Fundamental Mechanisms, Predictive Modeling, and Novel ... · Task 4: Moderate-to-high (T=800 –...

Fundamental Mechanisms, Predictive Modeling,

and Novel Aerospace Applications of Plasma Assisted Combustion

AFOSRMURI Kick off meeting

The Ohio State UniversityNov 4, 2009

Drexel Group: Main TasksThrust 1. Experimental studies of nonequilibrium air-fuel plasma kinetics using advanced non-intrusive diagnostics

Task 1: Low-to-Moderate (T=300-800 K) temperature, spatial and time-dependent radical species concentration and temperature measurements in nanosecond pulse plasmas in a variety of fuel-air mixtures pressures (P=0.5-5 atm), and equivalence ratiosTask 4: Moderate-to-high (T=800 – 1800 K) temperature PAC oxidation kinetics in Discharge Shock Tube Facility at pressures up to 10 barTask 5: PAC oxidation and combustion initiation at high pressure, high temperature conditions

Thrust 2. Kinetic model development and validationTask 8: Development and validation of a predictive kinetic model of non-equilibrium plasma fuel oxidation and ignitionTask 9: Mechanism Reduction and Dynamic Multi-time Scale Modeling of Detailed Plasma-Flame Chemistry

Thrust 3. Experimental and modeling studies of fundamental nonequilibriumdischarge processesTask 10: Characterization and Modeling of Nsec Pulsed Plasma Discharges

Thrust 4. Studies of diffusion and transport of active species in representative two-dimensional reacting flow geometries Task 13: Ignition and flameholding in high-speed non-premixed flowsTask 14: High Fidelity Modeling of Plasma Assisted Combustion in Complex Flow Environments

Drexel Group: International Collaboration

International Collaborators

Svetlana Starikovskaya (Ecole Pol) – Thrust 1 Alexander Rakitin (NEQLab) – Thrust 1Boris Potapkin (KIAE) – Thrust 2Alexander Konnov (VUB) – Thrust 2Nickolay Aleksandrov (MIPT) – Thrust 3Sergey Pancheshnyi (Univ Toulouse) – Thrust 3Sergey Leonov (IVTAN) – Thrust 4

Physics of Nonequilibrium Systems Laboratory

Range of Parameters – Combustion Kinetics

P, atm

0.02 1 40

T, K

250 K

2500 K

S/I

φ

0.1

3.0

1

Problems of Plasma-Chemical Models

Availability and accuracy of data on electron collision cross sections

+ H2 CH4 C2H6 C3H8? C4H10 C5H12 …

Availability and accuracy of chemical models below self-ignition point

+ H2? CH4 C2H6 C3H8 C4H10 C5H12 …

Availability and accuracy of physical and chemical models for non-equilibrium conditions

+ Radical’s mechanism ? Ionic chain mechanism? Energy chain mechanism


Models for Low-Temperature Plasma Assisted Combustion

Starikovskii et al.,

Plasma Physics Reports, 2000 (26) 701

O2 + e- + M → O2- + M

H2 + O2- → OH- + OH

OH + H2 → H2O + HOH- + H → H2O + e-

H + O2 + M → HO2 + MOH- + HO2 → H2O + O2 + e-

Starikovskii,Chemical Physics Reports, 2003 (11) 1

N2O* + H → N2* + OHCO + OH → CO2* + HCO2* + N2O → N2O* + CO2N2* + N2O → N2O* + N2


PAC: Where we are

P, atm

0.02 1 40

T, K

250 K

2500 K

S/I

φ

0.1

3.0

E/n, Td

1000

B/S

1

1

300

Mechanisms of Plasma Influence

1. Heating

2. Turbulization

3. Momentum Transfer

4. Electrons/Ions Diffusion/Drift

5. Dissociation, Ionization


Shock Wave - Nonequilibrium Plasma Interaction


Relaxation of Nonequilibrium Plasma. Air. P1 ~ 20 Torr

0 50 100 150 200 250 300 350 400 450 5000.96

0.98

1.00

1.02

1.04

1.06

1.08

1.10

1.12

1.14V/

V 0

Pre-trigger Time, μs

V, Base 3-4 Ms=3.0 Ms=2.3 Ms=2.2 Ms=2.2 Ms=1.8 Ms=1.56

τE


Relaxation of Nonequilibrium Plasma. Air. P1 ~ 20 Torr

Mechanism of fast heating in discharge plasmas (low E/N)

