Numerical Simulations of Flat Laminar Premixed Methane-Air Flames at Elevated Pressure

Goswami, M Mayuri; Coumans, K Kris; Bastiaans, Rjm Rob; Konnov, Alexander A.; Goey, de Lph Philip

doi:10.1080/00102202.2014.934619

Cited by 13 publications

(9 citation statements)

References 10 publications

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“…The empty squares and circles in Figures 2 and 3 are experimental results from Ref. [24,28]. It is seen that the induction times predicted by the detailed chemical model [20] are in a good agreement with the experimental results but differ up to three orders of magnitude from that predicted by the one-step model.…”

Section: Hydrogen-air: One-step and Detailed Chemical Mechanismssupporting

confidence: 57%

“…The multi-step detailed mechanism chosen to model methane-air chemistry is the reduced detailed reaction model DRM-19 developed by Kazakov and Frenklach [22], which consists of 19 species and 84 reactions. The mechanism DRM-19 has been chosen for simulating as it was extensively validated by many researchers for combustion characteristics of CH 4 /air related to ignition delay times and laminar flame velocities over a wide range of pressures, temperatures, and equivalence ratios [23][24][25].…”

Section: Methane/air Chemistry: a Single-step And Multi-step Mechanismsmentioning

confidence: 99%

“…The induction times for hydrogen/air at pressures P = 5 atm and 10 atm computed using the one-step model Equation (1) and using the detailed chemical model [20] and experimental results from Ref. [24,28] are shown in Figures 2 and 3. The empty squares and circles in Figures 2 and 3 are experimental results from Ref.…”

Section: Hydrogen-air: One-step and Detailed Chemical Mechanismsmentioning

confidence: 99%

See 2 more Smart Citations

Influence of chemical kinetics on spontaneous waves and detonation initiation in highly reactive and low reactive mixtures

Liberman

Wang

Qian

et al. 2018

Combustion Theory and Modelling

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Understanding the mechanisms of explosions is important for minimizing devastating hazards. Due to the complexity of real chemistry, a single-step reaction mechanism is usually used for theoretical and numerical studies. The purpose of this study is to look more deeply into the influence of chemistry on detonation initiated by a spontaneous wave. Results of high resolution simulations performed for one-step models are compared with simulations for detailed chemical models for highly reactive and low reactive mixtures. The calculated induction times for H2/air and for CH4/air are validated against experimental measurements for a wide range of temperatures and pressures. It is found that the requirements in terms of temperature and size of the hot spots, which produce a spontaneous wave capable to initiate detonation, are quantitatively and qualitatively different for one-step models compared to the detailed chemical models. The time and locations when the exothermic reaction affects the coupling between the pressure wave and spontaneous wave are considerably different for a one-step and detailed models. The temperature gradients capable to produce a detonation and the corresponding size of hot spots are much shallower and, correspondingly, larger than those predicted with one-step models. The impact of detailed chemical model is particularly pronounced for the methane-air mixture. In this case, not only the hot spot size is much greater than that predicted by a one-step model, but even at elevated pressure the initiation of detonation by a temperature gradient is possible only if the temperature outside the gradient is so high, that can ignite thermal explosion. The obtained results suggest that the one-step models do not reproduce correctly the transient and ignition processes, so that interpretation of the simulations performed using a one-step model for understanding mechanisms of flame acceleration, DDT and the origin of explosions must be considered with great caution.

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Section: Hydrogen-air: One-step and Detailed Chemical Mechanismssupporting

confidence: 57%

Section: Methane/air Chemistry: a Single-step And Multi-step Mechanismsmentioning

confidence: 99%

Section: Hydrogen-air: One-step and Detailed Chemical Mechanismsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of chemical kinetics on spontaneous waves and detonation initiation in highly reactive and low reactive mixtures

Liberman

Wang

Qian

et al. 2018

Combustion Theory and Modelling

View full text Add to dashboard Cite

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“…Hermanns [45] specified this range to be ≤ 60 cm/s in relation to the measurements in [37]. These recommendations are associated with the tolerated increase of the flame surface, typically by 0.5%, as discussed by Goswami et al [46]. In the present work, gas velocities from 9 cm/s up to 55 The measurements were performed on the experimental setup shown in Fig.…”

