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Combustion, Explosion and Shock Waves

2021 year, number 6

1.
Kerosene Combustion in a Pseudoshock with Varied Conditions at the Scramjet Combustor Model

P. K. Tretyakov, A. V. Tupikin, V. N. Zudov
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: combustor, supersonic combustion ramjet (scramjet), supersonic flow, wave structures, combustion in a pseudoshock

Abstract >>
Results of studying kerosene combustion in a pseudoshock with varied temperature and velocity at the scramjet combustor model are presented. Thermodynamic estimates show that either a supersonic or transonic flow can be retained over the combustor duct at parameters corresponding to the Mach number at the engine entrance М0 » 4.5. The possibility of the pseudoshock regime in the constant-section part of the combustor is experimentally studied in the case where the Mach number behind the inlet (at the combustor entrance) is М c > 1. Conditions of initiation and evolution of this combustion mode under a pulsed-periodic action on the flow are determined.



2.
Hedvall Effect in Self-Propagating High-Temperature Synthesis in Mechanically Activated Compositions

M. A. Korchagin1,2, A. I. Gavrilov1, D. V. Dudina1,3, B. B. Bokhonov1, N. V. Bulina1
1Institute of Solid State Chemistry and Mechanochemistry Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630128 Russia
2Novosibirsk State Technical University, Novosibirsk, 630073 Russia
3Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: Hedvall effect, self-propagating high-temperature synthesis, mechanical activation

Abstract >>
The Hedvall effect was implemented in self-propagating high-temperature synthesis (SHS) in two low-energy compositions TiNi + 1.1C and Ni3Al + 1.2Si using preliminary mechanical activation (MA) in an energy-intensive planetary ball mill. The dependences of the initiation temperature and the maximum reaction temperature on the MA time were obtained. The MA modes providing the solid-state mode of the self-propagating reaction were determined. The results of X-ray phase and electron microscopic examination of MA and SHS products are given.



3.
Combustion of Large Monolithic Titanium Particles in Air. I. Experimental Techniques, Burning Time and Fragmentation Modes

O. G. Glotov1,2, N. S. Belousova1,2, G. S. Surodin1
1Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Novosibirsk State Technical University, Novosibirsk, 630073 Russia
Keywords: titanium particle, titanium agglomerate, diameter, combustion in air, fragmentation, "star" fragmentation mode, "spruce branch" fragmentation mode, burning time, fragmentation time

Abstract >>
A technique for obtaining large burning monolithic titanium particles is described. The combustion of particles with a diameter of 120 ÷ 540 mm in free fall in air at atmospheric pressure is investigated. The burning time and the characteristic time of the beginning and end of fragmentation as a function of particle diameter are determined by processing video recordings of combustion of more than 250 particles. Two fragmentation modes are described. It is found that their occurrence depends on the diameter of the burning particle. The boundary particle size separating the modes is determined. It is shown that the fragmentation regularities and characteristic times for titanium agglomerates and monolithic particles of the indicated sizes differ slightly.



4.
Effect of Titanium Content and Mechanical Activation on Ni-Al-Ti Combustion

N. A. Kochetov
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, 142432 Russia
Keywords: combustion, mechanical activation, intermetallic compounds, nickel aluminide, titanium nickelide, titanium aluminide, Heusler phases

Abstract >>
This paper describes the effect of preliminary mechanical activation (MA) and Ti content on a maximum temperature, a maximum burning rate, the size of composite particles, the yield of a mixture after MA, the elongation of samples during combustion, and the phase composition and morphology of combustion products in the Ni-Ti-Al system. The preliminary MA of a Ni + Al + Ti mixture expands the limit of titanium content at which samples can burn without preheating, from 17 to 59 % (by weight). Mechanical activation reduces the number of phases in the products and increases the burning rate, while the maximum synthesis temperature decreases. An increase in the Ti content in the Ni + Al + Ti mixture reduces the rate and maximum combustion temperature of both the initial and MA mixture. In addition, as the titanium content increases, the average size of composite particles decreases and the yield of the activated mixture becomes larger. During the combustion of MA mixtures with a high (24 ÷ 52 %) titanium content, the Ti2Ni phase and the Ni2TiAl Heusler phase predominate in the products, and traces of melting are visually observed. In the activated Ni + Al + Ti mixture, the Ti content at which the content of the Heusler phase in the combustion products is maximum is revealed. For most of the observed dependences, an explanation is proposed.



