Turbulent flames premixed

Thomas, A., The development of wrinkled turbulent premixed flames, Combustion and Flame, 65,291-312,1986. 

The relevance of premixed edge flames to turbulent premixed flames can also be understood in parallel to the nonpremixed cases. In the laminar flamelet regime, turbulent premixed flames can be viewed as an ensemble of premixed flamelets, in which the premixed edge flames can have quenching holes by local high strain-rate or preferential diffusion, corresponding to the broken sheet regime [58]. 

R. Balachandran, B.O. Ayoola, C.R Kaminski, A.R Dowling, and E. Mastorakos. Experimental investigation of the non linear response of turbulent premixed flames to imposed inlet velocity oscillations. Combust. Flame, 143 37-55, 2005. 

R. Clavin and E.D. Siggia. Turbulent premixed flames and sound generation. Combust. Sci. Technol., 78 147-155,1991. 

The knowledge of turbulent premixed flames has improved from this very simple level by following the progress made in experimental and numerical techniques as well as theoretical methods. Much employed in early research, the laboratory Bunsen burners are characterized by relatively low turbulence levels with flow properties that are not constant everywhere in the flame. To alleviate these restrictions, Karpov et al. [5] pioneered as early as in 1959 the studies of turbulent premixed flames initiated by a spark in a more intense turbulence, produced in a fan-stirred quasi-spherical vessel. Other experiments carried out among others by Talantov and his coworkers allowed to determine the so-called turbulent flame speed in a channel of square cross-section with significant levels of turbulence [6]. 

At the beginning of the twenty-first century, it is interesting to try to summarize what has been experimentally established, and what remains partially or entirely unclear about turbulent premixed flames. The hope is that the results of this state of knowledge will... 

Turbulent mass burning rate versus the turbulent root-mean-square velocity by Karpov and Severin [18]. Here, nis the air excess coefficient that is the inverse of the equivalence ratio. (Reprinted from Abdel-Gayed, R., Bradley, D., and Lung, F.K.-K., Combustion regimes and the straining of turbulent premixed flames. Combust. Flame, 76, 213, 1989. With permission. Figure 2, p. 215, copyright Elsevier editions.)... 

Methane-air Bunsen burner turbulent premixed flame. 

This recent attempt differs from the previous classification where the wrinkled flamelet regime has been considered up to rj = (5l- Chen and Bilger have proposed to tentatively classify the different turbulent premixed flame structures they observed among four different regimes ... 

The interest of studying turbulent premixed flames for modern gas turbines and jet engine afterburners... 

Nevertheless, despite all these remarkable achievements, some open questions still remain. Among them is the influence of the molecular transport properties, in particular Lewis number effects, on the structure of turbulent premixed flames. Additional work is also needed to quantify the flame-generated turbulence phenomena and its relationship with the Darrieus-Landau instability. Another question is what are exactly the conditions for turbulent scalar transport to occur in a coimter-gradient mode Finally, is it realistic to expect that a turbulent premixed flame reaches an asymptotic steady-state of propagation, and if so, is it possible, in the future, to devise an experiment demonstrating it ... 

R. Abdel-Gayed, D. Bradley, and F.K.-K. Lung 1989, Combustion regimes and the straining of turbulent premixed flames. Combust. Flame 76 213-218. 

J.P. Dumont, D. Durox, and R. Borghi 1993, Experimental study of the mean reaction rates in a turbulent premixed flame. Combust. Sci. Technol. 89 219-251 (more informations through www.informaworld.com). 

Y.C. Chen and R. Bilger 2001, Simultaneous 2-D imaging measurements of reaction progress variable and OF radical concentration in turbulent premixed flames Instantaneous flame front structure. Combust. Sci. Tech. 167 187-222 (more informations through www.infor-maworld.com). 

R. Borghi 1985, On the structure and morphology of turbulent premixed flames, in C. Bruno and S. Casci (Eds.), Recent Advances in the Aerospace Sciences, Plenum Press, New York, pp. 117-138. 

F. Dinkelacker 2003, Experimental validation of flame regimes for highly turbulent premixed flames. Proceedings of the First European Combustion Meeting ECM2003. See also the 27th Symp.(Int.) on Combustion, pp. 857-865, 1998. 

J.H. Frank, P.A. Kalt, and R.W. Bilger 1999, Measurements of conditional velocities in turbulent premixed flames by simultaneous OH PLIF an PIV, Combust. Flame 116 220-232. 

H. Kobayashi, T. Tamura, K. Maruta, T. Niioka, and RA. Williams 1996, Burning velocity of turbulent premixed flames in a high pressure environment, Proc. Combust. Inst. 26 389-396. 

FUatyev, S.A., J.F. Driscoll, C.D. Carter, J.M. Donbar, Measured properties of turbulent premixed flames for model assessment, including burning velocities, stretch rates, and surface densities. Combust Flame, 2005. 141(1-2) 1-21. 

Turbulent modeling, 11 781 Turbulent noise detectors, 11 673 Turbulent premixed flames, 7 445-446 Turf growth regulators, 13 54 Turf growth retardant, 13 57 Turkeys, nutrient requirements of, 10 842t Turmeric, 23 171 Turnaround period, 19 494 Turnarounds, industrial hygiene and, 14 210... 

The complexity of the turbulent reacting flow problem is such that it is best to deal first with the effect of a turbulent field on an exothermic reaction in a plug flow reactor. Then the different turbulent reacting flow regimes will be described more precisely in terms of appropriate characteristic lengths, which will be developed from a general discussion of turbulence. Finally, the turbulent premixed flame will be examined in detail. 

The first expression here is very similar to the Damkohler result for A and B equal to 1. Since the turbulent exchange coefficient (eddy diffusivity) correlates well with IqU for tube flow and, indeed, /0 is essentially constant for the tube flow characteristically used for turbulent premixed flame studies, it follows that... 

Spalding, D. B. 1959. Theory of rate of spread of confined turbulent premixed flames. 7th Symposium (International) on Combustion Proceedings. Baltimore The Wilhams and Wilkins Co. 595-603. 

Shepherd, I. G., J. R. Hertzberg, and L. Talbot. 1992. Flame holding in unconfined turbulent premixed flames. In Major research topics in combustion. Eds. M. Y. Hussaini, A. Kumar, and R. G. Voigt. ILAE/NASA LaRC ser. New York Springer-Verlag. 253-70. 

In configuration (4) a turbulent premixed flame is stabilized at the exit of a tube by a pressure gradient along the direction of mean flame propagation, induced by transverse swirl, but again the turbulence is inhomogeneous and there is appreciable mean flow. 

Mungal, M.G., L. Lourenco, and A. Krothapalh. 1995. Instantaneous velocity measurements in laminar and turbulent premixed flames using on-line PIV. Combustion Science Technology 106 239-65. 

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