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Mechanism of Flame Propagation above the Surface of a Flammable Liquid Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 V. V. Zamashchikov
Abstract Combustion of vapors of a flammable liquid whose temperature is below the flash point is under study. In this case, the flame propagates along the surface of the liquid due to being heated by combustion products. The velocities of an oxidizer moving towards the flame, which propagates at velocities comparable to the laminar burning rate of premixed hydrocarbon flames, are measured. The measurements
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URGENT COMMUNICATION The Deceleration Curve of the von Neumann Spike Is the New Feature of Detonating Explosives Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 V. I. Tarzhanov
Abstract A new characteristic of detonating explosives is proposed—the deceleration curve of the von Neumann spike. An example of plotting such a curve on the basis of experimental data obtained at the All-Russian Scientific Research Institute of Technical Physics for detonating plastic-bobded TATB is given.
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Reaction of Cylindrical 09G2S and 10KhSND Steel Shells with Longitudinal and Annular Welded Joints to Explosive Loading Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 K. V. Erofeev, V. A. Ogorodnikov, M. A. Syrunin, D. V. Khanin
Abstract Large explosion-proof chambers are manufactured using cylindrical shells made of sheet metal by rolling and welding with addition of longitudinal and circumferential seams. In this case, one should make a choice of steel with increased strength or ductility. In this regard, this work presents the results of a study of the reaction of such 09G2S and 10KhSND steel shells to dynamic loading.
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Phase Formation in the SHS of a Ti–B Mixture with the Addition of Si 3 N 4 Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 D. Yu. Kovalev, A. S. Konstantinov, S. V. Konovalikhin, A. V. Bolotskaya
Abstract The structure and phase composition of a material obtained via SHS in the combustion of a 87% Ti + 13% B powder mixture with the addition of Si3N4 is under study. The phase formation mechanism in this system is discussed. It is established that the material contains 64% of the TiB phase with an orthorhombic structure and 36% of the solid boron solution in titanium (\(\alpha\)-Ti[B]). The boron
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Hydrocarbon Fuels: Gas-Dynamic and Energy Parameters of Detonation Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 A. A. Vasil’ev, V. A. Vasil’ev
Abstract Data on the most important combustion and detonation parameters, such as wave velocities, pressures and temperatures of products, specific energy release of mixtures are presented for saturated hydrocarbons C\(_{n}\)H\(_{2n + 2 }\) [from methane (\(n\) = 1) to eicosane (\(n\) = 20)] and unsaturated hydrocarbons C\(_{n}\)H\(_{2n}\)[from ethylene (\(n\) = 2) to eicosene (\(n\) = 20)], also methanol
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Thermochemical and Energy Characteristics of Dimers of Terfurazanoazepines Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 D. B. Lempert, A. I. Kazakov, A. V. Nabatova, D. V. Dashko, A. I. Stepanov, G. V. Shilov, S. M. Aldoshin
Abstract The heat of combustion and the enthalpy of formation of 7,7′-bis(terfurazan[3,4-b:3,4′-d:3″,4″-f]azepine (I) and 1,1′-dioxide-7,7′-bis(terfurazan[3,4-b:3,4′-d:3″,4″-f] azepine (II), were experimentally determined. Product I was studied by X-ray diffraction analysis, and its crystallographic characteristics were determined. The efficiency of using compounds I and II as components of solid composite
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Effect of the Reinforced Concrete Slab on the Blast Shock Wave Properties Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 S.-C. Lin, S. Gao, J.-Q. Han
Abstract Based on advanced numerical simulation technologies, such as the birth and death of element technique, large displacement technique, and fluid-solid coupling mechanism, and combined with the strain rate effect of concrete and steel materials, a complicated finite element model of a TNT–air–slab system is set up using the nonlinear explicit dynamic finite element analysis software LS-DYNA.
