Laminar flame speeds of methane/air mixtures at engine conditions: Performance of different kinetic models and power-law correlations

Wang, Yiqing; Movaghar, Ashkan; Wang, Ziyu; Liu, Zefang; Sun, Wenting; Egolfopoulos, Fokion N.; Chen, Zheng

doi:10.1016/j.combustflame.2020.05.004

Cited by 56 publications

(32 citation statements)

References 33 publications

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“…In the existing literatures, ,,− power-law correlations were used to fit the stoichiometric methane–air laminar flame speed at 0.1 MPa. However, as shown in Figure , the discrepancy is quite large when the preheating temperature is high ( T u > 550 K).…”

Section: Results and Discussionmentioning

confidence: 99%

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Luo

Wang

et al. 2021

ACS Omega

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Lean premixed combustion is one of the most effective methods to constrain pollutant emissions for modern industrial gas turbines. An experimental study was performed on its propagation speed and internal structure at engine-relevant temperatures. A Bunsen burner was employed for the measurement with an optical schlieren system. The results show that the increase of preheating temperature dramatically accelerates the propagation of methane flames. The numerical results predicted by GRI-Mech 3.0, FFCM-1, and USC Mech II were also compared. The GRI-Mech 3.0 seems to overestimate the laminar flame speed at high operating conditions, while FFCM-1 underestimates the laminar flame speed compared to the present experimental data. The prediction by FFCM-1 shows good agreement with the overall existing data. The USC Mech II seems to overestimate the laminar flame speed at fuel-lean conditions while shows good agreement with present experimental measurements at stoichiometric conditions when the inlet temperature increases. It is also indicated that the flame is thinned at high-temperature conditions and the importance of CO production to the propagation speed increases. Finally, based on the experimental data, an empirical correlation of the laminar flame speed was developed in the range of T u = 300–800 K and ϕ = 0.7–1.0, the maximum deviation of which was less than 8%. The results of this study may contribute to the optimization of advanced gas turbine combustors.

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Section: Results and Discussionmentioning

confidence: 99%

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Luo

Wang

et al. 2021

ACS Omega

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“…In the simulations of both Bunsen flames and SEFs, the detailed kinetic model for methane oxidation, GRI-Mech 3.0, 50 is used and the mixture-averaged transport model is used for the diffusion velocity. It is noted that recently several kinetic models have been developed for methane, and their performance in predicting premixed methane/air flames was assessed by Wang et al 51 They found that, at ambient conditions, the results predicted by seven kinetic models are very close, while larger discrepancy is observed for engine-relevant conditions. 51 Because this work considers premixed flames at normal temperature and pressure, GRI-Mech 3.0 is used here, and the present conclusions are expected to be independent of the kinetic model used in simulations.…”

Section: Bunsen Flamementioning

confidence: 99%

“…It is noted that recently several kinetic models have been developed for methane, and their performance in predicting premixed methane/air flames was assessed by Wang et al 51 They found that, at ambient conditions, the results predicted by seven kinetic models are very close, while larger discrepancy is observed for engine-relevant conditions. 51 Because this work considers premixed flames at normal temperature and pressure, GRI-Mech 3.0 is used here, and the present conclusions are expected to be independent of the kinetic model used in simulations. If HRR under engine-relevant conditions is studied in future works, GRI-Mech 3.0 should not be used.…”

