Computational study of non-ideal and mildly-unstable detonation waves

Sow, Aliou; Chinnayya, A.; Hadjadj, A.

doi:10.1016/j.compfluid.2015.06.027

Cited by 6 publications

(3 citation statements)

References 31 publications

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“…The mean curvature of the detonation front was computed from the averaged shape of the combined wave. At each time step, the position of every point constituting the leading shock was also detected by means of a pressure threshold and then averaged during the simulation by the following discrete mean procedure 53 . Consider the temporal mean ψ of a given variable ψ where T = t − t 0 is the sampling period.…”

Section: A Detonation Velocity Deficitmentioning

confidence: 99%

A computational study of the interaction of gaseous detonations with a compressible layer

2017

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The propagation of two-dimensional cellular gaseous detonation bounded by an inert layer is examined via computational simulations. The analysis is based on the high-order integration of the reactive Euler equations with a one-step irreversible reaction. To assess whether the cellular instabilities have a significant influence on a detonation yielding confinement, we achieved numerical simulations for several mixtures from very stable to mildly unstable. The cell regularity was controlled through the value of the activation energy, while keeping constant the ideal Zel’dovich - von Neumann - Döring (ZND) half-reaction length. For stable detonations, the detonation velocity deficit and structure are in accordance with the generalized ZND model, which incorporates the losses due to the front curvature. The deviation with this laminar solution is clear as the activation energy is more significant, increasing the flow field complexity, the variations of the detonation velocity, and the transverse wave strength. The chemical length scale gets thicker, as well as the hydrodynamic thickness. The sonic location is delayed due to the presence of hydrodynamic fluctuations, for which the intensity is increased with the activation energy as well as with the losses to a lesser extent. The flow field has been studied through numerical soot foils, detonation velocities, and 2D detonation front profiles, which are consistent with experimental findings. The velocity deficit increases with the cell irregularity. Moreover, the relation between the detonation limits obtained numerically and in detonation experiments with losses is discussed.

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Section: A Detonation Velocity Deficitmentioning

confidence: 99%

A computational study of the interaction of gaseous detonations with a compressible layer

2017

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“…Furthermore, Sow, Chinnayya & Hadjadj (2014) proposed the Favre average procedure for the detonation in the non-inertial instantaneous shock frame to take into account the unsteadiness of the shock front. So far, the Favre average procedure to obtain 1-D profiles was applied to planar detonations Radulescu et al 2007;Maxwell et al 2017;Taileb et al 2018;Sow, Lau-Chapdelaine & Radulescu 2021;Taileb, Meluguizo-Gavilances & Chinnayya 2021b), in non-uniform mixtures (Mi, Timofeev & Higgins 2017a;Mi et al 2017b), in mixtures with concentration gradients (Han, Wang & Law 2019), in mixtures with fluctuations in concentrations (Zhou et al 2022), cylindrical detonation (Han et al 2017), also in non-ideal configurations such as detonations bounded by an inert layer (Reynaud, Virot & Chinnayya 2017;Reynaud et al 2020), with wall losses (Chinnayya, Hadjadj & Ngomo 2013;Sow et al 2014;Sow, Chinnayya & Hadjadj 2015, in two-phase detonations with water spray (Watanabe et al 2019(Watanabe et al , 2020(Watanabe et al , 2021 and with fuel spray (Jourdaine, Tsuboi & Hayashi 2022).…”

Section: Introductionmentioning

confidence: 99%

“…2020), with wall losses (Chinnayya, Hadjadj & Ngomo 2013; Sow et al. 2014; Sow, Chinnayya & Hadjadj 2015, 2019), in two-phase detonations with water spray (Watanabe et al. 2019, 2020, 2021) and with fuel spray (Jourdaine, Tsuboi & Hayashi 2022).…”

Section: Introductionmentioning

confidence: 99%

Lagrangian dispersion and averaging behind a two-dimensional gaseous detonation front

et al. 2023

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Two-dimensional numerical simulations with the particle tracking method were conducted to analyse the dispersion behind the detonation front and its mean structure. The mixtures were 2H $_2$ –O $_2$ –7Ar and 2H $_2$ –O $_2$ of increased irregularity in ambient conditions. The detonation could be described as a two-scale phenomenon, especially for the unstable case. The first scale is related to the main heat release zone, and the second where some classical laws of turbulence remain relevant. The dispersion of the particles was promoted by the fluctuations of the leading shock and its curvature, the presence of the reaction front, and to a lesser extent transverse waves, jets and vortex motion. Indeed, the dispersion and the relative dispersion could be scaled using the reduced activation energy and the $\chi$ parameter, respectively, suggesting that the main mechanism driving the dispersion came from the one-dimensional leading shock fluctuations and heat release. The dispersion within the induction time scale was closely related to the cellular structure, particles accumulating along the trajectory of the triple points. Then, after a transient where the fading transverse waves and the vortical motions coming from jets and slip lines were present, the relative dispersion relaxed towards a Richardson–Obukhov regime, especially for the unstable case. Two new Lagrangian Favre average procedures for the gaseous detonation in the instantaneous shock frame were proposed and the mean profiles were compared with those from Eulerian procedure. The characteristic lengths for the detonation were similar, meaning that the Eulerian procedure gave the mean structure with a reasonable accuracy.

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Dynamics of Chapman-Jouguet pulsating detonations with Chain-Branching kinetics: Fickett’s analogue and Euler equations

Sow

Lau-Chapdelaine

Radulescu

2023

Proceedings of the Combustion Institute

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Computational study of non-ideal and mildly-unstable detonation waves

Cited by 6 publications

References 31 publications

A computational study of the interaction of gaseous detonations with a compressible layer

A computational study of the interaction of gaseous detonations with a compressible layer

Lagrangian dispersion and averaging behind a two-dimensional gaseous detonation front

Dynamics of Chapman-Jouguet pulsating detonations with Chain-Branching kinetics: Fickett’s analogue and Euler equations

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