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Combustion and Detonation Waves in Gas Mixtures of CH 4 /Air, CH 4 /O 2 , and O 2 /Coal Dust Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 A. V. Pinaev, P. A. Pinaev
Abstract The combustion, explosion, and detonation in hybrid systems containing gas mixtures of CH4/air, CH4/O2, and O2/coal particles up to 200\(\mu\)m in size with a volume-averaged density of up to 700 g/m3 were studied on a vertical shock tube. X-ray diffraction patterns of the initial coal powder and coal samples subjected to high-temperature waves were analyzed. Data were obtained on the structure
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Diagnostics of the Chemical Reaction Zone in Detonation of Solid Explosives Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 A. P. Ershov, N. P. Satonkina, A. V. Plastinin, A. S. Yunoshev
Abstract In studies of the structure of the reaction zone in detonation waves of high explosives, it is common to measure the mechanical characteristics of the flow—the histories of particle velocity, pressure or density. Experience has shown that in such profiles, it is difficult to identify the chemical reaction zone. These distributions, as a rule, are distorted when the flow interacts with measuring
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Continuous Detonation of a Mixture of Gaseous Hydrogen and Liquid Oxygen in a Plane–Radial Combustor with Exhaustion Toward the Periphery Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 F. A. Bykovskii, S. A. Zhdan, E. F. Vedernikov, A. N. Samsonov, E. L. Popov
Abstract Regimes of continuous spin detonation and continuous multifront detonation of a gas–droplet mixture of gaseous hydrogen and liquid oxygen in a plane–radial combustor (internal diameter of 100 mm and external diameter of 300 or 200 mm) with exhaustion toward the periphery are obtained for the first time. The detonation front height of the gas–droplet mixture is greater than that of the gas
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Large Eddy Simulation of Lean Premixed Swirling Flames via Dynamically Thickened Flame Model Coupling with the REDIM Chemistry Table Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 H.-K. He, P. Wang, L. Xu, Q. Xu, L.-S. Jiang, P. Shrotriya
Abstract In this paper, the so-called REDIM–DTF sub-grid scale combustion model is proposed to improve the well-known dynamically thickened flame (DTF) combustion model by combining the DTF modeling strategy with the reaction-diffusion manifold (REDIM) chemistry table, which is generated from a detailed reaction mechanism. The new model is then used to calculate two lean premixed swirling flames in
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Direct Lightning Initiation of HMX Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 K. C. Chen, L. K. Warne, R. E. Jorgenson, J. H. Niederhaus
Abstract HMX can be detonated by an exploding bridgewire (EBW) or a slapper. Direct HMX detonation by an electrical arc has not been demonstrated. This paper shows that the shock from a 99% worst-case lightning current (200 kA and 500 ns rise time) can detonate standard-density HMX at elevated temperatures (i.e., HMX in the most sensitive \(\delta\)-phase at a temperature above 177°C) and that the
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Detonation Mechanism of PETN Explosives with Sodium Hydrocarbonate Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 I. A. Spirin, D. A. Pronin, E. S. Mitin, V. G. Simakov, V. A. Bragunets, A. V. Tsvetkov, E. E. Shestakov, Yu. M. Sustaeva, O. V. Shevlyagin, S. A. Vakhmistrov
Abstract The detonation of mixtures of highly dispersed PETN with sodium bicarbonate with a mass fraction of the latter up to 90% is investigated using radio interferometric method and electron-optical method NANOGATE-22 along with a method using a polyvinylidene fluoride pressure sensor. The experimental results obtained indicate the possibility of the existence of various detonation regimes in mixtures
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Preparation and Properties of a Flake Aluminum Powder in an Ammonium-Perchlorate-Based Composite Modified Double-Base Propellant Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-12-28 D.-Q. Wang, H.-M. Yu, J. Liu, F.-S. Li, X. X. Jin, S.-J. Zheng, T. T. Zheng, Y. Li, Z.-J. Zhang, D. Li, Z.-G. Lan
Abstract A flake aluminum powder (f-Al) is prepared by a bi-directional rotation mill method using a spherical aluminum powder (s-Al) as a raw material. Then, these two kinds of aluminum powders are used to prepare ammonium perchlorate-based composite modified double-base (AP-based CMDB) propellants. The properties of two kinds of AP-based CMDB propellants, such as the thermal decomposition performance
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Application of Synthesis Gas to Intensify Kerosene Combustion in a Supersonic Flow Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 P. K. Tretyakov, A. V. Tupikin, A. L. Kuranov, S. V. Kolosenok, A. A. Savarovskii, V. M. Abashev
Abstract This study experimentally confirms the intensification of kerosene combustion in the case where a mixture simulating steam reformation products in a model combustion chamber with a supersonic velocity of the flow at the inlet. It is shown that the used mixture has a higher chemical activity than ethylene. The use of steam reformation products of hydrocarbon or synthetic propellants in schemes
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Impact Sensitivity of Pyrotechnics: A Model Based on Activation Energy Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 S. P. Sivapirakasam, K. Harisivasri Phanindra, J. Rohin, S. L. Aravind
