scholarly journals Spectral and total radiation properties of turbulent carbon monoxide/air diffusion flames

AIAA Journal ◽  
1987 ◽  
Vol 25 (2) ◽  
pp. 339-345 ◽  
Author(s):  
G. M. Faeth ◽  
J. P. Gore ◽  
S.-M. Jeng
Keyword(s):  
Carbon Monoxide ◽  
Diffusion Flames ◽  
Total Radiation ◽  
Radiation Properties ◽  
Air Diffusion

scholarly journals A Numerical Study on the Effect of CO Addition on Flame Temperature and NO Formation in Counterflow CH4/Air Diffusion Flames

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Hongsheng Guo ◽  
W. Stuart Neill
Keyword(s):  
Carbon Monoxide ◽  
Strain Rate ◽  
Diffusion Flames ◽  
Numerical Study ◽  
Formation Rate ◽  
Flame Temperature ◽  
No Emission ◽  
No Formation ◽  
Air Diffusion ◽  
Emission Index

A numerical study was carried out to understand the effect of CO enrichment on flame temperature and NO formation in counterflow CH4/air diffusion flames. The results indicate that when CO is added to the fuel, both flame temperature and NO formation rate are changed due to the variations in adiabatic flame temperature, fuel Lewis number, and chemical reaction. At a low strain rate, the addition of carbon monoxide causes a monotonic decrease in flame temperature and peak NO concentration. However, NO emission index first slightly increases, and then decreases. At a moderate strain rate, the addition of CO has negligible effect on flame temperature and leads to a slight increase in both peak NO concentration and NO emission index, until the fraction of carbon monoxide reaches about 0.7. Then, with a further increase in the fraction of added carbon monoxide, all three quantities quickly decrease. At a high strain rate, the addition of carbon monoxide causes increase in flame temperature and NO formation rate, until a critical carbon monoxide fraction is reached. After the critical fraction, the further addition of carbon monoxide leads to decrease in both flame temperature and NO formation rate.

Spectral and Total Radiation Properties of Turbulent Hydrogen/Air Diffusion Flames

1987 ◽  
Vol 109 (1) ◽  
pp. 165-171 ◽  
Author(s):  
J. P. Gore ◽  
S.-M. Jeng ◽  
G. M. Faeth
Keyword(s):  
Diffusion Flames ◽  
Radiant Heat ◽  
Streamwise Velocity ◽  
Equilibrium Structure ◽  
Heat Fluxes ◽  
Laminar Flames ◽  
Spectral Radiation ◽  
Radiation Properties ◽  
Method Effects ◽  
Air Diffusion

A study of the structure and radiation properties of round turbulent hydrogen/air diffusion flames is described. Measurements were made of mean and fluctuating streamwise velocity, mean temperatures, species concentrations, spectral radiation intensities, and radiant heat fluxes. The measurements were used to evaluate predictions based on the laminar flamelet concept and narrow-band radiation models both ignoring (using mean properties) and considering (using a stochastic method) effects of turbulence/radiation interactions. State relationships found by correlating auxiliary measurements in laminar flames proved to be almost equivalent to conditions for local thermodynamic equilibrium. Structure and radiation predictions were reasonably good for present test conditions. Effects of turbulence/radiation interactions were significant for these flames, causing almost a 100 percent increase in spectral radiation intensities, in comparison to mean property predictions, upstream of the flame tip.

scholarly journals Structure and Radiation Properties of Luminous Turbulent Acetylene/Air Diffusion Flames

1988 ◽  
Vol 110 (1) ◽  
pp. 173-181 ◽  
Author(s):  
J. P. Gore ◽  
G. M. Faeth
Keyword(s):  
Radiative Heat ◽  
Diffusion Flames ◽  
Mixture Fraction ◽  
Heat Fluxes ◽  
Band Model ◽  
Spectral Radiation ◽  
Radiative Heat Loss ◽  
Radiation Properties ◽  
Air Diffusion ◽  
Laminar Flamelet

An experimental and theoretical study of the structure and radiation properties of luminous, round, turbulent acetylene/air diffusion flames is described. Measurements were made of mean and fluctuating velocities, mean concentrations, laser extinction (514 and 632.8 nm), spectral radiation intensities (1200–5500 nm), and radiative heat fluxes. The measurements were used to evaluate structure predictions based on the laminar flamelet concept, and radiation predictions based on a narrow-band model both ignoring and considering turbulence/radiation interactions. State relationships needed for the laminar flamelet concept were found from auxiliary measurements in laminar flames. Predictions were encouraging; however, quantitative accuracy was inferior to earlier findings for luminous flames. This is attributed to the large radiative heat loss fractions of acetylene/air flames (approaching 60 percent of the heat release rate); coupled structure and radiation analysis should be considered for improved results. The findings suggest significant turbulence/radiation interactions (increasing spectral intensities 40–100 percent from estimates based on mean properties); and that soot volume fractions may approximate universal fractions of mixture fraction in turbulent acetylene/air diffusion flames.

scholarly journals Structure and radiation properties of large-scale natural gas/air diffusion flames

1986 ◽  
Vol 10 (3-4) ◽  
pp. 161-169 ◽  
Author(s):  
J. P. Gore ◽  
G. M. Faeth ◽  
D. Evans ◽  
D. B. Pfenning
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Diffusion Flames ◽  
Radiation Properties ◽  
Air Diffusion

scholarly journals A Numerical Study on the Effect of CO Addition on Flame Temperature and NO Formation in Counterflow CH4/Air Diffusion Flames

2007 ◽  
Author(s):  
Hongsheng Guo ◽  
W. Stuart Neill
Keyword(s):  
Carbon Monoxide ◽  
Strain Rate ◽  
Diffusion Flames ◽  
Numerical Study ◽  
Formation Rate ◽  
Flame Temperature ◽  
No Emission ◽  
No Formation ◽  
Air Diffusion ◽  
Emission Index

A numerical study was carried out to understand the effect of carbon monoxide enrichment on flame temperature and NO formation in counterflow methane/air diffusion flames. Detailed chemistry and complex thermal and transport properties were employed. The results indicate that when carbon monoxide is added to the fuel, both flame temperature and NO formation rate are changed due to the variations in adiabatic flame temperature, fuel Lewis number and chemical reaction. The combination effects of three factors result in the different characteristics of flame temperature and NO formation at various strain rates, when carbon monoxide is added. At a low strain rate, the addition of carbon monoxide causes a monotonic decrease in flame temperature and peak NO concentration. However, NO emission index first slightly increases, and then decreases. When the value of strain rate is moderate, the addition of carbon monoxide has negligible effect on flame temperature and leads to a slight increase in both peak NO concentration and NO emission index, until the fraction of carbon monoxide reaches about 0.7. Then with a further increase in the fraction of added carbon monoxide, all three quantities quickly decrease. When strain rate is increased to a value close to the strain extinction limit of pure methane/air diffusion flame, the addition of carbon monoxide causes increase in flame temperature and NO formation rate, until a critical carbon monoxide fraction is reached. After the critical fraction, the further addition of carbon monoxide leads to decrease in both flame temperature and NO formation rate. The paper also analyzed the variation in the mechanism of NO formation, when carbon monoxide is added.

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