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The results of direct numerical modeling of combustion in a cone-shaped methane-air mixture flame directed at a flat, cold barrier are presented. Three cases with different distances between the burner nozzle and the barrier were considered. The study focused on analyzing nitrogen oxide formation in the wall region. It was found that when the barrier was positioned three calibers from the nozzle edge, a recirculation zone with an elevated concentration of nitrogen oxides (NO_x ) forms between the cone-shaped flame front and the cold wall. This increased NOx formation is offset in the downstream wall region.

Using a detailed kinetic mechanism of chemical interaction, the effect of adding ozone (or hydrogen peroxide) and helium as an inert diluent to a stoichiometric hydrogen-air mixture on the detonation wave parameters was numerically studied. It was found that the mole fractions of the additives can be selected such that the detonation wave cell size in the resulting mixture is close to the average cell size in the pure mixture, while the temperature of the detonation products is significantly reduced. It was shown that the introduction of hydrogen peroxide and helium reduces the stability of the detonation wave to disturbances caused by multiple obstacles (barriers) located in the channel, thereby contributing to the wave suppression. Conversely, detonation in a mixture with ozone and helium additives at selected concentrations is found to be more resistant to these disturbances than in the pure mixture.

A microscopic and diffraction study of detonation carbon in the products of benzotrifuroxane-based explosive compositions containing hexogen, octadecanoic acid, and TNT was conducted. Carbon species characteristic of pure benzotrifuroxane were observed in the detonation products of benzotrifuroxane-based compositions with individual benzotrifuroxane granules ranging in size from a few to tens of microns. No such species were detected in the submicron mixture of benzotrifuroxane and TNT.

Wide-range semiempirical equations of state for liquid and gaseous argon, krypton, and xenon are constructed, taking into account evaporation and thermal ionization, based on a modified van der Waals model for mixed substances. The empirical functions that specify the model have a simple form. They contain a small number of free parameters, selected based on the best possible description of the experimental data. A comparison of the model calculation results with experiment up to pressures of ≈1000 GPa and the results of calculations using other models at pressures above 1000 GPa is presented. In the limit of low density and high temperature, the model transforms into an equation of state for a mixture of ideal gases of atoms, ions of all multiplicities, and electrons with a concentration determined by the Saha system of equations.

The possibility of the existence of combustion waves in αCH₄/air gas mixtures and αCH₄/air/coal suspension dual-fuel heterogeneous mixtures (DGMs) with a methane volume concentration of α = 5 ÷ 8% was studied in a closed vertical shock tube and in a horizontal quartz tube open at one end. It was shown that the value of the lower concentration limit of methane flame propagation (LEL) α* and the flame stability are affected by the channel location relative to the gravity vector and the concentration of the coal suspension. In the vertical closed channel, combustion waves propagated from top to bottom in gas mixtures and DGMs at α ≥ 6%, but did not ignite at α ≤ 5.5%. In a horizontal tube, flame propagated in gas mixtures with α ≥ 6% and in a dual-fuel mixture with α ≥ 5.5%. Adding coal suspension to methane-air mixtures has little effect on flame velocity, increases brightness, and reduces the flame's LFL.

An experimental study of the ignition and combustion processes of composite liquid fuel (CLF) droplets based on coal cleaning waste in a high-temperature oxidizer environment at 700 ÷ 900 °C was performed. The effect of adding waste motor oil as a component of the CLF and as a feedstock for generating syngas, which was fed to the CLF combustion zone, was investigated. The feasibility of co-combustion of CLF with syngas was experimentally confirmed. The gas-phase ignition delay of CLF droplets with the addition of syngas to the combustion zone is 1.1 ÷ 1.2 times shorter compared to CLF combustion without the addition of syngas. Under these conditions, the heterogeneous ignition delay is 1.3 ÷ 1.7 times shorter, and the fuel burnout duration is 1.2 ÷ 1.5 times shorter. The use of waste oil as a component of composite fuel is characterized by a significant improvement in energy performance, which, combined with the increased combustion temperature, makes this strategy the most attractive for practical implementation.

The development of advanced technologies, such as oxy-drip-torch combustion, will solve a number of problems and improve the environmental situation associated with the combustion of hydrocarbon fuels (including waste) at power plants. In this study, experiments were conducted on a laboratory rig to study the autoignition of droplets of coal-water slurry in a tubular reactor. The dependence of the ignition induction period on the oxygen and carbon dioxide concentrations under adiabatic conditions was investigated. It was shown that increasing the O₂ concentration by 1% (volume) reduces the ignition time by 5.14% under the experimental parameters considered. It was found that increasing the CO₂ concentration in the flow at the same oxygen concentration does not significantly affect the ignition time under these conditions.

The oxidation properties of unmodified boron powders and boron modified with vanadium pentoxide gels were studied using X-ray phase analysis (XPA) using a synchrotron radiation source at a heating rate of 10°C/min in air. It was established that the mechanism underlying the activation of boron oxidation by vanadium pentoxide is the ability of vanadium pentoxide to transfer electrons and deliver oxygen to the boron surface upon dissolution in molten B₂O₃.

The principles of gasless combustion wave transition through an air gap separating two cylindrical samples of different diameters, prepared from a Ti--Si mixture, are examined. Critical conditions of the transition process are investigated using experimental and computational methods. A mathematical model is proposed, based on which the effective emissivity from the combustion surface is calculated in correlation with experimental data. The emissivity of titanium silicide is estimated.

Using mathematical modeling methods, we analyzed combustion failure of a cylindrical sample undergoing radiant heat transfer. A method is proposed for estimating critical parameters-the critical diameter, temperature, and velocity at the combustion limit-under conditions of predominantly radiant heat loss, typical of high-temperature SHS systems. The results are compared with similar values for maximum heat loss, cooling the cylinder surface to ambient temperature. The calculation results can be used to estimate the critical cylinder radius and the effective activation energy of the reaction. A method is proposed for estimating the effective activation energy of the heat release rate during gasless combustion of condensed media.