Turbulent explosion characteristics of stoichiometric syngas

Sun, Zuo-Yu

doi:10.1002/er.3922

Cited by 39 publications

(13 citation statements)

References 24 publications

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“…The peak pressure value alongside its leftward moving increases when increasing the hydrogen fraction in the mixture and/or equivalence ratio (Figure 5a-c), indicating the boost explosion in a shorter combustion duration. This is because the higher the partial volume of H 2 is, the more the amount of H, O, and OH radical mole fractions will be released during the combustion, enhancing the chemical reaction [1,22]. Moreover, Figure 5d also reveals a slight "leftward moving" of the pressure trace as increasing E ig from 2.4 mJ to 58 mJ, suggesting a shorter combustion duration.…”

Section: Resultsmentioning

confidence: 92%

“…[1,14,16,17,19,20] and the references therein), unfortunately, most of them focus on the laminar burning velocity of hydrogen-methane flames rather than their explosion duration characteristics. Recently, Sun et al [22] have conducted the stoichiometric syngas with different hydrogen concentrations (10−90% in volume fraction) in a spherical combustion chamber. They investigated that the increasing hydrogen fraction could raise the maximum pressure and shorten the explosion duration due to the increase in H + in the flame.…”

Section: Introductionmentioning

confidence: 99%

“…To quantify the explosion duration characteristics, many researchers investigated ignition delay time (lag duration) and flame rising time (fast burn duration) [22,[25][26][27]. The ignition delay time (t delay ) is the time duration between the start of spark command and the instant of appearance of pressure [22,25] or 10% of the total normalized cumulative heat release (NCHR) [26]. The flame rising time (t rising ) is defined as the time duration from 10% to 90% of the total NCHR [26].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Ignition Energy and Hydrogen Addition on Laminar Flame Speed, Ignition Delay Time, and Flame Rising Time of Lean Methane/Air Mixtures

et al. 2022

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A series of experiments were performed to investigate the effect of ignition energy (Eig) and hydrogen addition on the laminar burning velocity (Su0), ignition delay time (tdelay), and flame rising time (trising) of lean methane−air mixtures. The mixtures at three different equivalence ratios (ϕ) of 0.6, 0.7, and 0.8 with varying hydrogen volume fractions from 0 to 50% were centrally ignited in a constant volume combustion chamber by a pair of pin-to-pin electrodes at a spark gap of 2.0 mm. In situ ignition energy (Eig ∼2.4 mJ ÷ 58 mJ) was calculated by integration of the product of current and voltage between positive and negative electrodes. The result revealed that the Su0 value increases non-linearly with increasing hydrogen fraction at three equivalence ratios of 0.6, 0.7, and 0.8, by which the increasing slope of Su0 changes from gradual to drastic when the hydrogen fraction is greater than 20%. tdelay and trising decrease quickly with increasing hydrogen fraction; however, trising drops faster than tdelay at ϕ = 0.6 and 0.7, and the reverse is true at ϕ = 0.8. Furthermore, tdelay transition is observed when Eig > Eig,critical, by which tdelay drastically drops in the pre-transition and gradually decreases in the post-transition. These results may be relevant to spark ignition engines operated under lean-burn conditions.

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Section: Resultsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Ignition Energy and Hydrogen Addition on Laminar Flame Speed, Ignition Delay Time, and Flame Rising Time of Lean Methane/Air Mixtures

et al. 2022

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“…Four MFPs were mounted on the vessel in a format of Pyramid with the geometric centre located at the vessel's centre. As described in the previous literature, the porous plate split the swirl (generated by fan's rotary) into jets when the swirl past through; the jets from the 4 directions would collide with each other to form turbulence in the vessel's centre, and turbulent intensity was relevant to fan speed.…”

