Joint RANS/LES Modeling of Flameless Combustion
Vladimir L. Zimont, Valerio Battaglia
DOI: 10.4236/epe.2011.35077   PDF    HTML     5,150 Downloads   9,016 Views   Citations


We present our timesaving joint RANS/LES approach (we originally developed it for numerical simulations of turbulent premixed combustion) to simulate flameless combustion with separate injection of gas fuel and strong exhaust gas recirculation. It is based on successive RANS/LES numerical modeling where part of the information (stationary average fields) is achieved by RANS simulations and part (instantaneous nonstationary image of the process) by LES. The latter is performed using the RANS field of mean dissipation rate to model the sub-grid turbulent viscosity in the context of the Kolmogorov theory of small-scale turbulence. We analyze flameless combustion in the FLOX® combustor where we also simulate non-premixed flame combustion used for preliminary heating of the combustor. Different regimes take place using different systems of air injection. We applied for both regimes the simple assumption of “mixed is burnt”. The main results are the following: 1) RANS simulations demonstrate for used two injection systems respectively more compact flame and distributed flameless combustion. 2)There is agreement between RANS and corresponding LES results: RANS and averaged LES profiles of the velocity and temperature are in reasonable agreement. 3) LES modeling with Kolmogorov independent on time sub-grid viscosity reproduce instantaneous image of the process including the vortex structures. Probably due to using an annular injector system for air the instantaneous field of the temperature demonstrate significant irregularity in the beginning of the burner, which in an animation looks like moving coherent structures. 4) In the joint RANS/LES approach the computer time of the LES sub-problems is much shorter than classic LES modeling due to using time independent subgrid transport coefficients and avoiding long-continued simulations, which are necessary for averaging of instantaneous LES fields. Practically in our simulations time consuming of the LES sub-problem was only several times lager then the RANS one and it makes this approach suitable for industrial applications.

Share and Cite:

V. Zimont and V. Battaglia, "Joint RANS/LES Modeling of Flameless Combustion," Energy and Power Engineering, Vol. 3 No. 5, 2011, pp. 616-624. doi: 10.4236/epe.2011.35077.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] J. A. Wünning and J. G. Wünning, “Flamneless Oxida- tion to Reduce Thermal NO-Formation,” Progress in En- ergy and Combustion Science, Vol. 23, No. 1, 1997, pp. 81-94. doi:10.1016/S0360-1285(97)00006-3
[2] A. Cavaliere and M. De Joannon, “Mild Combustion,” Progress in Energy and Combustion Science, Vol. 30, No. 4, 2004, pp. 329-366. doi:10.1016/j.pecs.2004.02.003
[3] T. Hasegawa and R. Tanaka, “High Temperature Air Com- bustion: Revolution in Combustion Technology,” JSME International Journal, Series B, Vol. 40, No. 4, 1998, pp. 1079-1084
[4] J. G. Wünning, “FLOX?—Flameless Combustion,” Therm- process Symposium VDMA, Düsseldorf, 2003.
[5] J. G. Wünning, “Flameless Combustion and its Applications,” 14th IFRF Members Conference, Noordwijkerhout, 2004.
[6] P. J. Coelho and N. Peters, “Numerical Simulation of a Mild Combustion Burner,” Combustion and Flame, Vol. 124, No. 3, 2001, pp. 503-518. doi:10.1016/S0010-2180(00)00206-6
[7] S. Murer, B. Perenti and P. Lybaert, “Simulation of Fla- meless Combustion of Natural Gas in a Laboratory Scale Furnace,” Turkish Journal of Engineering & Environ- mental Sciences, Vol. 30, No. 3, 2006, pp. 135-143.
[8] V. Zimont and V. Battaglia, “Joint RANS/LES Numrical Simulations of Premixed Combustion at Strong Tuibu- lence,” Ninth International Conference on Numerical Com- bustion (SIAM), Sorrento, 7-10 April 2002, Paper No. 141, pp. 225-226.
[9] V. L. Zimont and V. Battaglia, “Joint RANS/LES Ap- proach to Premixed Flame Modelling in the Context of the TFC Combustion Model,” Flow, Turbulence and Com- bustion, Vol. 77, No. 1-4, 2006, pp. 305-331.
[10] V. L. Zimont, V. Moreau, V. Battaglia and R. Modi, “RANS and LES Modelling of the GE10 Combustor,” In: Biblioneca Termotechnica (Proceedings of the ASME ATI Conference on “Energy: Production, Distribution and Con- servation”, Milan, 14-17 May 2006), Vol. 2, No. 34, 2006, pp. 923-932.
[11] J. Smagorinsky, “General Circulation Experiments with the Primitive Equations I. The Basic Experiment,” Mon- thly Weather Review, Vol. 91, No. 3, 1963, pp. 99-164. doi:10.1175/1520-0493(1963)091<0099:GCEWTP>2.3.CO;2
[12] T. Plessing, N. Peters and G. Wunning, “Laseroptical In- vestigation of Highly Preheated Combustion with Strong Exhaust Gas Recirculation,” Symposium (International) on Combustion, Vol. 27, No. 2, 1998, pp. 3197-3204.
[13] A. N. Kolmogorov and A. N. Doklady, “The Local Structure of Turbulence in Incompressible Viscous Fluid for Very Large Reynolds Number,” Doklady AN SSSR, Vol. 30, No. 4, 1941, pp. 299-303. (Reprinted in Proceedings of the Royal Society of London. Series A, Vol. 434, 1991, pp. 9-13).

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.