Plasma Assisted Ignition and Combustion

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Moscow Institute of Physics and Technology

Plasma Assisted Ignition and Combustion

S.M.
Starikovsk
aia,

A.Yu.Starikovskii





Physics of Nonequilibrium Systems Laboratory

Plan of the Talk


1. Introduction: why nonequilibium PAI/PAC?


2. Typical schemes for PAI/PAC experiments;
general results


3. PAI kinetics: experiments and modeling


4. Perspectives

Physics of Nonequilibrium Systems Laboratory

“Fast flow” ignition (Mintoussov,
Starikovskii, 2005)

Physics of Nonequilibrium Systems Laboratory

Plasma
:
equilibrium or nonequilibrium?

Physics of Nonequilibrium Systems Laboratory

Initiation
H + O = 2 + 78 kJ
2
2
OH
Break
H HO
2
+ O + M = + M 203 kJ
-
2
H
+ wall
H OH O
+ O = + kJ
+ 70
2
Branching
Development: 2x
O OH H
+ H = + 8 kJ
+
2
OH H
+ H = H O + 62 kJ
2
-
2
Scheme of H
2
-
O
2

Combustion

Physics of Nonequilibrium Systems Laboratory

Comparison of the Reaction Rates

E/N=100
-
300 Td

K
d
=10
-
10
-
10
-
8

cm
3
/s

Physics of Nonequilibrium Systems Laboratory

Possible Mechanisms for PAI/PAC

-
Radical

mechanism


-
Ion

mechanism


-
Mechanism with
excited species:

electronic, vibrational excitation




Quantitative measurements
are necessary
Physics of Nonequilibrium Systems Laboratory

Complexity of the object


Physics of discharge
(n, E/N, densities of
ionized/excited species)
e
Chemistry (including
high-temperature reactions
and excited /ionized?/
Species)
Peculiarities of gas flow:
interaction with
discharge/chemistry
NO quantitative measurements?
Physics of Nonequilibrium Systems Laboratory

Scheme 1a: Discharge + Flow,
Quasistationary System

Plasma
action
Combustion
Gas flow
A) Fast Flows (M>1)

Physics of Nonequilibrium Systems Laboratory

Hypersonic MW ignition

Lebedev P., Klimov A., Proc.of WSMPA,


1999, IVTAN, Moscow, P.142



Physics of Nonequilibrium Systems Laboratory

Hypersonic MW ignition

Scheme of experimental
setup for hypersonic MW
ignition (a) and the
timeline of operation of
experimental setup (b).


Pressures and
temperatures as well as
times of discharge and
fuel injection are marked
in the scheme


Esakov I I, Grachev L P, Khodataev K V,
Vinogradov V A and Van Wie D M
Efficiency of propane
-
air mixture
combustion assisted by

deeply undercritical MW discharge in cold
high
--
speed airflow

44th AIAA Aerospace Sciences Meeting
and Exhibit (Reno, Nevada,

USA, 9
---
12 January 2006)

AIAA
-
2006
-
1212



Physics of Nonequilibrium Systems Laboratory

Scheme 1b: Discharge + Flow,
Quasistationary System

Plasma
action
Combustion
Gas flow
B) Slow Flows (1
-
10 m/s)

Physics of Nonequilibrium Systems Laboratory

Dt

= 0.3 ns

t
max

= 20 ns

Discharge Development in the Gas Flow.

U = 25 kV,
t
imp

= 25 ns, Propane
-
Air,
f

㴠〮=

0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
4.0
6.0
8.0
10.0
without discharge
25 kV positive polarity (d.c.)
25 kV negative polarity (pulse)
25 kV negative polarity (d.c.)
25 kV positive polarity (pulse)
Blow-off flow rate, m/s
Equivalence Ratio
Mintoussov E I, Pancheshnyi S V and Starikovskii A Yu

Propane
-
air flame control by non

equilibrium

low
-
temperature pulsed
nanosecond barrier discharge
.

