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Articoli di riviste sul tema "Flame-shock interaction"

Autore: Grafiati

Pubblicato: 29 marzo 2025

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1

Dong, G., B. Fan, M. Gui e B. Li. "Numerical simulations of interactions between a flame bubble with an incident shock wave and its focusing wave". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, n. 10 (29 giugno 2009): 2357–67. http://dx.doi.org/10.1243/09544062jmes1467.

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The numerical investigations of interactions between a flame bubble with an incident shock wave (IW) and its focusing wave (FW) in a reactive CH4—O2—N2 mixture are presented. The time-dependent, two-dimensional axisymmetric, reactive Navier—Stokes equations, with detailed chemical mechanisms, are employed to simulate the multiple shock—flame interactions process. The effects of the IW Mach number and chemical reactivity of mixture on flame structure and evolution are examined. The results of simulations show that the initial flame bubble can interact with IW, bow wave (BW), reflected BW, and FW in sequence. For the weak IW case, the repeated shock—flame interactions produce multiple Richtmyer—Meshkov (RM) instabilities that lead to the convolved flame with vortex structures, and the chemical heat release does not play a major role. While for the strong IW case, the multiple RM instabilities lead to the highly distorted flame with the complex vortices structures of large magnitude. With the lower reactive mixture, the instability process is the major mechanism for shock—flame interaction, while the chemistry only plays a minor role. However, with the higher reactive mixture, the distorted flame expands rapidly and finally forms the large-scale combustion through the interaction with FW. Both instability and chemical heat release play the important mechanisms in this case. The combustion acceleration in the highly reactive mixture can produce the stronger overpressure and the higher propagation speed of complex FW because of the chemi-acoustic interaction effect.

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2

Ju, Yiguang, Akishi Shimano e Osamu Inoue. "Vorticity generation and flame distortion induced by shock flame interaction". Symposium (International) on Combustion 27, n. 1 (gennaio 1998): 735–41. http://dx.doi.org/10.1016/s0082-0784(98)80467-0.

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3

Lutoschkin, E., M. G. Rose e S. Staudacher. "Pressure-Gain Combustion Using Shock–Flame Interaction". Journal of Propulsion and Power 29, n. 5 (settembre 2013): 1181–93. http://dx.doi.org/10.2514/1.b34721.

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4

Yarkov, Andrey, Ivan Yakovenko e Alexey Kiverin. "Mechanism of Spontaneous Acceleration of Slow Flame in Channel". Fire 7, n. 10 (10 ottobre 2024): 362. http://dx.doi.org/10.3390/fire7100362.

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This paper is devoted to the numerical analysis of the spontaneous acceleration of a slow flame in a semi-closed channel. In particular, the flow development in the channel ahead of the propagating flame is analyzed. The applied detailed numerical model allows the clear observation of all features intrinsic to the reacting flow evolution in the channel, including the formation of perturbations on the scale of the boundary layer and their further development. In all considered cases, perturbations of the boundary layer emerge in the early stages of flame acceleration and decay afterward. The flow stabilizes more rapidly in a narrow channel, where the velocity profile is close to the Poiseuille profile. At the same time, the compression waves generated in the reaction zone travel along the channel. The interaction between compression waves in the area of combustion products can lead to the formation of shock waves. The effect of shock waves on the flow in the fresh mixture causes an increase in the flame area and a corresponding flame acceleration. In addition, shock waves trigger boundary-layer instability in wide channels. The perturbations of the boundary layer grow and evolve into vortexes, while further vortex–flame interaction leads to significant flame acceleration.

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5

KHOKHLOV, A., E. ORAN, A. CHTCHELKANOVA e J. WHEELER. "Interaction of a shock with a sinusoidally perturbed flame". Combustion and Flame 117, n. 1-2 (aprile 1999): 99–116. http://dx.doi.org/10.1016/s0010-2180(98)00090-x.

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6

Fan, E., Weizong Wang e Tianhan Zhang. "Numerical investigation on flame dynamic and regime transitions during shock-cool flame interaction". Combustion and Flame 273 (marzo 2025): 113928. https://doi.org/10.1016/j.combustflame.2024.113928.

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7

Thomas, Geraint, Richard Bambrey e Caren Brown. "Experimental observations of flame acceleration and transition to detonation following shock-flame interaction". Combustion Theory and Modelling 5, n. 4 (dicembre 2001): 573–94. http://dx.doi.org/10.1088/1364-7830/5/4/304.

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8

Roy, Christopher J., e Jack R. Edwards. "Numerical Simulation of a Three-Dimensional Flame/Shock Wave Interaction". AIAA Journal 38, n. 5 (maggio 2000): 745–54. http://dx.doi.org/10.2514/2.1035.

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9

Ivanov, M. F., e A. D. Kiverin. "Generation of high pressures during the shock wave–flame interaction". High Temperature 53, n. 5 (settembre 2015): 668–76. http://dx.doi.org/10.1134/s0018151x15030086.

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10

Johnson, R. G., A. C. McIntosh, J. Brindley, M. R. Booty e M. Short. "Shock wave interaction with a fast convection-reaction driven flame". Symposium (International) on Combustion 26, n. 1 (gennaio 1996): 891–98. http://dx.doi.org/10.1016/s0082-0784(96)80299-2.

