Effects of the quantity and arrangement of reactive jet obstacles on flame acceleration and transition to detonation: A numerical study

Wang, Jiabao; Zhao, Xinyu; Fan, Lifeng; Pan, Jianfeng; Zhu, Yuejin

doi:10.1016/j.ast.2023.108269

Cited by 10 publications

(2 citation statements)

References 55 publications

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“…Hence, the upper-wall shock hot spot at 13.385 ms, which, over time, causes a detonation to detonation-induced combustion wave moves fast, and, finally, the de to the local explosion and the leading shock wave merge. This mecha can be similar to the one described by Wang et al [42]. They observed hot spot at the flame tip, which promptly consumed the surroundin leading to the initiation of a detonation.…”

Section: Effects Of Inhomogeneity On the Fa And Ddt In Lean Mixturessupporting

confidence: 87%

Numerical Investigation of the Effects of Diffusion Time on the Mechanisms of Transition from a Turbulent Jet Flame to Detonation in a H2-Air Mixture

Saeid,

Khadem,

Emami

et al. 2023

Fire

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The current study primarily aimed to simulate detonation initiation via turbulent jet flame acceleration in partial-premixed H2-air mixtures. Different vertical concentration gradients were generated by varying the duration of hydrogen injection (diffusion time) within an enclosed channel filled with air. H2-air mixtures with average hydrogen concentrations of 22.5% (lean mixture) and 30% (near stoichiometric mixture) were investigated at diffusion times of 3, 5, and 60 s. Numerical results show that the vertical concentration gradient significantly influences the early stage of flame acceleration (FA). In the stratified lean mixture, detonation began at all the diffusion times, and comparing the flame-speed graphs showed that a decrease in the diffusion time and an increase in the mixture inhomogeneity speeded up the flame propagation and the jet flame-to-detonation transition occurrence in the channel. In the stratified H2-air mixture with an average hydrogen concentration of 30%, the transition from a turbulent jet flame to detonation occurred in all the cases, and the mixture inhomogeneity weakened the FA and delayed the detonation initiation.

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Section: Effects Of Inhomogeneity On the Fa And Ddt In Lean Mixturessupporting

confidence: 87%

Numerical Investigation of the Effects of Diffusion Time on the Mechanisms of Transition from a Turbulent Jet Flame to Detonation in a H2-Air Mixture

Saeid,

Khadem,

Emami

et al. 2023

Fire

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“…Saeid et al [34] studied the spatial height ratio (S/H) of the obstacle spacing to the pipe diameter; they found that in inhomogeneous mixtures, detonation could not be triggered in the tube when the S/H was equal to 10 and that the DDT time was considerably reduced when the S/H was reduced to 2.5. Wang et al [35] investigated the effect of the number of jet obstacles on the DDT process, speculated that there existed an optimal number of jet obstacles, and concluded that the optimal number of jet obstacles may vary with changes in channel size and obstacle spacing. Coates et al [36] compared the influences of obstacles of different shapes on flame acceleration and found that rectangular obstacles induced the largest flame acceleration.…”

Section: Introductionmentioning

confidence: 99%

Combustion Mechanism of Gasoline Detonation Tube and Coupling of Engine Turbocharging Cycle

Huang,

Wang,

Shi

et al. 2024

Energies

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Traditional exhaust-gas turbocharging exhibits hysteresis under variable working conditions. To achieve rapid-intake supercharging, this study investigates the synergistic coupling process between the detonation and diesel cycles using gasoline as fuel. A numerical simulation model is constructed to analyze the detonation characteristics of a pulse-detonation combustor (PDC), followed by experimental verification. The comprehensive process of the flame’s deflagration-to-detonation transition (DDT) and the formation of the detonation wave are discussed in detail. The airflow velocity, DDT time, and peak pressure of detonation tubes with five different blockage ratios (BR) are analyzed, with the results imported into a one-dimensional GT-POWER engine model. The results indicate that the generation of detonation waves is influenced by flame and compression wave interactions. Increasing the airflow does not shorten the DDT time, whereas increasing the BR causes the DDT time to decrease and then increase. Large BRs affect the initiation speed of detonation in the tube, while small BRs impact the DDT distance and peak pressure. Upon connection to the PDC, the transient response rate of the engine is slightly improved. These results can provide useful guidance for improving the transient response characteristics of engines.

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Effects of mixture initial conditions on deflagration to detonation transition enhanced by transverse jets

Zhang,

Wang,

Wei

et al. 2024

Energy

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Effects of the quantity and arrangement of reactive jet obstacles on flame acceleration and transition to detonation: A numerical study

Cited by 10 publications

References 55 publications

Numerical Investigation of the Effects of Diffusion Time on the Mechanisms of Transition from a Turbulent Jet Flame to Detonation in a H2-Air Mixture

Numerical Investigation of the Effects of Diffusion Time on the Mechanisms of Transition from a Turbulent Jet Flame to Detonation in a H2-Air Mixture

Combustion Mechanism of Gasoline Detonation Tube and Coupling of Engine Turbocharging Cycle

Effects of mixture initial conditions on deflagration to detonation transition enhanced by transverse jets

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