The interaction of a firebrand shower with some types of combustible building materials and wood structures was studied experimentally. The heat flux generated by firebrands was determined, and the temperature fields of the most heat-stressed sections of the structures were analyzed. The heating rate of samples was estimated based on infrared thermography data. Under the selected experimental conditions, the bench sample was found to be the most resistant to ignition. Estimation of the near-surface temperature of the bench element showed that after 15-min continuous exposure to firebrands, the temperature in the zone of maximum accumulation of firebrands did not exceed 130°C. The wood fence model was found to be most prone to ignition (ignition delay time more than 15

В докладе представлены некоторые результаты многолетних экспериментальных исследований влияния модельных степных пожаров на характеристики атмосферы. Установлено локальное изменение метеопараметров и параметры наведенной атмосферной турбулентности, определены характерные газообразные продукты пиролиза и горения, которые попадают в атмосферу в результате природных пожаров. Полученные результаты позволят осуществлять оценку влияния массовых пожаров на экологию регионов, глобальные атмосферные и климатические процессы.

As the set of experiments result, statistically substantiated data were obtained on the laws of ignition of a model angular structure under conditions of a point source of heat exposure. The use of IR diagnostics made it possible to control the thermal picture in the experimental area, as well as to capture areas of the highest and lowest heating. In the Large Aerosol Chamber of IAO SB RAS, preliminary experiments were carried out on a “firebrand shower” model exposure, which is naturally occurring firebrands (flaming or glowing embers) with some types of construction materials (chipboards). The exposure of the samples to firebrands stream was provided using a firebrand generator of own original design. It was experimentally confirmed that particle size plays a significant role in the ignition of a building structure. If the characteristic particle size, which can be defined as the ratio of its volume to the surface area in contact with the wood, is less than a certain characteristic value, then the ignition mode with a sharp temperature maximum near the phase interface is not fulfilled. This can be explained by the prevailing heat removal into the external environment in comparison with the amount of heat coming from a heat gun and resulting from chemical reactions.

The paper presents results of an experimental study of the propagation characteristics of grassland fire front, its effect on meteorological parameters and the emission of gaseous combustion products. As a result of the study, it was found that the seat of fire of a small-scale combustion lead to an increase in air temperature by 2-3 degrees and a decrease in relative humidity by 5%. The highest pulsations amplitude of the wind velocity vertical component of 12 m/s was recorded using a weather station installed at a relatively low height. These pulsations are due to the strong inhomogeneous of the upward flow of combustion products.