Abstract This paper introduces a simple and new correlation between the impact sensitivity and activation energy for pyrotechnic compositions where both the fuel and oxidizer are inorganic in nature. The database consists of various drop height (impact sensitivity) and activation energy values obtained from in-house experimentation and various literature studies. This paper also proposes a method to
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Distribution of Aluminum Clusters and Their Ignition in Air during Dispersion of Aluminum Nanoparticles in a Shock Wave Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 P. S. Kuleshov, V. D. Kobtsev
Abstract The dispersion of oxidized Al nanoparticles into clusters by rapid heating in a shock wave has been studied. Cluster distribution characteristics were calculated as a function of the parameters of the initial nanoparticle distributions and the nature of the interaction of deformation waves with the nanoparticle shell and core. The studies were carried out using the author’s proposed resonance
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Computational and Experimental Study of Operation of Shaped Charges with Hemispherical Liners of Degressive Thickness Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 S. V. Fedorov, S. V. Ladov, Ya. M. Nikol’skaya, A. E. Kurepin, K. S. Kolobov
Abstract Operation of shaped charges with copper hemispherical liners of degressive (decreasing from top to bottom) thickness is experimentally studied. The velocity of the head of generated shaped-charge jets is determined along with how deep they penetrate a type-setting target made of steel disks and the sizes of holes made in the disks. The experimental data on an increase in the velocity and a
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Mathematical Model of Critical Condition for Friction Ignition Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 X.-Y. Liang, G.-B. Mi, P.-J. Li, J.-X. Cao, X. Huang
Abstract The effect of friction on the critical temperature of ignition is considered by establishing the friction ignition model based on the principle of the heterogeneous reaction of Semenov. The effects of the oxygen concentration, flow velocity, friction force, and contact area on the critical temperatures of two fireproof titanium alloys (TB12 and TF550) are studied. The results show that the
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Effect of the Aluminum Particle Size, Solid Content, and Aluminum/Oxygen Ratio on the Underwater Explosion Performance of Aluminum-Based Explosives Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 F. Xiao, W. Gao, J. Li, R. Yang
Abstract Several aluminum-based explosives are prepared and their underwater explosion performances, including the specific bubble energy and specific shock wave energy, are measured in underwater explosion experiments. The formulation characteristics of the explosives involve the aluminum/oxygen (Al/O) ratio, aluminum particle size, and the total content of all solid components, including ammonium
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Continuous Detonation of CH 4 /H 2 –Air Mixtures in an Annular Combustor with Varied Geometry Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 F. A. Bykovskii, S. A. Zhdan, E. F. Vedernikov
Abstract Regimes of continuous detonation of CH4/H2–air mixtures with mass fractions of H2 in the fuel equal to 0–1/5 are obtained in an annular combustor 503 mm in diameter with variation of the combustor geometry. The influence of the combustor geometry on the velocity and number of transverse detonation waves, pressure in the combustor, and specific impulse is considered. It is found that three-fold
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Review on Advanced Energetic Materials for Insensitive Munition Formulations Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 M. Anniyappan, M. B. Talawar, R. K. Sinha, K. P. S. Murthy
Abstract Insensitive munitions are munitions that are chemically stable enough to withstand thermal, mechanical, or electrical stimuli during storage and transportation, and can still explode as intended to defeat their targets. Extensive programmes have evolved worldwide for the development and introduction of insensitive munitions (IMs). The use of insensitive energetic materials significantly improves
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Structure of Detonation Waves in Mixtures of Tetranitromethane with Nitrobenzene and Methanol Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 A. V. Utkin, V. M. Mochalova, A. M. Astakhov, V. E. Rykova, S. A. Koldunov
Abstract Experimental studies of the structure of detonation waves in mixtures of tetranitromethane with methanol and nitrobenzene have been performed. Particle velocity profiles at the arrival of detonation waves at the interface with a water window were measured by a laser interferometer. It has been shown that the flow pattern in the reaction zone changes sharply at a concentration of diluents in
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Influence of the Strength of the Charge Case on the Performance of Solid-Propellant Pulsating Explosive Devices Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 V. O. Solov’ev, N. M. Ovchinnikov, M. S. Kel’ner
Abstract This paper presents the results of an experimental study of the influence of the strength of the thin-walled case of a PETN charge on the performance of small-sized pulsating explosive devices for various applications.
