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Title: Effects of hydrogen enrichment on adiabatic burning velocity and NO formation in methane + air flames

Abstract

Experimental measurements of the adiabatic burning velocity and NO formation in methane + hydrogen + air flames are presented. The hydrogen content in the fuel was varied from 0% to 35%. Non-stretched flames were stabilized on a perforated plate burner at 1 atm. The Heat Flux method was used to determine burning velocities under conditions when the net heat loss of the flame is zero. An overall accuracy of the burning velocities was estimated to be better than {+-}0.8 cm/s in the whole range of enrichment by hydrogen. A procedure for estimation of errors in equivalence ratio was extended to binary fuel mixtures. The relative accuracy of the equivalence ratio was found to be below 1.47%. Adiabatic burning velocities of methane + hydrogen + air mixtures were found in satisfactory agreement with the literature results and with the Konnov model predictions. A new correlation for the adiabatic laminar burning velocity of methane + hydrogen + air mixtures burning at standard conditions was derived. The NO concentrations as a function of equivalence ratio were measured using probe sampling at a fixed distance from the burner. In lean flames enrichment by hydrogen has little effect on [NO], while in rich flames themore » concentration of nitric oxide decreases significantly. The numerical predictions are in good agreement with the experiment. (author)« less

Authors:
; ;  [1]
  1. Department of Mechanical Engineering, Vrije Universiteit Brussel, IR-MECH, Pleinlaan 2, 1050 Brussels (Belgium)
Publication Date:
OSTI Identifier:
20864948
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Thermal and Fluid Science; Journal Volume: 31; Journal Issue: 5; Conference: MCS-4: 4. Mediterranean combustion symposium, Lisbon (Portugal), 6-10 Oct 2005; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; METHANE; HYDROGEN; AIR; VELOCITY; FLAMES; MIXTURES; NITRIC OXIDE; BURNERS; FORECASTING; CORRELATIONS; ACCURACY; HEAT FLUX; DATA COVARIANCES; TEMPERATURE RANGE 0273-0400 K; ADIABATIC PROCESSES; ATMOSPHERIC PRESSURE

Citation Formats

Coppens, F.H.V., De Ruyck, J., and Konnov, A.A. Effects of hydrogen enrichment on adiabatic burning velocity and NO formation in methane + air flames. United States: N. p., 2007. Web. doi:10.1016/J.EXPTHERMFLUSCI.2006.04.012.
Coppens, F.H.V., De Ruyck, J., & Konnov, A.A. Effects of hydrogen enrichment on adiabatic burning velocity and NO formation in methane + air flames. United States. doi:10.1016/J.EXPTHERMFLUSCI.2006.04.012.
Coppens, F.H.V., De Ruyck, J., and Konnov, A.A. Sun . "Effects of hydrogen enrichment on adiabatic burning velocity and NO formation in methane + air flames". United States. doi:10.1016/J.EXPTHERMFLUSCI.2006.04.012.
@article{osti_20864948,
title = {Effects of hydrogen enrichment on adiabatic burning velocity and NO formation in methane + air flames},
author = {Coppens, F.H.V. and De Ruyck, J. and Konnov, A.A.},
abstractNote = {Experimental measurements of the adiabatic burning velocity and NO formation in methane + hydrogen + air flames are presented. The hydrogen content in the fuel was varied from 0% to 35%. Non-stretched flames were stabilized on a perforated plate burner at 1 atm. The Heat Flux method was used to determine burning velocities under conditions when the net heat loss of the flame is zero. An overall accuracy of the burning velocities was estimated to be better than {+-}0.8 cm/s in the whole range of enrichment by hydrogen. A procedure for estimation of errors in equivalence ratio was extended to binary fuel mixtures. The relative accuracy of the equivalence ratio was found to be below 1.47%. Adiabatic burning velocities of methane + hydrogen + air mixtures were found in satisfactory agreement with the literature results and with the Konnov model predictions. A new correlation for the adiabatic laminar burning velocity of methane + hydrogen + air mixtures burning at standard conditions was derived. The NO concentrations as a function of equivalence ratio were measured using probe sampling at a fixed distance from the burner. In lean flames enrichment by hydrogen has little effect on [NO], while in rich flames the concentration of nitric oxide decreases significantly. The numerical predictions are in good agreement with the experiment. (author)},
doi = {10.1016/J.EXPTHERMFLUSCI.2006.04.012},
journal = {Experimental Thermal and Fluid Science},
number = 5,
volume = 31,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • Experimental measurements of adiabatic burning velocity and NO formation in (CH{sub 4} + H{sub 2}) + (O{sub 2} + N{sub 2}) flames are presented. The hydrogen content in the fuel was varied from 0 to 35% and the oxygen content in the air from 20.9 to 16%. Nonstretched flames were stabilized on a perforated plate burner at 1 atm. The heat flux method was used to determine burning velocities under conditions when the net heat loss of the flame is zero. Adiabatic burning velocities of methane + hydrogen + nitrogen + oxygen mixtures were found in satisfactory agreement with themore » modeling. The NO concentrations in these flames were measured in the burnt gases at a fixed distance from the burner using probe sampling. In lean flames, enrichment by hydrogen has little effect on [NO], while in rich flames, the concentration of nitric oxide decreases significantly. Dilution by nitrogen decreases [NO] at any equivalence ratio. Numerical predictions and trends were found in good agreement with the experiments. Different responses of stretched and nonstretched flames to enrichment by hydrogen are demonstrated and discussed. (author)« less
  • Experimental measurements of the adiabatic burning velocity and NO formation in C{sub 2}H{sub 4}+ O{sub 2}+ N{sub 2} flames are presented. The oxygen content in synthetic air varied from 18% down to 14%. Non-stretched flames were stabilized on a perforated plate burner at 1 atm. A heat flux method was used to determine the burning velocities under the conditions when the net heat loss of the flame is zero. Adiabatic burning velocities of ethylene + nitrogen + oxygen mixtures were found in good agreement with the modeling. Sampling measurements were performed at 10-20 mm from the burner and concentrations ofmore » stable species, CO, CO{sub 2}, O{sub 2} and NO{sub x} were recorded. The concentrations of CO, CO{sub 2} and O{sub 2} were compared with the modeling to reveal that the range of the flame conditions was less affected by the ambient air entrainment. The dependencies of [NO] as a function of equivalence ratio clearly possess two maxima: in stoichiometric mixtures due to Zeldovich thermal-NO mechanism and in rich mixtures at equivalence ratio close to 1.4 due to Fenimore prompt-NO mechanism. Dilution by nitrogen decreases [NO] at any equivalence ratio. Numerical predictions of the concentrations of NO in a post-flame zone of lean and stoichiometric flames are in good agreement with the experiments when downstream heat losses to the environment were taken into account. The predictions of the Konnov mechanism in rich ethylene flames reproduce trends of the experimental data with an under-prediction of about 10-15 ppm. (author)« less