Effect of buoyancy on soot formation in gas-jet diffusion flame

Jeon, Byoung-Ho; Choi, Jae-Hun

doi:10.1007/s12206-010-0406-4

Cited by 8 publications

(3 citation statements)

References 22 publications

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“…A factor of 2-4 increase in peak soot volume fraction was reported from 1 g to l g. Walsh et al [2] found that the laser induced incandescence (LII) signal of a methane coflow laminar diffusion flame increased by a factor of 15 during a parabolic flight. Jeon and Choi [3] studied the buoyancy effect on soot formation in a gas-jet diffusion flame in partial gravity conditions from 0.3 g to 1 g. The soot volume fraction was measured by extinction and found to increase with reduced gravity level. Reimann et al [4] performed LII in a drop tower, measuring both soot concentration and primary particle size.…”

Section: Introductionmentioning

confidence: 99%

An experimental and computational study of soot formation in a coflow jet flame under microgravity and normal gravity

Cao

Giassi

et al. 2015

Proceedings of the Combustion Institute

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Upon the completion of the Structure and Liftoff in Combustion Experiment (SLICE) in March 2012, a comprehensive and unique set of microgravity coflow diffusion flame data was obtained. This data covers a range of conditions from weak flames near extinction to strong, highly sooting flames, and enabled the study of gravitational effects on phenomena such as liftoff, blowout and soot formation. The microgravity experiment was carried out in the Microgravity Science Glovebox (MSG) on board the International Space Station (ISS), while the normal gravity experiment was performed at Yale utilizing a copy of the flight hardware. Computational simulations of microgravity and normal gravity flames were also carried out to facilitate understanding of the experimental observations. This paper focuses on the different sooting behaviors of CH 4 coflow jet flames in microgravity and normal gravity. The unique set of data serves as an excellent test case for developing more accurate computational models. Experimentally, the flame shape and size, lift-off height, and soot temperature were determined from line-of-sight flame emission images taken with a color digital camera. Soot volume fraction was determined by performing an absolute light calibration using the incandescence from a flame-heated thermocouple. Computationally, the MC-Smooth vorticity-velocity formulation was employed to describe the chemically reacting flow, and the soot evolution was modeled by the sectional aerosol equations. The governing equations and boundary conditions were discretized on an axisymmetric computational domain by finite differences, and the resulting system of fully coupled, highly nonlinear equations was solved by a damped, modified Newton's method. The microgravity sooting flames were found to have lower soot temperatures and higher volume fraction than their normal gravity counterparts. The soot distribution tends to shift from the centerline of the flame to the wings from normal gravity to microgravity.

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Section: Introductionmentioning

confidence: 99%

An experimental and computational study of soot formation in a coflow jet flame under microgravity and normal gravity

Cao

Giassi

et al. 2015

Proceedings of the Combustion Institute

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“…[5,6]. The trend of increase in both soot mass and size have been experimentally observed by Walsh et al [7], Jeon and Choi [8], and Reimann et al [9,10] using multiple optical measurement techniques. Experimental observations of non-buoyant round laminar jet diffusion flames were made for various jet flames burning in still air by Diez et al [11] on board the Space Shuttle Columbia to correlate soot volume fraction with estimated mixture fraction for a selection of fuels/pressures.…”

Section: Introductionmentioning

confidence: 59%

A computational study of soot formation and flame structure of coflow laminar methane/air diffusion flames under microgravity and normal gravity

Veshkini

Dworkin

2017

Combustion Theory and Modelling

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A computational study of soot formation and flame structure of coflow laminar methane/air diffusion flames under microgravity and normal gravityA numerical study is conducted of methane-air coflow diffusion flames at microgravity (µg) and normal gravity (1g), and comparisons are made with experimental data in the literature. The model employed uses a detailed gas phase chemical kinetic mechanism that includes PAH formation and growth, and is coupled to a sectional soot particle dynamics model. The model is able to accurately predict the trends observed experimentally with reduction of gravity without any tuning of the model for different flames. The microgravity sooting flames were found to have lower temperatures and higher volume fraction than their normal gravity counterparts. In the absence of gravity, the flame radii increase due to elimination of buoyance forces and reduction of flow velocity, which is consistent with experimental observations. Soot formation along the wings is seen to be surface growth dominated, while PAH condensation plays a more major role on centerline soot formation. Surface growth and PAH growth increase in microgravity primarily due to increases in the residence time inside the flame. The rate of increase of surface growth is more significant compared to PAH growth, which causes soot distribution to shift from the centerline of the flame to the wings in microgravity.

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“…Among practical combustion schemes for hydrocarbon fuels, along with catalytic and surface burning, the organization of diffusion and pre-mixed reactive gas jets is widespread. In technical applications, reactive diffusion jets are used: in the combustion chambers of heat and power boilers of various power classes; high-temperature technological process of heating, melting, drying and heat treatment of surfaces; associated gas combustion technologies in hydrocarbon fields; multi-flare burners of combustion chambers of condensing boilers of distributed energy [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The diffusion mechanism of flame propagation underlies the formation of forest and man-made fires.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of diffusion jet combustion in an ejection burner

et al. 2018

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In this work we present the results of computational and experimental studies on the burnout dynamics of diffusion gas jets in an ejection burner with a two-stage air ejection scheme. It is shown that usage of this scheme leads to an increase in the uniformity of the distribution of thermogasdynamic parameters at the burner outlet, an increase in the completeness of combustion of the fuel, and a more stable operation of the device.

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Effect of buoyancy on soot formation in gas-jet diffusion flame

Cited by 8 publications

References 22 publications

An experimental and computational study of soot formation in a coflow jet flame under microgravity and normal gravity

An experimental and computational study of soot formation in a coflow jet flame under microgravity and normal gravity

A computational study of soot formation and flame structure of coflow laminar methane/air diffusion flames under microgravity and normal gravity

Dynamics of diffusion jet combustion in an ejection burner

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