Spectral Radiation Properties of Partially Premixed Turbulent Flames

2003 ◽  
Vol 125 (6) ◽  
pp. 1065-1073 ◽  
Author(s):  
Yuan Zheng ◽  
R. S. Barlow ◽  
Jay P. Gore
Keyword(s):  
Reynolds Number ◽  
Turbulent Flames ◽  
Turbulent Jet ◽  
Mean Square ◽  
Autocorrelation Coefficient ◽  
Spectral Radiation ◽  
Length Scales ◽  
Premixed Turbulent Flames ◽  
Power Spectral ◽  
Radiation Properties

Instantaneous spectral radiation intensities of three standard turbulent jet flames were measured and simulated in this study. In the simulation, a recently developed technique was adapted to reconstruct the local integral time and length scales in the flames. The simulated radiation properties, including mean, root mean square, probability density function, power spectral density and autocorrelation coefficient, were generally within 10% of the measurements. The macro time and length scales were found to increase with increasing distance from the axis and the radial averages of these scales were found to increase with down stream distance but decrease with Reynolds number.

Spectral Radiation Properties of a Turbulent Ethylene Pool Fire

2008 ◽  
Author(s):  
Kaushik Biswas ◽  
Yuan Zheng ◽  
Jay Gore
Keyword(s):  
Pool Fires ◽  
Spectral Radiation ◽  
Gaseous Species ◽  
Burner Exit ◽  
Power Spectral ◽  
Radiation Properties ◽  
Power Spectral Densities ◽  
Past Data ◽  
Spectrally Resolved ◽  
Oscillation Frequencies

In the present work, line-of-sight spectral radiation intensities (Iλ) were measured in a 7.1 cm ethylene (C2H4) buoyant diffusion flame, designed to mimic pool fires. Various time series statistics were calculated using the radiation data. Both soot and gaseous species had significant radiation emissions, emphasizing the need for spectrally-resolved radiation measurements. Significant fluctuations were observed in the radiation intensities from the fire, especially at higher elevations and near the flame edges. In addition, root-mean-square (rms) and probability density functions (PDF) of Iλ indicated higher fluctuations in soot compared to gaseous species. Autocorrelations of Iλ showed periodic oscillations due to the puffing phenomenon typically seen in pool fires. The observed oscillation frequencies ranged from 7.47 to 7.86 Hz and are in excellent agreement with empirical correlations based on past data. Characteristic frequencies of these oscillations were also reflected in the power spectral densities (PSD) of Iλ. Based on the measured autocorrelations of Iλ, it was observed that the integral time scales decrease with increasing height above the burner exit, which is expected since mean velocities increase with height due to combustion-induced buoyancy in pool fires and buoyant flames.

Transient Structure and Radiation Properties of Strongly Radiating Buoyant Flames

1992 ◽  
Vol 114 (3) ◽  
pp. 659-665 ◽  
Author(s):  
Y. R. Sivathanu ◽  
J. P. Gore
Keyword(s):  
Probability Density ◽  
Probability Density Functions ◽  
Density Functions ◽  
Spectral Densities ◽  
Spectral Radiation ◽  
Volume Fractions ◽  
Power Spectral ◽  
Radiation Properties ◽  
Power Spectral Densities ◽  
Instantaneous Temperature

Measurements of instantaneous temperature and soot volume fractions based on absorption and emission in highly buoyant turbulent acetylene/air and propylene/air flames are reported. These measurements are used to predict mean, rms, probability density functions, and power spectral densities of spectral radiation intensities along a representative horizontal chord in the flame. The results show the presence of large quantities of relatively cold soot in the vicinity of smaller amounts of hot soot particles. The resulting inhomogeneity in the temperature of soot in the flame leads to negative cross correlations between temperature and soot volume fractions. The treatment of such correlations was found necessary for predicting the observed probability density functions and the power spectral densities of spectral radiation intensities.

Modeling of liftoff heights of non-premixed turbulent flames in co-flows having various temperatures and O2 concentrations

Fuel ◽  
2021 ◽  
Vol 306 ◽  
pp. 121678
Author(s):  
Yuzuru Nada ◽  
Yoshiyuki Kidoguchi ◽  
Hidenari Sakai ◽  
Yuto Moriyama
Keyword(s):  
Turbulent Flames ◽  
Premixed Turbulent Flames

Time-resolved density measurements in premixed turbulent flames

AIAA Journal ◽  
1984 ◽  
Vol 22 (5) ◽  
pp. 655-663 ◽  
Author(s):  
F. C. Gouldin ◽  
K. V. Dandekar
Keyword(s):  
Turbulent Flames ◽  
Time Resolved ◽  
Density Measurements ◽  
Premixed Turbulent Flames
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