Low (< 20 Td) E/N:

e + N2 , O2

- elastic scattering

- rotational excitation

100 101 102 1030

50

100

O2(ion)O2(rot)

O2(el)

N2(ion)

N2(el)

O2(vib)

N2(rot)

N2(vib)

Frac

tiona

l ene

rgy

depo

sitio

n, %

E/n, Td

Air

Mechanism of fast heating in discharges (moderate E/N)

Moderate (20 - 200 Td) E/N:

Popov (2001) heating → 28 % of power spent on N2* + O2

*

e + O2 → e + 2O + ΔE

e + N2 → e + N2*(A, B, C, a’, ...)

N2*(A, B, C, a’, ...) + O2 → N2 + 2O + ΔE

O(1D) + N2 → O + N2 + ΔE k ~ 10-10 cm3/s

Mechanism of fast heating in discharge plasmas (high E/N)

High (> 200 Td) E/N:

electron-ion and ion-ion recombinationkinetics

100 1000

10

20

30

40

50

28% of energy spent on N2(el) + O2(el)(Popov (2001))

Hea

ting

perc

enta

ge, %

E/N, Td

ne0=1014 cm-3; dry air ne0=1015 cm-3; dry air ne0=1014 cm-3; 1 % H2O ne0=1015 cm-3; 1 % H2O

e + O2+ → O + O* + ΔE

O2- + O2

+ + M→ 2O2 + M + ΔE

Aleksandrov et al. (2009)


Heat Release and Shock Waves Formation by “Nonequilibrium” Plasma

50 ns, ΔT = 420 K

7 ns, ΔT = 240 K

Energy Distribution in Gas Discharge

100 101 102 1030

50

100

O2(ion)O2(rot)

O2(el)

N2(ion)

N2(el)

O2(vib)

N2(rot)

N2(vib)

Frac

tiona

l ene

rgy

depo

sitio

n, %

E/n, Td

Air

Molecular Oxygen ExcitationTo directly observe the influence of SDO on the combustion of H2-O2 mixture

Delivering sufficient amount of SDOMinimizing the effect of O atomLower the inlet temperature

V V Smirnov, O M Stelmakh, V I Fabelinsky, D N Kozlov, A M Starik and N S Titova,J. Phys. D: Appl. Phys. 41 (2008)

SDO kinetic analysis

The ignition time as a function of SDO mole fraction in oxygen.T=775 K and P=10 Torr in the H2:O2=5:2 mixture

0% 1.2% 4% 6%

-2,0

-1,5

Experiment Calculations Calculations with

laminar boundary layerlg(t,s)

SDO mole fraction


Auto-ignition

6% SDO

The evolution in time of the mole fractions of the main component for autoignition (a) and ignition with 6% singlet delta oxygen. The gas temperature

evolution is represented by the thick red line.

1E-6 1E-5 1E-4 1E-3 0.01 0.11E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

1

H2 O2 SDO O H OH HO2 H2O H2O2 O(1D) O2(1S) O3 Temp

800

1200

1600

2000

2400

Temeprature, K

1E-6 1E-5 1E-4 1E-3 0.01 0.11E-8

1E-7

1E-6

1E-5

1E-4

1E-3

0.01

0.1

1

H2 O2 SDO H O OH HO2 H2O H2O2 O(1D) O2(1S) O3 Temp

Time s

800

1200

1600

2000

2400

Temperature, K

Possible reasons

Radical generation efficiency

Auto SDOO2+M=O+O+M (slow)