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Thermodynamically Consistent Detonation Model for Solid Explosives Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 H. Zheng, M. Yu
Abstract An improved reactive flow model with thermodynamic consistency is proposed to deal with the detonation hydrodynamics of solid explosives. Based on the assumption that the chemical mixture composed of solid-phase reactants and gas-phase products can arrive at mechanical equilibrium, but cannot arrive at thermal equilibrium, the solid-phase reactants and gas-phase products may possess one pressure
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Effect of SiO 2 Content and Mechanical Activation on Ni–Al–SiO 2 Combustion Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 N. A. Kochetov, A. E. Sychev
Abstract This study describes the effect of preliminary mechanical activation and SiO2 quartz content on combustion rate, maximum combustion temperature, sample elongation during combustion, compressibility of mixtures, composite particle size, phase composition, and the structural features of combustion products in a Ni–Al–SiO2 system. In Ni–Al–SiO2 initial mixtures, not subjected to mechanical activation
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Evaluation of the Suppression Conditions for Combustion and Detonation Waves Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-11-11 A. A. Vasil’ev
Abstract Formulas based on conservation laws are proposed for evaluating the conditions for combustion and detonation waves using dust or water clouds. The formulas allow the determination of the minimum concentration of dust or atomized water droplets in a cloud and the minimum length of the cloud. Specific data on the conditions for quenching methane–air mixtures typical of coal mines are given.
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Effects of the Particle Size and Agglomeration on the Minimum Explosible Concentration and Flame Propagation Velocity in Dust Clouds Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 K. Ichinose, T. Mogi, R. Dobashi
Abstract The flame propagation behavior and the effect of particle agglomeration are examined by changing the size of PMMA particles in laboratory-scale experiments. PMMA particles having a very narrow size distribution are used. We show that the minimum explosible concentration increases as the particle size decreases. On the other hand, the flame propagation velocity also increases as the particle
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Thermochemical and Energy Characteristics of N-(2,2-bis(methoxy-NNO-azoxy)ethyl)nitramines Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 I. N. Zyuzin, D. B. Lempert, A. V. Nabatova, A. I. Kazakov
Abstract The standard enthalpies of formation of 1,1-bis(methoxy-NNO-azoxy)-3-nitro-3-azabutane and 1,1,8,8-tetrakis (methoxy-NNO-azoxy)-3,6-dinitro-3,6-diazaoctane were experimentally determined to be 87.7 \(\pm\) 3.9 and 283.8 \(\pm\) 6.2 kJ/mol, respectively. Calculations have shown that solid composite propellants containing these two compounds as gasifying components in metal-free compositions
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Kinetic Simulation of Unsteady Detonation with Thermodynamic Nonequilibrium Effects Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 C. Lin, K. H. Luo
Abstract Thanks to its mesoscopic kinetic nature, the discrete Boltzmann method has a capability of investigating unsteady detonation with essential hydrodynamic and thermodynamic nonequilibrium effects. In this work, an efficient and precise reactive discrete Boltzmann method is employed to investigate the impact of the amplitude and wave length of the initial perturbation, as well as of the chemical
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Radiative Extinction of Laminar Diffusion Flame above the Flat Porous Burner in Microgravity: A Computational Study Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 E. A. Kuznetsov, A. Yu. Snegirev, E. S. Markus
Abstract Transient dynamics of formation and extinction of methane- and ethylene-fueled flames above the flat porous burner in an oxidizing atmosphere is numerically investigated. The simulated scenarios replicate the experimental conditions of the BRE (Flamenco) project of the ACME program focusing on combustion research in microgravity. The 3D unsteady model includes the multi-step and multi-component
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Effect of Particle Size on Boron Combustion in Air Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 A. P. Shpara, D. A. Yagodnikov, A. V. Sukhov