5.
Effect of Compression Pressure on Combustion of Tapes Obtained by Rolling a Ti + 1.7B Powder Mixture

S. G. Vadchenko, D. S. Suvorov, O. K. Kamynina, N. I. Mukhina
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, 142432 Russia
Keywords: self-propagating high-temperature synthesis (SHS), combustion, reaction tapes, rolling, titanium, boron, pressure

Abstract >>
Combustion during self-propagating high-temperature synthesis of Ti + 1.7B reaction tapes obtained by rolling from a powder mixture is experimentally investigated. Dependences between the combustion wave propagation velocity in the reaction tapes and the applied pressure are revealed. It is shown that the burning rate of the tapes weakly depends on the compression pressure within 0.001 ÷ 4 MPa. At a compression pressure above 0.5 MPa, unreacted regions appear during the combustion of the tapes. The limiting pressure at which the combustion stops is determined as 12 MPa.



6.
Effect of Modification of Tetryl Detonation Nanodiamonds on Combustion of Model Paste-Like Propellants

S. Yu. Naryzhnyi, A. S. Kozlov, V. Yu. Dolmatov, V. V. Fomenko, G. V. Semashkin, V. A. Marchukov, S. V. Desyatov
Special Design and Technology Bureau "Tekhnolog", Saint-Petersburg, 192076 Russia
Keywords: propellant, composite propellant, paste-like propellant, detonation nanodiamonds, oxidizer modification, tetryl, burning rate, specific impulse

Abstract >>
Detonation nanodiamonds (DND) represent a unique material combining the properties of a rather passive diamond core with an active carbon shell. The effect of disaggregated DND (T-DND) and detonation carbon (diamond batch mixture (T-DBM)) obtained in an explosion of tetryl (2,4,6-trinitro-N-methyl-N-nitroaniline) and preliminary deposited onto ammonium perchlorate granules in the process of its crystallization on the burning rate of a paste-like propellant is studied. T-DND is preliminary cured at 430 °C for two hours. The method used in the present study is chemical deposition (forced crystallization) of ammonium perchlorate from a saturated aqueous solution also containing T-DND or T-DBM by isopropanol in the ratio of 1 : 2. The burning rates of compositions are determined as functions of pressure in the range up to 1 200 atm. It is demonstrated that the use of detonation nanodiamonds and diamond batch mixture leads to an increase in the propellant burning rate approximately by 26 and 15 %, respectively, while the temperature of combustion products decreases approximately by »240 °C at 100 atm.



7.
Effect of Particle Orientation on the Burning Rate of Ammonium-Perchlorate-Based Solid Propellants

S. Gallier, M. Plaud
ArianeGroup, Vert le Petit, 91710 France
Keywords: heterogeneous propellant, burning rate, hump effect (on the pressure-time curve), ammonium perchlorate

Abstract >>
This paper addresses the effect of oxidizer particle orientation on the burning rate of ammonium-perchlorate-based heterogeneous solid propellants. Mesoscale numerical simulations are conducted assuming that oxidizer particles are ellipsoidal and have different orientations with respect to the combustion direction. The particle orientation is found to produce a significant effect on the burning rate, up to 5 ÷ 10 % depending on the particle aspect ratio or particle loading. Particles aligned normal to the combustion surface are found to burn faster than those aligned parallel to this surface. This strong impact of the orientation can help explain the well-known hump effect in solid propulsion.