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11

Roy, Christopher J., e Jack R. Edwards. "Numerical simulation of a three-dimensional flame/shock wave interaction". AIAA Journal 38 (gennaio 2000): 745–54. http://dx.doi.org/10.2514/3.14476.

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12

Yu, Ke, Yong Hu, Chunyan Gao e Yong Jiang. "Investigation into the Suppression Effect of Water Mist on the Self-ignition and Flame Propagation of High-pressure Hydrogen Release". Journal of Physics: Conference Series 2860, n. 1 (1 ottobre 2024): 012001. http://dx.doi.org/10.1088/1742-6596/2860/1/012001.

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Abstract The self-ignition accident of pressurized hydrogen leakage is regarded as one of the big potential risks in its wide utilization. In this work, a detailed investigation into the suppression effect of water mist on the hydrogen self-ignition and flame propagation is performed. A parametric study of the effect of water concentration and droplet size on flame dynamic is conducted. The results show that the fine water mist effectively reduces the shock-heating temperature, significantly prolonging the ignition time and distance. The water droplets have a direct contact with the fast growing flame, which leads to more intense two-phase interaction that results in the decoupling of shock wave from the leading flame and a more pronounced bimodal flame structures. The droplet size is found to have small effect when the water concentration is low, and the mist with a medium size of 50 μm shows a better inhibitory performance.

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13

Clarke, J. F. "Comment on ‘Experimental observation of flame acceleration and transition to detonation following shock–flame interaction’". Combustion Theory and Modelling 6, n. 3 (settembre 2002): 523–25. http://dx.doi.org/10.1088/1364-7830/6/3/401.

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14

Iwata, Kazuya, Sou Suzuki, Reo Kai e Ryoichi Kurose. "Direct numerical simulation of detonation–turbulence interaction in hydrogen/oxygen/argon mixtures with a detailed chemistry". Physics of Fluids 35, n. 4 (aprile 2023): 046107. http://dx.doi.org/10.1063/5.0144624.

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Direct numerical simulation is conducted to address the detonation–turbulence interaction in a stoichiometric hydrogen/oxygen/argon mixture. The argon dilution rate is varied so that the mixture composition is 2H2 + O2 + 7Ar and 2H2 + O2 + Ar to discuss the effects of cell regularity on the sensitivity to turbulence. Turbulent Reynolds number and turbulent Mach number are taken to be common for both mixtures. The results show that the shock and flame of detonation in both mixtures are significantly deformed into corrugated ones in the turbulent flow, producing many small unburned gas pockets. However, one-dimensional time-averaged profiles reveal the different sensitivity of the mixtures: in the highly diluted mixture (2H2 + O2 + 7Ar), the reaction progress is not much influenced by turbulence, whereas in the less-diluted mixture (2H2 + O2 + Ar), the reaction takes place more rapidly with turbulence. Analysis of the properties of turbulence and turbulent fluctuations in the detonations clarifies that the direct contribution of turbulence to the flame front is weaker; there is no clear correlation between the heat release and the curvature of the flame. On the other hand, a broader Mach number distribution just upstream of the shock front creates more hot spots in the less-diluted mixture, which results in a shorter induction length. These results indicate that the main contribution of turbulence is creation of different shock strength, which could lead to different reaction rates depending on the cell regularity.

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15

Huang, Jin, Xiangyu Gao e Cheng Wang. "Flame acceleration and deflagration-to-detonation transition in narrow channels with thin obstacles". Modern Physics Letters B 32, n. 29 (20 ottobre 2018): 1850354. http://dx.doi.org/10.1142/s0217984918503542.

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The entire process of deflagration-to-detonation transition (DDT) in narrow channels with thin obstacle configurations is studied through high-resolution simulations. The results show that the confinement and disturbance of obstacles promote considerably the flame acceleration and DDT. There exist two modes of DDT associating with obstacle spacing S. For small spacing S, the flame acceleration depends on strong confinement and jet flow between obstacles; eventually DDT occurs due to early burning amplified by shocks in front of the flame. However, for large spacing S, the flame acceleration is mainly attributed to turbulence; DDT results from the interaction of reflection shock with turbulent flame. It is found that the run-up distance of DDT in the obstructed channels shortens significantly, as compared with that in the smooth channel.

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16

Thomas, G. O., R. J. Bambrey e C. J. Brown. "Reply to Comment on ‘Experimental observations of flame acceleration and transition to detonation following shock–flame interaction’". Combustion Theory and Modelling 6, n. 3 (settembre 2002): 527–28. http://dx.doi.org/10.1088/1364-7830/6/3/402.

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17

Giannuzzi, P. M., M. J. Hargather e G. C. Doig. "Explosive-driven shock wave and vortex ring interaction with a propane flame". Shock Waves 26, n. 6 (29 febbraio 2016): 851–57. http://dx.doi.org/10.1007/s00193-016-0627-2.

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18

Wei, Haiqiao, Jianfu Zhao, Xiaojun Zhang, Jiaying Pan, Jianxiong Hua e Lei Zhou. "Turbulent flame–shock interaction inducing end-gas autoignition in a confined space". Combustion and Flame 204 (giugno 2019): 137–41. http://dx.doi.org/10.1016/j.combustflame.2019.03.002.

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19

Doig, Graham, Zebulan Johnson e Rachel Mann. "Interaction of shock tube exhaust flow with a non-pre-mixed flame". Journal of Visualization 16, n. 3 (26 giugno 2013): 173–76. http://dx.doi.org/10.1007/s12650-013-0166-1.

