The structure of turbulent nonpremixed flames

Bilger, R.W.

doi:10.1016/s0082-0784(89)80054-2

Cited by 315 publications

(115 citation statements)

References 23 publications

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“…The mixture fraction ζ is defined by a linear combination of elemental mass fractions using the weight factors following Bilger's [28] formulation. The mixture fraction is normalized so that it has its minimum and maximum value in the oxidizer (ζ = 0) and fuel (ζ = 1), respectively.…”

Section: Tabulation Of Iml Flameletsmentioning

confidence: 99%

Development of a novel flamelet-based model to include preferential diffusion effects in autoignition of CH4/H2 flames

Abtahizadeh

Goey

Oijen

2015

Combustion and Flame

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Section: Tabulation Of Iml Flameletsmentioning

confidence: 99%

Development of a novel flamelet-based model to include preferential diffusion effects in autoignition of CH4/H2 flames

Abtahizadeh

Goey

Oijen

2015

Combustion and Flame

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“…As a result, the mixture fraction Z is required to describe the local mixture composition and it is defined following Bilger (1988) as…”

Section: Partially Premixed Flame Modellingmentioning

confidence: 99%

Modelling of Turbulent Premixed and Partially Premixed Combustion

Veera¹,

Masood²,

Ruan³

et al. 2012

Advanced Fluid Dynamics

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“…Other elemental mass fractions or a combination of them, as proposed by Bilger [37] can also be used to examine the state relationships. Figure 8 presents the modified mixture fraction (left) and heat release rate (right) contours for the 1-and 0-g flames established at φ = 2.0, V reac = 30 cm s -1 , and V air = 0.…”

Section: State Relationships For Unsteady Partially Premixed Flamesmentioning

confidence: 99%

Structure of Unsteady Partially Premixed Flames and the Existence of State Relationships

Aggarwal

2009

International Journal of Spray and Combustion Dynamics

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In this study, we examine the structure and existence of state relationships in unsteady partially premixed flames (PPFs) subjected to buoyancy-induced and external perturbations. A detailed numerical model is employed to simulate the steady and unsteady two-dimensional PPFs established using a slot burner under normal and zero-gravity conditions. The coflow velocity is parametrically varied. The methane-air chemistry is modeled using a fairly detailed mechanism that contains 81 elementary reactions and 24 species. Validation of the computational model is provided through comparisons of predictions with nonintrusive measurements. The combustion proceeds in two reaction zones, one a rich premixed zone and the other a nonpremixed zone. These reaction zones are spatially separated, but involve strong interactions between them due to thermochemistry and scalar transport. The fuel is mostly consumed in the premixed zone to produce CO and H 2 , which are transported to and consumed in the nonpremixed zone. The nonpremixed zone in turn provides heat and H-atoms to the premixed zone. For the range of conditions investigated, the zero-g partially premixed flames exhibit a stable behavior and a remarkably strong resistance to perturbations. In contrast, the corresponding normal-gravity flames exhibit oscillatory behavior at low coflow velocities but a stable behavior at high coflow velocities, and the behavior can be explained in terms of a global and convective instabilities. The effects of coflow and gravity on the flames are characterized through a parameter V R , defined as the ratio of coflow velocity to jet velocity. For V R ≤ 1 (low coflow velocity regime), the structures of both 0-and 1-g flames are strongly sensitive to changes in V R , while they are only mildly affected by coflow in the high coflow velocity regime (V R > 1). In addition, the spatio-temporal characteristics of the 0-and 1-g flames are markedly different in the first regime, but are essentially similar in the second regime. A more significant difference in the first regime between these flames is the presence of a flow instability that manifests itself through the self-excited oscillations of the 1-g flame and the concomitant flickering of the nonpremixed reaction zone. For V R ≤ 1, as the coflow velocity is increased, the oscillation amplitude decreases and the oscillation frequency increases, both of which are in accord with previous experimental and International journal of spray and combustion dynamics · Volume . 1 · Number . 3 . 2009 -pages 339-364 339 1 email: ska@uic.edu computational results concerning 1-g jet diffusion flames. The modified conserved scalar approach is found to be effective in characterizing the flame structure and developing state relationships for both steady and unsteady partially premixed flames. This is demonstrated by the fact that the temperature as well as the major and minor species profiles follow similar state relationships in terms of the modified mixture fraction for the 0-and 1-g flames, even though ...

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The structure of turbulent nonpremixed flames

Cited by 315 publications

References 23 publications

Development of a novel flamelet-based model to include preferential diffusion effects in autoignition of CH4/H2 flames

Development of a novel flamelet-based model to include preferential diffusion effects in autoignition of CH4/H2 flames

Modelling of Turbulent Premixed and Partially Premixed Combustion

Structure of Unsteady Partially Premixed Flames and the Existence of State Relationships

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