8.
Interruption of Detonation Wave Propagation in the Air-Gas Mixtures of Unitary Fuel as a Layer of Inhomogeneous Inert Particles

U. A. Nazarov
Samarkand State Architectural and Construction Institute, Samarkand, 703000 Uzbekistan
Keywords: combustion, detonation, detonation wave, unitary fuel, inert particles, mass particle content

Abstract >>
This paper describes the results of a numerical study pertaining to the interruption of detonation wave propagation in air-gas mixtures of unitary fuel as a layer of inhomogeneous inert particles. It is shown that the layer diameter, layer length, and the inhomogeneity of inert particles affect this process. It is revealed that, if the total mass of the mixture is fixed, a layer with a linearly decreasing concentration of inert particles attenuates detonation waves much better than that a linearly increasing and uniform concentration of inert particles.



9.
Wave Absorption Properties of Co-C Nanoparticles Prepared by the Gaseous Detonation Method

T.-J. Zhao1,2,3, X.-H. Wang2, S. Kang1, Z.-F. Wang1, H.-H. Yan2
1Henan University, Kaifeng, 475004 China
2Dalian University of Technology, Dalian, 116024 China
3Henan Provincial Research Center of Engineering on Intelligent Construction of Rail Transit, Kaifeng, 475004 China
Keywords: gaseous detonation, wave absorption, Co-C nanoparticles, impedance matching

Abstract >>
Co-C nanoparticles are synthesized via the detonation of benzene and oxygen with cobalt(III) acetylacetonate as a precursor, and the influence of heat treatment on their physical performances is explored. The results indicate that the crystallinity and degree of graphitization of Co-C nanoparticles are dramatically improved after heat treatment, and the impedance matching degree also increases significantly. The wave absorption property is enhanced by more than six times, and the minimum reflection loss is -17.5 dB at 16.98 GHz. The impedance mismatching is the main reason for the poor wave absorption of original Co-C nanoparticles. The temperature plays an important role in the impedance matching degree and wave absorption performance, and a heat-treated process can be a useful way to solve impedance mismatching of Co-C nanoparticles prepared by gaseous detonation.



10.
Length of the Pre-Detonation Segment in Phlegmatized HMX Samples as a Function of the Velocity and Size of a Spherical Impactor

G. V. Belov, A. A. Sedov, I. V. Oleinikov, N. I. Shustova, A. V. Kudashov, A. V. Shishkanov, E. S. Mitin, G. A. Kozlov, I. N. Poroshin, M. A. Tyapin, A. N. Tyurin, A. M. Gruzdev
Institute of Experimental Physics, Russian Federal Nuclear Center, Sarov, 607188 Russia
Keywords: phlegmatized HMX, impactor, detonation, pre-detonation segment

Abstract >>
Experimental results on the parameters of detonation process formation in phlegmatized HMX as functions of the velocity and size of spherical impactors are reported. Data on the threshold velocity of the impactor resulting in detonation initiation and on the length of the pre-detonation segment in the velocity range from 882 to 1 333 m/s are obtained. The results are compared with available experimental data on the length of the pre-detonation segment for plane shock waves. The radio interferometry method of registration of the evolution of the explosion process initiated by the impactor is demonstrated to be fairly informative.



11.
Influence of Aluminum Additive on the Detonation Velocity and Propulsive Capability of an Emulsion Explosive

A. S. Yunoshev1,2, A. V. Plastinin1, M. S. Voronin1,3
1Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Novosibirsk State University, Novosibirsk, 630090 Russia
3Novosibirsk State Technical University, Novosibirsk, 630073 Russia
Keywords: emulsion explosive, propulsive capability, aluminized explosive

Abstract >>
The detonation velocity and propulsive capability of an aluminized emulsion explosive sensitized by Expancel polymer microballoons was measured. The density of the investigated explosive compositions was 0.2 ÷ 1.4 g/cm3, and the mass content of aluminum powder was 0 ÷ 0.29. The propulsive capability was measured using the cylinder expansion test.



