Pressure effect on soot formation in turbulent diffusion flames

Roditcheva, Olga; Bai, Xue‐Song

doi:10.1016/s0045-6535(00)00255-1

Cited by 27 publications

(14 citation statements)

References 16 publications

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“…The calculated soot volume fraction at the two last locations in the flame is under-predicted, which is possibly a consequence of inaccurate temperature predictions. This contrasts to the flamelet predictions of Roditcheva and Bai [51] which accurately simulate the radial temperature profile at all axial locations, but imprecisely compute the radial soot yields.…”

Section: Methane-air Elevated Pressure Flamescontrasting

confidence: 68%

“…Although it is believed that both physical and chemical effects play important roles in soot formation at high pressure, a number of numerical simulation studies show that the influence of pressure is primarily a physical phenomenon rather than a chemical one. Roditcheva and Bai [51] argued that in addition to the increase of density and soot precursor species concentrations, which result in an increase of soot surface growth rate, the increase of residence time also contributes by giving allowance to the relatively slow soot chemistry. However, Liu et al [53] confirmed from their simulations that soot particles experience almost the same residence times at different pressures.…”

Section: Methane-air Elevated Pressure Flamesmentioning

confidence: 99%

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Conditional moment closure modelling of soot formation in turbulent, non-premixed methane and propane flames

Woolley

Fairweather

Yunardi

2009

Fuel

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Published paperPresented are results obtained from the incorporation of a semi-empirical soot model into a first-order conditional moment closure (CMC) approach to modelling turbulent, non-premixed methane-and propane-air flames. Soot formation is determined via the solution of two transport equations for soot mass fraction and particle number density, with acetylene and benzene employed as the incipient species responsible for soot nucleation, and the concentrations of these calculated using a detailed gas-phase kinetic scheme involving 70 species. The study focuses on the influence of differential diffusion of soot particles on soot volume fraction predictions. The results of calculations are compared with experimental data for atmospheric and 3 atmosphere methane flames, and propane flames with air preheated to 323 K and 773 K. Overall, the study demonstrates that the model, when used in conjunction with a representation of differential diffusion effects, is capable of accurately predicting soot formation in the turbulent non-premixed flames considered.

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Section: Methane-air Elevated Pressure Flamescontrasting

confidence: 68%

Section: Methane-air Elevated Pressure Flamesmentioning

confidence: 99%

Conditional moment closure modelling of soot formation in turbulent, non-premixed methane and propane flames

Woolley

Fairweather

Yunardi

2009

Fuel

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“…(5), 1 m 2 for laminar rich premixed C 2 H 4 =air flames and various laminar and turbulent diffusion flames (Fischer & Moss, 1998) and m ¼ 3 for laminar CH 4 =air non-premixed flame at pressures lower than 30 bar (Roditcheva & Bai, 2001). The opposite reported dependence of soot formation on pressure may be caused by two factors.…”

Section: Ultra Rich Premixed Combustion Of Natural Gas 445mentioning

confidence: 98%

Prediction and Measurement of the Product Gas Composition of the Ultra Rich Premixed Combustion of Natural Gas: Effects of Equivalence Ratio, Residence Time, Pressure, and Oxygen Concentration

Albrecht¹,

Kok²,

Dijkstra³

et al. 2009

Combustion Science and Technology

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The ultra rich combustion (partial oxidation) of natural gas to hydrogen and carbon monoxide is theoretically and experimentally investigated. The effect of the process parameters equivalence ratio, residence time, pressure, and composition of the oxidizer is explored. Computations are performed with the use of the chemical kinetics simulation package CHEMKIN. First, the ultra rich combustion process is modeled as a freely propagating flame in order to establish the rich flame propagation properties. An Arrhenius correlation of the laminar flame speed with the adiabatic flame temperature is found with activation temperature 20,000 K. Subsequently, perfectly stirred reactor (PSR) computations were performed. From these, it is concluded that optimal natural gas conversion to hydrogen and carbon monoxide requires a residence time of at least 50 ms and, depending on residence time, an equivalence ratio between 2 and 4. To reach chemical equilibrium in ultra rich mixtures, the residence time is very long (>1000 ms). The model predictions are validated by experiments on ultra rich combustion of natural gas by means of air enriched to 40% oxygen concentration at up to 3 bar and 300 kW. The effect of equivalence ratio at residence time 50 ms was investigated. Good comparison was found between measurements and model predictions on carbon monoxide, hydrogen, and the soot precursor acetylene. It can be concluded that the model provides reliable information on product gas concentrations as a result of ultra rich combustion of natural gas.

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“…Since the heat release rates are higher at a low pressure, the radiation fractions become even lower in Lhasa, especially for the acetylene fi res. Higher radiation fl ux and radiation fraction in Hefei are due to the increased soot formation at a higher pressure (Intasopa, 2011;Roditcheva and Bai, 2001). …”

Section: Radiation Fluxmentioning

confidence: 99%

Influence of High Altitude on Combustion Efficiency and Radiation Fraction of Hydrocarbon Fires

Yao

et al. 2017

Heat Trans Res

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Pressure effect on soot formation in turbulent diffusion flames

Cited by 27 publications

References 16 publications

Conditional moment closure modelling of soot formation in turbulent, non-premixed methane and propane flames

Conditional moment closure modelling of soot formation in turbulent, non-premixed methane and propane flames

Prediction and Measurement of the Product Gas Composition of the Ultra Rich Premixed Combustion of Natural Gas: Effects of Equivalence Ratio, Residence Time, Pressure, and Oxygen Concentration

Influence of High Altitude on Combustion Efficiency and Radiation Fraction of Hydrocarbon Fires

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