Experimental Studies of the Pyrolysis and Oxidation of Diesel
Type Fuels
N. Chaumeix
1
Naples, 23-02_2012
ICARE – CNRS
Institut de Combustion, Aérothermique
Réactivité et Environnement
1c, avenue de la Recherche Scientifique
45071 Orléans – Cedex 2 – France
Orléans
Paris
ICARE is in Orléans,
125 km from Paris
Total staff : 110
35 Researchers
30 Engineers and technicians
30 PhD students and post-docs
15 Various trainees
Where is ICARE ?
Research domains of ICARE
Energy & Environment
Propulsion & Space
• Combustion
• Chemical kinetics
• Plasmas physics
• Fluid mechanics, turbulence
• Two phase flows
• Supersonic, hypersonic flows
• Ionized, rarefied flows
Application domains
• Aerospace propulsion
• Electric propulsion
• Liquid and solid propulsion
• Atmospheric reentry
• Atmospheric chemistry
• Energy production
• Alternative fuels, biofuels, hydrogen
• Pollutant emissions reductions
• Industrial risk prevention
Main cooperations
International co-operations: All EU countries, Russia, USA, Canada, China, Japon, Ukraine, Turkey, Argentine, etc
Research Activities of the S. W. Group
Combustion Chemistry
Elementary Reaction Rates involving O and H atoms
Pollutant Formation from Gasoline Components
Reduced Mechanism of soot precursors from kerosene fuel
Soot Formation from fuels
• Diesel, Gasoline, kerosenes
Soot Oxidation
• In engine conditions behind shock waves
• Particles Filter
Research Activities of the S. W. Group
Flame and Explosions Dynamics
Laminar Flame properties and their instabilities
DDT using hot jet ignition
Flame acceleration in obstructed areas
Detonation criteria and industrial safety
Hypergolic limits of propellant agents
Propellants for PDE
Solid Explosives and their thermal aging
Main Objectives
SLOW
DEFLAGRATIONS
HIGHLY ACCELERATED
DEFLAGRATIONS
DETONATIONS
stable & unstable
COMBUSTION CHEMISTRY
Chemical Explosion
Premixed Flames
Laminar or turbulent
Methodology and Techniques
Several High Pressure Shock-Tubes
Laminar Flames
Spherical Bomb 8 l
Pmax = 75 bar
Tmax = 353 K
Spherical Bomb 56 l
Pmax = 75 bar
Tmax = 520 K
ENACCEF Accelerated Flame Facility
Simi
l-GV
Volume = 850 l
Pmax = 45 bar
Tmax = ambiant
Different obstacles
12
Experimental Studies of the Pyrolysis and Oxidation of Diesel
Type Fuels
N. Chaumeix
Naples, 23-02_2012
Motivations
To improve the knowledge of the chemistry
Need for fundamental data
Acquired in well-defined conditions
At conditions relevant to diesel engines
For pure fuels and surrogates
Identification of the main families
Identification of surrogates
Methodology applied
Soot tendency
Using a shock tube
Auto-ignition delay times
Using a shock tube
Laminer Flame Speeds
Using a spherical bomb
EXPERIMENTAL FACILITIES
Experimental setup
16
52 mmI.D.
LOW PRESSURE
5.15 m
HIGH PRESSURE2 m
Stainless SteelReservoir (30 liters)
He
Vacuum Pump
Pressure Gauge0 - 50 bars
Vacuum Pump
Pressure TransducersCP4 CP3 CP2 CP1
Pressure Gauge0-10 torrs
Magnetic Stirring Ar
0-102
torrs
Pressure Gauges
Vacuum Pump
11
4 m
m
Tolu
en
e
0-103
torrs0-104
torrs
Gas syringe
Setup (shock tube, pipes, tank) @ 405±2K
► Laser Extinction
Diagnostics Coupled to the Shock Tube
CH1 CH2
Transmitted Light
PM Narrow-band
Filter
He - Ne
Laser Pressure Transducer
Oscillocope
Numérique
Quartz
Window
0 0.4 0.8 1.2 1.6 2Temps (ms)
Lumière transmise
Pression
Diagnostics Coupled to the Shock Tube
Shock Tube End
Removable plate
5 nm5 nm
Outer shell
0,35 nm
0,14 nm
Inner core
Sonic Waves ► TEM at low and High Resolution
Diagnostics Coupled to the Shock Tube
Shock Tube End
Removable plate
0 100 200 300 400 500 600
0
100000
200000
300000
400000
500000
23
39
47
69
178
202
228
252
276
300
326
350
374
398
424
472
498
a.i.
