An n-dodecane spray flame was simulated using a dynamic structure large-eddy simulation (LES) model coupled with a detailed chemistry combustion model to understand the ignition processes and the quasi-steady state flame structures. This study focuses on the effect of different ambient oxygen concentrations, 13%, 15%, and 21%, at an ambient temperature of 900 K and an ambient density of 22.8 kg/m3, which are typical diesel-engine relevant conditions with different levels of exhaust gas recirculation (EGR). The liquid spray was treated with a traditional Lagrangian method. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. It is observed that the main ignitions occur in rich mixture, and the flames are thickened around 35–40 mm off the spray axis due to the enhanced turbulence induced by the strong recirculation upstream, just behind the head of the flames at different oxygen concentrations. At 1 ms after the start of injection (SOI), the soot production is dominated by the broader region of high temperature in rich mixture instead of the stronger oxidation of the high peak temperature. Multiple realizations were performed for the 15% O2 condition to understand the realization-to-realization variation and to establish best practices for ensemble-averaging diesel spray flames. Two indexes are defined. The structure-similarity index (SSI) analysis suggests that at least 5 realizations are needed to obtain 99% similarity for mixture fraction if the average of 16 realizations is used as the target at 0.8 ms. However, this scenario may be different for different scalars of interest. It is found that 6 realizations would be enough to reach 99% of similarity for temperature, while 8 and 14 realizations are required to achieve 99% similarity for soot and OH mass fraction, respectively. Similar findings are noticed at 1 ms. More realizations are needed for the magnitude-similarity index (MSI) for the similar level of similarity as the SSI.

References

References
1.
Dec
,
J. E.
,
2009
, “
Advanced Compression-Ignition Engines Understanding the In-Cylinder Processes
,”
Proc. Combust. Inst.
,
32
(
2
), pp.
2727
2742
.
2.
Musculus
,
M. P.
,
Miles
,
P. C.
, and
Pickett
,
L. M.
,
2013
, “
Conceptual Models for Partially Premixed Low-Temperature Diesel Combustion
,”
Prog. Energy Combust. Sci.
,
39
(
2
), pp.
246
283
.
3.
Pickett
,
L.
,
Bruneaux
,
G.
, and
Payri
,
R.
,
2015
, “
Engine Combustion Network
,” Sandia National Laboratories, Albuquerque, NM, http://www.ca.sandia.gov/ecn
4.
Pei
,
Y.
,
Hawkes
,
E. R.
, and
Kook
,
S.
,
2013
, “
A Comprehensive Study of Effects of Mixing and Chemical Kinetic Models on Predictions of n-Heptane Jet Ignitions With the PDF Method
,”
Flow, Turbul. Combust.
,
91
(
2
), pp.
249
280
.
5.
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
.
6.
Bolla
,
M.
,
Farrace
,
D.
,
Wright
,
Y. M.
,
Boulouchos
,
K.
, and
Mastorakos
,
E.
,
2014
, “
Influence of Turbulence–Chemistry Interaction for n-Heptane Spray Combustion Under Diesel Engine Conditions With Emphasis on Soot Formation and Oxidation
,”
Combust. Theory Modell.
,
18
(
2
), pp.
330
360
.
7.
D'Errico
,
G.
,
Lucchini
,
T.
,
Contino
,
F.
,
Jangi
,
M.
, and
Bai
,
X.-S.
,
2013
, “
Comparison of Well-Mixed and Multiple Representative Interactive Flamelet Approaches for Diesel Spray Combustion Modelling
,”
Combust. Theory Modell.
,
18
(
1
), pp.
65
88
.
8.
Pei
,
Y.
,
Hawkes
,
E. R.
,
Kook
,
S.
,
Goldin
,
G. M.
, and
Lu
,
T.
,
2015
, “
Modelling n-Dodecane Spray and Combustion With the Transported Probability Density Function Method
,”
Combust. Flame
,
162
(
5
), pp.
2006
2019
.
9.
Kundu
,
P.
,
Pei
,
Y.