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20

Gui, Mingyue, Baochun Fan, Gang Dong e Jingfang Ye. "Interaction of a reflected shock from a concave wall with a flame distorted by an incident shock". Shock Waves 18, n. 6 (12 novembre 2008): 487–94. http://dx.doi.org/10.1007/s00193-008-0177-3.

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21

Wei, Haiqiao, Zailong Xu, Lei Zhou, Dongzhi Gao e Jianfu Zhao. "Effect of initial pressure on flame–shock interaction of hydrogen–air premixed flames". International Journal of Hydrogen Energy 42, n. 17 (aprile 2017): 12657–68. http://dx.doi.org/10.1016/j.ijhydene.2017.03.099.

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22

MAEDA, Shinichi, Yuki KURAMOCHI, Ryo ONO e Tetsuro OBARA. "Detonation transition process caused by interaction of convex flame with planar shock wave". Transactions of the JSME (in Japanese) 83, n. 850 (2017): 17–00049. http://dx.doi.org/10.1299/transjsme.17-00049.

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23

Picone, J. M., e J. P. Boris. "Vorticity generation by shock propagation through bubbles in a gas". Journal of Fluid Mechanics 189 (aprile 1988): 23–51. http://dx.doi.org/10.1017/s0022112088000904.

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Abstract (sommario):

We present a new theoretical model of ‘late-time’ phenomena related to the interaction of a planar shock with a local, discrete inhomogeneity in an ambient gas. The term ‘late-time’ applies to the evolution of the inhomogeneity and the flow field after interaction with the incident shock has ceased. Observations of a shock propagating through a bubble or a spherical flame have exhibited or implied the formation of vortex structures and have showed continual distortion of the bubble or flame. Our theory shows that this is due to the generation of long-lived vorticity at the edge of the discrete inhomogeneity. The vorticity interacts with itself through the medium of the fluid, and, depending on the geometry of the discrete inhomogeneity, can roll up into vortex filaments or vortex rings. To verify and amplify this theoretical description, we use numerical solutions of the fluid equations for conservation of mass, momentum, and energy to study the interaction of a weak shock with a cylindrical or spherical bubble. The simulated bubble has either a higher or lower density than the ambient gas. In this way, the calculations provide insights into the effects of both geometry and distortion of the local sound speed. The Mach number of the shock is 1.2, the ambient gas is air, and the pressure is 1 atmosphere. Because of the simple geometry of each bubble, the vorticity generated at the boundary rolls up into a vortex filament pair (cylindrical bubble) or a vortex ring (spherical bubble). The structural features and timescales of the phenomena observed in the calculations agree closely with recent experiments of Haas & Sturtevant, in which helium and Freon bubbles were used to provide the local departures from ambient density. The discussion of results includes a survey of alternative numerical methods, sources of uncertainty in velocities of interfaces or structures, as derived from the laboratory and numerical experiments, and the relationship of our analysis to other theories.

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24

Лобода, Е. Л., М. В. Агафонцев e А. А. Старосельцева. "Detonation processes in the combustion front of plant combustible materials". Pozharnaia bezopasnost`, n. 1(110) (15 marzo 2023): 27–34. http://dx.doi.org/10.37657/vniipo.pb.2023.110.1.002.

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Представлены результаты экспериментального исследования воздействия ударной волны на пламя при горении растительных горючих материалов. Ударная волна формировалась с помощью ударной трубы с различными насадками и источником энергии от порохового заряда. Для регистрации воздействия ударной волны на зону пиролиза применялись методы высокоскоростной ИК термографии в узкополосном диапазоне длины волны 2,5–2,7 мкм. Установлено, что при применении расширяющихся насадков в результате воздействия ударной волны на зону пиролиза происходит детонация продуктов пиролиза, которая приводит к прекращению пламенного горения. Much attention is currently being paid worldwide to improvement of existing and developing new effective ways to fight effectively natural fires, which occur annually in different countries and on a variety of landscapes. Given the annual increase in the number of wildfires and the often catastrophic consequences from them, it can be stated that the existing methods of firefighting are not effective enough. The methods used to extinguish large fires are usually based on the discharge of water by aircraft and the involvement of a large amount of manual labor of firefighters. This work is devoted to the study of the issue of extinguishing a natural fire by the impact of a shock wave on the burning zone. At present, the question of the interaction of the compaction shockwave with the flame during the combustion of plant combustible materials remains practically unstudied. Existing works in the field of shock waves impact on the fire front are limited to estimates of disruption of combustion conductors and formation of mineralized band. Modern research tools and methods allow to record and visualize the rapid processes, including in the flame. In particular, modern methods of infrared thermography make it possible to study both the temperature field in the flame and the structure of flow in it. Based on the original methods and approaches for application of high-speed infrared thermography developed at Tomsk State University, this work presents the results of an experimental study of the shock wave effect on the flame during combustion of plant flammable materials. A shock tube with different nozzles and an energy source from a gunpowder charge were used to form the shock wave. The impact of the shock wave on the pyrolysis zone was recorded in the narrow band infrared wavelength range of 2.5–2.7 μm. It has been established that the impact of the shock wave on the pyrolysis zone, when expanding nozzles are used, results in the detonation of pyrolysis products, which leads to the cessation of flame combustion and subsequent decrease in the surface temperature of plant combustibles below the autoignition temperature. This effect leads to a break in the chain of transformation and energy release during combustion. The obtained result should be considered as a fundamental basis for the development of new effective means of extinguishing large natural fires based on the impact of a shock wave.

