Three-dimensional spatial flamelet statistics for premixed turbulent combustion modeling

Shy, S.S.; Jang, R.H.; Gee, Ken

doi:10.1016/s0082-0784(96)80227-x

Cited by 7 publications

(1 citation statement)

References 11 publications

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“…Furthermore, it is worthwhile using the present apparatus to obtain su¯cient images of turbulent ®ame fronts for experimental analysis of premixed turbulent combustion modelling. We have established several methods of ®amelet statistics, such as analysis of the BML model (Shy et al . 1996b) and analysis of ®ame surface density transport equation (Shy et al 1999b) for liquid ®ames.…”

Section: Discussionmentioning

confidence: 99%

An experimental correlation of turbulent burning velocities for premixed turbulent methane-air combustion

Shy

Lin

Wei

2000

Proc. R. Soc. Lond. A

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This paper is devoted to the general correlation of turbulent burning velocities in terms of straining rates for premixed ®ames propagating in intense turbulence. This problem was investigated by the Leeds group led by Professor Bradley and many other researchers. We present here a new methodology based upon a downward propagating premixed CH 4 {air ®ame through a nearly isotropic turbulent ®ow eld with a pair of specially designed ion probes for quantitative measurements of turbulent burning velocities. The improvements are that the ®ame propagation is not in®uenced by the ignition source and the unwanted turbulence from walls, e¬ects of buoyancy and pressure rise due to burning are minimized, and a greater parameter range than hitherto is covered. The results show that both the turbulent burning velocity bending and the vitality of turbulent premixed ®ames are certain and surprising. Logarithmic plots of turbulent burning velocities S T =S L ¡ 1 against the turbulent intensities u 0 =S L reveal a transition, where S L is the laminar burning velocity. Across the transition, the slope n changes from positive to negative when values of u 0 =S L and/or Karlovitz number are greater than some critical values. This transition seems to correspond to the Klimov{Williams criterion that separates corrugated ®amelets from distributed reaction zones. Interestingly, no global quenching of premixed turbulent ®ames is observed, even at u 0 =S L º 40, a value signi cantly higher than in most previous measurements. At a xed u 0 =S L , values of the S T =S L data vary with the equivalence ratio ¿ . This indicates that the common expression of the form S T =S L = 1 + C(u 0 =S L ) n cannot be applicable generally, because values of the constant C are di¬erent for di¬erent mixture compositions. It is found that all of the present data with di¬erent values of ¿ can be approximated by a simple expression, (S T ¡ S L )=u 0 º 0:06Da 0:59 , where Da is the Damk ohler number. Hence a better correlation of turbulent burning velocities in terms of straining rates for premixed turbulent (methane{air) combustion is proposed.

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Section: Discussionmentioning

confidence: 99%