Effects of inert dilution on the lean blowout characteristics of syngas flames

Li, Suhui; Zhang, Xiaoyu; Zhong, Di; Weng, Fanglong; Li, Shaoshuai; Zhu, Min

doi:10.1016/j.ijhydene.2016.02.099

Cited by 24 publications

(3 citation statements)

References 44 publications

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“…al. [21] studied the effects of diluents on the LBO limits of premixed syngas flames by using an atmospheric swirl flow combustor. Results showed that the LBO limits increase with the dilution ratio of N 2 , and that the inert dilution dominates the LBO behaviour of syngas with low H 2 content.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

H2-rich syngas strategy to reduce NOx and CO emissions and improve stability limits under premixed swirl combustion mode

Samiran

Jaafar

et al. 2016

International Journal of Hydrogen Energy

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The combustion performance of H 2-rich model syngas was investigated by using a premixed swirl flame combustor. Syngas consisting mainly of H 2 and CO was blended with components such as CH 4 and CO 2 in a mixing chamber prior to combustion at atmospheric condition. The global flame appearance and emissions performance were examined for high (H 2 /CO = 3) and moderate (H 2 /CO = 1.2) H 2-rich syngases. Results showed that higher H 2 fractions in the syngases produce lower NO x emissions per kWh basis across all equivalence ratios tested. CO emissions are equivalence ratio dependent and are less affected by the H 2 fraction in the syngas. Increasing CO 2 diluent ratios result in the decrease of NO x , particularly for moderate H 2-rich syngases. In contrast, syngas without CO shows an increase of NO x with increasing CO 2 for fuel-lean mixtures. Addition of CO 2 increases the lean blowout limit of all syngases. Higher fraction of H 2 produces lower lean blowout limits due to the characteristics of high diffusivity of hydrogen molecules and high flame speed that assist in the stabilisation of the flame under flame-lean conditions. The range of blowout limits for moderate and high H 2-rich and pure hydrogen syngases under diluent ratios up to 25% were within the range of φ = 0.12-0.15.

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Section: Accepted Manuscriptmentioning

confidence: 99%

H2-rich syngas strategy to reduce NOx and CO emissions and improve stability limits under premixed swirl combustion mode

Samiran

Jaafar

et al. 2016

International Journal of Hydrogen Energy

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“…Favre mean mixture fraction f 2 variance of mixture fraction m a total mass flow rate of combustor inlet, kg/s m f mass flow rate of fuel, kg/s m pri mass flow rate through primary swirler, kg/s m sec mass flow rate through secondary swirler, kg/s P 3 inlet pressure, Kpa PDF probability density function q LBO overall fuel/air ratio at lean blow-out, g/kg q LBO, predict lean blow-out predicted by empirical model, g/kg r correlation coefficient IRZ inner recirculation zone T 3 inlet temperature of combustor, K T crit threshold value of temperature, K V c combustor volume ahead of dilution holes, m 3…”

Section: Nomenclaturementioning

confidence: 99%

“…It is essentially flame extinction at flowing conditions. In gas turbine combustion, Lean Blow-Out (LBO) limit is a term referring to the equivalence ratio at which flame blow-out occurs when operated at lean fuel conditions (2) . The flame can only be stabilised above the LBO limit.…”

Section: Introductionmentioning

confidence: 99%

Flame volume prediction and validation for lean blow-out of gas turbine combustor

Ahmed

Huang

2017

Aeronaut. j.

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Lean Blow-Out (LBO) limits are critically important in the operation of aero engines. Previously, Lefebvre's LBO empirical correlation has been extended to the flame volume concept by the authors. Flame volume takes into account the effects of geometric configuration, spatial interaction of mixing jets, turbulence, heat transfer and combustion processes inside the gas turbine combustion chamber. For these reasons, LBO predictions based on flame volume are more accurate. Although LBO prediction accuracy has improved, it poses a challenge associated with Vfestimation in real gas turbine combustors. This work extends the approach of flame volume prediction based on fuel iterative approximation with cold flow simulations to reactive flow simulations. Flame volume for 11 combustor configurations were simulated and validated against experimental data. To make prediction methodology robust, as required in preliminary design stage, reactive flow simulations were carried out with the combination of presumed Probability Density Function (PDF) and discrete phase model (DPM) in Fluent 15.0 The criterion for flame identification was defined. Two important parameters—critical injection diameter (Dp,crit) and critical temperature (Tcrit)—were identified and their influence on reactive flow simulation was studied for Vfestimation. Results exhibit ±15% error in Vf estimation with experimental data.

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LES of Biomass Syngas Combustion in a Swirl Stabilised Burner: Model Validation and Predictions

Papafilippou,

Pignatelli,

Subash

et al. 2024

Flow Turbulence Combust

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In this work, numerical investigations were performed using large eddy simulations and validated against detailed measurements in the CeCOST swirl stabilised burner. Both cold and reactive flow have been studied and the model has shown a good agreement with experiments. The verification of the model was done using the LES index of quality and a single grid estimator. The cold flow simulations predicted results closely to experiments setting baseline for the reactive simulations. Coherent structures like the vortex rope above the swirler and a precessing vortex core in the combustion chamber were identified. The reactive conditions were modelled with the Flamelet generated manifold and artificially thickened flame models. Simulations were performed for an experimental syngas composition from black liquor gasification at three different CO2 dilution levels. Three different Reynolds numbers were investigated with the model matching closely to experimentally detected 2D flow field and OH for the most CO2 diluted mixture. It was found that the opening angles of the flames differ by a maximum of 13% between experiments and simulations. The most diluted fuel investigated experienced a liftoff distance of 23.5 mm at the Re 25 k. This was also the highest liftoff distance experienced in this cohort of fuels. The same fuel also proved to have the thickest flame annulus at 78.5 mm. Overall, in cases with no experimental data available the predictions made by the model follow the same trends which hints its applicability to higher Re cases.

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Effects of inert dilution on the lean blowout characteristics of syngas flames

Cited by 24 publications

References 44 publications

H2-rich syngas strategy to reduce NOx and CO emissions and improve stability limits under premixed swirl combustion mode

H2-rich syngas strategy to reduce NOx and CO emissions and improve stability limits under premixed swirl combustion mode

Flame volume prediction and validation for lean blow-out of gas turbine combustor

LES of Biomass Syngas Combustion in a Swirl Stabilised Burner: Model Validation and Predictions

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