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25

Gamba, Mirko, e M. Godfrey Mungal. "Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow". Journal of Fluid Mechanics 780 (3 settembre 2015): 226–73. http://dx.doi.org/10.1017/jfm.2015.454.

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We have investigated the properties of transverse sonic hydrogen jets in high-temperature supersonic crossflow at jet-to-crossflow momentum flux ratios$J$between 0.3 and 5.0. The crossflow was held fixed at a Mach number of 2.4, 1400 K and 40 kPa. Schlieren and$\text{OH}^{\ast }$chemiluminescence imaging were used to investigate the global flame structure, penetration and ignition points;$\text{OH}$planar laser-induced fluorescence imaging over several planes was used to investigate the instantaneous reaction zone. It is found that$J$indirectly controls many of the combustion processes. Two regimes for low (${<}1$) and high (${>}3$)$J$are identified. At low$J$, the flame is lifted and stabilizes in the wake close to the wall possibly by autoignition after some partial premixing occurs; most of the heat release occurs at the wall in regions where$\text{OH}$occurs over broad regions. At high$J$, the flame is anchored at the upstream recirculation region and remains attached to the wall within the boundary layer where$\text{OH}$remains distributed over broad regions; a strong reacting shear layer exists where the flame is organized in thin layers. Stabilization occurs in the upstream recirculation region that forms as a consequence of the strong interaction between the bow shock, the jet and the boundary layer. In general, this interaction – which indirectly depends on$J$because it controls the jet penetration – dominates the fluid dynamic processes and thus stabilization. As a result, the flow field may be characterized by a flame structure characteristic of multiple interacting combustion regimes, from (non-premixed) flamelets to (partially premixed) distributed reaction zones, thus requiring a description based on a multi-regime combustion formulation.

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26

Gao Dongzhi, 高东志, 卫海桥 Wei Haiqiao, 周. 磊. Zhou Lei, 刘丽娜 Liu Lina, 赵健福 Zhao Jianfu e 徐在龙 Xu Zailong. "Experimental study of flame-shock wave interaction and cylinder pressure oscillation in confined space". Infrared and Laser Engineering 46, n. 2 (2017): 239004. http://dx.doi.org/10.3788/irla201746.0239004.

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Gao Dongzhi, 高东志, 卫海桥 Wei Haiqiao, 周. 磊. Zhou Lei, 刘丽娜 Liu Lina, 赵健福 Zhao Jianfu e 徐在龙 Xu Zailong. "Experimental study of flame-shock wave interaction and cylinder pressure oscillation in confined space". Infrared and Laser Engineering 46, n. 2 (2017): 239004. http://dx.doi.org/10.3788/irla20174602.239004.

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28

Pandey, Krishna Murari, e Sukanta Roga. "CFD Analysis of Hypersonic Combustion of H₂-Fueled Scramjet Combustor with Cavity Based Fuel Injector at Flight Mach 6". Applied Mechanics and Materials 656 (ottobre 2014): 53–63. http://dx.doi.org/10.4028/www.scientific.net/amm.656.53.

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This paper presents a numerical analysis of the inlet-combustor interaction and flow structure through a scramjet engine at a flight Mach 6 with cavity based injection. Fuel is injected at supersonic speed of Mach 2 through a cavity based injector. These numerical simulations are aimed to study the flow structure, supersonic mixing and combustion for cavity based injection. For the reacting cases, the shock wave pattern is modified which is due to the strong heat release during combustion process. The shock structure and combustion phenomenon are not only affected by the geometry but also by the flight Mach number and the trajectory. The inlet-combustor interaction is studied with a fix location of cavity based injection. Cavity is of interest because recirculation flow in cavity would provide a stable flame holding while enhancing the rate of mixing or combustion. The cavity effect is discussed from a view point of mixing and combustion efficiency.

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29

Rakotoarison, Willstrong, Andrzej Pekalski e Matei I. Radulescu. "Detonation transition criteria from the interaction of supersonic shock-flame complexes with different shaped obstacles". Journal of Loss Prevention in the Process Industries 64 (marzo 2020): 103963. http://dx.doi.org/10.1016/j.jlp.2019.103963.

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30

Goldfeld, Marat, e Alexey Starov. "Scheme of Hydrogen Ignition in Duct with Shock Waves". Siberian Journal of Physics 9, n. 2 (1 giugno 2014): 116–27. http://dx.doi.org/10.54362/1818-7919-2014-9-2-116-127.

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In article results of the analysis of processes of self-ignition and combustion propagation are given in the multi-injector combustion chamber with high supersonic speeds of an air flow. It is established that fuel ignition at high Mach numbers, bringing to flame propagation on all volume of combustor and combustion stabilization, happens not in recirculation area behind a step, and in the field of interaction of shock waves with an boundary layer on walls or behind this area downstream near an angular point of the combustion chamber. The scheme of development of process of combustion in the combustion chamber with significantly three-dimensional configuration is in details considered

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31

Hora, H., G. H. Miley, K. Flippo, P. Lalousis, R. Castillo, X. Yang, B. Malekynia e M. Ghoranneviss. "Review about acceleration of plasma by nonlinear forces from picoseond laser pulses and block generated fusion flame in uncompressed fuel". Laser and Particle Beams 29, n. 3 (settembre 2011): 353–63. http://dx.doi.org/10.1017/s0263034611000413.

