Investigation of nitrogen dilution effects on the laminar burning velocity and flame stability of syngas fuel at atmospheric condition

Prathap, Chockalingam; Ray, Anjan

doi:10.1016/j.combustflame.2008.04.005

Cited by 224 publications

(93 citation statements)

References 30 publications

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“…Figure 2 shows the measured laminar burning velocity of H 2 /CO/air mixtures compared with those of previous studies [42,[47][48][49][50][51][52]; all the data were measured with a spherically propagating flame at P u = 0.1 MPa and all data are in good agreement. This proves the correctness of the data obtained in this investigation.…”

Section: System Validation and Laminar Burning Velocitysupporting

confidence: 63%

Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

Sun

et al. 2014

Energies

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An experimental study of the intrinsic instabilities of H 2 /CO lean (φ = 0.4 to φ = 1.0) premixed flames at different hydrogen fractions ranging from 0% to 100% at elevated pressure and room temperature was performed in a constant volume vessel using a Schlieren system. The unstretched laminar burning velocities were compared with data from the previous literature and simulated results. The results indicate that excellent agreements are obtained. The cellular instabilities of syngas-air flames were discussed and critical flame radii were measured. When hydrogen fractions are above 50%, the flame tends to be more stable as the equivalence ratio increases; however, the instability increases for flames of lower hydrogen fractions. For the premixed syngas flame with hydrogen fractions greater than 50%, the decline in cellular instabilities induced by the increase in equivalence ratio can be attributed to a reduction of diffusive-thermal instabilities rather than increased hydrodynamic instabilities. For premixed syngas flames with hydrogen fractions lower than 50%, as the equivalence ratio increases, the cellular instabilities become more evident because the enhanced hydrodynamic instabilities become the dominant effect. For premixed syngas flames, the enhancement of cellular instabilities induced by the increase in hydrogen fraction is the result of both increasing diffusive-thermal and hydrodynamic instabilities.

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Section: System Validation and Laminar Burning Velocitysupporting

confidence: 63%

Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

Sun

et al. 2014

Energies

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“…The analysis of ignition properties for complete H 2 /CO composition range at elevated temperatures and pressures applicable to gas turbine premixed combustion was also reported [5]. At the same time, N 2 dilution effect on flame stability of premixed syngas fuel has been carried out [6]. Meanwhile investigations of the non-premixed combustion of syngas fuel mixtures including blended natural gas/hydrogen have been reported in the literature mainly on the flame stability issues.…”

Section: Introductionmentioning

confidence: 99%

Influence of fuel variability on the characteristics of impinging non-premixed syngas burning

Dinesh

Jiang

Oijen

et al. 2013

Proceedings of the Combustion Institute

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Investigations of instantaneous flame characteristics and near-wall heat transfer of syngas mixtures including H 2 -rich and H 2 -lean flames have been performed in an impinging non-premixed configuration for a Reynolds number of 2000 and a nozzle-to-plate distance of 4 jet nozzle diameters by direct numerical simulation and flamelet generated manifold chemistry. The results presented were obtained from simulations using a uniform Cartesian grid with 200 Â 600 Â 600 points. The spatial discretisation was carried out using a sixth-order accurate compact finite difference scheme and the discretised equations were advanced using a third-order accurate fully explicit compact-storage Runge-Kutta scheme. Results were discussed for the flame characteristics, reaction progress variable, velocity field and Nusselt number distributions. Significant differences have been found for the flame characteristics of syngas burning depending on the hydrogen, carbon monoxide, carbon dioxide and nitrogen percentages of the syngas mixture. High diffusivity in the H 2 -rich flame leads to form weaker vortical structures and thicker flames than those in the H 2 -lean flame. It has been observed that the maximum flame temperature decreases from the H 2 -rich to the H 2 -lean flames. It is also found that the maximum flame temperature occurs at the lean side of the stoichiometric mixture fraction of the syngas fuel mixtures. The composition of the syngas mixture has a significant impact on the flame characteristics of the impinging flame, including the near-wall flame structure and heat transfer.

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“…The primary focus is on the manifestation of this effect in the flame shape evolution, flame propagation speed, and burned gas speeds along the r-axis in chambers having a length greater than their diameter. These factors and conditions encompass all of the research conducted previously in cylindrical chambers [25,1,35,[37][38][39]. Figure 4 presents the experimental data for flame propagation speed history along the raxis of a closed cylindrical chamber for equivalence ratios of 1.0 and 3.0 and the numerical solution of the flamelet model for a cylindrical chamber of the same aspect ratio as the experiment.…”

Section: Effect Of Cylindrical Confinement On Laminar Flame Speed Meamentioning

confidence: 99%

Reduced and Validated Kinetic Mechanisms for Hydrogen-CO-sir Combustion in Gas Turbines

Ju¹,

Dryer²

2009

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Rigorous experimental, theoretical, and numerical investigation of various issues relevant to the development of reduced, validated kinetic mechanisms for synthetic gas combustion in gas turbines was carried out -including the construction of new radiation models for combusting flows, improvement of flame speed measurement techniques, measurements and chemical kinetic analysis of H 2 /CO/CO 2 /O 2 /diluent mixtures, revision of the H 2 /O 2 kinetic model to improve flame speed prediction capabilities, and development of a multi-time scale algorithm to improve computational efficiency in reacting flow simulations. Executive SummaryRigorous experimental, theoretical, and numerical investigation of various issues relevant to the development of reduced, validated kinetic mechanisms for synthetic gas combustion in gas turbines was carried out -including the construction of new radiation models for combusting flows, improvement of flame speed measurement techniques, measurements and chemical kinetic analysis of H 2 /CO/CO 2 /O 2 /diluent mixtures, revision of the H 2 /O 2 kinetic model to improve flame speed prediction capabilities, and development of a multi-time scale algorithm to improve computational efficiency in reacting flow simulations.An accurate spectral dependent radiation model is developed to predict flame speed and flammability of H 2 /CO/CO 2 /H 2 O/Air mixtures. The results showed that radiation reabsorption significantly extended the flammability limits. It was also demonstrated that accurate prediction of coal syngas flammability is not possible without appropriate consideration of radiation absorption by CO 2 and H 2 O.Methodologies to improve flame speed measurement were developed by experimental and theoretical investigation of the effect of non-spherical (i.e. cylindrical) bomb geometry on the evolution of outwardly propagating flames and the determination of laminar flame speeds. The cylindrical chamber boundary modifies the propagation rate through the interaction of the wall with the flow induced by thermal expansion across the flame (even with constant pressure), which leads to significant distortion of the flame surface for large flame radii. It was determined that these departures from the unconfined case, especially the resulting non-zero burned gas velocities, can lead to significant errors in flame speeds calculated using the conventional assumptions, especially for large flame sizes.The methodology to estimate the effect of nonzero burned gas velocities is applied to correct the flame speed for non-zero burned gas speeds, in order to extend the range of flame radii useful for flame speed measurements. Under the proposed scaling, the burned gas speed can be well approximated as a function of only flame radius for a given chamber geometry -i.e. the correction function need only be determined once for an apparatus and then it can be used for any mixture. Results indicate that the flow correction can be used to extract flame speeds for flame radii up to 0.5 times the wall radius wi...

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Investigation of nitrogen dilution effects on the laminar burning velocity and flame stability of syngas fuel at atmospheric condition

Cited by 224 publications

References 30 publications

Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

Influence of fuel variability on the characteristics of impinging non-premixed syngas burning

Reduced and Validated Kinetic Mechanisms for Hydrogen-CO-sir Combustion in Gas Turbines

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