Effects of gas preheat temperature on soot formation in co-flow methane and ethylene diffusion flames

2020 ◽  
Author(s):  
Sheng Qi ◽  
Zhiwei Sun ◽  
Zhihua Wang ◽  
Yingzu Liu ◽  
Yong He ◽  
...  
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Preheat Temperature

Effects of the Gas Preheat Temperature and Nitrogen Dilution on Soot Formation in Co-flow Methane, Ethane, and Propane Diffusion Flames

2020 ◽  
Author(s):  
Yong He ◽  
Sheng Qi ◽  
Siyu Liu ◽  
Shirong Xin ◽  
Yanqun Zhu ◽  
...  
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Preheat Temperature ◽  
Nitrogen Dilution

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 Experimental characterization of the different nitrogen dilution effects on soot formation in ethylene diffusion flames

2017 ◽  
Vol 36 (2) ◽  
pp. 3227-3235 ◽  
Author(s):  
Q. Wang ◽  
G. Legros ◽  
J. Bonnety ◽  
C. Morin
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Experimental Characterization ◽  
Nitrogen Dilution ◽  
Dilution Effects

Soot formation in ducted turbulent diffusion flames

AIAA Journal ◽  
1991 ◽  
Vol 29 (6) ◽  
pp. 932-935 ◽  
Author(s):  
T. Neill ◽  
I. M. Kennedy
Keyword(s):  
Turbulent Diffusion ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Turbulent Diffusion Flames

The influence of nitrogen and hydrogen addition/dilution on soot formation in coflow ethylene/air diffusion flames

Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122244
Author(s):  
Andisheh Khanehzar ◽  
Francisco Cepeda ◽  
Seth B. Dworkin
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Hydrogen Addition ◽  
Air Diffusion

Analytical Formulation-Based Soot Modelling in Ethylene Laminar Jet Diffusion Flames

2021 ◽  
Author(s):  
Amit Makhija ◽  
Krishna Sesha Giri
Keyword(s):  
Volume Fraction ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Mixture Fraction ◽  
Soot Volume Fraction ◽  
Smoke Point ◽  
Computational Time ◽  
Detailed Model ◽  
Conservation Equations ◽  
Oxidation Rates

Abstract Soot volume fraction predictions through simulations carried out on OpenFOAM® are reported in diffusion flames with ethylene fuel. A single-step global reaction mechanism for gas-phase species with an infinitely fast chemistry assumption is employed. Traditionally soot formation includes inception, nucleation, agglomeration, growth, and oxidation processes, and the individual rates are solved to determine soot levels. However, in the present work, the detailed model is replaced with the soot formation and oxidation rates, defined as analytical functions of mixture fraction and temperature, where the net soot formation rate can be defined as the sum of individual soot formation and oxidation rates. The soot formation/oxidation rates are modelled as surface area-independent processes. The flame is modelled by solving conservation equations for continuity, momentum, total energy, and species mass fractions. Additionally, separate conservation equations are solved to compute the mixture fraction and soot mass fraction consisting of source terms that are identical and account for the mixture fraction consumption/production due to soot. As a consequence, computational time can be reduced drastically. This is a quantitative approach that gives the principal soot formation regions depending on the combination of local mixture fraction and temperature. The implemented model is based on the smoke point height, an empirical method to predict the sooting propensity based on fuel stoichiometry. The model predicts better soot volume fraction in buoyant diffusion flames. It was also observed that the optimal fuel constants to evaluate soot formation rates for different fuels change with fuel stoichiometry. However, soot oxidation strictly occurs in a particular region in the flame; hence, they are independent of fuel. The numerical results are compared with the experimental measurements, showing an excellent agreement for the velocity and temperature. Qualitative agreements are observed for the soot volume fraction predictions. A close agreement was obtained in smoke point prediction for the overventilated flame. An established theory through simulations was also observed, which states that the amount of soot production is proportional to the fuel flow rate. Further validations underscore the predictive capabilities. Model improvements are also reported with better predictions of soot volume fractions through modifications to the model constants based on mixture fraction range.

scholarly journals Soot formation in hydrocarbon/air laminar jet diffusion flames

1996 ◽  
Vol 27 (1) ◽  
pp. 87
Author(s):  
P.B. Sunderland ◽  
G.M. Faeth
Keyword(s):  
Diffusion Flames ◽  
Soot Formation ◽  
Laminar Jet ◽  
Jet Diffusion Flames

scholarly journals A Numerical Investigation of Thermal Diffusion Influence on Soot Formation in Ethylene/Air Diffusion Flames

2004 ◽  
Vol 18 (2) ◽  
pp. 139-151 ◽  
Author(s):  
Hongsheng Guo ◽  
Fengshan Liu ◽  
Gregory J. Smallwood ◽  
Ömer L. Gülder
Keyword(s):  
Numerical Investigation ◽  
Thermal Diffusion ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Air Diffusion

Experiments and numerical simulation on soot formation in opposed-jet ethylene diffusion flames

1996 ◽  
Vol 26 (2) ◽  
pp. 2359-2368 ◽  
Author(s):  
H. Wang ◽  
D.X. Du ◽  
C.J. Sung ◽  
C.K. Law
Keyword(s):  
Numerical Simulation ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Opposed Jet
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