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AbstractIn addition to the matured “laser inertial fusion energy” with spherical compression and thermal ignition of deuterium-tritium (DT), a very new alternative for the fast ignition scheme may have now been opened by using side-on block ignition aiming beyond the DT-fusion with igniting the neutron-free reaction of proton-boron-11 (p-11B). Measurements with laser pulses of terawatt power and ps duration led to the discovery of an anomaly of interaction, if the prepulses are cut off by a factor 108(contrast ratio) to avoid relativistic self focusing in agreement with preceding computations. Applying this to petawatt (PW) pulses for Bobin-Chu conditions of side-on ignition of solid fusion fuel results after several improvements in energy gains of 10,000. This is in contrast to the impossible laser-ignition of p-11B by the usual spherical compression and thermal ignition. The side-on ignition is less than ten times only more difficult than for DT ignition. This is essentially based on the instant and direct conversion the optical laser energy by the nonlinear force into extremely high plasma acceleration. Genuine two-fluid hydrodynamic computations for DT are presented showing details how ps laser pulses generate a fusion flame in solid state density with an increase of the density in the thin flame region. Densities four times higher are produced automatically confirming a Rankine-Hugoniot shock wave process with an increasing thickness of the shock up to the nanosecond range and a shock velocity of 1500 km/s which is characteristic for these reactions.

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32

Gao, Tianyun, Heiko Schmidt, Marten Klein, Jianhan Liang, Mingbo Sun, Chongpei Chen e Qingdi Guan. "One-dimensional turbulence modeling of compressible flows: II. Full compressible modification and application to shock–turbulence interaction". Physics of Fluids 35, n. 3 (marzo 2023): 035116. http://dx.doi.org/10.1063/5.0137435.

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One-dimensional turbulence (ODT) is a simulation methodology that represents the essential physics of three-dimensional turbulence through stochastic resolution of the full range of length and time scales on a one-dimensional domain. In the present study, full compressible modifications are incorporated into ODT methodology, based on an Eulerian framework and a conservative form of the governing equations. In the deterministic part of this approach, a shock capturing scheme is introduced for the first time. In the stochastic part, one-dimensional eddy events are modeled and sampled according to standard methods for compressible flow simulation. Time advancement adjustments are made to balance comparable time steps between the deterministic and stochastic parts in compressible flows. Canonical shock–turbulence interaction cases involving Richtmyer–Meshkov instability at Mach numbers 1.24, 1.5, and 1.98 are simulated to validate the extended model. The ODT results are compared with available reference data from large eddy simulations and laboratory experiments. The introduction of a shock capturing scheme significantly improves the performance of the ODT method, and the results for turbulent kinetic energy are qualitatively improved compared with those of a previous compressible Lagrangian ODT method [Jozefik et al., “Simulation of shock–turbulence interaction in non-reactive flow and in turbulent deflagration and detonation regimes using one-dimensional turbulence,” Combust. Flame 164, 53 (2016)]. For the time evolution of profiles of the turbulent mixing zone width, ensemble-averaged density, and specific heat ratio, the new model also yields good to reasonable results. Furthermore, it is found that the viscous penalty parameter Z of the ODT model is insensitive to compressibility effects in turbulent flows without wall effects. A small value of Z is appropriate for turbulent flows with weak wall effects, and the parameter Z serves to suppress extremely small eddy events that would be dissipated instantly by viscosity.

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Xui, Rui, Xing Zheng, Lianjie Yue, Shikong Zhang e Chao Weng. "Study of shock train/flame interaction and skin-friction reduction by hydrogen combustion in compressible boundary layer". International Journal of Hydrogen Energy 45, n. 31 (giugno 2020): 15683–96. http://dx.doi.org/10.1016/j.ijhydene.2020.04.027.

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Shao, Haibin, Tingwei Wang e Qitu Zhang. "Ceramifying Fire-Resistant Polyethylene Composites". Advanced Composites Letters 19, n. 5 (settembre 2010): 096369351001900. http://dx.doi.org/10.1177/096369351001900501.

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Glass fillers were added into polyethylene (PE) with the aim to prepare fire-resistant PE composites. The effect of glass additives on ceramification of the composites and the properties of ceramic residue was investigated. Scanning electron microscopy (SEM) showed that there was a stronger interaction between glass fibres than that between glass powders. A torque rheometer was used to explore the rheological behaviour. It was concluded that expansion of composites was driven by the motion of low molecular weight substances such as water, carbon dioxide pyrolysed during heat treatment, while softened inorganic additives shrank at elevated temperature resulted in shrinkage of composites. The effect of the form and softening point of glass additives on waterproofness and thermal shock resistance of residue was investigated. The results showed that the composition significantly affected the compactness of residue. Thermal shock resistance of residues of each composite was good. Combustion tests showed that flame retardance and anti-dripping of the composites should be improved.

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Lalousis, P., I. B. Földes e H. Hora. "Ultrahigh acceleration of plasma by picosecond terawatt laser pulses for fast ignition of fusion". Laser and Particle Beams 30, n. 2 (9 marzo 2012): 233–42. http://dx.doi.org/10.1017/s0263034611000875.