m/z
0 100 200 300 400 500 600
0
100000
200000
300000
400000
50000023
39
47
69
178
202
228
252
276
300
326
350
374
398
424
472
498
a.i.
m/z
0 100 200 300 400 500 600
0
100000
200000
300000
400000
500000
23
39
47
69
178
202
228
252
276
300
326
350
374
398
424
472
498
a.i.
m/z178 - 572 amu
LDIToFMS
Sampling Holder Soot on the plate
Mechanical chopper at 40KHz
m = mirror
d.m.= dichroic mirror
f = interferential filter
pol=polarizator
M=monochromator
PMT = photomultiplier
L = lens
PHD = photodiode
488 nm
Ar ion laser
IR laser
chopper
periscope
d.m m
PHD+f
488+632.8 nm 90°
L
pol
PMT
pol PMT
PHD L
L
fv I/I0 Extinction diode laser l = 800 nm
Scattering Ar+ laser l = 488 nm Iscat & I/I0 dp
Diagnostics Coupled to the Shock Tube
► Laser Scattering / Extinction
Gas inlet
Gas Sampling Behind the RSW
Sampling Bulb
Electromagnet
PM
Filter at 307 nm
Photomultiplier
C4
F1 F2
OH* spontaneous emission
PM
Photomultiplier
CH* spontaneous emission
Filter at 432 nm
15
Auto_ignition Delay times
SW speed and Auto-ignition
0 4E-005 8E-005 0.00012
Time (s)
-0.05
0
0.05
0.1
0.15
0.2
0.25
Pre
ssu
reS
ign
al
-2
-1.6
-1.2
-0.8
-0.4
0
Em
iss
ion
Sig
na
l (V
)
ind
(a.u
.)0 4E-005 8E-005 0.00012
Time (s)
-0.05
0
0.05
0.1
0.15
0.2
0.25
Pre
ssu
reS
ign
al
-2
-1.6
-1.2
-0.8
-0.4
0
Em
iss
ion
Sig
na
l (V
)
ind
(a.u
.)
-0.0004 -0.0003 -0.0002 -0.0001 0
Time (s)
-0.1
0
0.1
0.2
0.3
0.4
0.5
Pr e
ss
ure
Sig
na
l
n-propylcyclohexane
C2 : -3.869E-004
C3: -1.968E-004
C4 : -2.500E-007
-0.0004 -0.0003 -0.0002 -0.0001 0
Time (s)
-0.1
0
0.1
0.2
0.3
0.4
0.5
Pr e
ss
ure
Sig
na
l
n-propylcyclohexane
C2 : -3.869E-004
C3: -1.968E-004
C4 : -2.500E-007
(a.u
.)
