Effects of steam dilution on laminar flame speeds of H2/air/H2O mixtures at atmospheric and elevated pressures

Lyu, Yajin; Qiu, Penghua; Liu, Li; Yang, Chen; Sun, Shaozeng

doi:10.1016/j.ijhydene.2018.02.065

Cited by 37 publications

(7 citation statements)

References 60 publications

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“…Thermal NO x is dependent on the peak temperature, thus reducing with steam/water addition to either fuel or air 20 – 27 . The addition of steam alters the NO x formation path, which can also help in the reduction of the NO x emission 23 – 25 , 28 . Steam dilution also increases the OH radicals,, which helps oxidize CO–CO 2 29 , 30 .…”

Section: Introductionmentioning

confidence: 99%

“…Steam dilution also increases the OH radicals,, which helps oxidize CO–CO 2 29 , 30 . Lyu et al, 28 varied the steam dilution in H 2 /Air system from 0 to 30% while varying the equivalence ratio from 0.9 to 3 and pressure up to 3 atm. They observed a constant reduction of laminar flame speed with pressure beyond steam dilution of 12%.…”

Section: Introductionmentioning

confidence: 99%

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Adaptability of different mechanisms and kinetic study of methane combustion in steam diluted environments

Mohapatra

Mohapatro

Pasha

et al. 2022

Sci Rep

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The chemical kinetics of methane oxidation in a steam-diluted environment are studied in the present study. Various well-validated mechanisms for methane combustion are adopted and compared with experimental data. Ignition delay, laminar flame speed, and emissions for CH4 combustion with steam dilution are discussed. Cumulative relative error parameter was determined for all mechanisms considered in this study to evaluate the prediction level in quantifiable terms. Reaction pathways under no and steam-diluted environments are analyzed, and key elementary reactions and species are identified in these conditions. The analysis gives a relative idea of the applicability of some of the reduced mechanisms for the diluted steam conditions. This study aims to guide future computational fluid dynamics simulations to accurately predict combustion characteristics in these conditions. Computations of laminar flame speed from GRI-3.0, Aramco3.0, Curran, and San Diego mechanisms were the most precise under diluted steam conditions. Similarly, for the calculation of ignition delay of methane under the steam dilution, the Aramco mechanism and the Curran’s mechanism were able to predict the experimentally observed values most closely. Sensitivity study for the OH concentrations shows that the H-abstraction of methane from OH radicals has an opposing trend with dilution for Aramco and GRI-3.0 mechanism. On the other hand, CO and NO emissions were reduced significantly, with the dilution increased from 0 to 20%. The third-body effect of steam is observed to dominate the deviation observed between the detailed and reduced mechanism. For low operating pressure conditions, the GRI-3.0 mechanism gives an excellent prediction, whereas, for applications like gas turbines and furnaces, Aramco-3.0 and Curran mechanisms can be adopted to give good results. The San Diego mechanism can be chosen for low computational facility purposes as it shows very good predictions for ignition delay and laminar flame speed computations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adaptability of different mechanisms and kinetic study of methane combustion in steam diluted environments

Mohapatra

Mohapatro

Pasha

et al. 2022

Sci Rep

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“…The spontaneous emission from flames can be used, alone or combined with other methods to characterise a combustion mode. The chemiluminescence emitted by a hydrocarbon fuel flame, when acquired by optical devices such as spectrometers [4e8], or CCD cameras [9e16] provide valuable information regarding the combustion process, which has been experimentally related to heat release [17,18], equivalence ratio [19e21], temperature [22,23], pressure [24] and pollutant formation [25e27] in a variety of burners [28e30]. The captured information from flame images, after extracting relevant features, can be used to design predictive models aiming at combustion monitoring and control.…”

Section: Introductionmentioning

confidence: 99%

Effects of hydrogen and primary air in a commercial partially-premixed atmospheric gas burner by means of optical and supervised machine learning techniques