42nd AIAA Aerospace Sciences Meeting and
Exhibit (Reno, Nevada, USA, 5

8

January 2004)

AIAA
-
2004
-
1013

Physics of Nonequilibrium Systems Laboratory

Bluff
-
body nozzle with ns discharge

Galley D, Pilla G, Lacoste D, Ducruix S, Lacas F, Veynante D and Laux C O Plasma
-
enhanced combustion of
a lean premixed air
-
propane turbulent flame using a nanosecond repetitively pulsed plasma. 43rd AIAA
Aerospace Sciences meeting and Exhibit (Reno, Nevada, USA, 10
--
13 January 2005) AIAA
-
2005
-
1193

Physics of Nonequilibrium Systems Laboratory

Discharge enhanced flame stabilization

The improvement of liftoff jet velocity as a function of normalized co
-
flow speed. Here S
L
is a laminar flame speed.
SECD is a single electrode corona discharge, USRD is a ultra
-
short repetitively pulsed discharge


Kim W, Do H, Mungal M G and Cappelli M A Flame stabilization enhancement and NOx production

using ultra short repetitively pulsed plasma discharges. 44th AIAA Aerospace Sciences Meeting and Exhibit (Reno, Nevada, USA,

9
-
12 January 2006) AIAA
-
2006
-
560

Physics of Nonequilibrium Systems Laboratory

Ignition of a gas flow by RF
discharge

Flow temperatures in transverse RF discharge in air flow at
different pressures and mass flow rates. RF power is 200~W

Chintala N, Meyer R, Hicks A, Bao A, Rich J W, Lempert W R and Adamovich I V 2005

Nonthermal ignition of premixed hydrocarbon
--
air flows by nonequilibrium radio frequency plasma.

J.Propulsion and Power 21(4) 583
-
90

Physics of Nonequilibrium Systems Laboratory

Scheme 2 (PAI): pulsed discharge +
ignition. No flow!

Plasma
action
Combustion
Time
Kof L M, Starikovskii A Yu (1996)
26th Int. Symp. on WIP Abstracts
Comb.
Physics of Nonequilibrium Systems Laboratory

3) Volume repetitive nanosecond discharge

U=
-
11 kV, t=25 ns, Gate=1 ns, f=40 Hz

Dl
㴳〰
-
㠰〠湭

N.Marchenko, N.Anikin S.Starikovskaia, A.Starikovskii (2005)
Physics of Nonequilibrium Systems Laboratory

Typical behavior of electric field

0
5
10
15
20
25
10
2
10
3
FIW front structure
[N
2
+
(B
2
S
+
u
)], cm
-3
[N
2
(C
3
P
u
)], cm
-3
n
e
, cm
-3
E/N, Td
Time, ns
10
10
10
11
10
12
10
13
Pancheshnyi S V,
Starikovskaia S M,
Starikovskii A Yu 1999 2219
J.Phys.D.: Appl.Phys.
32
Physics of Nonequilibrium Systems Laboratory

How does it works: decrease of
ignition delay time (PAI)

10
10
10
10
Time, sec
-9
-7
-5
-3
Autoignition

Plasma
-
assisted ignition

S.A. Bozhenkov, S.M. Starikovskaia, A.Yu. Starikovskii,
133 (2003) 133-146
Combust. Flame,
Physics of Nonequilibrium Systems Laboratory

Comparison of experiments and
numerical modeling: CH
4
-
C
5
H
12

mixtures

0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
10
0
10
1
10
2
10
3
10
4
10
5
CH
4
-C
5
H
12
,
PAI, 0.2-0.7 atm
C
2
H
6
-C
5
H
12
,
auto, 0.2-0.7 atm
CH
4
, auto, 0.4-0.7 atm
CH
4
, auto, 2 atm


Ignition delay time,

s
1000/T, K
-1
Auto Exp, C2H6
Auto Calc, C2H6
PAI Exp, C2H6
PAI Calc, C2H6
,
,
,

C3H8
,
,
,

C4H10
,
,
,

C5H12
I.N. Kosarev, N.L. Aleksandrov, S.V. Kindysheva, S.M. Starikovskaia, A.Yu. Starikovskii,
submitted (Manuscript No CNF-D-07-00020)
Combust. Flame,
Moscow Institute of Physics and Technology

Kinetics of Plasma Assisted Ignition at
Elevated Temperatures

S.M.
Starikovsk
aia
,

N.L.Aleksandrov, S.V.Kindusheva,

I.N.Kosarev,
A.
Yu.
Starikovskii




I.N. Kosarev, N.L. Aleksandrov, S.V. Kindysheva, S.M. Starikovskaia, A.Yu. Starikovskii,
submitted (Manuscript No CNF-D-07-00020)
Combust. Flame,
Physics of Nonequilibrium Systems Laboratory