Volume : 56 L
Pmax = 50 Bars
Tmax = 470 K
Central Ignition
4 Silica Windows
diameter=550 mm
Schlieren System
High Speed Numerical Camera
VHT
SparkElectrodes
Oscilloscope
HT
High Voltage
Source
Spherical
Bomb
Current Probe
To the Camera
I
Hig
h vo
ltag
e
prob
e /1
000
Experimental Setup: Laminar
study
24
Spatial flame speed determination
Electrodes
Burned gases
Fresh gases
Flame front
25
Outward Spherical Flame Front Propagation
26
u
b
b
u
u
bb
b
bSL P
P
T
T
M
M
dt
dP
P3
rVSEschenbach & Agnew
(1958) expression
• M : relative molar mass
• P, T : pressure and temperature
• r : flame radius
• : gas expansion ratio
s
LV
SIn the early stages of the flame propagation
• t : time
• u : relative to unburned gas
• b : relative to burned gas
o Spherical flame o Curvature and thickness negligible o Adiabatic process and isentropic compression o Chemical equilibrium behind the flame front o No dissociation or reactions in the fresh gas o Local deposit of the energy
Spatial flame speed determination
0 0.004 0.008 0.012 0.016Time (s)
0
10
20
30
40
50
Rad
ius (
mm
)
E.R. =1.05
E.R.=1.2
E.R.=0.85
s
L
VS
Pressure
remains
constant
0 0.2 0.4 0.6Time (s)
-2
0
2
4
6
Over
pre
ssu
re(b
ar)
G222 + Air - MANIP 187
Equivalence ratio = 1.05 and
Pini = 1 bar T= 363 K
-0.02 0 0.02 0.04
Time (s)
0
2
4
Ov
erp
ress
ure
(b
ar)
G222 + Air - MANIP 187
Equivalence ratio = 1.05 and
Pini = 1 bar T= 363 K
Pressure
Observation Window
t= 0.00033s t= 0.0025 s t= 0.0035 s
t= 0.00616s t= 0.009 s t= 0.01183s
Vburned
=
0.8 %Vtotal
27
Unstretched velocity
f
S
r
V2
LVV ss LSS LL
Finite flame thickness
A uniform & well-defined stretch
Visualisation of the flame propagation
o Laminar flame velocity versus stretch
o Derive the laminar flame velocity at zero-stretch
28
EXEMPLE OF STUDIES
Real Fuels
Conventional Diesel Fuel C7C15
C8
C10
C9
C14
C11
C12
C15
C13
C13
C12
C11
C7C8
C9
C10
C14C7C15
C8
C10
C9
C14
C11
C12
C15
C13
C13
C12
C11
C7C8
C9
C10
C14 C8
C10
C9
C14
C11
C12
C15
C13
C13
C12
C11
C7C8
C9
C10
C14 n-paraffins:
57.22 %mass
iso-paraffins:
42.78 %mass
Fisher-Tropsch Cut at 403 K Fuel
Conventional Gazoline Fuel
Data source: TOTAL
Studied Fuels
Hydrocarbons representing major component of the real fuel
Diesel : n-hexadecane, butyl-benzene, n-heptyl benzene, decaline, a-methylnaphtalene, propyl-cyclohexane, butyl-benzene, 2,2,4,4,6,8,8 heptamethylnonane
Gazoline : iso-octane, toluene, 1-hexene, 2M2B
Kerosenes : n-decane, trimethyl-benzene, cyclohexane, n-propylbenzene
Fischer-Tropsch : propyl-cyclohexane, 2,2,4,4,6,8,8 heptamethylnonane
Additives
ETBE , Thiophene, 3-methyl-thiophene
8
Diesel Fuel
Pure Fuels
n-decane, n-propylcyclohexane, n-butylbenzène
Mixtures 60/40 (v/v)
n-decane/n-propylcyclohexane
n-decane/n-butylbenzene
Mixtures 40/30/30 (v/v/v)
n-decane/n-propylcyclohexane/n-butylbenzene
EGR mixture (according to PSA) :
77,6 % N2 + 11,5 % O2 + 6,8 % CO2 + 0,2 % CO + 3,9 % H2O
Studied Fuels
Diesel Surrogate
47 % Propyl-cyclohexane + 22 % Heptamethylnonane + 31 % Butyl-benzene
Gazoline Surrogate
50 % Iso-Octane + 35%Toluene + 15%1-Hexene
Kerosene Surrogate
80% n-decane + 20% n-propylbenzene
Real Fuel : Fischer-Tropsch
Cut at 403 K
What is soot ?