González-Espinosa

Gil

Royo-Pascual³

et al. 2020

International Journal of Hydrogen Energy

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“…Masri et al [14] investigated piloted H 2 -CO 2 fuel flames in the Sydney burner using a joint Raman-Rayleigh-LIF technique, noting that differential diffusion and the H radical play a role near lean extinction and also that CO 2 may react to give CO. A jet-stirred reactor study by Cong and Dagaut [15] supports this, concluding that H 2 oxidation was inhibited by decreased OH production in the presence of CO 2 as it reacts with H radicals, CO 2 +H = CO+OH, when adding 30% CO 2 to a lean H 2 -O 2 -N 2 mixture at φ = 0.2. In studies evaluating steam dilution effects on S L , both Kuznetsov et al [16] and Lyu et al [17] note a nonmonotonic pressure effect (increase followed by decrease with increasing pressure) in H 2 -O 2 and H 2 -air mixtures, respectively, with the effect in the latter observed up to 12%vol H 2 O. This has been identified as related to the increased role of third body reactions such as H+O 2 (+M) = HO 2 (+M) with increasing pressure [16,17].…”

Section: Introductionmentioning

confidence: 99%

“…In studies evaluating steam dilution effects on S L , both Kuznetsov et al [16] and Lyu et al [17] note a nonmonotonic pressure effect (increase followed by decrease with increasing pressure) in H 2 -O 2 and H 2 -air mixtures, respectively, with the effect in the latter observed up to 12%vol H 2 O. This has been identified as related to the increased role of third body reactions such as H+O 2 (+M) = HO 2 (+M) with increasing pressure [16,17]. Similar nonmonotonic behaviour of the extinction strain rate, κ ext , as a function of pressure was observed by Niemann et al [18] in a diffusion counterflow flame with H 2 -N 2 fuel and air as oxidizer, influenced by the same third body reaction noted previously.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Kinetic Evaluation of Pressurized Lean Premixed Hydrogen-Air Flame Stability With Carbon Dioxide and Steam Dilution

Runyon

Pugh

Giles

et al. 2020

Volume 4B: Combustion, Fuels, and Emissions

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A study has been undertaken to experimentally and numerically evaluate the use of carbon dioxide or steam as premixed fuel additive in hydrogen-air flames to aid in the development of lean premixed (LPM) swirl burner technology for low NOx operation. Chemical kinetics modelling indicates that the use of CO2 or steam in the premixed reactants reduces H2-air laminar flame speed and adiabatic flame temperature within the well-characterized range of preheated LPM methane-air flames, albeit in markedly different proportions; for example, nearly 65 %vol CO2 as a proportion of the fuel is required for a reduction in laminar flame speed to equivalent CH4-air values, while approximately 30 %vol CO2 in the fuel is required for an equivalent reduction in adiabatic flame temperature, significantly impacted by the increased heat capacity of CO2. The 2nd generation high-pressure generic swirl burner, designed for use with LPM CH4-air, was therefore utilized to experimentally investigate the influence of CO2 and steam dilution on pressurized (up to 250 kW/MPa), preheated (up to 573 K), LPM H2-air flame stability using high-speed OH* chemiluminescence. In addition, exhaust gas emissions, such as NOx and CO, have been measured in comparison with equivalent thermal power conditions for CH4-air flames, showing that low NOx operation can be achieved. Furthermore, pure LPM H2-air flames are characterized for the first time in this burner, stabilized at low equivalence ratio (approximately 0.24) and increased Reynolds number at atmospheric pressure compared to the stable CH4-air flame (equivalence ratio of 0.55). The influence of extinction strain rate is suggested to characterize, both experimentally and numerically, the observed lean flame behavior, in particular as extinction strain rate has been shown to be non-monotonic with pressure for highly-reactive and diffuse fuels such as hydrogen.

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Effects of steam dilution on laminar flame speeds of H2/air/H2O mixtures at atmospheric and elevated pressures

Cited by 37 publications

References 60 publications

Adaptability of different mechanisms and kinetic study of methane combustion in steam diluted environments

Adaptability of different mechanisms and kinetic study of methane combustion in steam diluted environments

Effects of hydrogen and primary air in a commercial partially-premixed atmospheric gas burner by means of optical and supervised machine learning techniques

Experimental and Kinetic Evaluation of Pressurized Lean Premixed Hydrogen-Air Flame Stability With Carbon Dioxide and Steam Dilution

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