In this work, a single sector lean burn model combustor operating in pilot only mode has been investigated using both experiments and computations with the main objective of analyzing the flame structure and soot formation at conditions relevant to aero-engine applications. Numerical simulations were performed using the large eddy simulation (LES) approach and the conditional moment closure (CMC) combustion model with detailed chemistry and a two-equation model for soot. The CMC model is based on the time-resolved solution of the local flame structure and allows to directly take into account the phenomena associated to molecular mixing and turbulent transport, which are of great importance for the prediction of emissions. The rig investigated in this work, called big optical single sector rig, allows to test real scale lean burn injectors. Experiments, performed at elevated pressure and temperature, corresponding to engine conditions at part load, include planar laser-induced fluorescence of OH (OH-PLIF) and phase Doppler anemometry (PDA) and have been complemented with new laser-induced incandescence (LII) measurements for soot location. The wide range of measurements available allows a comprehensive analysis of the primary combustion region and can be exploited to further assess and validate the LES/CMC approach to capture the flame behavior at engine conditions. It is shown that the LES/CMC approach is able to predict the main characteristics of the flame with a good agreement with the experiment in terms of flame shape, spray characteristics and soot location. Finite-rate chemistry effects appear to be very important in the region close to the injection location leading to the lift-off of the flame. Low levels of soot are observed immediately downstream of the injector exit, where a high amount of vaporized fuel is still present. Further downstream, the fuel vapor disappears quite quickly and an extended region characterized by the presence of pyrolysis products and soot precursors is observed. The strong production of soot precursors together with high soot surface growth rates lead to high values of soot volume fraction in locations consistent with the experiment. Soot oxidation is also very important in the downstream region resulting in a decrease of the soot level at the combustor exit. The results show a very promising capability of the LES/CMC approach to capture the main characteristics of the flame, soot formation, and location at engine relevant conditions. More advanced soot models will be considered in future work in order to improve the quantitative prediction of the soot level.

References

References
1.
Lindstedt
,
R.
, and
Louloudi
,
S.
,
2005
, “
Joint-Scalar Transported PDF Modeling of Soot Formation and Oxidation
,”
Proc. Combust. Inst.
,
30
(
1
), pp.
775
783
.
2.
Jenny
,
P.
,
Roekaerts
,
D.
, and
Beishuizen
,
N.
,
2012
, “
Modeling of Turbulent Dilute Spray Combustion
,”
Prog. Energy Combust. Sci.
,
38
(
6
), pp.
846
887
.
3.
Pera
,
C.
,
Réveillon
,
J.
,
Vervisch
,
L.
, and
Domingo
,
P.
,
2006
, “
Modeling Subgrid Scale Mixture Fraction Variance in LES of Evaporating Spray
,”
Combust. Flame
,
146
(
4
), pp.
635
648
.
4.
Olguin
,
H.
, and
Gutheil
,
E.
,
2014
, “
Influence of Evaporation on Spray Flamelet Structures
,”
Combust. Flame
,
161
(
4
), pp.
987
996
.
5.
Triantafyllidis
,
A.
,
Mastorakos
,
E.
, and
Eggels
,
R.
,
2009
, “
Large Eddy Simulations of Forced Ignition of a Non-Premixed Bluff-Body Methane Flame With Conditional Moment Closure
,”
Combust. Flame
,
156
(
12
), pp.
2328
2345
.
6.
Garmory
,
A.
, and
Mastorakos
,
E.
,
2015
, “
Numerical Simulation of Oxy-Fuel Jet Flames Using Unstructured LES-CMC
,”
Proc. Combust. Inst.
,
35
(
2
), pp.
1207
1214
.
7.
Zhang
,
H.
,
Garmory
,
A.
,
Cavaliere
,
D. E.
, and
Mastorakos
,
E.
,
2015
, “
Large Eddy Simulation/Conditional Moment Closure Modeling of Swirl-Stabilized Non-Premixed Flames With Local Extinction
,”
Proc. Combust. Inst.
,
35
(
2
), pp.
1167
1174
.
8.
Ukai
,
S.
,
Kronenburg
,
A.
, and
Stein
,
O.
,
2015
, “
Large Eddy Simulation of Dilute Acetone Spray Flames Using CMC Coupled With Tabulated Chemistry
,”
Proc. Combust. Inst.
,
35
(
2
), pp.
1667
1674
.
9.
Giusti
,
A.
, and
Mastorakos
,
E.
,
2017
, “
Detailed Chemistry LES/CMC Simulation of a Swirling Ethanol Spray Flame Approaching Blow-Off
,”
Proc. Combust. Inst.
