Structure of Detonation Waves in Mixtures of Tetranitromethane with Nitrobenzene and Methanol
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Structure of Detonation Waves in Mixtures of Tetranitromethane with Nitrobenzene and Methanol A. V. Utkina , V. M. Mochalovaa , A. M. Astakhovb , V. E. Rykovaa , and S. A. Koldunova
UDC 534.222.2
Published in Fizika Goreniya i Vzryva, Vol. 56, No. 5, pp. 69–79, September–October, 2020. Original article submitted October 1, 2019; revision submitted December 16, 2019; accepted for publication December 24, 2019.
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 the vicinity of stoichiometry, resulting in a decrease in the amplitude of the von Neumann spike up to its complete disappearance. The detonation waves are stable to the formation of a cellular structure of the front over almost the entire concentration range, except in the range near the limiting values. At the same time, the amplitude values of particle velocity show poor reproducibility from experiment to experiment performed under the same conditions. The obtained experimental dependences of detonation velocity on the concentrations of methanol and nitrobenzene are in good agreement with thermodynamic calculations. Keywords: tetranitromethane, methanol, nitrobenzene, detonation, von Neumann spike, instability, detonation velocity, Chapman–Jouguet parameters. DOI: 10.1134/S001050822005007X
INTRODUCTION In liquid explosives, the chemical reaction takes place in a volume, which, at first glance, greatly simplifies the analysis and description of the initiation and propagation of detonation in comparison with pressed explosives, whose kinetics is determined by the heterogeneous structure of the material. In practice, the flow pattern arising from the detonation of liquid explosives is often so complex and diverse that it is not possible to describe it even approximately using the classical Zel’dovich–Neumann–D¨ering (ZND) model [1]. A distinctive feature of liquid explosives is the possibility of propagation of steady and unsteady detonation waves in them [2]. Instability leads to the formation of a cellua
Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, 142432 Russia; [email protected]. b Reshetnev Siberian State University, Krasnoyarsk, 660037 Russia.
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lar structure of the detonation front and the occurrence of failure reaction waves at the edge of the charge. The latter phenomenon changes the nature of the critical diameter of liquid explosives, which in this case is not described by the Khariton criterion [3]. However, even in steady detonation waves, the flow in the reaction zone is not always consistent with the ZND theory. It has been shown [4, 5] that, e.g., in mixtures of nitromethane with diethylenetriamine and mixtures of tetranitromethane with methanol or nitrobenz
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