,
Wang
,
M.
,
Raju
,
M.
, and
Som
,
S.
,
2014
, “
Evaluation of Turbulence Chemistry Interaction Under Diesel Engine Conditions With Multi-Flamelet RIF Model
,”
Atomization Sprays
,
24
(
9
), pp.
779
800
.
10.
Chishty
,
M.
,
Pei
,
Y.
,
Hawkes
,
E.
,
Bolla
,
M.
, and
Kook
,
S.
,
2014
, “
Investigation of the Flame Structure of Spray-A Using the Transported Probability Density Function
,”
19th Australasian Fluid Mechanics Conference
, Melbourne, Australia, Dec. 8–11.
11.
Pope
,
S. B.
,
2000
,
Turbulent Flows
,
Cambridge University Press
, Cambridge, UK.
12.
Pope
,
S. B.
,
2004
, “
Ten Questions Concerning the Large-Eddy Simulation of Turbulent Flows
,”
New J. Phys.
,
6
(
1
), p.
35
.
13.
Rutland
,
C.
,
2011
, “
Large-Eddy Simulations for Internal Combustion Engines: A Review
,”
Int. J. Engine Res.
,
12
(5), pp.
421
451
.
14.
Bekdemir
,
C.
,
Somers
,
L.
,
de Goey
,
L.
,
Tillou
,
J.
, and
Angelberger
,
C.
,
2013
, “
Predicting Diesel Combustion Characteristics With Large-Eddy Simulations Including Tabulated Chemical Kinetics
,”
Proc. Combust. Inst.
,
34
(
2
), pp.
3067
3074
.
15.
Tillou
,
J.
,
Michel
,
J.-B.
,
Angelberger
,
C.
, and
Veynante
,
D.
,
2014
, “
Assessing LES Models Based on Tabulated Chemistry for the Simulation of Diesel Spray Combustion
,”
Combust. Flame
,
161
(
2
), pp.
525
540
.
16.
Ameen
,
M. M.
, and
Abraham
,
J.
,
2014
, “
RANS and LES Study of Lift-Off Physics in Reacting Diesel Jets
,”
SAE
Paper No. 2014-01-1118.
17.
Irannejad
,
A.
,
Banaeizadeh
,
A.
, and
Jaberi
,
F.
,
2015
, “
Large Eddy Simulation of Turbulent Spray Combustion
,”
Combust. Flame
,
162
(
2
), pp.
431
450
.
18.
Gong
,
C.
,
Jangi
,
M.
, and
Bai
,
X.-S.
,
2014
, “
Large Eddy Simulation of n-Dodecane Spray Combustion in a High Pressure Combustion Vessel
,”
Appl. Energy
,
136
, pp.
373
381
.
19.
Pei
,
Y.
,
Hawkes
,
E. R.
, and
Kook
,
S.
,
2013
, “
Transported Probability Density Function Modelling of the Vapour Phase of an n-Heptane Jet at Diesel Engine Conditions
,”
Proc. Combust. Inst.
,
34
(
2
), pp.
3039
3047
.
20.
Hawkes
,
E.
,
Pei
,
Y.
,
Kook
,
S.
, and
Sibendu
,
S.
,
2013
, “
An Analysis of the Structure of an n-Dodecane Spray Flame Using PDF Modelling
,”
Australian Combustion Symposium
, Perth, Australia, Nov. 6–8.
21.
Xue
,
Q.
,
Som
,
S.
,
Senecal
,
P. K.
, and
Pomraning
,
E.
,
2013
, “
Large Eddy Simulation of Fuel-Spray Under Non-Reacting IC Engine Conditions
,”
Atomization Sprays
,
23
(
10
), pp.
925
955
.
22.
Bhattacharjee
,
S.
, and
Haworth
,
D. C.
,
2013
, “
Simulations of Transient n-Heptane and n-Dodecane Spray Flames Under Engine-Relevant Conditions Using a Transported PDF Method
,”
Combust. Flame
,
160
(
10
), pp.
2083
2102
.
23.
