on experimental data. The model addresses both the process of convective mass transfer in the gas phase and the phase transition process of evaporation of the liquid used as the wetting material.
Our model stands out for the fact that it takes into account an important factor in its formulation: the impact of the radiant flux to the surface of forest fuel. The model helps to calculate internal nonstationary processes that occur as a result of the impact, including convection and thermal conductivity, radiation, evaporation of water or liquids of special composition, filtration of vapors to the heated surface, water vapor injection into the near-surface area, and thermal decomposition of forest fuel. In addition, the model takes into account time-varying parameters and combustion process properties, which makes it possible to adjust calculations for different flame heights,
The proposed numerical model can be used to determine with adequate accuracy temperature distributions and other physical characteristics of forest fuel over a certain time interval, which is important for the process analysis. Thus, the model makes it possible to estimate the width of the water line required for fire containment. In addition, similar calculations for other extinguishing agents based on water and various types of forest fuels can be made using the proposed model as well.
In the next stage of the study, the scientists plan to scale up the process and calculate the physical and chemical processes for the situations when the flame height reaches 15 meters. They also plan to use the model to analyze various properties of extinguishing materials that can potentially be used to set up a fire suppressing wet line ahead of the combustion front.