Section: Methodsmentioning

confidence: 94%

Laminar premixed flat non-stretched lean flames of hydrogen in air

Алексеев

Christensen

Berrocal

et al. 2015

Combustion and Flame

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Laminar burning velocity of lean hydrogen + air flames at standard conditions is still a debated topic in combustion. The existing burning velocity measurements possess a large spread due to the use of different measurement techniques and data processing approaches. The biggest uncertainty factor in these measurements comes from the necessity to perform extrapolation to the flat flame conditions, since all of the previously obtained data were recorded in stretched flames. In the present study, laminar burning velocity of lean hydrogen + air flames and its temperature dependence were for the first time studied in stretch-free flat flames on a heat flux burner. The equivalence ratio was varied from 0.375 to 0.5 and the range of the unburned gas temperatures was 278-358 K. The flat flames tended to form cells at adiabatic conditions, therefore special attention was paid to the issue of their appearance. The shape of the flames was monitored by taking OH * images with an EM-CCD camera. In most cases, the burning velocity had to be extrapolated from flat subadiabatic conditions, and the impact of this procedure was quantified by performing measurements in H 2 + air mixtures diluted by N 2 . The effect of extrapolation was estimated to be of negligible importance for the flames at standard conditions. The measured burning velocities at 298 K showed an important difference to the previously obtained literature values. The temperature dependence of the burning velocity was extracted from the measured results. It was found to be in agreement with the trends predicted by the detailed kinetic modeling, as opposed to a vast majority of the available literature data.

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“…These models are selected due to lesser number of species and ensure reasonably faster computations. The reaction mechanism DRM-19 has been chosen as a main one for simulating as it was extensively validated by many researchers for combustion characteristics related to ignition delay times and laminar flame velocities over a wide range of pressures, temperatures, and equivalence ratios [28,29,30]. The results for all chemical models were compared with the standard detailed reference mechanism GRI 3.0…”

Section: Comparison Of Simplified and Detailed Chemical Schemesmentioning

confidence: 99%

Influence of chemical kinetics on detonation initiating by temperature gradients in methane/air

Wang

Qian

Liu

et al. 2018

Combustion and Flame

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Different simplified and detailed chemical models and their impact on simulations of combustion regimes initiating by the initial temperature gradient in methane/air mixtures are studied. The limits of the regimes of reaction wave propagation depend upon the spontaneous wave speed and the characteristic velocities of the problem. The present study mainly focus to identify conditions required for the development a detonation and to compare the difference between simplified chemical models and detailed chemistry. It is shown that a widely used simplified chemical schemes, such as one-step, two-step and other simplified models, do not reproduce correctly the ignition process in methane/air mixtures. The ignition delay times calculated using simplified models are in orders of magnitude shorter than the ignition delay times calculated using detailed chemical models and measured experimentally. This results in considerably different times when the exothermic reaction affects significantly the ignition, evolution, and coupling of the spontaneous reaction wave and pressure waves. We show that the temperature gradient capable to trigger detonation calculated using detailed chemical models is much shallower (the size of the hot spot is much larger) than that, predicted by simulations with simplified chemical models. These findings suggest that the scenario leading to the deflagration to detonation transition (DDT) may depend greatly on the chemical model used in simulations and that the Zel'dovich gradient mechanism is not necessary a universal mechanism triggering DDT. The obtained results indicate that the conclusions derived from the simulations of DDT with simplified chemical models should be viewed with great caution.

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Numerical Simulations of Flat Laminar Premixed Methane-Air Flames at Elevated Pressure

Cited by 13 publications

References 10 publications

Influence of chemical kinetics on spontaneous waves and detonation initiation in highly reactive and low reactive mixtures

Influence of chemical kinetics on spontaneous waves and detonation initiation in highly reactive and low reactive mixtures

Laminar premixed flat non-stretched lean flames of hydrogen in air

Influence of chemical kinetics on detonation initiating by temperature gradients in methane/air

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