Laboratory investigation of fire exposure on wood by thermal imagery and thermocouple approach

The impact of spot fire on wood different-shaped samples (flat and cylindered sample) is studied under laborator

Simulation of impact assessment of crown forest fires on boundary layer of atmosphere using software PHOENICS

Mathematical model of heat and mass transfer of crown forest fire is used in this paper, which is developed on the base of experimental research data and laws and methods of mechanics of reacting media. The numerical calculation carried out using software PHOENICS for non stationary three dimensional case. K-ε model of turbulence is taken into account. It is studied the influence of temperature and wind velocity in boundary layer of atmosphere on the turbulent kinematic viscosity coefficient value and distribution of temperature above the crown forest fire front

Application of thermography in experimental studies of plasma jets

The paper presents the experimental studies of the optical properties for the plasma jet in the mid-IR range

Justification of choice of the spectral range for the study of combustion processes with the use of thermography in the middle IR range

The paper presents the emission spectra of flame formed during combustion of different fuels and gives the grounds for application of various narrow spectral ranges in the mid-infrared region to record the temperature fields in flame and flame screened objects

The effect of pressure pulsation on diffusion combustion

The paper presents the results of a study of diffusion combustion of gasoline in the presence of external pressure pulsations with small amplitude. It is found that external pressure pulsations lead to characteristic changes in the temperature field, which are expressed by an increase in the amplitude of the temperature pulsation for certain modes of pressure pulsations. Analysis of the spectra of temperature changes in the entire recorded area showed an unevendistribution of frequency maxima

Modeling of wood surface ignition by wildland firebrands

The probability of structural ignition is dependent both on physical properties of materials and the fire exposure conditions. In this study, the effect of firebrand characteristics (i.e., firebrand size, number of firebrands) on wood ignition behavior was considered. Mathematical modeling and laboratory experiment were conducted to better understand the conditions of wood ignition by a single or group of firebrands with different geometry. This model considers the heat exchange between the firebrands, wood layer and the gas phase, moisture evaporation in the firebrands and the diffusion gases of water vapor in the pyrolysis zone. In order to test and verify the model, a series of experiments to determine probability and conditions for ignition of wood-based materials (plywood, oriented strand board, chipboard) caused by wildland firebrands (pine twigs with a diameter of 6–8 mm and a length of 40 ± 2 mm) were conducted. The experiments investigated the firebrand impact on the wood layer under different parameters, such as firebrand size and quantity, wind speed, and type of wood. The results of experiments showed that the increase in wind speed leads to the increase in probability of wood ignition. Based on the received results, it can be concluded that the ignition curve of wood samples by firebrands is nonlinear and depends on the wind speed and firebrand size as well as their quantity. At the same time, there is no ignition of wood samples in the range of wind speed of 0–1 m/s. The ignition of wood is possible with a decrease in the distance between the firebrands with a decrease in the firebrand length. This result agrees more closely with the model

Effect of wood structure geometry during firebrand generation in laboratory scale and semi-field experiments

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

Thermography of flame during diesel fuel combustion with steam gasification

The paper represents a study concerning the combustion of liquid hydrocarbon fuel in a perspective burner device with the controlled forced supply of overheated steam into the combustion zone, using diesel fuel. The thermal imaging measurements are conducted for the outer flame of the burner device in the wide range of regime parameters (flow rate and temperature of steam). A thermal imaging camera (FLIR, JADE J530SB) is used in the experiments. The effective emissivity coefficient of flame is obtained versus the flow rate of steam supplied. The steam parameters are found to influence on the temperature in the outer flame of the burner device

Introduction

The history of the All-Russian Scientific Conference “Conjugate Problem of Mechanics of Reactive Mediums, Informatics and Ecology” had started with scientific seminars, which began in 1973 at the initiative of young personnel of the Aerothermochemistry Department of the Research Institute of Applied Mathematics and Mechanics of Tomsk State University. They tested new scientific results and established channels with leading scientists of scientific schools