12.
Simple Model for Predicting Detonation Velocity of Organic, Inorganic, and Mixed Explosives

S. P. Sivapirakasam1, N. Venu Kumar1, G. Jeyabalaganesh1, K. Nagarjuna2
1National Institute of Technology, Tiruchirappalli, Tamil Nadu, India 620015
2University of Hyderabad, Hyderabad, India 500046
Keywords: detonation velocity, detonation products, heat of reaction

Abstract >>
In this study, a new model based on a single equation is developed for estimating the detonation velocity of any organic/inorganic explosives. The new model is based on adaptation of feasible rules, oxygen balance, and heat of reaction for identification of detonation products. The final results of the new model for the detonation velocity are in good agreement with available experimental values, as well as with the Becker-Kistiakowsky-Wilson model values of the EXPLO5 software and with results obtained by other methods. The results reveal the minimum relative deviation percentage error for all the organic, inorganic, and mixed explosives as compared to other models. Therefore, the newly developed simple model and rules will be useful for a scientist/chemist to predict the detonation velocity of any new explosives without depending upon expensive computer codes.



13.
Temperature of Polymethyl Methacrylate in the Secondary Shock Wave

S. A. Bordzilovskii1, M. S. Voronin1,2, S. M. Karakhanov1
1Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Novosibirsk State Technical University, Novosibirsk, 630073 Russia
Keywords: polymethyl methacrylate, reflected shock wave, equation of state, pyrometry

Abstract >>
The brightness temperature of polymethyl methacrylate loaded by a shock wave reflected from a transparent LiF or sapphire window was measured by a pyrometric method. The pressure range in the primary wave was 20 ÷ 40 GPa, and that in the reflected wave was 30 ÷ 78 GPa. At the intensity of the primary shock wave in the range of low pressures (19.2 ÷ 20.8 GPa), the temperature values in the reflected wave lie on a single Hugoniot within the experimental error, as opposed to what might be expected from the gas-dynamic calculation for the case of loading by two shock waves. As the primary shock wave pressure increases to 38 ÷ 41 GPa, the reflected wave temperature ((2.4 ÷ 2.6) · 103 K) becomes smaller than on the single Hugoniot (3.1 · 103 K), but remain larger than those calculated by the equation of state (2.3 · 103 K) under the assumption that the composition of polymethyl methacrylate is inert. It is concluded that this form of the temperature dependence is due to the depolymerization and subsequent decomposition of polymethyl methacrylate.



14.
Sound Velocity in Natural Shock-compressed Uranium in a Pressure Range of 20 - 260 GPa

D. G. Pankratov, A. K. Yakunin, A. G. Poptsov, D. T. Yusupov
All-Russian Scientific Research Institute of Technical Physics, Snezhinsk, 456770 Russia
Keywords: natural uranium, sound velocity, phase transition, shock-wave loading, manganin sensor method, indicator method

Abstract >>
This paper presents the results of sound velocity measurements performed in natural uranium during the high-rate deformation of sound in α- and γ-phase regions, as well as in the melting region at the shock front. The processes are recorded using the manganin sensor method (range 20 ÷ 110 GPa) and the indicator method (range 70 ÷ 260 GPa). In the region of the solid uranium phase, changes in Poisson's ratio, Young's modulus, bulk modulus, and shear modulus along the uranium shock adiabat are determined.



15.
Effect of Controlled Perturbations on Buckling of a Conical Liner During Shaped-Charge Jet Formation

Ya. L. Luk'yanov, V. V. Pai
Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: charge shaping process, liner buckling, controlled perturbations

Abstract >>
The influence of controlled perturbations on the buckling of conical liners during their explosive compression is under study. In this case, there is folding on the inner surface of the liners, oriented along the generatrix of the cone. It is revealed that, as the Reynolds number increases, so does the number of fold, while the geometric dimensions of experimental devices remain the same. It is shown that scratching on the inner surface of the cladding makes it possible to control its buckling process.