Soot is:
Solid phase with condensed molecules
Mainly carbon and H with a ratio 8/1
The density is roughly 1.85 g/cm3
The primary particle is spherical
Soot is constituted of
Soluble fraction that depends strongly on the combustion conditions (fuel, engine load, injection system
Dry fraction which is characterised by a turbostratic structure
34
SOOT TENDENCY OF FUELS
Soot Organization
From the texture point of view
o soot is a particle of about a micrometer size
o If one looks closer, they are in fact agglomerate of primary spheres with an average size about 10 & 40 nm
o Their number can be as high as 100s
The size is the main factor in the toxicity of soot particles
36
100 nm
Toluene pyrolysis @ 2000 K &14 bars
50 nm
Microtexture and structure
37
5 nm
TEM @ low resolution x 50 000
TEM @ high resolution x 310 000
Objectives of the Study
How long does it take to form soot?
How much soot can be formed?
What is exactly formed?
How do soot look like ?
What kind of species are adsorbed on the surface ?
How can these data be useful to the soot modeling?
Soot Properties
Soot Optical Properties will depend on
Type of agregates
Mean diameter of the primary spheres
Micro-Structure
Soot Reactivity will depend on
Micro-Structure
Adsorbed phase
Refractive Index
Soot Oxidation Rate
Rea
ctio
n T
ime
First Ring Formation
Inception and Growth of PAHs
Soot Nucleation
Soot Growth due to surface
growth and coagulation
Bockhorn, 1994
Main Soot Formation Mechanism
Soot Volume Fraction Measurement
BEER-LAMBERT Law & Graham’s model (1975)
I0 I
I
I
mELf o
v ln)(6
l
0 0.0004 0.0008 0.0012
Time (s)
0
4E-007
8E-007
1.2E-006
So
ot
vo
lum
e f
racti
on
(cm
3/c
m3)
0
0.4
0.8
1.2
Pre
ss
ure
(a
.u.)
ind
fvmax
tkff
fln f
vv
v
I
Iln
Cl)m(E72
N
C
C 0
total
av
total
suies
l
Growth Constant
Soot Yield
Induction Delay
TR
EexpDiluantHCA indba
ind
Studied Parameters
Morphology and structure of the soot (T.E.M.) CRMD
Low Resolution: Aggregates, diameter distribution
High Resolution: Arrangement of the carbon layers
Adsorbed Phase on soot LSMCL, Metz
Experimental Conditions
FT (C11.23H24.46)
T5 (K) P5 (MPa)[Carbon]5
(atoms.cm-3)Eq. ratio
()
O2% (mol.)in Ar
0.4% mol.
1675-2540 1.24-1.71 (1,83-2,76).10+18 0%
1630-2325 1.51-1.65 (2.11-2,50).10+18 18 0.42%
1525-1920 1.05-1.48 (2,17-2,49).10+18 5 1.33%
0.2% mol. 1500-2225 1.15-1.65 (1,15-1.38).10+18 0%
Argon Dilution usually > 99 %
Induction Delay Times
4.0E-004 5.0E-004 6.0E-004 7.0E-004
1/T5 (K-1)
1
10
100
1000
Ind
ucti
on
dela
y t
ime (
µs)
Mathieu et al. (31st Symp):
: [C5] = 1.0±0.1x1018 at.cm-3
1100 < P5 (kPa) < 1650
Douce et al. (28th Symp):
1245 < P5 (kPa) < 1805
: [C5] = 2.0±0.4x1018 at.cm-3
: [C5] = 4.9±0.8x1018 at.cm-3
)(
21690exp][046.0 93.050.0
KTPxµs tolueneind
4 4.5 5 5.5 6 6.510000/T5 (K-1)
1
10
100
1000
10000
in
d (
µs)
