New effects of stratified gas detonation

Левин, В. А.; Мануйлович, И. С.; Марков, В. В.

doi:10.1134/s1028335810010064

Cited by 6 publications

(2 citation statements)

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“…The use of high-performance computers made it possible to study multi-dimensional flows related to the detonation due to the energy of the combustible mixture motion and its interaction with moving boundaries (see [36][37][38][39][40][41][42][43][44][45][46]). New regimes of the propagation of chemical reaction waves, including the galloping layered detonation, were discovered.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of spinning detonation in circular section channels

Левин

Manuylovich

Марков

2016

Comput. Math. and Math. Phys.

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Numerical simulation of three-dimensional structures of gas detonation in circular section channels that emerge due to the instability when the one-dimensional flow is initiated by energy supply at the closed end of the channel is performed. It is found that in channels with a large diameter, an irregular three-dimensional cellular detonation structure is formed. Furthermore, it is found that in channels with a small diameter circular section, the initially plane detonation wave is spontaneously transformed into a spinning detonation wave, while passing through four phases. A critical value of the channel diameter that divides the regimes with the three-dimensional cellular detonation and spinning detonation is determined. The stability of the spinning detonation wave under perturbations occurring when the wave passes into a channel with a greater (a smaller) diameter is investigated. It is found that the spin is preserved if the diameter of the next channel (into which the wave passes) is smaller (respectively, greater) than a certain critical value. The computations were performed on the Lomonosov supercomputer using from 0.1 to 10 billions of computational cells. All the computations of the cellular and spinning detonation were performed in the whole long three-dimensional channel (up to 1 m long) rather than only in its part containing the detonation wave; this made it possible to adequately simulate and investigate the features of the transformation of the detonation structure in the process of its propagation. INTRODUCTIONThe study of detonation waves in gases is mainly stimulated by the desire to use them for practical purposes in impulse facilities and special energy systems designed for rockets and other flying vehicles. Large magnitudes of the gas dynamics parameters and the complex flow pattern behind the detonation wave front significantly complicate both the experimental and theoretical study of detonation. The main source of information about detonation waves is the experimental study. Among the experimenters, a special place is held by Soloukhin (see [1][2][3][4][5][6]). His works became handbooks for generations of researchers. A significant contribution to the study of detonation was made by his colleagues, disciples, and students. As experimental data were accumulated, theoretical detonation models were improved as well. For example, the two-stage model, which takes into account the ignition delay and a finite time of the subsequent heat emission, makes it possible to describe the nonstationary nonlinear wave structure of detonation (see [7]). In the framework of the infinitely thin detonation wave, the asymptotic nature of the transition of the plane wave to the Chapman-Jouguet regime was established; in the framework of the cylindrical and spherical model, it was found that this transition occurs at a finite distance from the point of the detonation wave formation (see [8,9]). Within the two-stage model, the initial phase of the flow initiated by a point explosion was analytically investigated...

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of spinning detonation in circular section channels

Левин

Manuylovich

Марков

2016

Comput. Math. and Math. Phys.

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“…The study is performed using a modified Godunov method of the first order in space and time [9], which is effective for calculations of various problems of shock and detonation waves [10][11][12][13][14][15][16][17].…”

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Detonation initiation by rotation of an elliptic cylinder inside a circular cylinder and deformation of the channel walls

Левин

Мануйлович

Марков

2010

J Appl Mech Tech Phy

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The possibility of initiating detonation in a closed field due to motion of its boundaries for a one-step kinetic model is studied by numerical simulation of the problems of flow of a propane-air mixture inside and outside a rotating elliptic cylinder enclosed in a circular cylinder; in rotation of a circular cylinder with parabolic blades uniformly distributed along its boundary, or in rotation of a starshaped figure with parabolic rays originating from the center of rotation; and in a plane chamber with deformable walls. Critical parameter values for which detonation occurs are determined. A method of approximate description of the processes occurring in three-dimensional helical channels is considered. In the numerical study of these processes, software based on the Godunov scheme was used.Introduction. Among the problems of wave processes in reactive gas mixtures, self-sustained detonation propagation holds a special place. Continuing attention to this problem is due, in particular, to the use of detonations in various human activities. Increased interest in detonation in the last decade has been motivated by attempts to use detonation in propulsion units. Estimates show that the thermal efficiency of engines using detonation combustion is much higher than the efficiency of conventional combustion devices. In this case, the main problem is detonation initiation. Traditionally, there are two approaches to solving this problem. The first involves the ignition of a mixture by a weak energy source with subsequent deflagration-to-detonation transition implemented by special devices boosting combustion. This leads to transition from normal combustion to a detonation mode. The second approach, called direct initiation of detonation, consists of detonation initiation by a shock wave propagating from an external energy source, for example, igniting of an explosive or electrical or laser breakdown. Detonation can be initiated by a shock wave propagating ahead of a body moving at hypersonic velocity in a combustible mixture or ahead of an immovable body in hypersonic flow. In the late 1990s, a new method of initiation using the cumulation effect of an initially weak shock wave near the axis or center of symmetry [1, 2] was studied in a one-dimensional approach. An extension of this approach to two-dimensional plane and axisymmetric flows is the original method of contoured tubes [3,4], according to which a weak shock wave moving in a channel interacts with the walls, resulting in cumulation near the axis creation of favorable conditions for ignition and transformation of the shock to a detonation wave. According to the hypersonic analogy [5,6], the tube flow is similar to the axisymmetric one-dimensional unsteady flow produced by a piston whose radius varies with time according to the shape of the tube contour. Investigations of the detonation initiation by a piston have led to the conclusion that it is effective from the point of view of minimization of both power inputs and the time required for detonation initiation ...

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