Abstract Mathematical modeling of combustion of micron-sized and nanometer boron particles in air with allowance for changes in the heat and mass transfer mechanism and a decreasing particle size is carried out. The Knudsen number is taken as an indicator of a transition from one state to another: a continuous medium assumption is valid for describing the heat and mass transfer mechanisms in the case
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Calculation of Shock Waves in an Explosion of a Liquid Gas Pressure Reservoir Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 S. E. Yakush
Abstract Rapid phase transitions occurring with a sharp increase in a specific volume can be accompanied by explosive gas-dynamic phenomena. A model is presented for calculating shock waves generated in the atmosphere during an explosion of a liquid gas pressure reservoir, based on the assumption of a thermodynamically equilibrium state of a vapor–liquid mixture in which both vapor and liquid have
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Ignition Delay of Fluorinated Ethylene Propylene Wire Insulation in a Forced Flow Field in Microgravity Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 K. Wang, J. Fang, J.-W. Wang, S.-M. Zheng, J.-F. Guan, H. R. Shah, J.-J. Wang, Y.-M. Zhang
Abstract Fluorinated ethylene propylene (FEP) wire insulation ignition is investigated in a forced flow field in microgravity and normal gravity with a continuous current. First, FEP insulation melts and decomposes, causing jet bursting in both normal gravity and microgravity. Second, the forced flow and gravity produce minor effects on the core heating and bursting time, while the pyrolysis time increases
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Study of Shock-Compressed Argon Plasma Using Microwave Diagnostics Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 E. N. Bogdanov, M. V. Zhernokletov, G. A. Kozlov, A. V. Rodionov
Abstract A microwave diagnostics method and radio interferometers with wavelengths of 3.2 and 2.1 mm are used to study the kinematic and electrophysical characteristics of shock-compressed argon plasma, which is initially at atmospheric pressure. This research study is carried out at pressures of 12–56 MPa, shock wave velocities of 3.1–6.2 km/s, temperatures 9000–19 000 K, and densities 0.006–0.012 g/cm3
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On the Nature of the Synergistic Effect in Flames of Methane and Formaldehyde Mixtures with Air Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 V. M. Shvartsberg, V. A. Bunev
Abstract This paper deals with the nature of the synergistic effect in flames of methane and formaldehyde mixtures with air. Combustion of mixtures of different fuels is of great practical and fundamental interest. It has been found that the addition of formaldehyde to a rich methane/air flame at a constant concentration of methane first reduces the flame speed and then begins to increase it. The synergism
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Explosive Shaped Projectors for Forming High-Velocity Compact Elements Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 S. I. Gerasimov, D. V. Malyarov, A. G. Sirotkina, S. A. Kapinos, A. P. Kalmykov, A. S. Knyazev
Abstract This study presents a review of high-velocity projection methods and devices intended for the experimental study of the protection of equipment and structures from a high-velocity impact by compact elements, particularly protecting spacecrafts from collision with natural meteorite particles. Explosive projectors used in experiments to test protective structures at high impact velocities are
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Radiative Fraction and Flame Length of Propane Jet Diffusion Flames in a Crossflow Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 J.-W. Wang, J. Fang, J.-F. Guan, L.-Y. Zhao, S.-B. Lin, H. R. Shah, Y.-M. Zhang, J.-H. Sun
Abstract Many industrial combustion devices rely on jet flame combustion in the crossflow to achieve mixing and reaction. Previous research offers a limited predictive capability regarding the coupling effects of the crossflow and jet flow on the flame radiative fraction. In this work, a new theoretical equation is derived to relate the radiative fraction to the fuel flow rate and the crossflow velocity
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Effects of Inert Particulate Additives on Ignition and Flame Propagation in Dust–Air Mixtures Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 K. Hüttenbrenner, H. Kern, S. Tomasch, H. Raupenstrauch