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AbstractA fundamental different mechanism dominates laser interaction with picosecond-terawatt pulses in contrast to the thermal-pressure processes with ns pulses. At ps-interaction, the thermal effects are mostly diminished and the nonlinear (ponderomotive) forces convert laser energy instantly with nearly 100% efficiency into the space charge neutral electron cloud, whose motion is determined by the inertia of the attached ion cloud. These facts were realized only by steps in the past and are expressed by the ultrahigh plasma acceleration, which is more than few thousand times higher than observed by any thermokinetic mechanism. The subsequent application for side-on ignition of uncompressed fusion fuel by the ultrahigh accelerated plasma blocks is studied for the first time by using the genuine two-fluid hydrodynamics. Details of the shock-like flame propagation can be evaluated for the transition to ignition conditions at velocities near 2000 km/s for solid deuterium-tritium.

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Lin, Jyh-Woei. "Space Radiation of Solar Storm: A Meeting Report in Taiwan". European Journal of Environment and Earth Sciences 2, n. 6 (11 novembre 2021): 10–11. http://dx.doi.org/10.24018/ejgeo.2021.2.6.202.

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Solar storm was an effect when Sun was active. Solar flares flame released a large amount of energy and caused a large-scale explosion. A large amount of coronal matter was ejected into space by plasma composed of electrons and protons. Their shock waves or magnetic clouds and the earth Magnetic storms generated by the interaction of magnetic fields caused disturbances and squeezing of the earth’s magnetosphere. A solar flare was a phenomenon of solar storm. It had huge eruptions of electromagnetic radiation. The sudden electromagnetic energy traveled with the speed of light. Large solar flare might affect the effects of reliability of electronic components in satellites and could cause economic losses by soft error and could affect human health through the space radiation, especially causing cancer.

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Kasymov, D., e O. Galtseva. "On the design of some devices for localization and extinguishing wildfires of different intensities". Bulletin of the Karaganda University. "Physics" Series 97, n. 1 (30 marzo 2020): 115–24. http://dx.doi.org/10.31489/2020ph1/115-124.

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Topicality of the study of natural fires and techniques to control them is obvious. About 18 000 people in the Russian Federation lose annually their lives as a result of forest fires. Analysis is shown that forest fires are particularly frequent in Siberia and the Far East of Russia, where the number of deaths from forest fires up to 10 000 people exceeds the same indicator in the European part of Russia by 4–5 times. General situation in the world shows shortcomings in the existing system of monitoring forests and the low efficiency of the methods used to localize and extinguish fires. Development of devices for localizing and extinguishing wildfires of various intensities is considered, based on knowledge of flame structure, including drying, heating, pyrolysis and mixing with atmospheric oxygen zones, which can be affected by relatively low energy disturbances (shock waves) minimizing environment damage. Theoretical and experimental studies show that shock waves lead to increasing pressure in them at the time of interaction with unstable zones, which increases the suppression efficiency further. It is shown that the practical use of considered technological solutions will make it possible to increase the effectiveness and efficiency of measures to suppress wildfires.

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Karimi, Abdullah, e M. Razi Nalim. "Ignition by Hot Transient Jets in Confined Mixtures of Gaseous Fuels and Air". Journal of Combustion 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/9565839.

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Ignition of a combustible mixture by a transient jet of hot reactive gas is important for safety of mines, prechamber ignition in IC engines, detonation initiation, and novel constant-volume combustors. The present work is a numerical study of the hot jet ignition process in a long constant-volume combustor (CVC) that represents a wave rotor channel. The hot jet of combustion products from a prechamber is injected through a converging nozzle into the main CVC chamber containing a premixed fuel-air mixture. Combustion in a two-dimensional analogue of the CVC chamber is modeled using a global reaction mechanism, a skeletal mechanism, or a detailed reaction mechanism for three hydrocarbon fuels: methane, propane, and ethylene. Turbulence is modeled using the two-equation SSTk-ωmodel, and each reaction rate is limited by the local turbulent mixing timescale. Hybrid turbulent-kinetic schemes using some skeletal reaction mechanisms and detailed mechanisms are good predictors of the experimental data. Shock wave traverse of the reaction zone is seen to significantly increase the overall reaction rate, likely due to compression heating, as well as baroclinic vorticity generation that stirs and mixes reactants and increases flame area. Less easily ignitable methane mixture is found to show slower initial reaction and greater dependence on shock interaction than propane and ethylene.

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Wang, Kan, Yang Liu, Hao Wang, Xiaolei Liu, Yu Jiao e Yujian Wu. "Dynamic Process and Damage Evaluation Subject to Explosion Consequences Resulting from a LPG Tank Trailer Accident". Processes 11, n. 5 (16 maggio 2023): 1514. http://dx.doi.org/10.3390/pr11051514.