Experimental setup for plasma ignition

Physics of Nonequilibrium Systems Laboratory

Setup for nanosecond Electrical
Measurements

Physics of Nonequilibrium Systems Laboratory

Scheme of the experiment

Incident ShW
Reflected ShW
Temperature
Schlieren detector
OH (CH) emission
D
t
Time
OH (CH) emission
D
t
Physics of Nonequilibrium Systems Laboratory


Parameters Varied in Experiments


Mixture composition

CH
4
/C
2
H
6
/C
3
H
8
/C
4
H
10
/C
5
H
12
-

O
2


Ar

(90%)


Temperature

950
-
2000 K


Pressure

0.2
-
1.0 atm

Physics of Nonequilibrium Systems Laboratory


Parameters Controlled in Experiments


Velocity of the Shock Wave
(T
5
, P
5
)


IR Emission of CO
2

at 4.21 mm
(T
5
)


Emission of OH at 306 nm
(t
ign
)


Emisison of CH at 431 nm
(t
ign
)



Distribution of potential along the gap
(E/N)


Electrical current
(energy input)

Physics of Nonequilibrium Systems Laboratory

Shift of the ignition delay time

-400
-200
0
200
-80
-60
-40
-20
0
20
40
60
80
4
3
2
1
(a)
t


Signals, a.u.
Time,

s
T
5
=1770 K;
P
5
=0.5 bar
-400
-200
0
200
-60
-40
-20
0
20
40
3
2
1
(b)
t


Signal, a. u.
Time,
m
s
T
5
=1400 K;
P
5
=0.5 bar
0.5
0.6
0.7
0.8
10
0
10
1
10
2
10
3
10
4
10
5
I'
II'
II
I
autoignition
I
g
n
i
t
i
o
n

d
e
l
a
y

t
i
m
e
,


s
1000/T
5
, K
Physics of Nonequilibrium Systems Laboratory

Particles, responsible for Ignition, are…

Ions?

Electronically excited
states?

Vibrationally
excited
species?

Atoms?

Radicals?

Physics of Nonequilibrium Systems Laboratory

Typical evolution of electric field

and current (CH
4
:O
2
:Ar;

T
5
=1450 K, n
5
=6x10
18

cm
-
3
)

0
20
40
60
80
100
R
e
d
u
c
e
d

e
l
e
c
t
r
i
c

f
i
e
l
d
,

T
d
0
20
40
60
80
100
120
140
0.0
0.5
1.0
1.5
2.0
2.5
Time, ns

C
u
r
r
e
n
t
,

k
A
(a)
(b)
Physics of Nonequilibrium Systems Laboratory

The peak E/n for C
2
H
6
-
C
5
H
12
-
containing
mixtures

Physics of Nonequilibrium Systems Laboratory

Specific energy input

0
500
1000
1500
0
10
20
30
40
50
T
5
=1450 K;
P
5
=1.2 bar
T
5
=1680 K;
P
5
=0.7 bar


Specific deposited energy, mJ/cm
3
Time, ns
Physics of Nonequilibrium Systems Laboratory

Composition of the mixtures

C2H6
C3H8
C4H10
C5H12
0.1
1
10
C
n
H
2n+2
O
2
Ar
% in the mixture
Hydrocarbon in the mixture
Physics of Nonequilibrium Systems Laboratory

Scheme of the Discharge Description

Uniform
Discharge
Experimentally
measured E/N
Experimentally
measured
energy input
Peak of high E/N values
Experimentally estimated
electron density
0D - description
Initial electron
density can
be taken as
a parameter
Densities
of dissociated
and excited species
Physics of Nonequilibrium Systems Laboratory

Typical densities of active species produced
by the discharge
vs

E/n: C
2
H
6
, C
5
H
12

10
100
0
5
10
15
20
T
5
=1250 K, P
5
= 0.63 bar, w=19.2 mJ/cm
3
C
5
H
9
C
5
H
10
C
5
H
11
H
O
C
5
H
12
Density, 10
15
cm
-3
E/n, Td
10
100
0
5
10
15
20
T
5
=1300 K, P
5
= 0.65 bar, , w=23.1 mJ/cm
3
C
2
H
3
C
2
H
4
C
2
H
5
H
O
C
2
H
6
Density, 10
15
cm
-3
E/n, Td
Physics of Nonequilibrium Systems Laboratory

