The influence of the heat capacity and diluent on detonation structure☆

Lefebvre, M. H.; Oran, E. S.; Kailasanath, K.; Tiggelen, Pierre Van

doi:10.1016/0010-2180(93)90062-8

Cited by 40 publications

(16 citation statements)

References 4 publications

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“…the model for the function "rhrel(t). In previous one-and two-dimensional simulations, Lefebvre et al (1993c) showed conclusively the large influence of the temperature dependence of the ratio of heat capacities and the influence of the heat release rate. Those calculations showed that models using a constant heat capacity equal to its initial value are not accurate enough to provide a good overall description of the detonation.…”

Section: Thermochemical Modelmentioning

confidence: 87%

“…On the other hand, when realistic functions for the heat capacity Cv(t) and energy release "rhrel(t) is implemented, the simulations match the results from the detailed models solving the whole chemical kinetics and correct thermophysics. These realistic functions Cv (t) and "rhrel(t) are derived from kinetic calculations that integrate a set of elementary chemical reactions subject to the constraints of steady-state shock hydrodynamics as described by Lefebvre et al (1993c).…”

Section: Thermochemical Modelmentioning

confidence: 99%

“…The function Cv(t) derived from this kinetic calculation takes into account a temperature-and composition dependence of the heat capacity. A detailed description of the implementation of the functions Cv(t) and "rhrel(t) is given by Lefebvre et al (1993c). …”

Section: Thermochemical Modelmentioning

confidence: 99%

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Modeling of gas phase detonation in complex reactive systems

1995

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Abstract.A numerical study of detonations in hydrogenoxygen-argon mixtures containing CF4 or CF3H is presented. Experiments have established the promoting effect of these additives on the detonation velocity. The Chapman-Jouguet model fails to explain the observed behavior and a numerical approach solving the steady equations of the fluid dynamics provides a first grasp of such an unexpected behavior. In this paper, we use a numerical model that solves the unsteady equations of the fluid dynamics to simulate the detonation wave and to predict the stabilized detonation velocity. The chemical model used is a parametric one that takes into account a temperature and composition dependence of the heat capacity. In a serie of one-dimensional calculations, we describe first the numerical ignition of the detonation wave. In particular, we examine the effect of the pressure in the driving gas section of the numerical domain. Then, we examine the influence of the additives on the detonation wave propagating in a mixture of H2/O2/Ar. We compare successfully the results of the modeling to experimental data. The promoting behavior of both fluorocarbons is numerically observed up to about 10% of the additives. Our conclusion is that it is possible to model the overall description of a detonation wave in complex reactive system. Prerequisites are the knowledge of the chemical kinetics to within a reasonable accuracy, robust algorithm for computing the fluid dynamics and attention to coupling.

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Section: Thermochemical Modelmentioning

confidence: 87%

Section: Thermochemical Modelmentioning

confidence: 99%

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Modeling of gas phase detonation in complex reactive systems

1995

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“…[2][3][4][5][6][7][8][9][10][11] Shock configurations of detonation, distribution of energy release, and maximum pressure contours have been investigated by numerical simulations. [12][13][14][15][16][17] A main feature of gaseous detonation is the Ó 2005 The Japan Society for Aeronautical and Space Sciences complex interaction of incident shocks, Mach stems, and transverse waves. Triple points are formed at the intersection of the transverse wave with the Mach stem and the incident shock, and diamond-shaped patterns called cellular structures are left on smoked foils.…”

Section: Introductionmentioning

confidence: 99%

“…When the post-shock temperature is relatively low at about 1,000 K, the induction distance is larger and more sensitive to fluctuations that can lead to hot or cold spots in the flow. 16) Takai et al 10) studied the irregularity of hydrogen-air mixtures. These authors examined postshock conditions and discussed the change in system properties when hydrogen-oxygen mixture is diluted with nitrogen, which interferes with the chain-branching reaction and destroys the regular structure.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Acoustic Coupling of Transverse Waves in Two-Dimensional H2-O2-Diluent Detonations

Inaba

Matsuo

Tanaka

2005

Trans. Japan Soc. Aero. S Sci.

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Two-dimensional computations of stoichiometric hydrogen-oxygen detonations diluted with nitrogen/argon were performed using a detailed chemical reaction mechanism at initial pressures 0.101 and 0.013 MPa. With increasing channel widths, the relation between the channel widths normalized by half-reaction lengths and the transverse wave strengths defined by pressure ratio across a reflected shock are examined. Various mixture conditions are compared for the maximum channel width where a single transverse wave appears, because numerical cell widths and aspect ratios of the cell are in comparative agreement with previous experimental data. In a mixture diluted with nitrogen at 0.101 MPa, the strong transverse detonation with a transverse wave strength of 1.5 overdrives the transverse wave at 1.3 times faster velocities than the speed of sound in detonation products and makes the maximum channel width larger than those of other conditions. In the presence of strong transverse detonation, acoustic coupling between the transverse wave and the acoustic wave does not apply. The empirical irregularity of the cell with the mixture diluted by nitrogen is interpreted as flexibility of the cell width due to the strong transverse detonation and instability due to out-of-phase acoustic coupling.

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Detonation Limits in Gaseous Systems

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2015

The Modes of Gaseous Combustion

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The influence of the heat capacity and diluent on detonation structure☆

Cited by 40 publications

References 4 publications

Modeling of gas phase detonation in complex reactive systems

Modeling of gas phase detonation in complex reactive systems

Numerical Investigation on Acoustic Coupling of Transverse Waves in Two-Dimensional H2-O2-Diluent Detonations

Detonation Limits in Gaseous Systems

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