Influence of kinetics on DDT simulations

Dounia, Omar; Vermorel, Olivier; Misdariis, Antony; Poinsot, Thiérry

doi:10.1016/j.combustflame.2018.11.009

Cited by 50 publications

(8 citation statements)

References 43 publications

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“…Numerical simulation results were obtained using identical mathematical models and source data (Figs. [15][16][17][18][19][20]. The form and orientation of the isosurface resembles that for design variant 1, though with smaller deformation of the base.…”

Section: Discussionmentioning

confidence: 87%

“…Paper [20] examined chemical modelling and its influence on the transition of combustion conditions from deflagration to detonation. It was shown that, in the case of hydrogen-air mixtures, the multi-step chemical description is far more restrictive than the single-step model when it comes to the necessary conditions for a hot spot to lead to detonation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator

Авраменко

2021

Fr. Ukr. J. Chem.

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Numerical methods are used to study the process of combustion of a stoichiometric hydrogen-oxygen mixture. The mathematical models were validated using experimental data. The combustion process is modelled in the three-dimensional unsteady formulation. With account of the recommendations of other authors, the turbulent flows are described in the paper using the standard k-ε turbulence model. The Eddy Dissipation Model (EDM) is used to describe the process of combustion of the hydrogen-oxygen mixture. The description of the complex heat transfer between the gas, flame and walls in the paper accounts for radiant heat transfer by using the P1 model. The paper deals with combustion processes in a burner and a model steam generator. Numerical methods were used to evaluate the effect of inlet flow turbulisation, and the flow rate and the method of feeding extra water to the combustion chamber on the process of combustion of the stoichiometric hydrogen-oxygen mixture. The influence of the design and operating mode factors on the alteration of the flame-steam interface and on the flame extinguishing conditions were studied. The results obtained can be used in future in designing equipment that uses hydrogen as a fuel to increase nuclear power plant (NPP) manoeuvrability.

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Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator

Авраменко

2021

Fr. Ukr. J. Chem.

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“…[11] using one-step chemistry and by Dounia et al [27] using detailed chemistry. As discussed previously, in all the cases presented in Fig.…”

Section: Detonation Initiation Mechanismmentioning

confidence: 99%

Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

Zhu

Tang

Lai

et al. 2022

ASME 2022 ICE Forward Conference

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Numerical simulations are performed to study the process of flame propagation through a small orifice and transition to detonation in a confined pre-chamber/main-chamber system. The numerical model solves the fully compressible Navier-Stokes equations by a high-order numerical algorithm on a dynamically adapting mesh, coupled with a single-step chemical-diffusive model for a stoichiometric ethylene-oxygen mixture. Four successive stages, namely laminar flame propagation, jet flame formation, flame distortion by shock waves, and transition to detonation, are observed. Parametric studies with varying nozzle diameters and initial temperatures are tested to investigate the effect of nozzle size and the stochasticity of deflagration-to-detonation transition (DDT). The results suggest that the case with a smaller nozzle size, d = 1.5 mm, requires a longer time for the flame to evolve and transition into a detonation. A small change in the initial temperature results in clear fluctuations of flame surface length in the turbulent flame regime. In addition, the case with the smaller orifice size is shown to be more sensitive to the initial temperature. Due to the stochastic nature of DDT, the time and location for detonation initiation vary in all cases. Nevertheless, the detonation mechanism remains the same and is independent of the small variations in the initial temperature or the orifice size.

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“…While numerical simulations using complex chemistry with detailed chemical reaction rates are nowadays possible with increasing computational resources, it remains challenging to fully synthesize and explain the tremendous amount of chemical kinetic and flow field information that are generated from the computation. In fact, although recent studies have shown that detailed chemical kinetics plays an important role in detonation dynamics and its use may introduce additional transient and multiscale effects [52][53][54][55], qualitative comparison with simulations using a detailed reaction mechanism has shown the simplified chemistry models, e.g., one-step or two-step chain-branching type kinetics, correctly elucidate the underlying physics of the ODW dynamics, importantly the two transition processes this study is focusing on, e.g., References [38,39,56]. In addition, the two-step induction-reaction kinetics, consisting of a thermally neutral induction step followed by a main heat release reaction layer, provides a compromise on the detailed chemistry model.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Chemical Reactivity on the Formation of Gaseous Oblique Detonation Waves

Yan

Teng

et al. 2019

Aerospace

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High-fidelity numerical simulations using a Graphics Processing Unit (GPU)-based solver are performed to investigate oblique detonations induced by a two-dimensional, semi-infinite wedge using an idealized model with the reactive Euler equations coupled with one-step Arrhenius or two-step induction-reaction kinetics. The novelty of this work lies in the analysis of chemical reaction sensitivity (characterized by the activation energy E a and heat release rate constant k R ) on the two types of oblique detonation formation, namely, the abrupt onset with a multi-wave point and a smooth transition with a curved shock. Scenarios with various inflow Mach number regimes M 0 and wedge angles θ are considered. The conditions for these two formation types are described quantitatively by the obtained boundary curves in M 0 -E a and M 0 -k R spaces. At a low M 0 , the critical E a,cr and k R,cr for the transition are essentially independent of the wedge angle. At a high flow Mach number regime with M 0 above approximately 9.0, the boundary curves for the three wedge angles deviate substantially from each other. The overdrive effect induced by the wedge becomes the dominant factor on the transition type. In the limit of large E a , the flow in the vicinity of the initiation region exhibits more complex features. The effects of the features on the unstable oblique detonation surface are discussed.Aerospace 2019, 6, 62 2 of 17 the conditions and interpret the observed flow field regimes in terms of competing reactions and flow-quenching effects.Alternatively, an oblique detonation wave can be induced by a wedge in an incoming reactive flow [20][21][22]. A standing oblique detonation wave attached to the wedge tip presents a more practical configuration for engine operation [23][24][25]. There has been indeed a remarkable progress in understanding the fundamental aspects of oblique detonation waves induced by a semi-infinite, two-dimensional wedge. Analytical solutions such as wave angles and steady structures as the basic foundation were sought in a number of pioneering works using detonation polar analysis by approximating the ODW as an oblique shock wave (OSW) coupled with an instantaneous post-shock heat release [26][27][28][29]. In later studies, it has been demonstrated that the ODW formation structure induced by the wedge is more complex. In many cases, an oblique shock wave first forms upon the flow interaction with the wedge igniting the combustible flow mixture, and subsequently transits into an oblique detonation wave [30]. Due to the strong coupling sensitivity between fluid dynamics and chemical reactions, as well as the inherent unstable nature of detonation waves [31], it remains technically challenging to establish steady oblique detonations in high-speed combustible mixtures for practical propulsion applications, and such success requires fundamental understanding of the initiation structure of oblique detonation waves. To this end, the dynamics of ODW formation has recently drawn significant research attention...

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Influence of kinetics on DDT simulations

Cited by 50 publications

References 43 publications

Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator

Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator

Parametric Studies of Deflagration-to-Detonation Transition in a Pre-Chamber/Main-Chamber System

The Effect of Chemical Reactivity on the Formation of Gaseous Oblique Detonation Waves

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