Kinetics in the discharge

10
100
10
-5
10
-4
10
-3
CH
H
2
CH
2
CH
3
H
O
T = 1450 K; P = 1.2 bar
Mole fraction
Time, ns
10
100
10
-6
10
-5
10
-4
CH
3
+
Ar*
Ar*
O
2
+
e
O
2
* (
D
E=4.5 eV)
T = 1450 K; P = 1.2 bar
Mole fraction
Time, ns
Physics of Nonequilibrium Systems Laboratory

Densities of active species produced
by the discharge in CH
4
:O
2
:Ar
vs

n
5

2
3
4
5
6
7
10
-3
10
-2
Mole fraction
n
5
, 10
18
cm
-3

[O],
I


[H],
I


[CH
3
],
I


[O],
II


[H],
II


[CH
3
],
II

Physics of Nonequilibrium Systems Laboratory

Densities of active species produced
by the discharge: all mixtures

1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.01
0.1
Radicals, molar fraction
n
5
, cm
-3
C
2
H
6
C
3
H
8
C
4
H
10
C
5
H
12
Physics of Nonequilibrium Systems Laboratory

Kinetics of the ignition: reaction rates

(T
5
=1530 K, n
5
=5x10
18

cm
-
3
)

10
-1
10
0
10
1
10
2
1x10
3
10
4
10
-8
10
-7
10
-6
1x10
-5
1x10
-4
10
-3
10
-2


Reaction rate, mole/cm
3
s
Time,

s

O+CH4<=>OH+CH3

H+O2<=>O+OH

H+CH4<=>CH3+H2

OH+CH4<=>CH3+H2O
O+CH3<=>H+CH2O
OH+H2<=>H+H2O
HCO+M<=>H+CO+M
10
-1
10
0
10
1
10
2
1x10
3
10
4
10
-8
10
-7
10
-6
1x10
-5
1x10
-4
10
-3
10
-2
T=1533 K; P=1.1 bar


Reaction rate, mole/cm
3
s
Time,

s

O+CH4<=>OH+CH3

H+O2<=>O+OH

H+CH4<=>CH3+H2

OH+CH4<=>CH3+H2O
CH3+O2<=>O+CH3O
CH3+O2<=>OH+CH2O
CHO+M<=>H+CO+M
Physics of Nonequilibrium Systems Laboratory

Kinetics of the ignition: kinetic curves

(T
5
=1530 K, n
5
=5x10
18

cm
-
3
)

10
-1
10
0
10
1
10
2
10
3
10
4
10
-6
1x10
-5
1x10
-4
10
-3
10
-2
10
-1
OH,
H,
CO
2
,
O
Temperature, K
CH
3
,
H
2
O,
H
2
,
CO
CH
4
O
2


Mole fraction
Time,

s
1500
2000
2500
Autoignition

10
-1
10
0
10
1
10
2
10
3
10
4
10
-6
1x10
-5
1x10
-4
10
-3
10
-2
10
-1
Plasma Assisted Ignition
CH
2
O
H
2
O
CO
2
CO
2
H
2
CO
H
2
O
CH
3
H
OH
O
CH
4
O
2


Mole fraction
Time,

s
1500
2000
2500


Temperature, K

Plasma assisted ignition is characterized by:




slow increase of gas temperature



developed kinetics of intermediates



partial fuel conversion during induction time

Physics of Nonequilibrium Systems Laboratory

PAI: Radical Mechanism

Recombination
of radicals, T
D
Radicals
Initiation
of chemical
chains
Radicals
Physics of Nonequilibrium Systems Laboratory

Sensitivity analysis

-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
T=1533 K; P=1.1 bar (exp), 111 mks
(
t
i
-
t
0
)
/
t
0
au t o
dis cha rg e
O+CH3<=>H+CH2 O
O+CH4<=>OH+CH3
H+O2<=>O+OH
H+CH3(+M)<=>CH4(+M)
H+CH4<=>CH3+H2
H+CH2O<=>HCO+H2
OH+H2<=>H+H2O
OH+CH3 <=>CH2+H2O
OH+CH4<=>CH3+H2 O
HO2+CH3<=>OH+CH3 O
CH3+O2 <=>O+CH3 O
CH3+O2<=>OH+CH2O
2CH3(+M)<=>C2H6(+M)
2CH3<=>H+C2H5
CH3 +HCO<=>CH4+CO
HCO+M<=>H+CO+M
CH3+OH<=>CH2O+H2
Physics of Nonequilibrium Systems Laboratory

