The work presents the study results of the flow swirling impact on the heat transfer of equilibrium dissociating dinitrogen tetroxide. It was shown that heat transfer intensifies with an increase in the swirling intensity, which leads to an increase in the Nusselt number. Heat transfer of the flow depends on the integral intensity of the swirl, as well as of the organizing rotation method in the flow. Turbulent disturbances under active effect arise in the flow, which leads to an increase in heat transfer coefficient. Centrifugal forces contribute to the weakening of turbulent heat transfer and a decrease in heat transfer under a conservative effect.
The study investigates the transition process from a ground fire to a crown fire. The studies were carried out in seminatural conditions on the territory of the Base Experimental Complex (BEC) of the IAO SB RAS. Previously, reconstruction of the forest canopy was carried out. The emergence of a crown fire occurred due to the transition of a ground fire to the bottom layers and further to the crowns of trees. Non-contact diagnostic methods (IR thermography) were predominantly used to measure combustion front parameters.
The article presents the results of a series of mesoscale experiments to study wildfires and their impact on the atmosphere. A change in meteorological parameters, a significant increase in fluctuations of the refractive index, speed of sound and temperature in the vicinity of the experiment, which are a reflection of the occurrence of turbulent processes in the atmosphere, were established, experimental data were obtained on changes in the concentration of methane and carbon dioxide as a result of a fire, and data were obtained on the mechanism of occurrence of crown fire.
Numerical simulation of the lift and spread of contaminants formation is carried out. Calculations show that the interaction of the impurity cloud with the surrounding air is insignificant for static atmospheric conditions, and dilution occurs at higher altitudes. An increase in the atmospheric turbulence intensity followed by stronger mixing, while an increase in the cloud size and a greater dilution of the contaminant is observed. The performed calculations made it possible to determine the level of pollution for various meteorological conditions and sources of pollution.
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.
The paper presents the experimental study results on the effect of heat flux emitted by a standard source on the charring and ignition characteristics of pine wood. Using a new method of setting the experiment with the recording of IR image, the charring rate and depth of the wood as a result of heat exposure from a standard source. The influence of several fire retardants on the charring rate and depth of samples is analysed. The use of noncontact IR diagnostics allows one to analyse the charring rate of pine wood depending on the intensity of heat flux and to draw up the temperature field.
The paper represents the experimental study of combustion over the surface of a vertically-mounted oriented strand board panel under different environmental conditions. An infrared camera was used to obtain the sequences of thermograms characterizing the heat flow pattern on the surface of the sample during vertical combustion and determine the velocity of the combustion wave under laboratory and field conditions. In addition, the change in the angle of the combustion front was estimated depending on time.
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