Nonluminous diffusion flame of diluted acetylene in oxygen-enriched air

Sugiyama, Gen

doi:10.1016/s0082-0784(06)80691-0

Cited by 27 publications

(9 citation statements)

References 5 publications

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“…The positive value of the radial velocity is a typical feature of highly diluted diffusion flames burning in oxygen [17]. In the high-temperature region of a diffusion flame, in fact, two mechanisms tend to accelerate the flow, buoyancy, and thermal expansion.…”

Section: Resultsmentioning

confidence: 99%

Structure of laminar coflow spray flames at different pressures

Russo¹,

Gomez²

2002

Proceedings of the Combustion Institute

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Experiments were conducted on laminar spray diffusion flames of ethanol/argon burning in oxygen at pressures of 1 and 3 atm. The flames were physically characterized by measuring droplet velocities and sizes by phase-Doppler anemometry, and gas temperature by thin-filament pyrometry and thermocouples. The flames exhibited a cold core, where little vaporization occurred, surrounded by a primary diffusion flame enveloping most of the droplet cloud. Their structure was strongly influenced by the Peclet number for heat transfer that, by regulating the heat penetrating into the core, and, consequently, the growth of the thermal boundary layer, affected the droplet vaporization history. At pressures above the atmospheric, because of density effects on thermal diffusivity, the boundary layer growth above the burner was reduced and so was the vaporization region. Complete evaporation of the droplets before they reached the primary diffusion flame was ensured if a suitably defined Damkö hler number of evaporation, Da v , was smaller than 1. Conversely, if Da v Ͼ 1, droplets penetrated the flame, ignited by a flame transfer process that was captured photographically, and burned isolated on the oxidizer side. These conditions of internal or partial group combustion prevailed in the lower part of the flame. Farther up in the flame, this combustion regime progressively shifted toward that of external group combustion, with fewer and fewer direct droplet/flame interactions.

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Section: Resultsmentioning

confidence: 99%

Structure of laminar coflow spray flames at different pressures

Russo¹,

Gomez²

2002

Proceedings of the Combustion Institute

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“…A first conclusion on the structure of the flames can be drawn on the basis of the presented data. Differently from diffusion flames in air [18], these highly diluted diffusion flames were momentumcontrolled in the center while presenting a buoyancycontrolled annulus on the outside. For flames at lower Ri, buoyancy "intervention" was delayed with respect to flames with higher buoyancy to inertia ratio.…”

Section: Gas Velocity Scaling and Self-similar Behaviormentioning

confidence: 99%

Physical characterization of laminar spray flames in the pressure range 0.1–0.9 MPa

Russo

Gomez

2006

Combustion and Flame

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“…While fast mixing reduces soot formation within diffusion flames, past studies of both laminar opposed and coflowing jet diffusion flames show that the way that mixing is carried out is important as well [9][10][11][12][13][14][15][16][17]. In fact, existing evidence from both laminar and turbulent jet diffusion flames, and from empirical industrial practice, suggests that soot reductions can be achieved most effectively by ensuring that velocities normal to the flame sheet are directed from the fuel-rich toward the fuel-lean side.…”

Section: Motivatedmentioning

confidence: 99%

“…Studies of effects of velocities normal to the flame sheet on soot formation have been carried out in laminar opposed and coflowing jet diffusion flames [9][10][11][12][13][14][15][16][17]. During most of these studies [9][10][11][12][13][14][15], velocities normal to the flame sheet were varied by varying the compositions of the oxidant-and fuel-carrying streams. For example, diluting the fuel stream with an inert gas (e.g., nitrogen) while enriching the oxidant stream by removing existing diluent (e.g., removing nitrogen from air) promotes increased velocities normal to the flame sheet directed from the fuel-rich toward the fuel-lean side and yields reduced soot concentrations in the flame [9--14].…”

Section: Motivatedmentioning

confidence: 99%