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The involvement of liquefied petroleum gas (LPG), which is highly combustible and explosive, greatly increases risk in road transport. A 3D numerical model was conducted in FLACS, which depicts the dynamic process and variation of combined effects along the multi-directions of LPG explosion under an actual case. With the simulation of scenarios, power-law explosion and fireball models were used to reproduce the results, and the dynamic evolution of specific parameters during the LPG explosion process was analyzed. The results reveal that the LPG explosion’s expansion around the expressway moved along the spaces between obstacles, while conditions at the site of the accident had an enhancement effect on LPG/air mixture accumulation. The propagation trajectory of the shock wave in the horizontal direction presented a regular circle within 623.73 ms, and the overpressure was enough to lead to extensive damage to surrounding structures. Further, shock wave-driven overpressure brought hazards to buildings further afield with multiple peak values. The influence of the LPG explosive fireball evolution is significantly reflected in the injury range of the heat flux; the maximum diameter of the on-site fireball eventually extended to 148.19 m. In addition, the physical effect indicated that the turbulence intensity induced by the surrounding buildings in the accident site significantly promoted the interaction between the shock wave and flame propagation. This research proposes a detailed analysis of damage coupling characteristics caused by an LPG tank trailer explosion integrated with a FLACS-mirrored model, which are useful for blast-resistant design and disposal planning under similar accidental circumstances.

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40

DOU, HUA-SHU, ZONGMIN HU e BOO CHEONG KHOO. "COMPUTATIONAL STUDY OF DEFLAGRATION TO DETONATION TRANSITION IN A STRAIGHT DUCT: EFFECT OF ENERGY RELEASE". International Journal of Modern Physics: Conference Series 19 (gennaio 2012): 62–72. http://dx.doi.org/10.1142/s2010194512008598.

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Numerical simulation based on the Euler equation and one-step reaction model is carried out to investigate the process of deflagration to detonation transition (DDT) occurring in a straight duct. The numerical method used includes a high resolution fifth-order weighted essentially nonoscillatory scheme for spatial discretization, coupled with a third order total variation diminishing Runge-Kutta time stepping method. In particular, effect of energy release on the DDT process is studied. The model parameters used are the heat release at q =50, 30, 25, 20, 15, 10 and 5, the specific heat ratio at 1.2, and the activation temperature at Ti =15, respectively. For all the cases, the initial energy in the spark is about the same compared to the detonation energy at the Chapman-Jouguet (CJ) state. It is found from the simulation that the DDT occurrence strongly depends on the magnitude of the energy release. The run-up distance of DDT occurrence decreases with the increase of the energy release for q =50~20, and increases with the increase of the energy release for q =50~20. It is concluded from the simulations that the interaction of the shock wave and the flame front is the main reason for leading to DDT.

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Dou, Hua-Shu, Zongmin Hu, Boo Cheong Khoo e Zonglin Jiang. "Numerical Simulation of Deflagration to Detonation Transition in a Straight Duct: Effects of Energy Release and Detonation Stability". Advances in Applied Mathematics and Mechanics 6, n. 06 (dicembre 2014): 718–31. http://dx.doi.org/10.4208/aamm.2013.m159.

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Abstract (sommario):

AbstractNumerical simulation based on the Euler equation and one-step reaction model is carried out to investigate the process of deflagration to detonation transition (DDT) occurring in a straight duct. The numerical method used includes a high resolution fifth-order weighted essentially non-oscillatory (WENO) scheme for spatial discretization, coupled with a third order total variation diminishing Runge-Kutta time stepping method. In particular, effect of energy release on the DDT process is studied. The model parameters used are the heat release atq= 50,30,25,20,15,10 and 5, the specific heat ratio at 1.2, and the activation temperature atTi= 15, respectively. For all the cases, the initial energy in the spark is about the same compared to the detonation energy at the Chapman-Jouguet (CJ) state. It is found from the simulation that the DDT occurrence strongly depends on the magnitude of the energy release. The run-up distance of DDT occurrence decreases with the increase of the energy release forq= 50 ~ 20, and increases with the increase of the energy release forq= 20 ~ 5. This phenomenon is found to be in agreement with the analysis of mathematical stability theory. It is suggested that the factors to strengthen the DDT would make the detonation more stable, and vice versa. Finally, it is concluded from the simulations that the interaction of the shock wave and the flame front is the main reason for leading to DDT.

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Gamezo, Vadim N., Alexei M. Khokhlov e Elaine S. Oran. "The influence of shock bifurcations on shock-flame interactions and DDT". Combustion and Flame 126, n. 4 (settembre 2001): 1810–26. http://dx.doi.org/10.1016/s0010-2180(01)00291-7.

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43

Ciccarelli, Gaby, Craig T. Johansen e Michael Parravani. "The role of shock–flame interactions on flame acceleration in an obstacle laden channel". Combustion and Flame 157, n. 11 (novembre 2010): 2125–36. http://dx.doi.org/10.1016/j.combustflame.2010.05.003.

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44

Jiang, Hua, Gang Dong, Xiao chen e Jin-Tao Wu. "Numerical simulations of the process of multiple shock–flame interactions". Acta Mechanica Sinica 32, n. 4 (27 aprile 2016): 659–69. http://dx.doi.org/10.1007/s10409-015-0552-0.

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45

Кузнецов, А. Е., А. П. Инчиков, Е. А. Соина e Л. А. Орлов. "Procedure for arramgement of fire extinguishing by the units of FPS GPS EMERCOM of Russia at facilities with explosive materials handling". Pozharnaia bezopasnost`, n. 3(112) (15 settembre 2023): 49–53. http://dx.doi.org/10.37657/vniipo.pb.2023.112.3.005.