Section: Methodsmentioning

confidence: 99%

Structure of turbulent rich hydrogen-air premixed flames

Sun

2018

Int J Energy Res

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Summary In the present article, series of experiments were conducted to study the structure characteristics of premixed flames in turbulent rich hydrogen‐air mixtures within a constant‐volume turbulent combustion system, 7 equivalence ratios (1.2, 1.4, 1.6, 1.8, 2.0, 2.2, and 2.5), and 5 turbulent intensity (0, 0.494, 0.742, 1.080, and 1.309 m/s) were studied. With the increase of turbulent intensity, the cellularity degree was obviously enhanced for turbulence promoted the formation and the development of initial cracks by wrinkling flame‐front; furthermore, the enhanced hydrodynamic instability was also one important reason. Turbulence would change the linear growth of critical radius to equivalence ratio into nonlinear, but the variation extents had limitation. The wrinkling index of flame‐front would rise as flame expanded, and the wrinkling index on flames with similar size would be increased with the increase of turbulence once the turbulent intensity was sufficiently high. From the variations of the root mean square of related oscillation on flame‐front, it could be found that the partial amount of oscillation induced by sole turbulence was declined as flame expanded for the breakup of large eddies.

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“…The explosion duration and in-chamber pressure are the critical physicochemical properties [10,11] of combustible fuel/air mixtures and are essential for designing better syngas-fueled applications [12]. Available data in the literature [4,8,[12][13][14] indicated that the explosion duration was experimentally quantified by the flame development time (0-10% burned mass fraction) and flame rising time (10-90% burned mass fraction).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Explosion Characteristics and General Correlations of Lean H2/CO/CH4/Air Mixtures in Quiescence

Nguyen

et al. 2023

International Journal of Energy Research

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A comprehensive understanding of the combustion characteristics of complex and changeable synthesis gas (syngas) compositions is essential for the further development of syngas-fueled engines with high thermal efficiency and low emissions. This study investigated explosion duration properties and laminar burning velocity ( S L ) of multicomponent syngas/air using the pressure-rise method. The lean multicomponent syngas/air mixtures at various equivalence ratios ( ϕ = 0.6 , 0.7, and 0.8) containing different volumetric fractions of H2 (10–30%), CO (10–30%), and CH4 (40–60%) were conducted in a cylindrical constant volume combustion chamber using a dual-coil car ignition system. The explosion duration was characterized by the flame development time (FDT) and flame rising time (FRT), where FDT (FRT) is the time between spark ignition and 10% (10% and 90%) of the total heat release. The results showed that the values of FDT were approximately twofold of the FRT values, and they decreased with increasing H2 or CO content in the mixture. The leaner the mixture, the faster would be the reduction in the FRT and FDT as increasing H2 and/or CO content. Moreover, FDT and FRT were the shortest at a (H2/(H2+CO)) ratio of 0.5, at which the CH4 content was the lowest. Beyond this ratio, FDT and FRT increased, suggesting a significant effect of CH4 concentration. The shorter the FRT value, the higher would be the S L value. The current S L values, together with previous syngas data, could be well represented by a modified correlation with a slight discrepancy. This suggests a possible self-similar propagation of syngas/air laminar flames, regardless of the equivalence ratio, constituent fraction, temperature, pressure, and dilution. Additionally, a small value of mean absolute percentage error (~10.8%) revealed a better correlation for predicting S L values of syngas fuels.

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Turbulent explosion characteristics of stoichiometric syngas

Cited by 39 publications

References 24 publications

Effect of Ignition Energy and Hydrogen Addition on Laminar Flame Speed, Ignition Delay Time, and Flame Rising Time of Lean Methane/Air Mixtures

Effect of Ignition Energy and Hydrogen Addition on Laminar Flame Speed, Ignition Delay Time, and Flame Rising Time of Lean Methane/Air Mixtures

Structure of turbulent rich hydrogen-air premixed flames

Experimental Study of Explosion Characteristics and General Correlations of Lean H2/CO/CH4/Air Mixtures in Quiescence

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