,
36
(
2
), pp.
2625
2632
.
10.
Tyliszczak
,
A.
,
2015
, “
LES-CMC Study of an Excited Hydrogen Flame
,”
Combust. Flame
,
162
(
10
), pp.
3864
3883
.
11.
Zhang
,
H.
, and
Mastorakos
,
E.
,
2016
, “
Prediction of Global Extinction Conditions and Dynamics in Swirling Non-Premixed Flames Using LES/CMC Modelling
,”
Flow Turbul. Combust.
,
96
(
4
), pp.
863
889
.
12.
Giusti
,
A.
, and
Mastorakos
,
E.
,
2016
, “
Numerical Investigation Into the Blow-Off Behaviour of Swirling Spray Flames Using the LES/CMC Approach
,” 11th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (ETMM), Sicily, Italy, Sept. 21–23.
13.
Giusti
,
A.
,
Kotzagianni
,
M.
, and
Mastorakos
,
E.
,
2016
, “
LES/CMC Simulations of Swirl-Stabilised Ethanol Spray Flames Approaching Blow-Off
,”
Flow Turbul. Combust.
,
97
(
4
), pp.
1165
1184
.
14.
Kronenburg
,
A.
,
Bilger
,
R.
, and
Kent
,
J.
,
2000
, “
Modeling Soot Formation in Turbulent Methane-Air Jet Diffusion Flames
,”
Combust. Flame
,
121
(
1–2
), pp.
24
40
.
15.
Bolla
,
M.
,
Wright
,
Y. M.
,
Boulouchos
,
K.
,
Borghesi
,
G.
, and
Mastorakos
,
E.
,
2013
, “
Soot Formation Modeling of n-Heptane Sprays Under Diesel Engine Conditions Using the Conditional Moment Closure Approach
,”
Combust. Sci. Technol.
,
185
(
5
), pp.
766
793
.
16.
Schneider
,
D.
,
Meier
,
U.
,
Quade
,
W.
,
Koopman
,
J.
,
Aumeier
,
T.
,
Langfeld
,
A.
,
Behrendt
,
T.
,
Hassa
,
C.
, and
Rackwitz
,
L.
,
2010
, “
A New Test Rig for Laser Optical Investigations of Lean Jet Burners
,”
27th International Congress of the Aeronautical Sciences
(
ICAS
), Nice, France, Sept. 19–24.http://www.icas.org/ICAS_ARCHIVE/ICAS2010/PAPERS/409.PDF
17.
Freitag
,
S.
,
Behrendt
,
T.
,
Heinze
,
J.
,
Lange
,
L.
,
Meier
,
U.
,
Rackwitz
,
L.
, and
Hassa
,
C.
,
2011
, “
Study of an Airblast Atomizer Spray in a Lean Burn Aero-Engine Model Combustor at Engine Conditions
,” 24th European Conference on Liquid Atomization and Spray Systems (
ILASS
), Estoril, Portugal, Sept. 5–7.https://www.researchgate.net/publication/225022153_Study_of_an_Airblast_Atomizer_Spray_in_a_Lean_Burn_Aero-Engine_Model_Combustor_at_Engine_Conditions
18.
Meier
,
U.
,
Lange
,
L.
,
Heinze
,
J.
,
Hassa
,
C.
,
Sadig
,
S.
, and
Luff
,
D.
,
2014
, “
Optical Methods for Studies of Self-Excited Oscillations and the Effect of Dampers in a High Pressure Single Sector Combustor
,”
ASME
No. GT2014-25873.
19.
Heinze
,
J.
,
Meier
,
U.
,
Behrendt
,
T.
,
Willert
,
C.
,
Geigle
,
K.
,
Lammel
,
O.
, and
Lückerath
,
R.
,
2011
, “
PLIF Thermometry Based on Measurements of Absolute Concentrations of the OH Radical
,”
Z. Phys. Chem.
,
225
(11–12), pp.
1315
1341
.
20.
Klimenko
,
A.
, and
Bilger
,
R.
,
1999
, “
Conditional Moment Closure for Turbulent Combustion
,”
Prog. Energy Combust. Sci.
,
25
(
6
), pp.
595
687
.
21.
Mortensen
,
M.
, and
Bilger
,
R. W.
,
2009
, “
Derivation of the Conditional Moment Closure Equations for Spray Combustion
,”
Combust. Flame
,
156
(
1
), pp.
62
72
.
22.
Anand
,
M. S.
,
Eggels
,
R.
,
Staufer
,
M.
,
Zedda
,
M.
, and
Zhu
,
J.
