Laminar flamelet model prediction of NO x formation in a turbulent bluff-body combustor

Abstract

A bluff-body combustor, with recirculation zone and simple boundary conditions, is ideal as a compromise for an industrial combustor for validating combustion models. This combustor, however, has proved to be very challenging to the combustion modellers in a number of previous studies. In the present study, an improved prediction has been reported through better representation of turbulence effect by Reynolds stress transport model and extended upstream computational domain. Thermo-chemical properties of the flame have been represented by a laminar flamelet model. A comparison among reduced chemical kinetic mechanism of Peters and detailed mechanisms of GRI 2.11, GRI 3.0, and San Diego has been studied under the laminar flamelet modelling framework. Computed results have been compared against the well-known experimental data of Sydney University bluff-body CH₄/H₂ flame. Results show that the laminar flamelet model yields very good agreement with measurements for temperature and major species with all the reaction mechanisms. The GRI 2.11 performs better than the other reaction mechanisms in predicting minor species such as OH and pollutant NO. The agreement achieved for NO is particularly encouraging considering the simplified modelling formulation utilized for the kinetically controlled NO formation.

Keywords

bluff-body combustion laminar flamelet

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References

Jones

W. P.

Whitelaw

J. H.

Calculations method for reacting turbulent flows: A review

Combust. Flame, 48, 1982, 1–26.

Peters

Laminar flamelet models in nonpremixed turbulent combustion. Prog. Energy Combust. Sci., 10, 1984, 319–339.

Peters

Laminar flamelet concepts in turbulent combustion. Proc. Combus. Inst., 21, 1986, 1231–1250.

Bray

K. N. C.

Peters

N. Laminar flamelets in turbulent flames. In Turbulent reacting flows (Eds Libby

P. A.

Williams

F. A.

), 1994, chapter 2, pp. 63–113 (Academic Press, London).

Bilger

R. W.

Conditional moment closure for turbulent reacting flows. Phys. Fluids A, 5(2), 1993, 436–444.

Pope

S. B.

PDF methods for turbulent reactive flows. Prog. Energy Combust. Sci., 11, 1985, 119–192.

Pope

S. B.

Computations of turbulent combustion: Progress and challenges. Proc. Combust. Inst., 23, 1990, 591–612.

Muradoglu

Liu

Pope

S. B.

PDF modelling of a bluff-body stabilized turbulent flame. Combust. Flame, 132, 2003, 115–137.

Barlow

R. S.

Smith

N. S. A.

Chen

J. Y.

Bilger

R. W.

Nitric oxide formation in dilute hydrogen jet flames: Isolation of the effects of radiation and turbulence-chemistry submodels. Combust. Flame, 117, 1999, 4–31.

10.

Kronenburg

Bilger

R. W.

Kent

J. H.

Second-order conditional moment closure for turbulent jet diffusion flames. Proc. Combust. Inst., 27, 1998, 1097–1104.

11.

Roomina

M. A.

Bilger

R. W.

Conditional moment closure (CMC) predictions of a turbulent methane-air jet flame. Combust. Flame, 125, 2001, 1176–1195.

12.

Mahmud

Sangha

S. K.

Costa

Santos

Experimental and computational study of a lifted, non-premixed turbulent free jet flame. Fuel, 86, 2007, 793–806.

13.

Hossain

Malalasekera

Modelling of a bluff body stabilised CH₄/H₂ flame based on a laminar flamelet model with emphasis on NO prediction. Proc. Instn Mech. Engrs, Part A: J. Power and Energy, 217, 2005, 201–210.

14.

Kim

S. H.

Huh

K. Y.

Use of the conditional moment closure model to predict NO formation in a turbulent CH₄/H₂ flame over a bluff-body. Combust. Flame, 130, 2002, 94–111.

15.

Sreedhara

Huh

K. Y.

Modeling of turbulent, two-dimensional nonpremixed CH₄/H₂ flame over a bluffbody using first- and second-order elliptic conditional moment closures. Combust. Flame, 142, 2005, 119–134.

16.

Dally

B. B.

Fletcher

D. E.

Masri

A. R.

Flow and mixing fields of turbulent bluff-body jets and flames. Combust. Theory Model., 2, 1998, 193–219.

17.

Merci

Dick

Vierendeels

Roekaerts

Peeters

T. W. J.

Application of a new cubic turbulence model to piloted and bluff-body diffusion flames. Combust. Flame, 126, 2001, 1533–1556.

18.

Naud

Roekaerts

Numerical investigation of a bluff-body stabilised nonpremixed flame with differential Reynolds-stress models. Flow, Turbul. Combust., 70, 2003, 211–240.

19.

Yan

Thiele

Buffat

A turbulence model sensitivity study for CH₄/H₂ bluff-body stabilized flames. Flow, Turbul. Combust, 73, 2004, 1–24.

20.

Kempf

Lindstedt

R. P.

Janicka

Large-eddy simulation of a bluff-body stabilised nonpremixed flame. Combust. Flame, 144, 2006, 170–189.

21.

Raman

Pitsch

Large-eddy simulation of a bluff-body-stabilised non-premixed flame using a recursive filter-refinement procedure. Combust. Flame, 142, 2005, 329–347

22.

Masri

A. R.

Available from http://www.aeromech.usyd.edu.au/thermo.uids/, accessed 11 December 2007.

23.

Launder

B. E.

Reece

G. J.

Rodi

Progress in the development of a Reynolds-stress turbulence closure. J. Fluid Mech., 68, 1975, 537–566.

24.

Lien

F. S.

Leschziner

M. A.

Assessment of turbulent-transport models including non-linear RNG eddy-viscosity formulation and second-moment closure for flow over a backward-facing step. Comput. Fluids., 23, 1994, 983–1004.

25.

Naot

Shavit

Wolfshtein

Interaction between components of the turbulent velocity correlation tensor. Isr. J. Technol., 1970, 8, 259–269.

26.

Pitsch

A C++ computer program for 0-D and 1-D laminar flame calculation. Available from http://www.stanford.edu/group/pitsch/CES.html, accessed 11 December 2007.

27.

Peters

Flame calculations with reduced mechanisms an outline. In Reduced kinetic mechanisms for applications in combustion systems (Eds Peters

Rogg

), 1993, chapter 1, pp. 3–14 (Springer-Verlag, Berlin).

28.

Available from http://diesel.me.berkeley.edu/∼gri_mech/new21/version21/text21.html, accessed 11 December 2007.

29.

Available from http://www.me.berkeley.edu/gri-mech/releases.html, accessed 11 December 2007.

30.

Available from http://www-mae.ucsd.edu/∼combustion/cermech/, accessed 11 December 2007.

31.

Dally

B. B.

Masri

A. R.

Barlow

R. S.

Fiechtner

G. J.

Instantaneous and mean compositional structure of a bluff-body stabilized nonpremixed flame. Combust. Flame, 114, 1998, 119–148.

32.

Kuan

T. S.

Lindstedt

R. P.

Transported probability density function modeling of a bluff-body stabilised turbulent flame. Proc. Combust. Inst., 30, 2005, 767–774.

33.

Ravikanti

Odedra

Malalasekera

, Steady/unsteady flamelet modelling of NO_x in turbulent bluff-body stabilized non-premixed flames. In Work in progress abstracts of the 31st International Symposium on Combustion, 2006, p. 337 (The Combustion Institute, Pittsburgh).

34.

Ravikanti

Malalasekera

Hossain

Mahmud

Flamelet based NO_x-radiation integrated modelling of turbulent non-premixed flame using Reynolds-stress closure. Flow, Turbul. Combust, 81, 2008, 301–319.