Section: Bunsen Flamementioning

confidence: 99%

Heat Release Rate Markers for Highly Stretched Premixed CH₄/Air and CH₄/H₂/Air Flames

et al. 2021

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Accurate quantification of heat release rate (HRR) profiles is useful for identifying important combustion processes in practical engines. This study aims to show whether the conventional HRR markers can still be used for highly stretched premixed methane/air flames with and without hydrogen addition. The correlation of formaldehyde-based molar concentrations, [H][CH 2 O] and [OH][CH 2 O], with HRR is numerically studied for highly stretched premixed CH 4 /air and CH 4 /H 2 /air flames. Two types of premixed flames are considered: the spherically expanding flame (SEF) starting from a highly positively stretched ignition kernel and the Bunsen flame with a high negative stretch rate at the flame tip. It is found that both [H][CH 2 O] and [OH][CH 2 O] can qualitatively describe the spatial distribution of HRR profiles in these two types of flames. In comparison to [H][CH 2 O], [OH][CH 2 O] is slightly better because it has a higher correlation coefficient and weaker sensitivity to the stoichiometry. However, during the ignition-influenced regime of SEFs, the magnitude of HRR cannot be accurately correlated by the concentrations of CH 2 O, OH, and H. Besides, hydrogen addition does not change the good spatial reconstruction qualities of these two HRR markers when its volume fraction in methane/hydrogen binary fuel blends is below 70%. The present results demonstrate that the conventional HRR markers, [OH][CH 2 O] and [H][CH 2 O], can be used to quantify the shape of HRR profiles even for highly stretched premixed flames with a small amount of hydrogen addition. Nevertheless, the magnitude of HRR cannot be accurately correlated by these two HRR markers for a highly stretched ignition kernel and hydrogen-dominated binary fuel blends.

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“…CHEMKIN III is a software whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. The thermodynamic data pertaining to substances related to each unit reaction were extracted from NASA CEA code [22,23] and GRI Mech 3.0 code [24,25] databases. Table 1 lists the experimental and modeling conditions.…”

Section: Experimental and Modeling Conditionsmentioning

confidence: 99%

Reaction Characteristics of NOx and N2O in Selective Non-Catalytic Reduction Using Various Reducing Agents and Additives

Park

Dong

2021

Atmosphere

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Artificial nitrogen oxide (NOx) emissions due to the combustion of fossil fuels constitute more than 75% of the total NOx emissions. Given the continuous reinforcement of NOx emission standards worldwide, the development of environmentally and economically friendly NOx reduction techniques has attracted much attention. This study investigates the selective non-catalytic reduction (SNCR) of NOx by methane, ammonia, and urea in the presence of sodium carbonate and methanol and the concomitant generation of N2O. In addition, the SNCR mechanism is explored using a chemical modeling software (CHEMKIN III). Under optimal conditions, NOx reduction efficiencies of 80–85%, 66–68%, and 32–34% are achieved for ammonia, urea, and methane, respectively. The N2O levels generated using methane (18–21 ppm) were significantly lower than those generated using urea and ammonia. Addition of sodium carbonate and methanol increased the NOx reduction efficiency by methane to ≥40% and 60%, respectively. For the former, the N2O level and reaction temperature further decreased to 2–3 ppm and 850–900 °C, respectively. The experimental results were well consistent with simulations, and the minor discrepancies were attributed to microscopic variables. Thus, our work provides essential guidelines for selecting the best available NOx control technology.

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Laminar flame speeds of methane/air mixtures at engine conditions: Performance of different kinetic models and power-law correlations

Cited by 56 publications

References 33 publications

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Heat Release Rate Markers for Highly Stretched Premixed CH₄/Air and CH₄/H₂/Air Flames

Reaction Characteristics of NOx and N2O in Selective Non-Catalytic Reduction Using Various Reducing Agents and Additives

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Laminar flame speeds of methane/air mixtures at engine conditions: Performance of different kinetic models and power-law correlations

Cited by 56 publications

References 33 publications

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Experimental Investigation of Lean Methane–Air Laminar Premixed Flames at Engine-Relevant Temperatures

Heat Release Rate Markers for Highly Stretched Premixed CH4/Air and CH4/H2/Air Flames

Reaction Characteristics of NOx and N2O in Selective Non-Catalytic Reduction Using Various Reducing Agents and Additives

Contact Info

Product

Resources

About

Heat Release Rate Markers for Highly Stretched Premixed CH₄/Air and CH₄/H₂/Air Flames