A numerical study of the effect of pressure on the formation of NOx and soot in an axisymmetric 30 deg counterrotating axial swirler lean low-NOx gas turbine combustor has been conducted. This has previously been studied experimentally and this CFD investigation was undertaken to explain the higher than expected NOx emissions. The combustion conditions selected for the present study were 300 K inlet air, 0.4 overall equivalence ratio, and pressures of 1 and 10 bar. The numerical model used here involved the solution of time-averaged governing equations using an elliptic flow-field solver. The turbulence was modeled using algebraic stress modeling (ASM). The thermochemical model was based on the laminar flame let formulation. The conserved scalar/assumed pdf approach was used to model the turbulence chemistry interaction. The study was for two pressure cases at 1 and 10 bar. The turbulence–chemistry interaction is closed by assumption of a clipped Gaussian function form for the fluctuations in the mixture fraction. The kinetic calculations were done separately from the flowfield solver using an opposed laminar diffusion flame code of SANDIA. The temperature and species profiles were made available to the computations through look-up tables. The pollutants studied in this work were soot and NO for which three more additional transport equations are required, namely: averaged soot mass fraction, averaged soot particle number density, and finally averaged NO mass fraction. Soot oxidation was modeled using molecular oxygen only and a strong influence of pressure was predicted. Pressure was shown to have a major effect on soot formation.

Issue Section:
Gas Turbines: Combustion and Fuels
Topics:
Combustion chambers, Gas turbines, Pollution, Pressure, Soot, Turbulence, Chemistry, Nitrogen oxides, Algebra, Combustion, Computation, Computational fluid dynamics, Computer simulation, Density, Diffusion flames, Emissions, Flames, Flow (Dynamics), Fluctuations (Physics), Gaussian distribution, Modeling, Oxidation, Oxygen, Particulate matter, Scalars, Stress, Temperature
1.
Alizadeh, S., and Moss, J. B., 1993, “Flowfield Prediction of NOx and Smoke Production in Aircraft Engines,” AGARD-CP-536.
2.
Amin, E. M., 1991, “Influence of Counter-rotating Swirl on Combustion and Emissions,” M.Sc. thesis, University of Leeds.
3.
Amin, E. M., 1994, “CFD Modelling of Turbulent Diffusion Flames,” PhD Thesis, University of Leeds.
4.
Andrews, G. E., Amin, E. A., Ahmed, N. T., and Kowkabi, M., 1991, “Counter Rotating Double Axial Swirlers With Fuel Injection in the Counter Swirl Shear Layer,” presented at the Japanese International Gas Turbine Congress, Yokohama.
5.
Bilger
R. W.
,
1976
, “
Turbulent Jet Diffusion Flames
,”
Prog. Energy Combust. Sci.
, Vol.
1
, pp.
87
–
109
.
6.
Bilger
R. W.
,
1989
, “
Turbulent Diffusion Flames
,”
Ann. Rev. Fluid Mech.
, Vol.
21
, p.
101
101
.
7.
Bradley, D., Dixon-Lewis, G., El-Din Habik, E., and Mushi, E. M. J., 1985, Twentieth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, p. 931.
8.
Corr
R. A.
,
Malte
P. C.
, and
Marinov
N. M.
,
1992
, “
Evaluation of NOx Mechanisms for Lean, Premixed Combustion
,”
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
114
, p.
425
425
.
9.
Dupont, V., Pourkashanian, M., and Williams, A., 1993, “Predictions of Prompt NOx in Hydrocarbon Air Flames,” AGARD Conf. Proc. CP 536, p. 3-1–3-13.
10.
Fairweather, M., Jones, W. P., and Lindstedt, R. P., 1991, Twenty Fourth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, PA.
11.
Fairweather
M.
,
Jones
W. P.
, and
Lindstedt
R. P.
,
1991
,
Combust. Flame
, Vol.
87
, pp.
289
–
305
.
12.
Fairweather
M.
,
Jones
W. P.
, and
Lindstedt
R. P.
,
1992
,
Combust. Flame
, Vol.
89
, pp.
45
–
63
.
13.
Fenimore
C. P.
, and
Jones
G. W.
,
1967
,
J. of Phys. Chem.
, Vol.
71
, p.
593
593
.
14.
Flower, W. L., and Bowman, C. T., 1985, Twentieth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, p. 1035.
15.
Flower, W. L., and Bowman, C. T., 1987, “Soot Production in Axisymmetric Laminar Diffusion Flames at Pressures From One to Ten Atmosphere,” Twenty-First Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, p. 1115.
16.
Garo
A.
,
Lahaye
J.
, and
Prado
G.
,
1990
,
Combust. Flame
, Vol.
76
, pp.
226
–
233
.
17.
Lefebvre, A. H., 1983, Gas Turbine Combustion, Hemisphere Publishing Corp., Washington, DC.
18.
Lefebvre
A. H.
,
1985
,
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
107
, p.
24
24
.
19.
Leung
K. M.
,
Lindstedt
R. P.
, and
Jones
W. P.
,
1991
,
Combust. Flame
, Vol.
87
, pp.
289
–
305
.
20.
Maans, H. G., and Miller, I. M., 1980, NASA T. P. 1673.
21.
Miller, I. M., 1978, NASA T. P. 1318.
22.
Moss, J. B., Stewart, C. D., and Syed, K. J., 1988, “Flowfield Modelling of Soot Formation at Elevated Pressures,” Twenty-Second Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, p. 413.
23.
Nicol, D., Malte, P. C., Lai, J., Marinov, N. N., Pratt, D. T., and Corr, R. A., 1992, “NOx Sensitivities for Gas Turbine Engines Operated on Lean-Premixed Combustion and Conventional Diffusion Flames,” ASME Paper No. 92-GT-115.
24.
Nikjooy
M.
,
So
R. M.
, and
Peck
R. E.
,
1988
, “
Modelling of Jet and Swirl-Stabilised Reacting Flows in Axisymmetric Combustors
,”
Combust. Sci. and Tech.
, Vol.
58
, pp.
135
–
153
.
25.
Rizk, N. K., and Mongia, H. C., 1986, AIAA Paper No. 86-1531.
26.
Rizk, N. K., and Mongia, H. C., 1992, Twenty-Fourth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, p. 1063.
27.
Rodi
W.
,
1976
, “
A New Algebraic Relation for Calculating the Reynolds Stresses
,”
ZAMM
, Vol.
56
, p.
219
219
.
28.
Shaw
H.
,
1974
, “
The Effects of Water, Pressure, and Equivalence Ratio on Nitric Oxide Production in Gas Turbines
,”
ASME JOURNAL OF ENGINEERING FOR POWER
, Vol.
96
, pp.
240
–
246
.
29.
Valachovic, T. G., 1993, “Numerical Predictions of Idle-Power Emissions From Gas Turbine Combustors,” ASME Paper No. 93-GT-175.
30.
Wagner, H. Gg., 1987, “The Influence of Pressure on Soot Formation,” AGARD-CP-422.
31.
Yoshihara, Y., Kazakov, A., Wang, H., and Franklach, M., 1994, Twenty-Fifth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh.
32.
Zel’dovich
Ya. B.
,
1946
,
Acta Physicochim. (USSR)
, Vol.
21
, p.
577
577
.
This content is only available via PDF.
Copyright © 1997
 by The American Society of Mechanical Engineers
You do not currently have access to this content.