,
2013
, “
An Advanced Unstructured-Grid Finite-Volume Design System for Gas Turbine Combustion Analysis
,”
ASME
Paper No. GTINDIA2013-3537.
23.
Tyliszczak
,
A.
,
Cavaliere
,
D. E.
, and
Mastorakos
,
E.
,
2014
, “
LES/CMC of Blow-Off in a Liquid Fueled Swirl Burner
,”
Flow Turbul. Combust.
,
92
(
1
), pp.
237
267
.
24.
Triantafyllidis
,
A.
, and
Mastorakos
,
E.
,
2010
, “
Implementation Issues of the Conditional Moment Closure Model in Large Eddy Simulations
,”
Flow Turbul. Combust.
,
84
(
3
), pp.
481
512
.
25.
Garmory
,
A.
, and
Mastorakos
,
E.
,
2011
, “
Capturing Localised Extinction in Sandia Flame F With LES-CMC
,”
Proc. Combust. Inst.
,
33
(
1
), pp.
1673
1680
.
26.
Donde
,
P.
,
Raman
,
V.
,
Mueller
,
M. E.
, and
Pitsch
,
H.
,
2013
, “
LES/PDF Based Modeling of Soot-Turbulence Interactions in Turbulent Flames
,”
Proc. Combust. Inst.
,
34
(
1
), pp.
1183
1192
.
27.
Lignell
,
D. O.
,
Chen
,
J. H.
, and
Smith
,
P. J.
,
2008
, “
Three-Dimensional Direct Numerical Simulation of Soot Formation and Transport in a Temporally Evolving Nonpremixed Ethylene Jet Flame
,”
Combust. Flame
,
155
(
1–2
), pp.
316
333
.
28.
Nehse
,
M.
,
Warnatz
,
J.
, and
Chevalier
,
C.
,
1996
, “
Kinetic Modeling of the Oxidation of Large Aliphatic Hydrocarbons
,”
Proc. Combust. Inst.
,
26
(
1
), pp.
773
780
.
29.
Leung
,
K.
,
Lindstedt
,
R.
, and
Jones
,
W.
,
1991
, “
A Simplified Reaction Mechanism for Soot Formation in Nonpremixed Flames
,”
Combust. Flame
,
87
(
3
), pp.
289
305
.
30.
Slavinskaya
,
N. A.
,
Riedel
,
U.
,
Dworkin
,
S. B.
, and
Thomson
,
M. J.
,
2012
, “
Detailed Numerical Modeling of PAH Formation and Growth in Non-Premixed Ethylene and Ethane Flames
,”
Combust. Flame
,
159
(
3
), pp.
979
995
.
31.
Gepperth
,
S.
,
Koch
,
R.
, and
Bauer
,
H.-J.
,
2013
, “
Analysis and Comparison of Primary Droplet Characteristics in the Near Field of a Prefilming Airblast Atomizer
,”
ASME
Paper No. GT2013-94033.
32.
Abramzon
,
B.
, and
Sirignano
,
W.
,
1989
, “
Droplet Vaporization Model for Spray Combustion Calculations
,”
Int. J. Heat Mass Transfer
,
32
(
9
), pp.
1605
1618
.
33.
Schmehl
,
R.
,
Maier
,
G.
, and
Wittig
,
S.
,
2000
, “
CFD Analysis of Fuel Atomization, Secondary Droplet Breakup and Spray Dispersion in the Premix Duct of a LPP Combustor
,” 8th International Conference on Liquid Atomization & Spray Systems (
ICLASS
), Pasadena, CA, July 16–20https://www.researchgate.net/publication/319624165_CFD_Analysis_of_Fuel_Atomization_Secondary_Droplet_Breakup_and_Spray_Dispersion_in_the_Premix_Duct_of_a_LPP_Combustor.
34.
De
,
S.
, and
Kim
,
S. H.
,
2013
, “
Large Eddy Simulation of Dilute Reacting Sprays: Droplet Evaporation and Scalar Mixing
,”
Combust. Flame
,
160
(
10
), pp.
2048
2066
.
35.
Langella
,
I.
, and
Swaminathan
,
N.
,
2016
, “
Unstrained and Strained Flamelets for LES of Premixed Combustion
,”
Combust. Theory Modell.
,
20
(
3
), pp.
410
440
.
36.
Sidey
,
J. A. M.
,
Giusti
,
A.
, and
Mastorakos
,
E.
,
2016
, “
Simulations of Laminar Non-Premixed Flames of Kerosene With Hot Combustion Products as Oxidiser
,”
Combust. Theory Modell.
,
120
(
5
), pp.
958
973
.
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