Markstein numbers in counterflow, methane- and propane- air flames: a computational study

Davis, Scott; Quinard, Joel; Searby, Geoffrey

doi:10.1016/s0010-2180(02)00368-1

Cited by 91 publications

(76 citation statements)

References 36 publications

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“…However, this does not pose a problem here because only the velocity of the cold gas ahead of the flame appears in the theory leading to Eqs. 1 and 2; see [1][2][3][4][5]. Comparisons with flames in unseeded mixtures show that the additional fuel in the oil drops has no noticeable effect on the flame.…”

Section: Experimental Setup and Techniquesmentioning

confidence: 99%

“…However, the question arises as to what extent can these results be used for real flames of finite thickness, for which even the definitions of propagation velocity and front curvature are ambiguous. For planar stationary flames in the stagnation point flow, the question has been addressed by Davis et al [4,5], who used numerical computations to show that Eqs. 1 and 2 can still be used if the velocity U n and the strain rate are understood as those of the cold gas upstream of the flame (the outer solution in the asymptotic description) extrapolated to the reaction region of the flame.…”

Section: Introductionmentioning

confidence: 99%

“…This configuration was considered before by Mungal et al [10]. It allows to simultaneously measure the planar flame propagation velocity, the local flame propagation velocity (defined as in [4][5][6][7]), and the curvature of the flame tip. In addition, strongly curved flames can be obtained by increasing the ratio UO/UL of the gas injection velocity to the velocity of the planar flame.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Curvature and Velocity of Methane-Air Bunsen Flame Tips

García-Soriano

García‐Ybarra

Higuera³

2011

Flow Turbulence Combust

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PIV and photographic recording are used to measure the velocity of the fresh gas and the shape of the reaction layer in a region around the tip of a methaneair Bunsen flame attached to a cylindrical burner. The results compare well with numerical simulations carried out with an infinite activation energy reaction model. The experimental and numerical results confirm that the well-known linear relation between flame velocity and flame stretch derived from asymptotic theory for weakly curved and strained flames is valid for small and moderate values of the flame stretch if the modified definition of stretch introduced by Echekki and Mungal (Proc Combust Inst 23:455-461, 1990) and Poinsot et al. (Combust Sci Technol 81:45-73, 1992) is used. However, the relation between flame velocity and modified stretch ceases to be linear and approaches a square root law for large values of the stretch, when the curvature of the flame tip becomes large compared to the inverse of the thickness of a planar flame.

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Section: Experimental Setup and Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Curvature and Velocity of Methane-Air Bunsen Flame Tips

García-Soriano

García‐Ybarra

Higuera³

2011

Flow Turbulence Combust

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“…The subscripts u and b refer respectively to unburnt and burnt gases. Using the values of Ma determined by Davis et al [33] and following the same approach as in [28], three characteristic lengths can be calculated:…”

Section: : Discussionmentioning

confidence: 99%

Premixed flames propagating freely in tubes

Almarcha

Denet

Quinard

2015

Combustion and Flame

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This paper reports an experimental investigation of premixed propane and methane-air flames propagating freely in tubes 1.5 m long and with diameters 54 and 94 mm. Two regimes of propagation are distinguished by correlating the flame speed and the radius of curvature at the flame tip. The characteristic lengths are then related to the cut-off wavelengths estimated from linear theories and compared to previous results of Michelson-Sivashinsky simulations.

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“…To understand the flame dynamics and flame structure clearly, some researchers (Davis et al [43], Akkerman and Bychkov [44], et al) have provided detailed data and results on the inner mechanism of laminar flame structure change, such as the laminar flame velocity, the effective flame thickness, the ratio of the unburnt to burnt gas density and the effective Markstein number. The relevant dynamic parameters in Table 1 can be used as a reference to describe the flame dynamics and flame structure [42].…”

Section: Flame Structure Characteristic Based On High Speed Schlierenmentioning

confidence: 99%

Effect of CH4–Air Ratios on Gas Explosion Flame Microstructure and Propagation Behaviors

Chen

Zhang

2012

Energies

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Abstract:To reveal the inner mechanism of gas explosion dynamic behavior affected by gas equivalent concentration, a high speed Schlieren image system and flow field measurement technology was applied to record the gas explosion flame propagation and flame structure transition. The results show that a flame front structure transition occurs, followed by a flame accelerating propagation process. The laminar to turbulence transition was the essential cause of the flame structure changes. The laminar flame propagation behavior was influenced mainly by gas expansion and fore-compressive wave effect, while the turbulent flame speed mostly depended on turbulence intensity, which also played an important role in peak value of the explosive pressure and flame speed. On the condition that the laminar-turbulent transition was easier to form, the conclusion was drawn that, the lowest CH 4 concentration for maximum overpressure can be obtained, which was the essential reason why the ideal explosive concentration differs under different test conditions.

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Markstein numbers in counterflow, methane- and propane- air flames: a computational study

Cited by 91 publications

References 36 publications

Curvature and Velocity of Methane-Air Bunsen Flame Tips

Curvature and Velocity of Methane-Air Bunsen Flame Tips

Premixed flames propagating freely in tubes

Effect of CH4–Air Ratios on Gas Explosion Flame Microstructure and Propagation Behaviors

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