Experimental Studies of the Pyrolysis and Oxidation of Diesel … · 2013. 2. 6. · u b b u u b b...

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


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


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


► 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



8 12 16 20 24 28 32 36 40 44

0

20

40

60

80

Num

ber

of

part

icle

s


TEM – Size distribution

Toluene Pyrolysis

(T5=1700 K ; P5= 1714 kPa)

Nb of data points used : 446



Toluene Oxidation (=5)

(T5= 1685 K ; P5= 1266 kPa)




Toluene Oxidation (=18)

(T5=1685 K ; P5= 1802 kPa)




Nu

mb

er

of p

art

icle

s

8 12 16 20 24 28 32 36 40 44

0

20

40

60


8 12 16 20 24 28 32 36 40 44

0

4

8

12

16

20

Nu

mb

er

of p

art

icle

s


8 12 16 20 24 28 32 36 40 44

0

10

20

30

Nu

mb

er

of p

art

icle

s


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


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


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

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