Abstract Non-combustible solid materials play a major role as inerting agents in explosion prevention. While the importance and application of these materials are well understood, there is still a lack of information about the actual mechanisms responsible for explosion suppression. Especially, the role of inert materials with a large specific surface area and the influence of the moisture content
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Laminar Burning Velocity of the Dimethyl Carbonate–Air Mixture Formed by the Li-Ion Electrolyte Solvent Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-08-21 M. Henriksen, K. Vaagseather, A. V. Gaathaug, J. Lundberg, S. Forseth, D. Bjerketvedt
Abstract If a Li-ion cell fails and the electrolyte leaks out into air, a flammable premixed gas cloud can be formed. The electrolyte combustion energy is 65–70% of the total energy content of the cell. The main objective of this study is to determine the laminar burning velocity and the Markstein length for dimethyl carbonate and propane in a 20-liter explosion sphere with initial conditions at 100 kPa
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Temperature Measurement of the Shaped-Charge Jet from a Conical Liner Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 V. V. Pai, V. M. Titov, Ya. L. Luk’yanov, K. M. Zubashevskii
Abstract To measure the temperature of shaped-charge jets, we fabricated three-layer copper–copper–Constantan liners consisting of a solid copper conical shell with a cone angle of 45° and a wall 1.5 mm thick and a shell pressed into it and rolled from a 1.0 mm thick copper sheet clad on the inside with a Constantan layer 0.5 mm thick by explosive welding. Then, the Constantan layer was partially removed
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Thermochemical and Energy Characteristics of Symmetric Nitro and Azido Derivatives of Diazen-Ter-Furazans Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 D. B. Lempert, A. I. Kazakov, V. S. Sannikov, A. V. Nabatova, D. V. Dashko, A. I. Stepanov
Abstract The heat of combustion and enthalpy of formation of bis(4\(''\)-nitro[3,3\('\):4\('\),3\(''\)]terfurazan-4-yl)-diazene (DNFNF) and (bis(4\(''\)-azido-[3,3\('\):4\('\),3\(''\)]terfurazan-4-yl)-diazene (DAzFNF) were first experimentally determined. It is found that the energy increment for replacing the nitro group with an azide group in the furazan cycle averages 290 kJ/mol and is close to
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Critical Conditions and Induction Time of Ignition for a Methane–Air Mixture Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 O. B. Kudryashova, Yu. A. Galenko, E. V. Sypin, M. O. Sysoeva
Abstract Combustion and ignition processes are considered from the standpoint of the theory of thermal ignition and reaction kinetics. An analytical solution to the problem of thermal hotspot ignition is obtained to describe the ignition of reactive gas mixtures. As a result of this solution, the critical ignition conditions and induction time were determined. A solution to the problem of ignition
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Phase and Structural Transformations of Weld Metal under High-Velocity Impact Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 T. I. Tabatchikova, A. N. Morozova, N. A. Tereshchenko
Abstract The change in the structure of welds made with a new welding wire and subjected to high-velocity impact was investigated by optical and scanning electron microscopy and X-ray diffraction analysis. It is shown that after welding, a structure consisting of martensite, \(\delta\)-ferrite, and metastable austenite is formed in the weld metal. The subsequent severe impact leads to hardening of
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Mathematical Modeling of Crown Forest Fire Spread in the Presence of Fire Breaks and Barriers of Finite Size Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 V. A. Perminov, V. I. Marzaeva
Abstract The spread of crown forest fires in the presence of fire breaks and barriers of finite sizes was studied by mathematical modeling. Mathematically, this problem reduces to solving the Reynolds equations for turbulent flow taking into account chemical reactions. The control volume method was used to obtain a discrete analog. The fields of temperature, concentrations of oxygen and volatile pyrolysis
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Effect of Initial Temperature and Mechanical Activation on Synthesis in a Ti + Al System Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 N. A. Kochetov, B. S. Seplyarskii
