Fine structure of the leading front of a gas detonation

Manzhalei, V. I.

doi:10.1007/bf00740325

Cited by 27 publications

(14 citation statements)

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“…The multifront (cellular) structure of the transverse waves had been observed earlier experimentally on soot imprints [14]. The secondary transverse waves that form the fine structure of the leading DW front (see Fig.1), had been observed in the experiments [15]. Thus, this simulation reproduces a real characteristic feature of the detonation of hydrocarbon mixtures -instability of the front of the transverse waves itself and instability the leading shock front of the DW.…”

Section: Simulation Of 2d Structure Of Propagating Dw In a Rich Methasupporting

confidence: 76%

Numerical simulation of classical and rotating detonation waves in methane mixtures

Trotsyuk

2017

J. Phys.: Conf. Ser.

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A numerical simulations of a two-dimensional multi-front irregular structure of the detonation wave (DW) in methane-based mixtures at normal initial condition have been conducted. The computations have been performed in a wide range of channel height. From the analysis of the flow structure and the number of primary transverse waves in channel, the dominant size of the detonation cell for studied mixtures has been determined. We have simulated the cellular front structure in stoichiometric methane-air and methane-oxygen mixtures, and in a rich (equivalence ratio φ=1.5) methane-air mixture. Based on the fundamental studies of front structure of the classical propagating DW in methane mixtures, numerical simulation of continuous spin detonation of rich (φ=1.2) methane-oxygen mixture has been carried out in the cylindrical detonation chamber (DC) of the rocket-type engine. We studied the global flow structure in DC, and the detailed structure of the front of the continuous rotating DW. Integral characteristics of the detonation process -the distribution of average values of static and total pressure along the length of the DC, and the value of specific impulse have been obtained. The geometric limit of stable existence of rotating DW has been determined. IntroductionOne of the most important problems in the theory of dynamic systems is the formation and destruction of ordered gas-dynamic structures in a reactive medium. An example of such a self-organizing system is a multi-front (cellular) DW steadily propagating in a reacting gas mixture. The complex threedimensional and time-dependent structure of the front of these waves propagating in constant crosssection channels shows some order, whose geometrical parameter is the size of the elementary cell of the DW − a 0 . Based on this value, it is possible to determine such parameters of detonation as critical conditions of detonation combustion, the critical energy of initiation detonation propagation limits, etc., i.e. to estimate the detonation hazard of gaseous mixture. Depending on the chemical composition of the gas, DW in some mixtures have very regular cellular structure, whereas in other mixtures DW shows very irregular chaotic cell structure. A very regular cellular DW structure in hydrogen-oxygen-argon mixtures was studied in our previous 2D numerical simulation [1]. A good agreement was obtained between the numerical results and experimental data on the size a 0 over a wide range of initial pressures and degrees of mixture dilution by argon. Then we have simulated the irregular detonation structure in stoichiometric methane-air [2] and methane-oxygen [3] mixtures.

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Section: Simulation Of 2d Structure Of Propagating Dw In a Rich Methasupporting

confidence: 76%

Numerical simulation of classical and rotating detonation waves in methane mixtures

Trotsyuk

2017

J. Phys.: Conf. Ser.

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“…It should be noted that in the papers of both groups of researchers, as well as in [5], nothing is said about the mechanism of formation of a pulsating detonation front in general and about the mechanism of formation of fine-structure waves in particular. It is only noted that numerical simulation of the two-dimensional cellular structure is performed using the Grib-Zel'dovichvon Neumann-Döring (GZND) detonation model [13][14][15][16].…”

Section: Mechanism Of Formation Of a Kinetically Unstable Pulsating Dmentioning

confidence: 97%

“…In most cases, failure of the ATEs 1 of shock-compressed material at the front of such local detonations occurs almost simultaneously with their initiation (and this leads to the appearance of islands of shock-compressed material at a pressure close to the pressure of the MCJ detonation products). In order for the two-dimensional cellular structure (waves of the fine structure of the main cells [5,[7][8][9]) to occur in the case of one-step reaction kinetics, it is necessary, first, that failure of the ATEs 1 do not occur over the entire surface of local divergent detonation waves. The second condition, without which the first is impossible in principle is that the development of ATEs 1 at the front of the local divergent detonation waves obeys the law of a thermal explosion that is degenerate to such an extent [26] that detonation of the shock-compressed material would be impossible.…”

Section: Formation Of Double-level Cellular Structures For One-step Cmentioning

confidence: 99%

“…Observation using trace imprints [1,2] have shown that the detonation of each gas mixture is characterized by a particular cellular structure. The first experimental observation of the fine structure of cells was reported in [5], where it is argued that, in the cells of some gas mixtures, there is a network of smaller traces left by the waves of the fine structure of the leading front. In [5], no photographs of trace imprints are given but it is noted that fine-structure waves are also observed in Töpler photographs in a plane channel [6].…”

Section: Introductionmentioning

confidence: 98%

“…Manzhalei performed [5] experiments with a number of gas mixtures in a tube of diameter 27 mm. Finestructure waves were recorded in mixtures of CH 4 +2O 2 , 3NH 3 +3O 2 , and C 6 H 14 +11O 2 .…”

Section: Introductionmentioning

confidence: 99%

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Two-dimensional cellular structure of a kinetically unstable detonation front

Dremin

2008

Combust Explos Shock Waves

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Based on previously published results on the detonation of gaseous and liquid explosives, an explanation is given to the formation of the two-dimensional cellular structure of the detonation front of some gas mixtures undergoing a two-step exothermic transformation at the wave front and suggestions are proposed for the mechanism of development of the two-dimensional cellular structure in the case of detonation transformation of gas mixtures with one-step chemical kinetics.

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