Laminar syngas–air premixed flames in a closed rectangular domain: DNS of flame propagation and flame/wall interactions

Jafargholi, Mahmoud; Giannakopoulos, George; Frouzakis, Christos E.; Boulouchos, Konstantinos

doi:10.1016/j.combustflame.2017.09.029

Cited by 17 publications

(4 citation statements)

References 44 publications

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“…From the fundamental perspective, there are many existing computational and experimental studies focusing on the interaction between a flame and a wall surface. 10–13 It has been well recognized that the quenching distance induced by heat loss to the wall is typically in the same order of flame thickness. 14 However, compared with the case with a dry wall, a fuel film places novel upstream boundary conditions of temperature and concentrations when a flame approaches its vicinity.…”

Section: Introductionmentioning

confidence: 99%

Fuel wall film effects on premixed flame propagation, quenching and emission

Tao

VanDerWege

et al. 2018

International Journal of Engine Research

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The formation of fuel wall film is a primary cause for efficiency loss and emissions of unburnt hydrocarbons and particulate matters in direct injection engines, especially during cold start. When a premixed flame propagates toward a wall film of liquid fuel, flame structure and propagation could be fundamentally affected by the vaporization flux and the induced thermal and concentration stratifications. It is, therefore, of both fundamental and practical significance to investigate the consequent effect of a wall film on flame quenching. In this work, the interaction of a laminar premixed flame and a fuel wall film has been studied based on one-dimensional direct numerical simulation with detailed chemistry and transport. The mass and energy balance at the wall film interface have been implemented as boundary condition to resolve vaporization. Parametric studies are further conducted with various initial temperatures of 600–800 K, pressures of 7–15 atm, fuel film and wall temperatures of 300–400 K. By comparing the cases with an isothermal dry wall, it is found that the existence of a wall film always promotes flame quenching and causes more emissions. Although quenching distance can vary significantly among conditions, the local equivalence ratio at quenching is largely constant, suggesting the dominant effects of rich mixture and rich flammability limit. By further comparing constant volume and constant pressure conditions, it is observed that pressure and boiling point variation dominate the vaporization boundary layer development and flame quenching, which further suggests that increased pressure during compression stroke in engines can significantly suppress film vaporization. Emissions of unburnt hydrocarbon, soot precursor and low-temperature products before and after flame quenching are also investigated in detail. The results lead to useful insights on the interaction of flame propagation and wall film in well-controlled simplified configurations and shed light on the development of wall film models in three-dimensional in-cylinder combustion simulation.

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Section: Introductionmentioning

confidence: 99%

Fuel wall film effects on premixed flame propagation, quenching and emission

Tao

VanDerWege

et al. 2018

International Journal of Engine Research

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“…It is important to remind that the flame speed throughout its propagation is decreasingly affected by stretch effects. In the constant volume method, the stretch effect on the laminar flame speed might be too large to be neglected for mixtures with Lewis numbers greatly deviating from unity and thus the stretch correction for obtaining accurate unstretched laminar flame speed is indispensable [25]. Chen et al [21] have numerically investigated stretch effects for the constant volume method for hydrogen/air, methane/air and propane/air mixtures.…”

Section: Stretch Effectsmentioning

confidence: 99%

“…If no heat losses occur between the unburnt compressed gas and the chamber wall, the final chamber pressure reaches the theoretical end-pressure, which is never the case. The upper limit in the flame radius must guarantee no heat losses to the wall [25]. The maximal radius considered by Yamamoto et al [26] is 99% of the total chamber dimension.…”

Section: Introductionmentioning

confidence: 99%

Development of an optically accessible apparatus to characterize the evolution of spherically expanding flames under constant volume conditions

Halter

Chen

Dayma

et al. 2020

Combustion and Flame

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Flame speed is extremely important as it affects the performances of many industrial systems. Moreover, its significance makes it a major target for the validation of kinetic mechanisms, which explains the necessity to provide ever more accurate data. Flame speed dependence on pressure and temperature conditions is interestingly assessed using, among others, spherically expanding flame in constant volume chambers. In these conditions, the flame speed derivation, based solely on the pressure evolution in the chamber, requires empirical models. The current study describes a perfectly spherical chamber with full optical access allowing simultaneous recording of the pressure inside the chamber and, fully innovative, of the flame radius evolution until the flame vanishes at wall. A careful description of the new set-up and of the accuracy of the measurements, in particular of the flame radius, are presented here. In parallel with experiments, one-dimensional transient simulations were carried out to identify the limits of the proposed new method. Then, the simultaneous use of pressure and flame radius information is compared to the traditional constant volume method based on empirical models. A first advantage relies in the direct detection of the development of instabilities during the flame propagation. In addition, although the flame speed is extremely sensitive to the flame radius determination, the actual experimental accuracy allows significant improvements in terms of accuracy, notably as initial pressure and temperature are elevated. This new set-up will allow major advances in the measurement of laminar flame velocity under extreme thermodynamic conditions.

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“…Alliche et al 17 used numerical simulation to investigate the extinguishing conditions of the flame, and the research results could predict the limit value of the heat loss coefficient during extinguishment. Jafargholi et al 18 found that the flame was frontally quenched on the horizontal wall, then propagated to the sidewall affected by the sidewall quenching, and finally triggered thermal diffusion instability along the front. Song et al 19,20 systematically analyzed the flame propagation and quenching in parallel narrow channels of different heights, and proposed criteria for judging the state of partially extinguished and completely extinguished flames.…”

mentioning

confidence: 99%

Investigation on quenching characteristics of parallel narrow channels for deflagration flames

Guo

Wang

et al. 2023

Fire and Materials

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A set of experimental equipment for quenching the deflagration flame in linked vessels with parallel narrow channels was proposed. The quenching effects of the deflagration flame in the linked vessels were investigated, the influence law and mechanism of parallel narrow channels on the deflagration flame was analyzed. The results showed that the Pmax and the (dP/dt)max at each position were both lower than without parallel narrow channels, which indicated that the propagation of flame was inhibited by parallel narrow channels effectively, and the explosion intensity was also reduced. The pressure oscillation phenomenon inside the linked vessels disappeared due to the inclusion of parallel narrow channels. The deflagration flame was successfully quenched when the channel gaps were 0.5, 1.5, and 3 mm, but failed to be quenched when the channel gap was 6 mm. The quenching distance and the average propagation velocity of the deflagration flame in parallel narrow channels increased with the increase of the channel gap. When the channel gap was 6 mm, the deflagration flame completely passed through parallel narrow channels, and the average propagation velocity of deflagration flame was significantly greater than that when the deflagration flame was successfully quenched.

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Laminar syngas–air premixed flames in a closed rectangular domain: DNS of flame propagation and flame/wall interactions

Cited by 17 publications

References 44 publications

Fuel wall film effects on premixed flame propagation, quenching and emission

Fuel wall film effects on premixed flame propagation, quenching and emission

Development of an optically accessible apparatus to characterize the evolution of spherically expanding flames under constant volume conditions

Investigation on quenching characteristics of parallel narrow channels for deflagration flames

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