The effect of concentration gradients on deflagration-to-detonation transition in a rectangular channel with and without obstructions – A numerical study

Azadboni, Reza Khodadadi; Heidari, Ali; Boeck, Lorenz R.; Wen, Jennifer X.

doi:10.1016/j.ijhydene.2019.01.157

Cited by 38 publications

(3 citation statements)

References 15 publications

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“…The structured mesh of 0.5 mm is used [37]. To avoid the influence of the mesh size on the simulation results, the flame front is encrypted, applying the adaptive refinement mesh method [38] according to the temperature gradient as shown in Figure 2. The ignition temperature is 2000 K.…”

Section: Geometry and Meshmentioning

confidence: 99%

Effect of Obstacle Gradient on the Deflagration Characteristics of Hydrogen/Air Premixed Flame in a Closed Chamber

Wang,

Zhong

2024

Processes

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In this paper, computational fluid dynamics (CFD) numerical simulation is employed to analyze and discuss the effect of obstacle gradient on the flame propagation characteristics of premixed hydrogen/air in a closed chamber. With a constant overall volume of obstacles, the obstacle blocking rate gradient is set at +0.125, 0, and −0.125, respectively. The study focuses on the evolution of the flame structure, propagation speed, the dynamic process of overpressure, and the coupled flame–flow field. The results demonstrate that the flame front consistently maintains a jet flame as the obstacle gradient increases, with the wrinkles on the flame front becoming increasingly pronounced. When the blocking rate gradients are +0.125, 0, and −0.125, the corresponding maximum flame propagation speeds are measured at 412 m/s, 344 m/s, and 372 m/s, respectively, indicating that the obstacle gradient indeed increases the flame propagation speed. Moreover, the distribution of pressure is closely related to changes in the flame structure, with the overpressure decreasing in the obstacle channel as the obstacle gradient increases. Furthermore, the velocity vector and vortex distribution in the flow field are revealed and compared. It is found that the obstacle tail vortex is the main factor inducing flame evolution and flow field changes in a closed chamber. The effect of the blocking rate gradient on flow velocity is also quantified, with instances of deceleration occurring when the blocking rate gradient is −0.125.

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Section: Geometry and Meshmentioning

confidence: 99%

Effect of Obstacle Gradient on the Deflagration Characteristics of Hydrogen/Air Premixed Flame in a Closed Chamber

Wang,

Zhong

2024

Processes

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“…2017; Khodadadi Azadboni et al. 2019; Zheng et al. 2019) and parallel (Thomas, Sutton & Edwards 1991; Kuznetsov et al.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, six typical distributions of inhomogeneous mixtures, as depicted in figure 1, have been considered so far. Figures 1(a) and 1(b) show reactants with fuel concentration gradient normal (Ishii & Kojima 2007;Lieberman & Shepherd 2007a,b;Kessler, Gamezo & Oran 2012;Ettner, Vollmer & Sattelmayer 2013;Boeck et al 2015;Grune et al 2017;Khodadadi Azadboni et al 2019;Zheng et al 2019) and parallel (Thomas, Sutton & Edwards 1991;Kuznetsov et al 1998;Boulal et al 2016Boulal et al , 2018Ma, Wang & Han 2020) to the detonation propagation direction, respectively. Figures 1(c) and 1(d) depict reactants with inert layers parallel (Houim & Fievisohn 2017;Reynaud, Virot & Chinnayya 2017;Maxwell & Melguizo-Gavilanes 2019;Taileb, Melguizo-Gavilanes & Chinnayya 2019) and normal (Gavrilenko, Krasnov & Nikolaev 1982;Bjerketvedt, Sonju & Moen 1986;Teodorczyk & Benoan 1996;Kuznetsov et al 1997;Li et al 2008;Fujii et al 2017;Ishii & Seki 2017;Peace & Lu 2017;Tang et al 2017;Peace & Lu 2018;Tang et al 2018;Chen, Liu & Wang 2019;Tang et al 2019a,b) to the detonation propagation direction, respectively.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies on detonation propagation in inhomogeneous mixtures with periodic reactant concentration gradient

et al. 2023

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In detonation engines and accidental explosions, a detonation may propagate in an inhomogeneous mixture with non-uniform reactant concentration. In this study, one- and two-dimensional simulations are conducted for detonation propagation in hydrogen/oxygen/nitrogen mixtures with periodic sinusoidal or square wave distribution of the reactant concentration. The objective is to assess the properties of detonation propagation in such inhomogeneous mixtures. Specifically, detonation quenching and reinitiation, cellular structure, cell size and detonation speed deficit are investigated. It is found that there exists a critical amplitude of the periodic mixture composition distribution, above which the detonation quenches. When the amplitude is below the critical value, detonation quenching and reinitiation occur alternately. A double cellular structure consisting of substructures and a large-scale structure is found for a two-dimensional detonation propagating in inhomogeneous mixtures with a periodic reactant concentration gradient. The detonation reinitiation process and the formation of the double cellular structure are interpreted. To quantify the properties of detonation propagation in different inhomogeneous mixtures, the large cell size, critical amplitude, transition distance and detonation speed deficit are compared for hydrogen/air without and with nitrogen dilution and for periodic sine wave and square wave distributions of the reactant concentration. The large-scale cell size is found to be linearly proportional to the wavelength, and both the critical amplitude and the transition distance decrease with the wavelength. The small detonation speed deficit is shown to be due to the incomplete combustion of the reactant. This work provides helpful understanding of the features of detonation propagation in inhomogeneous mixtures.

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Review on Large Eddy Simulation of Turbulent Premixed Combustion in Tubes

Luo

Dai

et al. 2020

J. Therm. Sci.

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The effect of concentration gradients on deflagration-to-detonation transition in a rectangular channel with and without obstructions – A numerical study

Abstract: Please refer to published version for the most recent bibliographic citation information. If a published version is known of, the repository item page linked to above, will contain details on accessing it.

Cited by 38 publications

References 15 publications

Effect of Obstacle Gradient on the Deflagration Characteristics of Hydrogen/Air Premixed Flame in a Closed Chamber

Effect of Obstacle Gradient on the Deflagration Characteristics of Hydrogen/Air Premixed Flame in a Closed Chamber

Numerical studies on detonation propagation in inhomogeneous mixtures with periodic reactant concentration gradient

Review on Large Eddy Simulation of Turbulent Premixed Combustion in Tubes

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