Home – Home – Jornals – Combustion, Explosion and Shock Waves 2026 number 1

The article presents experimental and calculated results of a study of the formation and growth of soot particles in a standard ethylene/air flat flame with dimethyl ether (DME) additive. Two-dimensional laser-induced incandescence (2D-LII) was used as an experimental method, obtaining data on the volume fraction of soot particles in the flame. The time-resolved LII signal provided information on the average soot particle size depending on the flame height. Kinetic modeling was performed using a modern kinetic mechanism of hydrocarbon pyrolysis and oxidation, including a sectional model of soot particle growth. It was shown that DME additives lead to a decrease in soot yield without significantly affecting the final particle size. Furthermore, DME additives slow down the initial stages of soot particle formation but accelerate their subsequent growth.

The mechanism of chain development during thermal gas-phase oxidation of methane was studied experimentally and theoretically. It was found that the rate-limiting step, which determines the overall process development, depends on the conditions. At a temperature of 728 K, the process is determined by the interaction of peroxide radicals with each other. Increasing the temperature to 873 K leads to an increased role for the reactions of peroxide radicals with formaldehyde, after which the rate-limiting step becomes the interaction of peroxide radicals with methane. Furthermore, changes in pressure and temperature have an equal effect on the concentration ratio of hydroperoxide and methylperoxide radicals, determined both by calculation and experiment.

A skeletal reaction mechanism for the ignition and combustion of complex dodecane/decane/isooctane/isocetane/toluene surrogates of kerosene-type aviation fuels has been developed. The mechanism includes submechanisms for the oxidation of dodecane, decane, isooctane, isocetane, and toluene in the high- and low-temperature regions, as well as in the inverse temperature coefficient zone. The mechanism was tested using experimental data on ignition delay time, normal flame propagation velocity, and component concentration distribution. The combustion characteristics of the surrogates were tested using the developed reaction mechanism, and a demonstration CFD simulation of the operating process in a low-emission combustor of a gas turbine engine using rich-lean combustion technology was conducted.

The results of an experimental study of the thermal oxidation characteristics and combustion product composition of coal slurry and composite fuels based on it, with the addition of water and dispersed wood, are presented. The positive effect of the additives on the critical ignition temperature, burnout efficiency, and anthropogenic gas emissions is substantiated. The main mechanisms and schemes for the formation and suppression of nitrogen oxides at different stages of thermal conversion are presented. The most effective conditions for reducing nitrogen oxide emissions are determined. Using a multicriteria analysis technique, the environmental, economic, and energy advantages of composite fuels over the original coal slurry are demonstrated. Dry fuel mixtures based on coal slurry and biomass with a mass fraction of the latter of 30 and 50% are found to have the greatest potential. Compared to coal slurry, the efficiency of such fuels is 30 to 45% higher. With maximum emphasis on environmental indicators, composite liquid fuels hold the greatest promise.

Detonation combustion modes of a two-phase mixture of TS-1 aviation kerosene and air in a 500 mm diameter radial vortex chamber with a center-facing outlet, a nozzle, and axial baffles equalizing the product flow in the axial direction were implemented and studied. Continuous spin and pulsating detonation modes were achieved with strong (detonation wave) and weak (with combustion transition to detonation) initiation. It was found that with weak initiation, continuous spin detonation with a single transverse detonation wave was always achieved upon reaching the maximum specific impulse in this experimental setup - I_sp,ƒ,max ≈ 1 600 s. A comparison was made between the specific impulses of this radial combustion chamber and chambers with annular cylindrical geometry, in which kerosene was burned in continuous multifront detonation modes. It was found that during detonation combustion of kerosene in cold air, the specific impulse values in annular cylindrical combustion chambers are higher than in radial combustion chambers. At hydrogen and air flow rates close to stoichiometry at the start of the combustion, autoignition followed by a transition to continuous spin detonation was observed. The transition time was reduced to 10 ms by forced (spark) initiation of the hydrogen-air mixture.

The energy potential of ten fluorodinitromethyl-ONN-azoxy compounds as binder plasticizers in model composite solid propellants of various formulations, with and without metal (aluminum hydride or metallic aluminum). The energy potential of these plasticizers was compared with that of the most energy-intensive known plasticizers (nitroglycerin, tetranitromethane, and dinitrofurazan) for model solid propellants intended for different stages of rocket systems. It was shown that almost all of the studied fluorodinitromethyl-ONN-azoxyfurazans, when used as active binder components, provide higher energy values than nitroglycerin and tetranitromethane, and some fluorodinitromethyl-ONN-azoxyfurazans even outperform dinitrofurazan. High-performance quantum-chemical calculations of the enthalpy of formation of new, not yet synthesized energy-intensive substances that are promising in various fields of application were carried out.