0.75 < [C]10-18 (at.cm-3) < 1.42
1.56 < [C]10-18 (at.cm-3) < 2.39
3.63 < [C]10-18 (at.cm-3) < 5.71
LP
HP
HP
TOLUENE PYROLYSIS
LP : 200 < P5 (kPa) < 460
HP : 1250 < P5 (kPa) < 1800
Douce et al. (28th Symp):
Induction Delay Times
4.0E-004 4.5E-004 5.0E-004 5.5E-004 6.0E-004
1/T5 (K-1)
10
100
1000
Ind
ucti
on
dela
y (
µs)
Fischer-Tropsch
n-decane [1]
Iso-octane [2]
cetane [3]
Iso-cetane [4]
Diesel surrogate [4]
Pyrolysis 1.400.4 MPa
2.00.5 C at. cm-3
Pyrolysis(2.00.5)x1018 at.cm-3
1.4 MPa 0.4
KTn
nµs
H
Cind
314,8
165000exp104,1
04,3
3R2 = 0,9355
4x10-4
5x10-4
6x10-4
7x10-4
1/T5 (K-1)
100
101
102
103
104
Ind
uct
ion
Del
ay
(µ
s)
n-hexadecane
decahydronaphtalene
n-heptylbenzene
Toluene
1-methylnaphtalene
Summary
46
C4 Route :
C2H3+C2H2C4H5
C2H+C2H2C4H3
puis,
C4H5+C2H2 +H
C4H3+C2H2C6H5
Slow Route
Aromatic
Aliphatic
Fast Route
C3 Route:
C3H3+C3H3C6H5+H
C3H3+C3H4 +H
2 nm
20 nm
+H
HACA Mechanism
HAP
+ H + H2
+C2H2
-H
+C2H2
-H
+H
-H2
+C2H2
Soot Yield - Toluene
1600 2000 2400 2800
T5 (K)
0
4
8
12
16
20
So
ot
Yie
ld (
%)
Douce et al. (PCI, 2000):
: [C5] = 2.0±0.4x1018 at.cm-3
Mathieu et al. (PCI, 2007) :
: [C5] = 1.0±0.1x1018 at.cm-3
2
max expT
TTAYY
opt
v
initial
av
initial
soot fC
N
C
CY
12][
][
• Soot Yield’s definition:
• Soot Yield’s representation:
Soot Yield
1200 1600 2000 2400 2800
T5 (K)
0
20
40
60
So
ot
Yie
ld (
%)
1-methylnaphtalene
Toluene
decahydronaphtalene
n-heptylbenzene
n-hexadecane
Douce et al. (PCI, 2000)
Mathieu et al. (Combst. Flame, 2009)
1600 2000 2400
T5 (K)
0
2
4
6
8
So
ot
yie
ld (
%)
Pyrolysis
ISO [10]
7MN (this work)
HDC [9]
1600 2000 2400
T5 (K)
0
2
4
6
8
So
ot
yie
ld (
%)
Pyrolysis
ISO [10]
7MN (this work)
HDC [9]
Effect of Oxygen
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-4
1/T5 (K-1)
101
102
103
104
Ind
uct
ion
del
ay
(µ
s)
DecahydronaphtalenePyrolysis
Equiv. Ratio = 18
Equiv. Ratio = 5
r = 0,994
r = 0,987
r = 0,994
1200 1600 2000 2400
T5 (K)
0
4
8
12
So
ot
Yie
ld (
%)
DecahydronaphtalenePyrolysis
Equiv. Ratio = 18
Equiv. Ratio = 5
Douce et al. (PCI, 2000)
TEM - Toluene / Ar
50
T5 = 1700 K ; P5 = 1714kPa
T5 = 2000 K
P5 = 1433kPa
446 measurements
Average dm = 26.2 nm
Standard deviation = 3.78
8 12 16 20 24 28 32 36 40 44
0
20
40
60
Num
ber
of
part
icle
s
Particle diameter (nm)
297 measurements
Average dm = 17.9 nm
Standard deviation = 1.71
8 12 16 20 24 28 32 36 40 44
0
20
40
60
80
Num
ber
of
part
icle
s
Particle diameter (nm)
TEM – Size distribution
Toluene Pyrolysis
(T5=1700 K ; P5= 1714 kPa)
Nb of data points used : 446
Average dm = 26.19 nm
Standard deviation = 3.78
Toluene Oxidation (=5)
(T5= 1685 K ; P5= 1266 kPa)
Nb of data points used : 81
Average dm = 17.95 nm
Standard deviation = 2.33
Toluene Oxidation (=18)
(T5=1685 K ; P5= 1802 kPa)
Nb of data points used : 150
Average dm = 26.44 nm
Standard deviation = 2.43