H2+O=OH+HO2+H=OH+O

OH+OH=H2O+O……

O2(a1 Δg)+H2=OH+OH (fast)OH+H2=H2O+H

O2(a1 Δg)+H=OH+OO2+H=OH+O

OH+OH=H2O+O…

O2(a1 Δg)+H2=OH+OH O2(a1 Δg)+H=OH+O

200% 100%~80 μs


Energy Distribution in O2-Ar (15%:85%) Mixture

74% energy in excitation of singlet oxygen at E/n= 5 TdApproximately 53% in singlet delta state

About 21% in singlet sigma state

1 10 100 10000

10

20

30

40

50

60

70

80

Ene

rgy

depo

sitio

n, %

Reduced Electric Field, Td

Ar(elastic) Ar(11.6eV) Ar(11.3eV) Ar(Ionization) O2(v=1) O2(v=2) O2(v=3) O2(1Δ) O2(1Σ) O2(4.5eV) O2(6.0eV) O2(8.4eV) O2(Ionization)

H + O2(1Δ) = OH + O

0,8 1 2 4 6 8 10 20 400,0

0,5

1,0

1,5

2,0

2,5

SDO

Exc

itatio

n Ef

ficie

ncy,

%

E/n, Td

E/n = 6 Td (=10−17 Vcm2)

N2 Elastique 1.8 % N2(ROT) 4 %

N2 (V=1) 49 % N2 (V=2) 7.3 % N2 (V=3) 1.4 % N2 (V=4) 0.2 %

O2 Elastique 0.3 % O2 (ROT) 0.2 % O2 (V=1) 17 % O2 (V=2) 11 %O2 (V=3) 4.1 %O2 (V=4) 1.4 %O2 (a1Δg) 2.2 %O2 (b1Σ) 0.1%

SDO Excitation efficiency in air plasma

Air Plasma


Shock Tube with Discharge Section.U ≤ 0.3 MV, M ≤ 3

Test Section of the Shock Tube

Starikovskaya et al


Main Processes During Discharge Phase

0 20 40 60 80 100

20000

40000

60000

80000

2

76

48

13 5

4

Rea

ctio

n R

ate

Time, ns

1 Ar + e- ⇒ Ar+ + e- + e-

2 O2 + e- ⇒ O + O + e-

3 CH4 + e- ⇒ CH3 + H + e-

4 Ar + e- ⇒ Ar* + e-

5 Ar* + O2 ⇒ Ar + O + O

6 Ar* + CH4 ⇒ Ar + CH2 + H + H

7 O2 + e- ⇒ O2* + e-

8 O2* + CH4 ⇒ O2 + CH3 + H

1


Radicals Production in DischargeCH4-containing mixture


Ignition Delay Time: Methane-Containing Mixture

0.5 0.6 0.7 0.8

100

101

102

103

104

105

I

II

III

autoignition

autoignition, experimentautoignition, calculations

PAI, calculationsPAI, calculations

PAI, experimentsPAI, experiments

PAIPAI

Igni

tion

dela

y tim

e, μ

s

1000/T5, K

CH4


90 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.901

10

100

1000In

duc

tion

tim

e, μs

1000/T, K-1

Auto Exp Auto Calc FIW Exp FIW Calc

(C5H12:O2) + 90% Ar

b)

C H5 12

RAMEC (for C1) + Westbrook (C2-C7) + High Pressure Adjustment


Experiment and Calculations in H2-Air Mixture


Modeling of Radicals Formation vs E/n (W=14 mJ/cm3)

10 1000.0

5.0x10-4

1.0x10-3

1.5x10-3

2.0x10-3

2.5x10-3

3.0x10-3

3.5x10-3

4.0x10-3

4.5x10-3

5.0x10-3

Den

sity

, cm

-3

E/N, Td

O H Sum

100 10000.0

5.0x10-4

1.0x10-3

1.5x10-3

2.0x10-3

2.5x10-3

3.0x10-3

3.5x10-3

4.0x10-3

Den

sity

, cm

-3E/N, Td

O H SumH2:O2:Ar=29.5:14.75:55.75

H2:O2:N2=29.5:14.75:55.75

Delay time for autoignition and plasma assisted ignition in CH4-containing mixture