The paper presents the results of measuring the velocity and density distributions in high-velocity (1.7 ÷ 4 km/s) shock-induced particle flows ejected from the free surface of tin and copper liners into vacuum (less than 10³ Pa) or nitrogen (10⁵ and 8 ⸱ 10⁵ Pa). Periodically repeating triangular grooves 50 μm deep and 250 μm wide (2a₀ / λ = 50/250 μm) were applied to the liner surfaces. Multi-frame recording using synchrotron radiation and laser heterodyne interferometry were used in the experiments. A pressure of ≈45 GPa in the shock waves emerging on the free surfaces of the liners led to the melting of tin, while copper remained in the solid state. A significant difference in the structure of the flows ejected from the surface of copper and tin liners and their deceleration velocities in the gas is observed.

The results of numerical simulations of experiments conducted using proton radiography and synchrotron radiation to record the motion of a flow of fine metal particles in gaseous media are presented. Particle ejection occurred as a result of a shock wave acting on the free surface of metal samples with small-scale, profiled initial disturbances. Numerical simulations were performed using a developed model of particle flow evolution in a gaseous medium, based on a model of the source of shock-wave dusting of metals, based on the physics of Richtmyer-Meshkov instability, and the laws of fragmentation of a single liquid droplet in a gas flow. The proposed model is shown to be in good agreement with experimental results.

The article presents the summarized results of a numerical analysis of the formation of a temperature field in a shock-compressed two-phase porous material in the absence and presence of phase transformations during plastic pore filling. Using mathematical modeling methods, the influence of mesoscopic processes of thermal dissipation and heat transfer on the resulting temperature field is investigated, and its topological features are determined in the presence of molten zones in the shock-compressed porous material.

The character, criteria, effects and other characteristics of damage to reinforced concrete beams under the action of explosive impact loading were studied experimentally and using numerical modeling methods. A fast method for obtaining the P-I curve of beam elements with arbitrary structural parameters is proposed. First, five model tests were conducted to study the dynamic response and damage parameters of two types of reinforced concrete beams with cross-sectional widths of 0.04 and 0.047 m under a 200 g TNT explosion at pre-detonation distances of 0.2 and 0.5 m and at blast locations above 1/2 and 1/4 of the span. The results showed that damage to the reinforced concrete beam was less with a cross-sectional width of 0.04 m and at a blast location above 1/2 of the span under the experimental conditions. The experimental results confirmed the effectiveness of the numerical modeling method. Based on a large number of numerical simulation results, the approximation formula for the P-I curve of reinforced concrete beams was simplified, and the influence of the following parameters on the P-I curve was investigated: stirrup reinforcement ratio ρs, longitudinal reinforcement ratio ρ, concrete axial compressive strength ƒ′_c, beam span L, beam cross-section height b, and beam cross-section width a. As a result, a method for quickly determining the P-I curve of reinforced concrete beam elements is proposed, which can be applied in the field of blast protection design and rapid damage assessment.

This article presents an analysis of the influence of the loading factor, a key parameter of the explosion welding process, on the interface morphology and mechanical properties of similar and dissimilar joints. The loading factor (the ratio of the explosive mass to the impact plate mass) determines the impact velocity, dynamic bending angle, and jet formation. It influences the nature of the interface, namely the formation of straight, wavy, or intermetallic layers, and therefore the weldability of dissimilar metals. Correct selection of the loading factor ensures high-quality welding with minimal defects, while excessive or insufficient loading factors lead to incomplete bonding or deterioration of the interface quality. This article summarizes the main experimental results and offers recommendations for process optimization and future research directions.

A method for studying the quasi-isentropic compressibility of condensed substances was tested using an experiment with a lead shell. This method utilizes multi-frame radiography and explosive spherical loading devices with gas symmetrization. At maximum compression, the average density of the lead shell was ≈52.3 g/cm³, with a compression ratio of ≈4.6. The total pressure in the lead at maximum compression was ≈3.2 TPa, with the cold component equal to ≈94% and the thermal component ≈6%. The pressure values were obtained from a one-dimensional numerical calculation, which accurately describes the compression dynamics of the lead shell, using the ROSA-MI EOS for lead.

For hemispherical cumulative liners of degressive thickness (decreasing from apex to base), an increase in the velocity of the leading portion of the forming cumulative jet is observed with increasing thickness difference between the apex and base of the liner, which is ensured by the process of its explosive compression becoming more spherically symmetric. Based on a numerical solution to a model problem of the inertial, centrally symmetric collapse of a shell in the shape of a spherical segment with a model material that does not resist all-round stretching, it is shown that the maximum velocity of cumulative jets from hemispherical liners of degressive thickness that do not undergo volumetric destruction should be higher than that of jets from conical liners -- at least 12 km/s for copper liners. The production of a coherent copper cumulative jet with a warhead velocity at the specified level was recorded in a numerical simulation of the explosion of a charge with a lining of degressive thickness, having a hemispherical outer surface and a semi-superellipsoidal inner surface with an exponent of 2.05 in the semi-superellipsoid equation.