Sooting Counterflow Diffusion Flames with Varying Oxygen Index

Vandsburger, Uri; Kennedy, Ian M.; Glassman, Irvin

doi:10.1080/00102208408923792

Cited by 83 publications

(21 citation statements)

References 17 publications

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“…It should be noted that this increase is not a thermal but a chemical effect. Earlier work by Vandsburger et aL (1984) showed that due to an increase in the oxygen index from 0.20 to 0.22, the peak soot loadings in ethene flames increased from 0.70£-06 to 1.0£-06 only as the flame temperature changed from 1825 to 1925 K. The present data show a much larger effect with only a 29 K increase in the flame temperature. The particle diameters increased substantially in ethene flames, whereas only small changes were observed in the other flames.…”

Section: Til Experimental Resultscontrasting

confidence: 39%

“…The soot volume fraction, particle size, and number density were determined from the laser light scattering and extinction (LLS) measurements. The arrangement of the optical components is shown in Figure 2 and the details of this system have already been published (Vandsburger et al, 1984). The data reduction was performed using Mie theory for light scattering and extinction by spherical particles.…”

Section: Introductionmentioning

confidence: 99%

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Fuel Oxygen Effects on Soot Formation in Counterflow Diffusion Flames

Hura

Glassman

1987

Combustion Science and Technology

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Section: Til Experimental Resultscontrasting

confidence: 39%

Section: Introductionmentioning

confidence: 99%

Fuel Oxygen Effects on Soot Formation in Counterflow Diffusion Flames

Hura

Glassman

1987

Combustion Science and Technology

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“…Fuel structure plays an important role in the formation and growth of PAHs and soot [5][6][7][8][9] because the concentrations of certain species, which can activate reactions related to PAH and soot, are highly dependent on fuel structure. Especially, the role of acetylene (C 2 H 2 ), which maintains a relatively high concentration in the high-temperature region, has been emphasized through the sequential pathway of H-abstraction-C 2 H 2 -addition (HACA) reactions [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Synergistic effect on soot formation in counterflow diffusion flames of ethylene–propane mixtures with benzene addition

Lee

Yoon

Chung

2004

Combustion and Flame

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“…The rate of soot production depends on the rate of surface growth and the rate of formation of soot precursor produced during fuel pyrolysis [18]. The latter process is more sensitive to oxygen concentration and flame temperature.…”

Section: Counterflow Field and Flame Appearancementioning

confidence: 99%

Water Droplets Behavior in Extinguishing the Methane-Air Counterflow Diffusion Flame

Yoshida¹,

Uendo²,

Takasaki³

et al. 2011

Fire Safety Science - Proceedings of the 10th International Sym

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The behavior of fine water droplets was investigated in a methane-air counterflow diffusion flame, specifically when the water droplets were added to the inlet air feed and used to extinguish the diffusion flame. The water droplets studied had a relatively broad size distribution (from 1 to 60 m), with the number mean diameter of 15 m and Sauter mean diameter of 25 m. With an increase in the velocity gradient, the flame approaches towards the stagnation plane and flame thickness decreases. The flame properties, such as flame location and flame thickness are insensitive to the water mass loading. Along the stagnation stream line, the velocity decreases towards a local minimum just before the flame front. In contrast, the velocity increases in the flame zone due to the thermal expansion, and then decreases towards the stagnation point. In the decelerating zone, the droplet mass flux decreases on approach to the flame zone due to a non-equilibrium in velocity of large droplets between liquid and gas phases. Furthermore, as the droplet-laden air approaches the flame front, the flow stream begins to diverge in the counterflow field. Since the small droplets move away from the burner axis, the divergence of the air flow acts to reduce the water droplet mass flux along the stagnation streamline. Large droplets moving faster than the air flow "catch up" to slower ones just before the flame front, and the mass flux of the droplets tends to increase, resulting in the droplets accumulating just before the flame zone. Measurements of the velocities of individual droplets show that large droplets move faster than the small droplets which are in equilibrium (in velocity) between liquid and gas phases. Droplet behavior was found to be controlled by the Stokes number. Equilibrium in velocity is re-established just in front of the flame zone. Closer to the flame front, evaporation occurs and the mass flux of the droplets decreases drastically. On the other hand, thermophoresis acts on extremely small droplets to move them along the steep temperature gradient and these droplets are forced from the high to low temperature regions against the convection velocity. The thermophoretic velocity was estimated in the present study to be compared with the measured convection velocity and it was concluded that the thermophoretic effect is negligibly small over all sizes of droplets.

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Sooting Counterflow Diffusion Flames with Varying Oxygen Index

Cited by 83 publications

References 17 publications

Fuel Oxygen Effects on Soot Formation in Counterflow Diffusion Flames

Fuel Oxygen Effects on Soot Formation in Counterflow Diffusion Flames

Synergistic effect on soot formation in counterflow diffusion flames of ethylene–propane mixtures with benzene addition

Water Droplets Behavior in Extinguishing the Methane-Air Counterflow Diffusion Flame

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