Nu
mb
er
of p
art
icle
s
8 12 16 20 24 28 32 36 40 44
0
20
40
60
Particle diameter (nm)
8 12 16 20 24 28 32 36 40 44
0
4
8
12
16
20
Nu
mb
er
of p
art
icle
s
Particle diameter (nm)
8 12 16 20 24 28 32 36 40 44
0
10
20
30
Nu
mb
er
of p
art
icle
s
Particle diameter (nm)
MET
52
1400 1600 1800 2000 2200
T5 (K)
10
20
30
40
Pri
mary
part
icle
s d
iam
ete
r (n
m)
Microtexture and structure
53
Raw Image Coherent Domain
% single layer
L : layer diameter
d002 : interlayer spacing
La : BSU diameter
Lc : BSU height
a : desorientation degree
Layer Extension
54
1% toluene + 99% Argon
T5 = 1718 K, P5 = 1720 kPa
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6La (nm)
0
0.2
0.4
0.6
0.8
Fré
quen
ce r
elat
ive
Toluene/Argon1700 K, 1714 kPa
Thickness: 0.247 nmLa moy = 0.58 nm
Toluene/Argon
T5 = 1700 K ; P5 = 1714kPa
Toluene/Argon
T5 = 2000 K ; P5 = 1433kPa
Mean diameter : 26 nm
Interlayer spacing :
- inner core : 0.43 nm
- outer shell : 0.39 nm
Carbon layer : 0.58 nm
Texture : spherical, homogeneous
Mean diameter : 18 nm
Interlayer spacing :
- inner core : 0.39 nm
- outer shell : 0.39 nm
Carbon layer : 0.58 nm
Texture : spherical, homogeneous
5. Soot micro-structure
(a) 1475 K
10 nm
(a) 1475 K
10 nm
(a) 1475 K
10 nm
(b) 1765 K
10 nm
(b) 1765 K
10 nm
(b) 1765 K
10 nm
(c) 2135 K
10 nm
(c) 2135 K
10 nm
(c) 2135 K
10 nm 10 nm
(d) 2135 K
10 nm
(d) 2135 K
10 nm
(d) 2135 K
(a) 1475 K
10 nm
(a) 1475 K
10 nm
(a) 1475 K
10 nm
(b) 1765 K
10 nm
(b) 1765 K
10 nm
(b) 1765 K
10 nm
(c) 2135 K
10 nm
(c) 2135 K
10 nm
(c) 2135 K
10 nm 10 nm
(d) 2135 K
10 nm
(d) 2135 K
10 nm
(d) 2135 K
x 310 000
La = Lateral extension of
the poly-aromatics layer.
Interlayer spacing as
the temperature of
formation (Douce et al.,
Proc. 4th Int. Conf. on Internal
Comb. Engine)
At 1475 K:
- Short La and low
degree of organization
- Short La = important
density of edge site
carbon atoms reactive
surface (Vander Wal and
Tomasek, Comb. and Flame 134,
2003)
Effect of Temperature on micr-structure
56
Optical Properties of Soot
57
Authors Spectral Domain Real Parti Imaginary Part
Erickson et coll. visible 1,4 1
Chippet et Gray Visible 1,9-2,0 0,35-0,50
Bockhorn et coll. Visible 1,1 0,37
Lee et Tien Visible 1,8-2,0 0,45-0,65
Dalzel et Sarofim Visible 1,57 0,56
Stagg et 633 nm 1,531±0,004 0,372±0,007
Charalampopoulos
Mullins et Williams 633 nm 1,91±0,02 0,425±0,035
Chang et Visible 1,94 0,6
Charalampopoulos
Habib et Vervisch 600-650 nm 1,47 0,24±0,01
Vaglieco et coll. 637 nm 2,515 0,836
Felske et coll. 2-10 µ m 2,46±0, 15 0,8±0,14
Effect of soot refractive index on Fv
58
P5 = 1299 kPa
T5 = 1865 K
0,4% de n-décane
99,6% d ’argon
[C]total = 2,01.1018 at.C/cm3
0 0.001 0.002 0.003 0.004
Temps (s)
-5E-007
0
5E-007
1E-006
1.5E-006
2E-006
Fra
ction
Volum
ique
(cm
3 d
e s
uies.
cm-3)
Felske et coll.