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Возгорания на объектах с обращением взрывчатых материалов имеют особенности: кроме опасных факторов пожара, воздействующих на людей и имущество, возможно влияние опасных факторов взрыва. Это диктует необходимость разработки безопасной и эффективной тактики тушения таких пожаров. Рассмотрены вопросы организации тушения пожаров специальными подразделениями федеральной противопожарной службы Государственной противопожарной службы МЧС России и их взаимодействия с дополнительными силами, привлекаемыми к тушению пожаров на объектах с наличием взрывчатых материалов, показана специфика боевых действий в условиях угрозы взрыва. Представлено содержание разработанных методических рекомендаций по действиям личного состава ФПС ГПС МЧС России при тушении пожаров на объектах с обращением взрывчатых материалов. In case of fires at facilities with the presence of explosive materials, dangerous explosion factors may occur – excessive pressure forming a shock air wave, flame force, fragments and debris during the destruction of devices, products and building structures, pieces of burning explosive materials, toxic combustion products. The solution of fire extinguishing issues is largely functionally assigned to special FPS GPS units. Successful fire fighting depends on the technical equipment of fire departments and their ability to operate in an explosion threat. It is necessary to use safe and effective tactics to extinguish such fires. The article deals with the organization of fire extinguishing by special FPS GPS units and their interaction with additional forces involved in extinguishing fires at facilities with the presence of explosive materials, shows the specifics of combat operations in the conditions of an explosion threat. It is shown that the issue of maximizing the use of robotic complexes, unmanned aerial vehicles and other technical means that allow remotely performing the required tasks is relevant. The content of the developed methodological recommendations on the actions of the personnel of the FPS EMERCOM of Russia in extinguishing fires at facilities with the explosive materials handling is presented. The document takes into account modern achievements of science and technology in the field of fire extinguishing of fire-explosive facilities, reflects the issues of the necessary technical equipment of fire protection units, defines scenarios for the development of fires, indicates ways to extinguish them, presents the basic principles of actions during extinguishing.

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Wang, Dandan, e Gang Dong. "Scalar characterisations of three-dimensional shock-flame interactions: similarity and inhomogeneity". Journal of Turbulence 21, n. 2 (1 febbraio 2020): 84–105. http://dx.doi.org/10.1080/14685248.2020.1734206.

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47

Massa, L., e P. Jha. "Linear analysis of the Richtmyer-Meshkov instability in shock-flame interactions". Physics of Fluids 24, n. 5 (maggio 2012): 056101. http://dx.doi.org/10.1063/1.4719153.

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48

RI, Zhdanov. "Intestinal Microbiota as a Necessary Basis for Homeostasis, General Pathology, and Ageing, or Back to Elia Metchnikov". Open Access Journal of Microbiology & Biotechnology 7, n. 3 (4 luglio 2022): 1–6. http://dx.doi.org/10.23880/oajmb-16000236.

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The article is aimed to overview the field of microbiota and endotoxin science and their role in the interaction with innate immune system and pathogenesis of a variety of acute and chronic diseases. The methodology for studying the LPS biological role under clinical conditions created by Russian scientists is based on the ability of LPS blood level reducing tools to increase the patient treatment efficacy. The next findings have been created and formulated: 1. The LPS and stress factors’ involvement to the induction of inflammation, general adaptation syndrome and disseminated intravascular coagulation (DIC) condition which represent starting points for the development of multiple organ failure syndrome; 2. The LPS involvement to pathogenesis of broncho-obstructive syndrome, of chronic hepatitis C, AIDS and SARS-COV-2, of atherosclerosis and acute myocardial infarction, of alimentary obesity, septic shock, and/or type 1 diabetes, of autoimmune diseases, etc.; 3. The creation of interdisciplinary definitions of inflammation and sepsis, and introduction into scientific semantics new definitions such as "Systemic Endotoxinemia" (SE) as an obligate homeostasis factor and "Endotoxin Aggression" (EA) as a pre-disease and/or universal factor of disease pathogenesis. Furthermore, it was found that some bacterial preparation have ability to strengthen the intestinal barrier, which appeared to be one of the most significant achievements of current clinical microbiology. The EA prevention and/or endotoxin elimination would become a mandatory component of the treatment and preventive medicine, including delaying aging. The finding that "inflammation as a driving forces of aging" would be considered as one of the most outstanding clinical achievements of the century. It is declared that aging represents “burning of human organism in the flame of inflammation”. It is suggested that a specific anti-endotoxin therapy could be developed to combat the pathogenesis of chronic and acute diseases. There are several approaches to reduce the LPS level in human body for health maintaining. The First International Congress "Intestinal Microbiota: Homeostasis, Inflammation, and Aging" is planned to be held in Russian Federation (not far from City-of-Kazan), from 6-8 September 2024. It may become the first worldwide discussion of the questions and problems raised here in sense of LPS-centered medicine, as well as a generalization of ideas on the role of intestinal endotoxins and stress in adaptation processes and induction of inflammation, inflammaging, and aging

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Al-Thehabey, Omar Yousef. "Modeling the amplitude growth of Richtmyer–Meshkov instability in shock–flame interactions". Physics of Fluids 32, n. 10 (1 ottobre 2020): 104103. http://dx.doi.org/10.1063/5.0021989.

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50

Johnson, R. G., A. C. McIntosh e X. S. Yang. "Modelling of fast flame–shock wave interactions with a variable piston speed". Combustion Theory and Modelling 7, n. 1 (marzo 2003): 29–44. http://dx.doi.org/10.1088/1364-7830/7/1/302.

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