Structure and stabilization mechanism of a microjet methane diffusion flame near extinction

2007 ◽  
Vol 31 (2) ◽  
pp. 3301-3308 ◽  
Author(s):  
C.-P. Chen ◽  
Y.-C. Chao ◽  
T.S. Cheng ◽  
G.-B. Chen ◽  
C.-Y. Wu
Keyword(s):  
Diffusion Flame ◽  
Stabilization Mechanism ◽  
Methane Diffusion ◽  
Near Extinction

Further analysis of chemical kinetic structure of a standoff microjet methane diffusion flame near extinction

2008 ◽  
Vol 152 (3) ◽  
pp. 461-467 ◽  
Author(s):  
T.S. Cheng ◽  
Y.-C. Chao ◽  
C.-P. Chen ◽  
C.-Y. Wu
Keyword(s):  
Diffusion Flame ◽  
Chemical Kinetic ◽  
Methane Diffusion ◽  
Near Extinction

The effect of sodium chloride on the nanoparticles observed in a laminar methane diffusion flame

2018 ◽  
Vol 188 ◽  
pp. 273-283 ◽  
Author(s):  
Alireza Moallemi ◽  
Mohsen Kazemimanesh ◽  
Larry W. Kostiuk ◽  
Jason S. Olfert
Keyword(s):  
Sodium Chloride ◽  
Diffusion Flame ◽  
Methane Diffusion

An Experimental Investigation of the Blowout Limits of a Jet Diffusion Flame in Co-Flowing Streams of Different Velocity and Composition

1993 ◽  
Vol 115 (2) ◽  
pp. 142-147 ◽  
Author(s):  
I. Wierzba ◽  
K. Kar ◽  
G. A. Karim
Keyword(s):  
Carbon Dioxide ◽  
Experimental Investigation ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Diffusion Flame ◽  
Detrimental Effect ◽  
Stream Velocity ◽  
Air Stream ◽  
Methane Diffusion ◽  
Flow Stream

The blowout limits of a methane diffusion flame in a co-flowing air-fuel or air-diluent stream were determined for a range of surrounding co-flow stream velocities, both laminar and turbulent, up to ~ 1.50 m/s. Methane, ethylene, propane and hydrogen were used as the fuels in the surrounding co-flow stream while nitrogen and carbon dioxide were used as diluents. The experimental results show that the velocity of the surrounding stream affects the blowout phenomena significantly. An increase in the stream velocity has a detrimental effect on the blowout limits at very low velocities up to 0.30 m/s (essentially laminar flow) and at velocities higher than 1.50 m/s (turbulent flow). The addition of a fuel to the air stream in most cases enhances the blowout limit of a methane diffusion flame. However, different trends in the variation of the blowout limits with the surrounding fuel concentration were observed, depending on the type of fuel used and on whether the surrounding coflow stream was laminar or turbulent. The addition of nitrogen or carbon dioxide to the air stream results in decreasing the blowout limits. The effect is more severe at the higher velocities.

Detailed Multi-dimensional Study of Pollutant Formation in a Methane Diffusion Flame

2012 ◽  
Vol 26 (3) ◽  
pp. 1598-1611 ◽  
Author(s):  
Rory F. D. Monaghan ◽  
Råbi Tahir ◽  
Alberto Cuoci ◽  
Gilles Bourque ◽  
Marc Füri ◽  
...  
Keyword(s):  
Diffusion Flame ◽  
Pollutant Formation ◽  
Methane Diffusion

Interaction of a water mist with a buoyant methane diffusion flame

1995 ◽  
Vol 24 (4) ◽  
pp. 359-381 ◽  
Author(s):  
Bruce Downie ◽  
Constantine Polymeropoulos ◽  
George Gogos
Keyword(s):  
Diffusion Flame ◽  
Water Mist ◽  
Methane Diffusion

Diffusional-thermal instability of diffusion flames

1996 ◽  
Vol 327 ◽  
pp. 273-301 ◽  
Author(s):  
J. S. Kim ◽  
F. A. Williams ◽  
P. D. Ronney
Keyword(s):  
Reaction Zone ◽  
Diffusion Flame ◽  
Thermal Instability ◽  
Eigenvalue Problems ◽  
Numerical Solutions ◽  
Diffusion Flames ◽  
Scalar Fields ◽  
Marginal Stability ◽  
Cube Root ◽  
Near Extinction

The diffusional–thermal instability, which gives rise to striped quenching patterns that have been observed for diffusion flames, is analysed by studying the model of a one-dimensional convective diffusion flame in the diffusion-flame regime of activation-energy asymptotics. Attention is focused principally on near-extinction conditions with Lewis numbers less than unity, in which the reactants with high diffusivity diffuse into the strong segments of the reaction sheet, so that the regions between the strong segments become deficient in reactant and subject to the local quenching that leads to the striped patterns. This analysis differs from other flame stability analyses in that the complete description of the dispersion relation is obtained from a composite expansion of the results of an analysis with the conventional convective-diffusive scaling and one with reaction-zone scaling. The results predict that striped patterns will occur, for flames sufficiently close to quasi-steady extinction, with a finite wavenumber that in convective–diffusive scaling is proportional to the cube root of the Zel'dovich number. The convective–diffusive response contributes to the stabilization of long-wavelength disturbances by through positive excess enthalpies by which the flame becomes more resistant to instability, while the reaction-zone response provides stabilization of short-wavelength disturbances by transverse diffusion, within the reactive inner layer, which relaxes the perturbed scalar fields towards their unperturbed states. As quasi-steady extinction is approached, marginal stability arises first at an intermediate range between these two scalings. Parametric results for this bifurcation point are obtained through numerical solutions of the associated generalized eigenvalue problems. Comparisons with measured pattern dimensions for different sets of reactants and diluents reveal excellent qualitative agreement.

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