Experimental Investigation on the Propagation Process of Combustion Wave in the Annular Channel Filled with Acetylene-Air/Oxygen Mixture

Gai, Jingchun; Qiu, Hua; Xiong, Cha; Huang, Zuohua

doi:10.1007/s10494-021-00301-x

Cited by 7 publications

(6 citation statements)

References 30 publications

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“…This flame length significantly exceeds that reported in relevant experiments in the literature. 13,[17][18][19] This is primarily attributed to the large curvature of the inner ring segment in our configuration. Previous studies have indicated that higher channel curvature favors the asymmetric expansion of the flame surface.…”

Section: Results and Discussion A Flame Acceleration And Ddt Processmentioning

confidence: 93%

“…At 34 ls, the shape of the flame front is similar to the shapes observed in the experiments reported in the literature. 17,18 At this time, the elongated funnelshaped region between the flame front and the outer wall is in a hightemperature, high-pressure state. In the subsequent evolution, a series of localized explosions occur in this region (36 ls), continuing to sweep through the unburned gas and spreading to the rest of the unburned mixture, ultimately forming a complete detonation wave (37 ls).…”

Section: Results and Discussion A Flame Acceleration And Ddt Processmentioning

confidence: 99%

“…[10][11][12] Research has indicated that the smaller the spiral curvature radius, the shorter the DDT (deflagration to detonation transition) distance. Subsequently, Kuznetsov et al, 13 our research team, [14][15][16] as well as Gai et al 17 and Pan et al, 18,19 observed significant differences in the morphology of the accelerated flame in curved and straight channels: The curved channels resulted in an asymmetric stretching of the flame front, with the flame propagating on the inner wall side. It is precisely this unique characteristic that gives curved channels a significant advantage in promoting flame acceleration.…”

Section: Introductionmentioning

confidence: 92%

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A novel configuration capable of enhancing flame acceleration and detonation

Li,

2024

Physics of Fluids

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This study proposes a novel design concept that leverages the geometric effects of channels with varying diameters and bends to boost flame acceleration and detonation in microchannels. A quasi-direct numerical simulation with detailed chemical kinetics is used to evaluate the processes of flame acceleration and detonation. A comparative study on the impact of equidistant spiral and converging spiral shapes of detonation channels on flame acceleration is conducted and discussed. The results indicate that in the low-speed and high-speed stages of flame propagation, Fermat's spiral channel exhibits a more significant promoting effect on flame acceleration compared to the Archimedes spiral channel. Fermat's spiral channel has significant advantages in terms of combustion efficiency and can save about 30% of fuel during the detonation process. This study helps to further reduce the scale of the detonation system.

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Section: Results and Discussion A Flame Acceleration And Ddt Processmentioning

confidence: 93%

Section: Results and Discussion A Flame Acceleration And Ddt Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

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A novel configuration capable of enhancing flame acceleration and detonation

Li,

2024

Physics of Fluids

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“…Under an asymmetric combustion condition where ϕ varies between the two sides, the value of τ relies on the local ϕ, rather than the global ϕ. This is logical since the heat release at each flame should be controlled by the local ϕ, rather than being influenced by the total ϕ [24,26]. Consequently, the heat release oscillation differs between the two sides, even when there is an identical flow rate oscillation.…”

Section: Setai Behavior Under Asymmetric Combustion Conditionmentioning

confidence: 99%

“…However, this flow rate oscillation could cause heat release oscillation, and there is also a phase difference between them due to the time needed for the combustion reaction. Moreover, the heat release delay time relative to the flow rate oscillation (τ) [26] is mainly influenced by the combustion ϕ. In such a mode, these three parameters ultimately affect the coupling between sound pressure and heat release oscillation, thus determining SETAI behavior.…”

Section: Introductionmentioning

confidence: 99%

Self-Excited Thermoacoustic Instability Behavior of a Hedge Premixed Combustion System with an Asymmetric Air/Fuel Supply or Combustion Condition

Du,

Zhang,

et al. 2023

Applied Sciences

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Self-excited thermoacoustic instability (SETAI) is an undesirable and dangerous phenomenon in combustion systems. However, its control is difficult, thus greatly limiting the development of combustion technology. Our previous works clarified how the premixed chamber length (LP) and equivalence ratio (φ) influence SETAI behavior in a symmetrical hedge premixed combustion system. On real-world sites, however, the supply structure or combustion condition in a multi-flame system could be asymmetric due to space limitations or combustion adjustment needs. This paper aims to clarify the SETAI behavior of a combustion system with an asymmetric supply structure or an asymmetric combustion condition. The results indicate that the sound pressure amplitude under strong oscillation can reach 160 dB, which is about 5% of the total pressure. The SETAI state under the asymmetric condition is determined by the coupling between the heat release oscillation and sound pressure oscillation on each side and their cooperation. The asymmetric supply structure leads to asynchronous heat release oscillations between the two sides; it may be that one promotes oscillation and that the other suppresses it, or that both have a promotion effect but with asynchronous action, thus partly canceling each other out to lower the system’s oscillation intensity. This brings an advantage for controlling SETAI, which can be achieved by only changing one side of the structure. The oscillation amplitude can be reduced by 80–90% by appropriately changing one LP only by ~20%. Under an asymmetric combustion condition with φ differing between the two sides, the heat release oscillation on each side is dependent on the local φ but not the global φ. Consequently, SETAI can also be controlled by changing the distribution but maintaining a constant fuel feeding rate and φ. The concepts identified in this paper demonstrate that SETAI can be effectively controlled by adopting an asymmetric φ distribution or an asymmetric structure of the supply system. This provides a convenient SETAI control approach without affecting the equipment’s thermal performance.

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