CH4:O2:N2:Ar = 1:4:15:80

0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90101

102

103

104

PAI with E(t)/N

PAIauto

auto0.5 atm

~0.5 atm

~2 atm

Igni

tion

dela

y tim

e, μ

s

1000/T, K-1

Aleksandrov et al. (2009)


Plasma Recombination at High Pressures and Temperatures

0 5 10 15 20 25 30 35 40 45 50

1012

p=2.56atm,T=2036Kp=2.2atm,T=2036Kp=1.96atm,T=2065Kp=1.9atm,T=2276K

p=1.5atm,T=2598Kp=1.07atm,T=2770K

n e, c

m-3

Время, мкс

p=1.68atm,T=2384K

N2

0.1 1 10

1010

1011

1012

p=2.1атм.,T=1989Kp=2атм.,T=2150Kp=2атм.,T=2100Kp=1.9атм.,T=2270Kp=1.8атм.,T=2558Kp=1.5атм.,T=2680Kp=1.1атм.,T=2990K

N2:O2:CO2=76:19:5

n e, c

m-3

Время, мкс

0.1 1 10

1012

p=2.3атм.,T=2316Кp=2атм.,T=2411Кp=1.7атм.,T=2442Кp=1.3атм.,T=2517Кp=1.1атм.,T=2845К

N2:H2:O2:CO2=67:15:11:7

n e, c

m-3

Время, мкс

N2:H2O:O2:OH:CO:CO2:H:O:H2=67:10:5:4:3.5:3:3:3:2

N2:H2:O2:CO2=67:15:11:7

After 10 μs, at 1atm., 2800К


Evolution in Time of Electron Density During Plasma Decay

500 1000 1500 2000 250010-8

10-7

10-6

p=0.4 atm

0.2

T, K

Effe

ctiv

e re

com

bina

tion

coef

ficie

nt, c

m3 s-1

)

500 1000 1500 2000 250010-8

10-7

10-6

p=0.4 atm0.2

T, K

Effe

ctiv

e re

com

bina

tion

coef

ficie

nt, c

m3 s-1

air

O2:N2:CO2=1:4:5 O2:N2:CO2=5:86:9

Dissociative electron-ion recombinatione + O2

+ → O + O

Electron attachment and detachmente + O2 + M → O2

- + MO2

- + O → e + O3

500 1000 1500 2000 250010-8

10-7

10-6

p=0.4 atm0.2

T, K

Effe

ctiv

e re

com

bina

tion

coef

ficie

nt, c

m3 s-1

)


Discharge Development at Different Overvoltage and Plasma Generation

10 100 1 0001E11

1E12

1E13

1E14

1E15

1E16

Elec

t ron

Den c

ity,c

m-3

Reduced El ectr ic Fi eld, Td

T = 8000 KT = 350 K

T = 400 K

T = 300 K

Arc Discharge: equilibrium plasmaApplications: melting & welding

MW Discharge: partial equilibriumApplications: plasma chemical conversion, chemical vapor deposition (CVD)

Glow Discharge: E/n close to the breakdown thresholdApplications: light sources, surface treatment, CVD

Streamer Discharge: overvoltage up to 200%Applications: surface treatment, flue gases treatment, electrical breakdown, power switches

Nanosecond Pulsed Discharge: overvoltage up to 10 timesApplications:• Plasma supported combustion• Plasma supported aerodynamics• Chemical conversion• CVD

Types of Gas Discharges and Their Applications

T = 4000 K

Types of Gas Discharges and Their Applications


Setup for OH Dynamic Measurements in Streamer Channel Afterglow

Pancheshnyi et al


LIF Diagnostics Setup: OH Profile Control

NdYAG laserDye laserDoublingsystem

Spectrometer

ICCD - camera

burner

LIF OHOH (X-A):

Excitation: Q1(6) 282.92 nm;Emission:

315nm, δλ=1.8 нм; Registration –

PicoStar LaVision ICCD камера

LIF OH

LIF Emission of OH at 300 K

1 10 100

0

50

100

150

200

250

Methane lean Ethane lean Propane lean Butane lean

Methane St Ethane St Propane St

Methane Rich

OH

LIF

, 300

K, 1

atm

Time, μs

0.1 1 10 100

1

10

100

Methane lean Ethane lean Propane lean Butane lean

Methane St Ethane St Propane St

Methane Rich

OH

LIF

, 300

K, 1

atm

Time, μs

LIF Emission of OH at 500 K

Methane

Ethane

300 K Versus 500 K LIF of OH


High-pressure Conditions:Always Non-Uniform

9 ns

11 ns

Pancheshnyi et al


Rapid Compression Machine:High-Pressure, Low-Temperature


PAC at High Pressure: ER = 1 (Rakitin et al)

T2 = 713 KP2 = 26.5 bar

Propane,Surface DBD,

< 50mJ


PAC at High Pressure: ER = 0.4 (Rakitin et al)

T2 = 794 KP2 = 32 bar

Propane,Surface DBD,

< 50mJ


Propane-Butane-Air Lean Mixtures. φ = 0.5 (C3:C4=85:15)

0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05 1,10 1,15

10

100

Igni

tion

Del

ay, µ

s

1000/T, K-1

P=500 atm P=210 atm P=66 atm P=20 atm P=4.7 atm Cadman et. al

P=10 atm


Propane-Butane-Air Mixture Ignition. φ = 0.5 (C3:C4=85:15). Calculations


Propane-Butane-Air Mixture Ignition. Experiment vs Calculations.

0,6 0,7 0,8 0,9 1,0 1,1 1,210

20

40

6080

100

200

400Ig

nitio

n De

lay,

µs

1000/T, K-1

, P=500 atm, P=210 atm, P=66 atm, P=20 atm, P=4.7 atm


Channels of Kinetic Scheme Optimization

Reaction T k

C3H8 + HO2 = C`H2C2H5 + H2O2 1200 2.5

C3H8 + HO2 = CH3C`HCH3 + H2O2 1200 2.5

O2C3H7 = HOOCH2C`HCH3 800-1000 0.2

CH3CHO2CH3 = CH3CH(OOH)C`H2 800-1000 0.2

OCHCH(OOH)CH3 = CH3CHO + HCO + OH 800 0.2

OCHCH2CH(OOH)2 = CH2O + CH2CHO + OH 800 0.2

CH3COCH2(OOH) = CH2O + CH3CO + OH 800 0.2

0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05 1,10 1,15 1,20 1,25

10

100

H2O

2 and HO

2Formation and Decomposition

Fueldecomposition

AlkylHydroperoxidesformation and decomposition

H2O2+M -> OH+OH+M

CH3+CH

3O

2 = CH

3O+CH

3O

Igni

tion

Dela

y (µ

s)

1000/T (K-1)

n-Hexane P = 220 atm n-Pentane P = 250 atm C

3H

8+C

4H

10 P=210 atm

Methane P = 150 atm

Konnov,Potapkin


Mixture C3H8:C4H10:Air = 1.8:0.3:97.9

0,7 0,8 0,9 1,0 1,1 1,2

10

100

C3H8:C4H10:Air=1.8:0.3:97.9Ig

nitio

n De

lay,

µs

1000/T, K-1

, P = 4.7 atm, P = 20 atm, P = 66 atm, P = 210 atm, P = 500 atm


Discharge Formation and Flame Stabilization in High Speed Flow

IVTAN (Sergey Leonov):M = 2Maximal stagnation pressure 1.8 BarStagnation temperature 670 KDischarge Power ~ 1 kW

DPI Shock Tunnel:M = 2-5Static pressure 0.1 - 1 BarStatic temperature 700-1000 KDischarge Power ~ 1 kW


Summary

Range of ParametersP = 0.1 – 70 atmT = 300 – 2000 KM = 0 - 5φ = 0.01 – 1E/n = 200-500 Td (Air)Fuels: H2, C1 – C4Acetones, Alcohols, CO

Experiment:Shock TubeShock TunnelRapid Compression MachinePremixed Flow Nozzle

Theory:Discharge ModelsPlasma Models Chemical Kinetic Models

Fundamental Mechanisms, Predictive Modeling, and Novel ... · Task 4: Moderate-to-high (T=800 –...

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