Chippet et coll.
Lee et coll.
Bockhorn et coll.
Dalzell et coll.
Erickson et coll.
Fractions Volumiques
P5 = 1299 kPa ; T5 = 1865 K
2m
1mIm)m(E
2
2
Species adsorbed on Soot
O. Mathieu et al, PCI, 2009
Mass increment sequences
of 24 amu between major peaks
interrupted by increment
of 26 amu
Major Peaks are Benzenoïd
LDIToFMS Study
0 100 200 300 400 500 600
0
100000
200000
300000
400000
500000
2339
47 69
178
202
228
252
276
300
326
350
374
398
424
472
498
a.i.
m/z
0 100 200 300 400 500 600
0
100000
200000
300000
400000
500000
2339
47 69
178
202
228
252
276
300
326
350
374
398
424
472
498
a.i.
m/z
1670 K
Rendement = 7 %
Major Peaks:
• Benzenoïd HAP : 202, 228, 252,
276…
• Non Benzenoïd HAP: 165, 190,
216, 240, 266, 290 & 314
1475 K
Ysuies = 1 %
O. Mathieu et al, PCI, 2009
AUTO_IGNITION DELAY TIMES
Fuel T (K) P (bar) Xfuel (ppmv) XO2 % Ar
(PCH) C9H18 1 250 – 1 800 10 - 20 75 – 1 000 4 500 – 68 000 93,1 – 99,75 0,2 – 1,5
(BBZ) C10H14 1 225 – 1 800 10 - 20 75 – 1 000 4 500 – 67 500 93,2 – 99,5 0,2 – 1,5
(DEC) C10H22 1 225 – 1 825 10 130 - 875 9 000 – 10 000 99 0,2 – 1,5
Mélange T (K) P (bar) Xmélange (ppmv) XO2 % Ar
C10H22 - C9H18 1 250 – 1 750 10 135 – 930 9 000 – 10 000 99 0,2 – 1,5
C10H22 -
C10H14
1 225 – 1 750 10 135 – 930 9 000 – 10 000 99 0,2 – 1,5
T (K) P (bar) Xmélange (ppmv) XO2 % Ar % EGR
1 275 – 1 850 10 90 - 600 5 800 – 10 000 99 0 et 40 0,2 – 1,5
17
Experimental Conditions
Pure Fuels
Binary Mixtures
Ternary Mixtures + EGR
Propyl-cyclohexane mixtures
0.0006 0.0007 0.0008
1/T5 (K-1)
10
100
1000
Déla
is d
'au
to-i
nfl
am
mati
on
(µs)
Effet de la Richesse à 10 bar et [HC]=Cste
= 1,5
= 1
= 0,5
= 0,4
= 0,3
= 0,2
0.0006 0.00064 0.00068 0.00072 0.00076
1/T5 (K-1)
10
100
1000
Déla
is d
'au
to-i
nfl
am
mati
on
(µs)
Effet de la Richesse à 20 bar et [O2]=Cste
= 1,5
= 1
= 0,5
= 0,4
= 0,3
= 0,2
0.0006 0.00065 0.0007 0.00075
1/T5 (K-1)
10
100
1000
Déla
is d
'au
to-i
nfl
am
mati
on
(µs)
Effet de la Richesse à 10 bar et [O2]=Cste
= 1,5
= 1
= 0,5
= 0,4
= 0,3
= 0,2
RTArOHCµs
000185exp10.40,3)(
39,022,1
2
80,0
189
5
inf r² = 0,97
Delays decrease when ER decreases
Correlation derived using these data and from the literature :
Dubois et al . Energy and Fuels (2009)
LAMINAR FLAME SPEEDS
Experimental Conditions
Molécule Tinitiale Pinitiale Xfuel (ppmv) XO2 (% mol) XN2
(% mol)
n-
propylcyclohexane
130°C 1 bar 83 - 260 20,44 -
20,80
76,89 -
78,30
0,55 - 1,75
n-butylbenzène 130°C 1 bar 85 - 266 20,44 -
