Investigation on the effect of electric fields on soot formation and flame structure of diffusion flames

1992 ◽  
Vol 24 (1) ◽  
pp. 1059-1066 ◽  
Author(s):  
L. Xie ◽  
T. Kishi ◽  
M. Kono
Keyword(s):  
Electric Fields ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Structure

The influences of electric fields on soot formation and flame structure of diffusion flames

1993 ◽  
Vol 2 (4) ◽  
pp. 288-293 ◽  
Author(s):  
Lin Xie ◽  
Takeyuki Kishi ◽  
Michikata Kono
Keyword(s):  
Electric Fields ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Structure

scholarly journals Effect of the Preheated Oxidizer Temperature on Soot Formation and Flame Structure in Turbulent Methane-Air Diffusion Flames at 1 and 3 atm: A CFD Investigation

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3671
Author(s):  
Subrat Garnayak ◽  
Subhankar Mohapatra ◽  
Sukanta K. Dash ◽  
Bok Jik Lee ◽  
V. Mahendra Reddy
Keyword(s):  
Mole Fraction ◽  
Air Temperature ◽  
Reaction Rate ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Structure ◽  
Soot Volume Fraction ◽  
Computational Domain ◽  
Pressure Elevation

This article presents the results of computations on pilot-based turbulent methane/air co-flow diffusion flames under the influence of the preheated oxidizer temperature ranging from 293 to 723 K at two operating pressures of 1 and 3 atm. The focus is on investigating the soot formation and flame structure under the influence of both the preheated air and combustor pressure. The computations were conducted in a 2D axisymmetric computational domain by solving the Favre averaged governing equation using the finite volume-based CFD code Ansys Fluent 19.2. A steady laminar flamelet model in combination with GRI Mech 3.0 was considered for combustion modeling. A semi-empirical acetylene-based soot model proposed by Brookes and Moss was adopted to predict soot. A careful validation was initially carried out with the measurements by Brookes and Moss at 1 and 3 atm with the temperature of both fuel and air at 290 K before carrying out further simulation using preheated air. The results by the present computation demonstrated that the flame peak temperature increased with air temperature for both 1 and 3 atm, while it reduced with pressure elevation. The OH mole fraction, signifying reaction rate, increased with a rise in the oxidizer temperature at the two operating pressures of 1 and 3 atm. However, a reduced value of OH mole fraction was observed at 3 atm when compared with 1 atm. The soot volume fraction increased with air temperature as well as pressure. The reaction rate by soot surface growth, soot mass-nucleation, and soot-oxidation rate increased with an increase in both air temperature and pressure. Finally, the fuel consumption rate showed a decreasing trend with air temperature and an increasing trend with pressure elevation.

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

2021 ◽  
Author(s):  
Armin Veshkini ◽  
Seth B. Dworkin
Keyword(s):  
Normal Gravity ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Numerical Study ◽  
Computational Study ◽  
Flame Structure ◽  
Chemical Kinetic ◽  
Surface Growth ◽  
Rate Of Increase

A numerical study is conducted of methane-air coflow diffusion flames at microgravity (μg) and normal gravity (lg), 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. Keywords: laminar diffusion flame,methane-air,microgravity, soot formation, numerical modelling

Structure of Laminar Coflow Methane–Air Diffusion Flames

1986 ◽  
Vol 108 (3) ◽  
pp. 640-648 ◽  
Author(s):  
K. Saito ◽  
F. A. Williams ◽  
A. S. Gordon
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Flame Structure ◽  
Measured Temperature ◽  
Composition Profiles ◽  
Air Diffusion

Measured temperature and composition profiles are reported for a number of flames. Implications concerning flame structure are deduced, with emphasis on soot formation and on correlations involving conserved scalars.

Soot Formation With Light Extinction and Grayscale Extraction Methods Applied to Ethanol-Gasoline Blends Laminar Flame

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Shengli Wei ◽  
Jie Chen ◽  
Rui Xu ◽  
Tongyuan Ding ◽  
Xiqian Zhao
Keyword(s):  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Laminar Flame ◽  
Flame Structure ◽  
Extraction Methods ◽  
Light Extinction ◽  
Flame Height ◽  
Laminar Diffusion Flames ◽  
Mass Flowrate

Abstract In this paper, the two-dimensional parallel light extinction method was carried out to study the soot formation in laminar diffusion flames of four different ethanol-gasoline blends, of which ethanol volume fractions ranging from 0% up to 100% (E0, E20, E80, and E100). The flame images were processed synthetically via matlab to accurately calculate the flame height. In addition, the flame structure was redefined as three zones to observe the soot formation. The results indicate that the flame height changes with the variation of gas volume flowrate and fuel mass flowrate during the experiment. In terms of soot formation, as the volume fraction of ethanol increases, the proportion of soot forming zone decreases, while the area of blue flame zone grows. Simultaneously, the transition zone accounts for about 21% of the total flame area, which has no significant change with the increase of ethanol volume fraction.

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

2021 ◽  
Author(s):  
Armin Veshkini ◽  
Seth B. Dworkin
Keyword(s):  
Normal Gravity ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Numerical Study ◽  
Computational Study ◽  
Flame Structure ◽  
Chemical Kinetic ◽  
Surface Growth ◽  
Rate Of Increase

A numerical study is conducted of methane-air coflow diffusion flames at microgravity (μg) and normal gravity (lg), 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. Keywords: laminar diffusion flame,methane-air,microgravity, soot formation, numerical modelling

scholarly journals Investigation of Thermal Radiation from Soot Particles and Gases in Oxy-Combustion Counter-Flow Flames

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1756
Author(s):  
Chaoyang Wang ◽  
Guangtong Tang ◽  
Huibo Yan ◽  
Lujiang Li ◽  
Xiaopei Yan ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Mixture Fraction ◽  
Flame Structure ◽  
Flame Temperature ◽  
Stoichiometric Mixture ◽  
Particle Radiation ◽  
Mixture Ratio ◽  
Soot Particles

Oxy-combustion with high flame temperature, low heat loss, high combustion efficiency, and low NOx emissions is being extensively studied. The thermal radiation from soot particles and gases in oxy-combustion accounts for the vast majority of the total heat transfer. Based on a detailed chemical reaction mechanism coupled with the soot particle dynamics model and optically thin radiation model, the influence of the flame structure and temperature distribution on the thermal radiation in oxygen-enriched counterflow diffusion flames was studied in this paper. The results revealed that reasonable assignment of total recycled flue gas and the degree of dilution of fuel and oxidant were critical, which can be used to adjust the overall radiation situation of the flame. At the same adiabatic flame temperature, as the fuel concentration decreased and the oxidant concentration increased (the stoichiometric mixture ratio is from 0.3 to 0.6), the soot formation decreased, which led to the particle radiation disappearing while the main radiation zone of gases moved 0.04 cm toward the fuel side. At the same stoichiometric mixture fraction (0.4), the radiation area was broadened and the radiation of soot particles was gradually enhanced with the adiabatic flame increasing from 2300 K to 2700 K.

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

2021 ◽  
Author(s):  
Armin Veshkini ◽  
Seth B. Dworkin
Keyword(s):  
Normal Gravity ◽  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Numerical Study ◽  
Computational Study ◽  
Flame Structure ◽  
Chemical Kinetic ◽  
Surface Growth ◽  
Rate Of Increase

A numerical study is conducted of methane-air coflow diffusion flames at microgravity (μg) and normal gravity (lg), 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. Keywords: laminar diffusion flame,methane-air,microgravity, soot formation, numerical modelling

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