Correlations for the Laminar-Burning Velocity of Methane/Diluent/Air Mixtures Obtained in Free-Fall Experiments

Stone, Richard; Clarke, A.G.; Beckwith, P.

doi:10.1016/s0010-2180(97)00329-5

Cited by 167 publications

(85 citation statements)

References 13 publications

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“…This deviation from the actual gases will have minimal impact on the results as nitrogen and carbon dioxide behave similarly in flames. Laminar flame speed and flame temperature for methane-air flames diluted with nitrogen and/or carbon dioxide have shown to exhibit similar behavior [15,16]. Diluting the reactants with a nitrogen-carbon dioxide-water vapor mixture also resulted in similar behavior to that of nitrogen [17].…”

Section: Approachmentioning

confidence: 92%

Impact of internal entrainment on high intensity distributed combustion

Khalil

Gupta

2015

Applied Energy

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h i g h l i g h t sExamined the role of entrainment on Distributed Combustion under different conditions. N 2 and CO 2 are used to simulate entrained combustion gases from within the combustor. Low O 2 concentration in the mixture prior to ignition fostered distributed reaction. Reaction distribution demonstrated at 15% O 2 and lower, with almost invisible flame. 80-90% NO reduction demonstrated at oxygen concentration of 15% in the mixture. a b s t r a c tColorless Distributed Combustion (CDC) has shown ultra-low emissions and enhanced performance of simulated gas turbine combustors. To achieve distributed combustion, the flowfield must be tailored for desirable mixture preparation within the combustor prior to mixture ignition. Though CDC have been extensively studied using a variety of geometries, heat release intensities, and fuels, the role of internally recirculated hot reactive gases needs to be further investigated and quantified to obtain the minimum requirement of internal entrainment for achieving distributed reaction condition. In this paper, the impact of internal entrainment of product gases on flame structure and behavior is investigated with focus on fostering distributed combustion and to provide guidelines for seeking distributed combustion. To simulate the recirculated gases from within the combustor, a mixture of nitrogen and carbon dioxide is introduced to the air stream prior to mixing with fuel and combustion. Increase in the amounts of nitrogen and carbon dioxide (simulating increased recirculation) increased the reaction volume to occupy larger volume with an overall enhanced and uniform distribution as revealed from the OH ⁄ chemiluminescence intensity. At the same time, the bluish flame is replaced with a more uniform almost invisible bluish flame. The increased recirculation also decreased the NO emission significantly for the same amount of fuel burned. Lowering oxygen concentration from 21% to 15% (due to increased recirculation) resulted in 80-90% reduction in NO with no impact on CO emission with sub PPM NO emission achieved at an equivalence ratio of 0.7. The same trend was demonstrated for a range of recirculated gases temperature. The reaction distribution was significantly enhanced with ultra-low emissions for oxygen concentration lower than 16% setting a minimum recirculation requirement for distributed combustion.

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Section: Approachmentioning

confidence: 92%

Impact of internal entrainment on high intensity distributed combustion

Khalil

Gupta

2015

Applied Energy

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“…Hydrogen enrichment alone leads to higher burning velocities [11,[16][17][18][19][20][21], while dilution by nitrogen leads to decrease of the burning velocity [20,[22][23][24] and to decrease of NO x emissions [25,26]. Simultaneous effects of the enrichment by hydrogen and dilution by nitrogen have been investigated [27,28], yet NO x formation has not been studied in laminar premixed nonstretched flames of these mixtures.…”

Section: Introductionmentioning

confidence: 99%

The effects of composition on burning velocity and nitric oxide formation in laminar premixed flames of CH4 + H2 + O2 + N2

Coppens

Ruyck

Konnov

2007

Combustion and Flame

166

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“…Accurate measurement of unstretched laminar burning velocity, especially for the heavier hydrocarbon fuels typically used in internal combustion engine applications, is necessary for assessing combustion theories and the validation of numerical models. Since the early 1990s, experimental investigations have utilized a variety of flame configurations, including both isobaric [1][2][3][4][5][6][7][8] and nonisobaric [9,10] outwardly propagating spherical flames, flat counterflow flames [11,12], and flat adiabatic flames stabilized above a perforated plate burner to achieve nearly stretch-free conditions [13]. The stagnation flow of Vagelopoulos and Egolfopoulos [14] facilitates direct measurements of unstretched burning velocities, therefore eliminating the extrapolation to zero stretch rate required by other methods.…”

Section: Introductionmentioning

confidence: 99%