20,81
76,87 -
78,30
0,55 - 1,76
n-décane 130°C 1 bar 87 - 237 20,49 -
20,81
77,08 -
78,28
0,65 - 1,79
Mélange dec-pch 130°C 1 bar 89 - 258 20,45 -
20,81
76,94 -
78,27
0,63 - 1,85
Mélange dec-bbz 130°C 1 bar 92 - 239 20,49 -
20,80
77,08 -
78,25
0,65 - 1,71
Gazole reconstitué 130°C 1 bar 90 - 251 20,47 -
20,80
77,75 -
78,52
0,63 - 1,76
n-propylcyclohexane /air
Laminar flame speed is maximum at m ≈ 1,07 (1,63 % HC in air)
Strong decrease of Sl° when different from m
No ignition was obtained for ≤ 0,6
Onset of wrinkling at ≥ 1,30 and no measurement is possible for ≥ 1,75
0.8 1.2 1.60.6 1 1.4 1.8
Richesse
200
400
600
100
300
500
Vit
esse F
on
dam
en
tale
de F
lam
me (
mm
.s-1)
Propylcyclohexane
Dubois et al . Energy and Fuels (2009)
Conclusion
This is a contribution to increase the database with fundamental data
Several facilities have been used
Different parameters have been measured
Consiglio Nazionale delle Ricerche
Istituto per l’Energetica e le Interfasi
I nstitut de
C ombustion
Aérothermique
R éactivité et
E nvironnement
Effect of Hydrogen addition on Soot Formation in a Shock Tube
S. De Iuliis*, N. Chaumeix**, M. Idir**, G. Zizak*, C.-E. Paillard**, A. Coghe***
*CNR-IENI, Milano, Italy ** CNRS-ICARE et Universitè d’Orleans, France
***POLIMI, Milano, Italy
scatt 160°
scatt 20°
scatt 90°
emiss
Laser
(Ar+, IR)
Shock tube with Ø = 87.4 mm
0 0.004 0.008
time (s)
0
1
2
3
4
-0.004
-0.002
0
0.002
0.004
0.006
-0.5
0
0.5
1
1.5
2
2.5
run501ext-IR
ext-488
pressure
inte
nsit
y (
a.u
.)
Typical time-resolved extinction/scattering measurements, raw data
100% ext
0% ext
2% C2H4 in Ar
0 0.004 0.008
time (s)
-0.3
-0.2
-0.1
0
0.1
-1.6
-1.2
-0.8
-0.4
0
0.4
-1.6
-1.2
-0.8
-0.4
0
0.4
-0.5
0
0.5
1
1.5
2
2.5
run501scatt@90
scatt@20
scatt@160
pressure
inte
ns
ity
(a
.u.)
0.000 0.001 0.002 0.003 0.004
0
5
10
15
20
25
30
35
40
1E11
1E12
1E13
1E14
dp [
nm
]
time [s]
Np [c
m-3
]
Soot Particles Parameters : Np, dm
3 ms
Growth characterized by two different rates (the faster at the beginning of soot nucleation).
The number density presents a fast increase due to soot nucleation, followed by a decrease due to coagulation mechanisms.
This work has been carried out thanks to A. Barret, D. Darius, F. Douce,
D. Ladril, O. Mathieu, T. M'Boko, J. Wen, M. Yahyaoui, S. De Iuliis, ….
Funded by TOTAL, PSA-Peugeot Citroen, CNRS, European Community
Collaboration with CNR-Milano, Polimi, U. of Totonto
72