О возникновении пожаров в лесах из-за возгорания лесного опада

Abstract

Fires in forests cause great environmental damage to our country due to loss of wood, destruction and damage to residential and industrial buildings and structures. Often fires in forests are accompanied by death of people. Large fires affect the pollution of the atmosphere, climate change in a certain area, generally have a negative impact on the environment of the affected regions, increase incidence and mortality rates of the population, create social tension in society. The paper analyzes the causes of anthropogenic and natural origin of fires. The main attention is paid to the conditions of spontaneous combustion of forest litter (litter) in coniferous forests, which can occur under certain conditions, even in winter, after snowfall. A physicochemical justification for the process of spontaneous combustion of forest litter is presented, and corresponding thermophysical calculations are made. It is shown that in the layer of litter of a certain thickness, a process of self-heating takes place and an increase in temperature due to an exothermic reaction, because of which the temperature rises in the litter - up to the temperature of spontaneous combustion. Such a picture will be observed until a certain self-heating temperature is reached at which the exothermic transformations in the material (decomposition, oxidation) begin, leading to self-heating of the material. When a certain temperature is reached, selfignition of the forest litter may occur. Specific examples of spontaneous combustion of forest litter in coniferous forests of the Voronezh region in the beginning of winter under a layer of snow and possible causes of spontaneous combustion of coniferous litter in forests during the summer are considered. It is shown that the process of spontaneous combustion can occur when certain climatic conditions are combined, as well as factors such as thickness, humidity and dispersed state, and the thermophysical characteristics of the litter, temperature and mobility of the atmosphere. Based on the solution of the equation of non-stationary Fourier thermal conductivity with an internal heat source, it is planned to determine the conditions for heat exchange on the surface and the thickness of the fallen layer of litter, in which a selfignition process may occur.