Abstract Synthesis is carried out in a Ti + Al mixture prepared by two methods, namely preliminary mechanical activation (MA) or preheating. Synthesis occurs in the cases of layer-by-layer combustion (SHS) and thermal explosion. The dependences of burning rates of activated Ti + Al mixtures on the MA duration are investigated. The relationships between the initial temperature and the rates and maximum
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Numerical Simulation of Detonation Combustion of Kerosene Vapors in an Expanding Nozzle Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 Yu. V. Tunik, G. Ya. Gerasimov, V. Yu. Levashov, N. A. Slavinskaya
Abstract The initiation and stabilization of detonation combustion of kerosene vapor in a supersonic air flow entering an expanding axisymmetric nozzle with a coaxial central body is numerically studied. Calculations are based on a reduced kinetic model of combustion, which includes 68 reactions for 44 components. Enthalpy and entropy of components are determined using approximating polynomials from
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Thermal Explosion in a 2Co–Ti–Al System: Combustion, Phase Formation, and Properties Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 M. L. Busurina, A. E. Sychev, I. D. Kovalev, A. V. Karpov, N. V. Sachkova
Abstract Combustion and the formation of structures and phases in a 2Co–Ti–Al system during self-propagating high-temperature synthesis in a thermal explosion are under study. It is determined that a single-phase product (a Co2TiAl Geissler compound) can be obtained in this system. Morphology, microstructure, and physical-magnetic properties of combustion products of the system are investigated.
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Algebraic Model for Chemiluminescence Emissions Suitable for Using in Complex Turbulent Propane Flame Simulations Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 I. Lytras, E. P. Mitsopoulos, E. Dogkas, P. Koutmos
Abstract The work presents a simplified algebraic model for calculating the OH*, CH*, and CO\(_{2}^*\) concentrations within the context of reduced propane flame oxidation treatment. Excited and precursor species are obtained through post-processing of the basic simulation results, employing well-established quasi-steady state expressions produced from the detailed chemiluminescence kinetics. Inaccuracies
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Detonation of Ethylene– and Propylene–Oxygen Explosive Mixtures and Their Use in Detonation Spraying Technology Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 D. K. Rybin, V. Yu. Ul’yanitskii, I. S. Batraev
Abstract Gas detonation in ethylene– and propylene–oxygen explosive mixtures was studied over a wide range of equivalence ratio. Detonation parameters were calculated using the DETON code. The experiments were performed on an improved detonation facility in which the flow feed of the components of the explosive mixture and the intensification of deflagration-to-detonation transition (DDT) due to charge
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New Calculation Method for the Delay Time of the Heat Conduction Delay Element Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 Sh. Liu, X.-J. Qiao, Sh.-M. Shi, Y.-L. Miao, W.-N. Liu
Abstract In order to ensure the safety and reliability of weapons, it is very important to grasp the influence of the inside and outside diameters of the shell on the delay time. In this paper, a fluid–solid coupling model is established for a metal baffle-type delay element with a silicon-based delay composition. The combustion flow field of the delay element with the inside diameter of 3, 4, and
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Combustion of Water–Methanol Solution Droplets in the Flame of a Gas Burner Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 A. S. Naumkin, B. V. Borisov
Abstract Evaporation of a water–methanol solution droplet is experimentally studied. This process is mathematically modeled. Based on the results of a comparative analysis of the results of physical and numerical studies, the parameters of the evaporation of a water–methanol solution droplet are determined for the purpose of using its combustion in mathematical modeling. The results of numerical studies
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On the Kinetic Mechanism of Ignition of Diborane Mixtures with Air Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 A. M. Savel’ev, P. S. Kuleshov, B. I. Lukhovitskii, A. V. Pelevkin, V. A. Savel’eva, A. S. Sharipov
Abstract A reaction model is proposed for calculating the process of ignition of diborane mixtures with air. The model summarizes the previously developed kinetic models of oxidation of diborane, boron, as well as lower oxides and hydroxides of boron. A distinctive feature of the model is the use of physically grounded rate constants of the most important reaction channels, which were either computed