Comparison of Experiments and
Numerical Modeling: All Mixtures

0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
10
0
10
1
10
2
10
3
10
4
10
5
CH
4
-C
5
H
12
,
PAI, 0.2-0.7 atm
C
2
H
6
-C
5
H
12
,
auto, 0.2-0.7 atm
CH
4
, auto, 0.4-0.7 atm
CH
4
, auto, 2 atm


Ignition delay time,

s
1000/T, K
-1
Auto Exp, C2H6
Auto Calc, C2H6
PAI Exp, C2H6
PAI Calc, C2H6
,
,
,

C3H8
,
,
,

C4H10
,
,
,

C5H12
Physics of Nonequilibrium Systems Laboratory

Experimental conditions: temperature

1
2
3
4
5
1200
1400
1600
1800
2000
PAI
Autoignition
T
5
, K
Number of C atoms
Physics of Nonequilibrium Systems Laboratory

Experimental conditions: densities

1
2
3
4
5
0
2
4
6
8
Autoignition
PAI
n
5
, 10
18
cm
-3
Number of C atoms
Physics of Nonequilibrium Systems Laboratory

Reduction of the ignition delay time


1
2
3
4
5
10
0
10
1
10
2
10
3
10-30 mJ/cm
3
PAI
Autoignition
Ignition delay time,

s
Number of C atoms
Physics of Nonequilibrium Systems Laboratory

Direction of the research

Physics of Nonequilibrium Systems Laboratory

Comparison of experiment (CH*)

and calculations (CH)

( )
a
(b)
2
1
1
0
20
40
60
80
100
0
10
20
30
40
50
60
C
3
H
8
:O
2
:Ar
T
5
=1480 K
P
5
=0.5 bar
S
i
g
n
a
l
,

a
r
b
.
u
n
.
Time,

s
0
20
40
60
80
100
0
10
20
30
40
C
4
H
10
:O
2
:Ar
T
5
=1440 K
P
5
=0.4 bar
S
i
g
n
a
l
,

a
r
b
.
u
n
.
Time,

s
2
Physics of Nonequilibrium Systems Laboratory

Kinetics of the ignition: kinetic curves

for C
2
H
6
-
containing mixture

10
-1
10
0
10
1
10
2
10
3
10
-6
10
-5
10
-4
10
-3
10
-2
10
-1
C
2
H
5
C
2
H
6
Plasma Assisted Ignition
CH
2
O
CO
2
H
2
CO
H
2
O
CH
3
H
OH
O
CH
4
O
2


Mole fraction
Time,

s
1400
1600
1800
2000
2200
2400

Temperature, K
Physics of Nonequilibrium Systems Laboratory

Development of surface nanosecond
discharge at high pressures


Optimization:

electrode system

HV pulse width

HV pulse amplitude


Measurements:

current and voltage

energy input

time/space/wavelength resolved emission

electric field

electron density

gas temperature

radicals

Physics of Nonequilibrium Systems Laboratory

Application of rapid compression
machine for plasma assisted ignition


Initial parameters:

Temperature 800
-
1000 K

Pressure is 10
-
200 atm




Measurements:


discharge parameters

electirc field

gas temperature

gas pressure

combustion intermediates


Modelling:

discharge action

ignition kinetics

Physics of Nonequilibrium Systems Laboratory

Conclusions


To

solve

PAI/PAC

problem

it

is

necessary

to

base

on

quantitative

data

obtained

in

experiments

and

supplementary

numerical

modeling




Experiments

and

modeling

have

been

made

to

obtain

and

to

explain

quantitatively

the

shift

of

the

ignition

delay

time

in

hydro
-

carbon
:
oxygen
:
Ar

mixtures

for

hydrocarbons

from

CH
4

to

C
5
H
12




Further

understanding

of

physics

of

PAI/PAC

processes

will

be

based

on

detailed

measurement

of

absolute

values

and

temporal

behavior

of

intermediates

as

well

as

on

the

development

of

kinetic

mechanisms

of

PAI/PAC



Physics of Nonequilibrium Systems Laboratory

Acknowledgements

Russian Foundation for Basic Research


Russian Department for Education


AFOSR EOARD