Pei
,
Y.
,
Hawkes
,
E. R.
,
Bolla
,
M.
,
Kook
,
S.
,
Goldin
,
G. M.
,
Yang
,
Y.
,
Pope
,
S. B.
, and
Som
,
S.
,
2015
, “
An Analysis of the Structure of an n-Dodecane Spray Flame Using TPDF Modelling
,”
Combust. Flame
(in press).
24.
Pei
,
Y.
,
Kundu
,
P.
,
Goldin
,
G. M.
, and
Som
,
S.
,
2015
, “
Large Eddy Simulation of a Reacting Spray Flame Under Diesel Engine Conditions
,”
SAE
Paper No. 2015-01-1844.
25.
Pei
,
Y.
,
Mehl
,
M.
,
Liu
,
W.
,
Lu
,
T.
,
Pitz
,
W. J.
, and
Som
,
S.
,
2015
, “
A Multi-Component Blend as a Diesel Fuel Surrogate for Compression Ignition Engine Applications
,”
ASME J. Eng. Gas Turbines Power
,
137
(
11
), p.
11502
.
26.
Pei
,
Y.
,
Davis
,
M. J.
,
Pickett
,
L. M.
, and
Som
,
S.
,
2015
, “
Engine Combustion Network (ECN): Global Sensitivity Analysis of Spray A for Different Combustion Vessels
,”
Combust. Flame
,
162
(
6
), pp.
2337
2347
.
27.
Pickett
,
L. M.
,
Genzale
,
C. L.
,
Bruneaux
,
G.
,
Malbec
,
L.-M.
,
Hermant
,
L.
,
Christiansen
,
C.
, and
Schramm
,
J.
,
2010
, “
Comparison of Diesel Spray Combustion in Different High-Temperature, High-Pressure Facilities
,”
SAE Int. J. Engines
,
3
(
2
), pp.
156
181
.
28.
Pickett
,
L. M.
,
Manin
,
J.
,
Genzale
,
C. L.
,
Siebers
,
D. L.
,
Musculus
,
M. P.
, and
Idicheria
,
C. A.
,
2011
, “
Relationship Between Diesel Fuel Spray Vapor Penetration/Dispersion and Local Fuel Mixture Fraction
,”
SAE Int. J. Engines
,
4
(
1
), pp.
764
799
.
29.
Skeen
,
S. A.
,
Manin
,
J.
, and
Pickett
,
L. M.
,
2015
, “
Simultaneous Formaldehyde PLIF and High-Speed Schlieren Imaging for Ignition Visualization in High-Pressure Spray Flames
,”
Proc. Combust. Inst.
,
35
(
3
), pp.
3167
3174
.
30.
Som
,
S.
, and
Aggarwal
,
S.
,
2010
, “
Effects of Primary Breakup Modeling on Spray and Combustion Characteristics of Compression Ignition Engines
,”
Combust. Flame
,
157
(
6
), pp.
1179
1193
.
31.
Senecal
,
P.
,
Richards
,
K.
,
Pomraning
,
E.
,
Yang
,
T.
,
Dai
,
M.
,
McDavid
,
R.
,
Patterson
,
M.
,
Hou
,
S.
, and
Shethaji
,
T.
,
2007
, “
A New Parallel Cut-Cell Cartesian CFD Code for Rapid Grid Generation Applied to In-Cylinder Diesel Engine Simulations
,”
SAE
Paper No. 2007-01-0159.
32.
Richards
,
K.
,
Senecal
,
P.
, and
Pomraning
,
E.
,
2013
, “
Converge (Version 2.1) Manual
,” Convergent Science, Inc., Madison, WI.
33.
Reitz
,
R. D.
,
1987
, “
Modeling Atomization Processes in High-Pressure Vaporizing Sprays
,”
Atomisation Spray Technol.
,
3
(4), pp.
309
337
.
34.
Patterson
,
M. A.
, and
Reitz
,
R. D.
,
1998
, “
Modeling the Effects of Fuel Spray Characteristics on Diesel Engine Combustion and Emission
,”
SAE
Paper No. 980131.