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Gas Bubble Dynamics in a Fluid with Chemical Reactions Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 K. O. Sabdenov
Abstract The formation and dynamics of a spherical gas bubble (from \(\approx1\)nm to 1 \(\mu\)m) in the liquid gasification zone of a solid high-energy material at high pressures is theoretically investigated. A simple model is proposed in which all thermodynamic parameters with the exception of fluid pressure and fluid velocity are independent of spatial variables. The stationary radius of bubbles
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Experimental Study of Deformation of Spheroplastics under Shock Compression Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 V. S. Ziborov, G. I. Kanel’, T. A. Rostilov
Abstract This paper describes an experimental study of the shock compression of samples simulating media with a given porosity using epoxy-based spheroplastics with filler made of glass microspheres with volume concentrations of 0.27 and 0.55. Shock adiabats in a pressure compression range of 0.1–1.2 GPa are obtained. The shock compression pressure at which the fracture of the used microspheres begins
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On the Structure of an Impact Jet with Flow Swirling and Combustion Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 D. K. Sharaborin, R. V. Tolstoguzov, V. M. Dulin, D. M. Markovich
Abstract The PIV and PLIF OH techniques were used to experimentally study the structure of a jet impinging on a flat obstacle with swirling and combustion of a propane–air mixture with an equivalence ratio of 0.7 for a nozzle–obstacle distance H/d = 1 and 3 and in the absence of the obstacle. The swirl ratio was 0.41 and 1.0, and the Reynolds number was 5 000. It is concluded that for both values of
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Combustion of Ferrotitanium in Nitrogen Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 A. A. Glazunov, Yu. M. Maksimov, L. N. Chukhlomina, B. Sh. Braverman, A. N. Avramchik
Abstract Combustion of FTi70 industrial ferrotitanium containing 65.9% Ti and a model alloy of iron with 30.6% Ti in nitrogen is described. It is shown that the degree of nitriding of the combustion products of industrial ferrotitanium is low. The distribution of nitrogen along the sample diameter is uneven. The dilution of the alloy with the final product increases in the degree of nitriding. The
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Development and Testing of the Laser System of Ignition of Rocket Engines Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 N. V. Pletnev, N. B. Ponomarev, G. A. Motalin, V. F. Murashov
Abstract This paper describes an experimental study pertaining to laser ignition of igniters of liquid rocket engines operating on such propellants as O\(_{2g}\) + kerosene, O\(_{2g}\) + ethanol, and O\(_{2g}\) + H\(_{2g}\), and to how they ignite the propellant of a model combustion chamber. A quartz fiber based optical device is described, which allows for multiple ignition of the igniter and the
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Prospects of Using Boron Powders As Fuel. II. Influence of Aluminum and Magnesium Additives and Their Compounds on the Thermal Behavior of Boron Oxide Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 A. N. Pivkina, D. B. Meerov, K. A. Monogarov, Yu. V. Frolov, N. V. Muravyev
Abstract Physicochemical changes occurring in an oxide shell of boron particles during heating are extremely important for the oxidation and combustion of boron, including those in solid propellant compositions. The Al2O3, MgO, MgF2, Al, and Mg impurities were experimentally discovered in an oxide layer on boron particles obtained by various methods. The goal of this work is to determine the effect
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Shock-Wave Initiation of a Thermite Mixture of Al + CuO Combust. Explos. Shock Waves (IF 0.84) Pub Date : 2020-07-24 S. Yu. Ananev, L. I. Grishin, A. Yu. Dolgoborodov, B. D. Yankovskii
Abstract The shock-wave initiation of chemical reaction in pressed pellets of a stoichiometric mixture of Al and CuO powders in a steel tube was studied. The dynamics of the chemical transformations in the heterogeneous flow of reaction products of the mixture with dispersion of the pressed pellet material in the unloading wave was investigated. From the results of pyrometric measurements, the maximum
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