For lean burn combustor development in low emission aero-engines, the pilot stage of the fuel injector plays a key role with respect to stability, operability, NOx emissions, and smoke production. Therefore it is of considerable interest to characterize the pilot module in terms of pilot zone mixing, fuel placement, flow field, and interaction with the main stage. This contribution focuses on the investigation of soot formation during pilot-only operation. Optical test methods were applied in an optically accessible single sector rig at engine idle conditions. Using planar laser-induced incandescence (LII), the distribution of soot and its dependence on air/fuel ratio, as well as geometric injector parameters, was studied. The data shows that below a certain air/fuel ratio, an increase of soot production occurs. This is in agreement with smoke number measurements in a standard single sector flame tube rig without optical access. Reaction zones were identified using chemiluminescence of OH radicals. In addition, the injector flow field was investigated with PIV. A hypothesis regarding the mechanism of pilot smoke formation was made based on these findings. This along with further investigations will form the basis for developing strategies for smoke improvement at elevated pilot-only conditions.

References

References
1.
Lazik
,
W.
,
Doerr
,
Th.
,
Bake
,
S. v. d.
,
Bank
,
R.
, and
Rackwitz
,
L.
,
2008
, “
Development of Lean-Burn Low-NOx Combustion Technology at Rolls-Royce Deutschland,”
ASME
Paper No. GT2008-5111510.1115/GT2008-51115.
2.
Jander
,
H.
, and
Wagner
,
H. G.
,
2005
, “
Formation of Flame Ions, Cluster, Nanotubes and Soot in Hydrocarbon Flames
,”
Proceedings of 5th International Seminar on Flame Structure
,
Novosibirsk, Russia
, July 11–14.
3.
Douce
,
F.
,
Djebaïli-Chaumeix
,
N.
,
Paillard
,
C.
,
Clinard
,
C.
, and
Rouzaud
,
J. N.
,
2000
, “
Soot Formation From Heavy Hydrocarbons Behind Reflected Shock Waves
,”
Symp. (Int.) Combust.
,
28
(
2
), pp.
2523
2529
.
4.
Joo
,
H. I.
, and
Gülder
,
Ö. L.
,
2010
, “
Soot Formation and Temperature Structure in Small Methane–Oxygen Diffusion Flames at Subcritical and Supercritical Pressures
,”
Combust. Flame
,
157
, pp.
1194
1201
.10.1016/j.combustflame.2009.11.003
5.
Yang
,
P.
, and
Seitzman
,
J. M.
,
2003
, “
Soot Concentration and Velocity Measurement in an Acoustic Burner
,”
AIAA
Paper No. 2003-1014.
10.2514/6.2003-1014
6.
Kock
,
B. F.
,
Tribalet
,
B.
,
Schulz
,
C.
, and
Roth
,
P.
,
2006
, “
Two-Color Time-Resolved LII Applied to Soot Particle Sizing in the Cylinder of a Diesel Engine
,”
Combust. Flame
,
147
, pp.
79
92
.10.1016/j.combustflame.2006.07.009
7.
Crua
,
C.
,
Evans
,
J. C.
,
Kennaird
,
D. A.
, and
Heikal
,
M. R.
,
2003
, “
In-Cylinder Study of the Formation, Autoignition and Soot Production of Diesel Sprays at Elevated Pressures
,”
9th International Conference on Liquid Atomization and Spray Systems (ICLASS)
Sorrento, Italy
, July 13–17.
8.
Hertler
,
D.
,
Stirn
,
R.
,
Arndt
,
S.
,
Grzeszik
,
R.
, and
Dreizler
,
A
,
2011
, “
Investigations of Soot Formation in an Optically Accessible Gasoline Direct Injection Engine by Means of Laser-Induced Incandescence (LII)
,”
Appl. Phys. B Lasers Opt.
,
104
(
2
), pp.
399
407
.10.1007/s00340-011-4392-8
9.
Gord
,
J. R.
,
Meyer
,
T. R.
,
Roy
,
S.
, and
Gogineni
,
S. P.
,
2004
, “
Studies of Hydroxyl Distribution and Soot Formation in Turbulent Spray Flames
,”
12th International Symposium on Applications of Laser Techniques to Fluid Mechanics
,
Lisbon, Portugal
, July 12–15.
10.
Geigle
,
K. P.
,
Zerbs
,
J.
, and
Guin
,
C.
,
2010
, “
Laser-Induced Incandescence for Soot Measurements in Technical Flames at Increased Pressure at the ONERA M1 Test Rig
,”
Proceedings Deutscher Luft- und Raumfahrtkongress
,
Hamburg, Germany
, August 31–September 2.
11.
Meier
,
U.
,
Heinze
,
J.
,
Lange
,
L.
,
Hassa
,
C.
,
Rackwitz
,
L.
, and
Doerr
,
T.
,
2012
, “
Characterisation of the Combustion Performance of Low Emission Fuel Injectors With Laser Measurements
,”
CEAS Aeronaut. J.
,
3
, pp.
45
53
.10.1007/s13272-012-0042-z
12.
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 Engine Burners
,”
27th International Congress of the Aeronautical Sciences (ICAS 2010), Nice, France, September 19–24
.
13.
High Pressure Combustor Test Rig 1 (HBK-1) and Test Section BOSS,”
2013, DLR Institute of Propulsion Technology, Köln, Germany, http://www.dlr.de/at/desktopdefault.aspx/tabid-1509/2443_read-3809/
14.
Optical Smoke Meter (OSM),
” 2013, Rotadata, Derby, UK, http://www.rotadata.com/pages/products/Optical-Smoke-Meter-OSM.php
15.
Behrendt
,
T.
,
Frodermann
,
M.
,
Hassa
,
C.
,
Heinze
,
J.
,
Lehmann
,
B.
, and
Stursberg
K.
,
1998
, “
Optical Measurements of Spray Combustion in a Single Sector Combustor From a Practical Fuel Injector at Higher Pressures
,”
RTO Applied Vehicle Technology Panel, Symposium on Gas Turbine Engine Combustion, Emissions and Alternative Fuels
,
Lisbon, Portugal
, October 12–16.
16.
Kohse-Höinghaus
,
K.
, and
Jeffries
,
J. B.
, eds.,
2002
,
Applied Combustion Diagnostics
,
Taylor & Francis
,
London
.
17.
Hoffmann
,
M.
,
Besseler
,
W. G.
,
Schulz
,
C.
, and
Jander
,
H.
,
2003
, “
Laser-Induced Incandescence for Soot Diagnostics at High Pressures
,”
Appl. Opt.
,
42
, pp.
2052
2082
.10.1364/AO.42.002052
18.
Willert
,
C.
, and
Jarius
,
M.
,
2002
, “
Planar Flow Field Measurements in Atmospheric and Pressurized Combustion Chambers
,”
Exp. Fluids
,
33
(
6
), pp.
931
939
.10.1007/s00348-002-0515-7
19.
Müller
,
A.
, and
Wittig
,
S
,
1994
, “
Experimental Study of the Influence of Pressure on Soot Formation in a Shock Tube
,”
Soot Formation in Combustion
(Springer Series in Chemical Physics),
H.
Bockhorn
, ed.,
Springer
,
Berlin
, pp.
350
370
.
20.
Kellerer
,
H.
,
Koch
,
R.
, and
Wittig
,
S.
,
2000
, “
Measurements of the Growth and Coagulation of Soot Particles in a High-Pressure Shock Tube
,”
Combust. Flame
,
120
(
1–2
), pp.
188
199
.10.1016/S0010-2180(99)00067-X
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