35.
Schmidt
,
D. P.
, and
Rutland
,
C.
,
2000
, “
A New Droplet Collision Algorithm
,”
J. Comput. Phys.
,
164
(
1
), pp.
62
80
.
36.
Frossling
,
N.
,
1956
,
Evaporation, Heat Transfer, and Velocity Distribution in Two-Dimensional and Rotationally Symmetrical Laminar Boundary-Layer Flow
, Vol.
168
,
NACA
, Washington, DC, pp.
AD–B189
.
37.
Liu
,
A. B.
,
Mather
,
D.
, and
Reitz
,
R. D.
,
1993
, “
Modeling the Effects of Drop Drag and Breakup on Fuel Sprays
,”
SAE
Paper No. 930072.
38.
Pomraning
,
E.
, and
Rutland
,
C. J.
,
2002
, “
Dynamic One-Equation Nonviscosity Large-Eddy Simulation Model
,”
AIAA J.
,
40
(
4
), pp.
689
701
.
39.
Senecal
,
P.
,
Pomraning
,
E.
,
Richards
,
K.
, and
Som
,
S.
,
2013
, “
An Investigation of Grid Convergence for Spray Simulations Using an LES Turbulence Model
,”
SAE
Paper No. 2013-01-1083.
40.
Senecal
,
P.
,
Pomraning
,
E.
,
Richards
,
K.
,
Briggs
,
T.
,
Choi
,
C.
,
McDavid
,
R.
, and
Patterson
,
M.
,
2003
, “
Multi-Dimensional Modeling of Direct-Injection Diesel Spray Liquid Length and Flame Lift-Off Length Using CFD and Parallel Detailed Chemistry
,”
SAE
Paper No. 2003-01-1043.
41.
Luo
,
Z.
,
Som
,
S.
,
Sarathy
,
S. M.
,
Plomer
,
M.
,
Pitz
,
W. J.
,
Longman
,
D. E.
, and
Lu
,
T.
,
2014
, “
Development and Validation of an n-Dodecane Skeletal Mechanism for Spray Combustion Applications
,”
Combust. Theory Modell.
,
18
(
2
), pp.
187
203
.
42.
Kodavasal
,
J.
,
Keum
,
S.
, and
Babajimopoulos
,
A.
,
2011
, “
An Extended Multi-Zone Combustion Model for PCI Simulation
,”
Combust. Theory Modell.
,
15
(
6
), pp.
893
910
.
43.
Hiroyasu
,
H.
, and
Kadota
,
T.
,
1976
, “
Models for Combustion and Formation of Nitric Oxide and Soot in Direct Injection Diesel Engines
,”
SAE
Paper No. 760129.
44.
Pei
,
Y.
,
Som
,
S.
,
Pomraning
,
E.
,
Senecal
,
P. K.
,
Skeen
,
S. A.
,
Manin
,
J.
, and
Pickett
,
L. M.
,
2015
, “
Large Eddy Simulation of a Reacting Spray Flame With Multiple Realizations Under Compression Ignition Engine Conditions
,”
Combust. Flame
,
162
(
12
), pp.
4442
4455
.
45.
Liu
,
K.
,
Haworth
,
D. C.
,
Yang
,
X.
, and
Gopalakrishnan
,
V.
,
2013
, “
Large-Eddy Simulation of Motored Flow in a Two-Valve Piston Engine: Pod Analysis and Cycle-to-Cycle Variations
,”
Flow, Turbul. Combust.
,
91
(
2
), pp.
373
403
.
46.
Hu
,
B.
,
Banerjee
,
S.
,
Liu
,
K.
,
Rajamohan
,
D.
,
Deur
,
J.
,
Xue
,
Q.
,
Som
,
S.
,
Senecal
,
P.
, and
Pomraning
,
E.
,
2015
, “
Large Eddy Simulation of a Turbulent Non-Reacting Spray Jet
,”
ASME
Paper No. ICEF2015-1033.
You do not currently have access to this content.