AFOSR MURI Kick off meeting · by Using a Plasma Assisted Jet Stirred Reactor with Molecular Beam...
Transcript of AFOSR MURI Kick off meeting · by Using a Plasma Assisted Jet Stirred Reactor with Molecular Beam...
Fundamental Mechanisms Predictive Modeling Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma
Assisted Combustion
AFOSRMURI Kick off meeting
The Ohio State University
Nov 4, 2009Miles – Shneider Group
PersonnelPersonnel
• Team• Richard Miles (PI)• Mikhail Shneider (Co PI)• Arthur Dogariu (Research Scientist)
S h il Z idi (R h S i ti t)• Sohail Zaidi (Research Scientist)• Chairajeev Kalra (Student- Princeton Plasma Science and Technology Fellow)• James Michael (Student - NDSEG Fellow) • Dimitry Opaits (Student)Dimitry Opaits (Student)• Phil Howard (Technical Support)
• International Collaborators• Sergey Leonov • Christophe Laux• Svetlana Starikovskaya• Boris Potapkin
N k l Al k d• Nickolay Aleksandrov,• (Peter Barker)
Miles – Shneider GroupP FPrimary Foci
• Thrust 1. Experimental studies of nonequilibrium air-fuel plasma kinetics using
advanced non-intrusive diagnostics• Task 2: Laminar Flow Reactor and Nanoparticle Studies at Low to
Intermediate Temperatures (Radar REMPI and Filtered Rayleigh p ( y gScattering in flames)
• Task 7: Fundamental studies on microwave enhanced combustion at atmospheric and higher pressures (Laser designated microwave driven ignition and microwave enhanced flame propagation)
• Thrust 3. Experimental and modeling studies of fundamental nonequilibrium discharge processes
T d d d• Task 10: Characterization and Modeling of Nsec Pulsed Plasma Discharges (Modeling and Radar REMPI of nonequilibrium states)
• Task 11: Experimental and Modeling Study of Plasma properties using Radar REMPI (Radar REMPI measurement of electron loss mechanism
d t d l l l t b d it )and rates and local electron number density)
Preliminary WorkPreliminary Work
• Radar REMPI• Atomic oxygen in a flame• NO mole fractions in laboratory air to <10 ppb
• Limited by natural NO concentration in NJ air (~10 ppb)y J ( pp )• Electron attachment and recombination rate measurements in
nitrogen, air and humid air• Laser designated microwave driven ignitionLaser designated microwave driven ignition
• Point ignition with 180 μJ, 200 fsec laser designator plus 50 mJ, 2 μsec microwave pulse
• Line ignition with 600 μJ 200 fsec laser designator plus 50 mJ 2 μsec• Line ignition with 600 μJ, 200 fsec laser designator plus 50 mJ, 2 μsec microwave pulse
• > 50% ignition kernel growth rate enhancement with triple pulsed microwavec owave
• Multiple point ignition
Radar REMPIRadar REMPI• Microwave scattering from laser-induced carriers
• Microwave illuminates the ionization spot.
• Microwave scattering is collected.
Laser
Microwave Beam
Microwave Echo
Microwave/laser measurement configuration. Thefocused laser creates a small region of ionization andthe microwaves are scattered from that region into themicrowave detector.
Microwave Experimental Setup:Homodyne and Heterodynee e e e
90 GHz
100 GHz10 GHz
Quadraturee
XY
10 GHzpre-amp mixers
mixercirculator
100 GHz horn
Laser
Heterodyne 100 and 90 GHz system. Homodyne 100 GHz system.
100 GHz probes the plasma, the phase shift is measured on the 10 GHz beating signal.
The quadrature mixer provides the X and Y
100 GHz probes the plasma.
The mixer output is proportional with the scattering amplitude hence electron density The quadrature mixer provides the X and Y
components, hence we also measure the phase. scattering amplitude, hence electron density
Sub-nanosecond temporal resolution!
Atomic oxygen in a flameAtomic oxygen in a flame4
• 2000K Methane Air flame
2
3
Gaussian fit, = 33.5 cm-1 HW1/e2
Cold air
• 2000K Methane – Air flame
• Atomic line of oxygen in flame is narrow (34 cm-1 limited by laser bandwidth)
0
1
88600 88625 88650 88675 88700
laser bandwidth)
• Spectral line in cold air –atomic oxygen via photolysis is 10 times broader: high
1.5
2.0
Gaussian fit, = 3.5 cm-1 HW1/e2
Flame, atomic oxygen line
After subtraction of cold air signalis 10 times broader: high temperature (50,000K) imposed by intense laser pulse.
0.5
1.0
Flame, atomic oxygen linepulse.
• Radar REMPI can distinguish between flame and photolysis atomic oxygen.
0
88600 88625 88650 88675 88700
Energy (cm-1)
atomic oxygen.
Resonant signal from atomic oxygen vs. equivalence ratio
60.0004Atomic Oxygen
Atomic oxygen line signal
5
6
0.0003
0.0004
Atomic Oxygen REMPI signalCalculated O mole fraction
4
0.0002
mpi
sig
nal
2
3
0.0001
Rem
10.60 0.75 0.90 1.05 1.20 1.35
0
Equilibrium model – 1D chemkin
Equivalence ratio
1+1 Radar REMPI in NO1+1 Radar REMPI in NO
1 0
1+1 REMPI in NO, laser at 226nm
2.0
1+1 Radar REMPI in NO
1.0pure NO (50 mTorr)NO (50 mTorr) and N2 (850 Torr)NO (50 mTorr) and dry air (850 mTorr)
sign
al fr
om N
O
1.5 20 Torr NO (80Torr N2)1 Torr NO (4 Torr N2)
0.5
zed
Rad
ar R
EMPI
0 5
1.0
Sign
al
00 50 100 150 200
Nor
mal
iz
0
0.5
40 50 60 70 80 90 00 0 50 100 150 200
Time (ns)
4414
4415
4416
441
4418
4419
4420
Energy (cm-1)
•Pure NO shows longer lifetime due to electron diffusion. In order to measure the recombination rate we suppress diffusion by •In order to measure the recombination rate we suppress diffusion by
adding N2. •In air we can measure attachment rate.
NO trace Detection(limited by background ~ 10 ppb NO in air)
0.03
0.02
air1ppb10ppb100ppb
0.01
100ppb
0
-0.01-20 -10 0 10 20 30
Time (ns)
Direct measurement of electron attachment in atmospheric air
P E Previous Extrapolated estimate for 850 Torr dry air
(78%N2, 21%O2, 1% Ar):
Identifying Electron loss mechanism and rate
0.8
NO at 0.13 Torr in 1atm. buffer (170ppm)
1
NO at 0.13 Torr in 1atm. buffer (170ppm)
0.6
Air buffer, dn/dt = -n2-n = 9.4x107s-1
N2 buffer, dn/dt = -n2 n0 = 14x107s-1 tNNtN
0
0
1)(
In N2:
recombination OT
0.4
mal
ized
Sig
nal
0.1m
aliz
ed S
igna
l
only, NOT an exponential decay
Attachment in air:
0.2
Nor
m
Nor
m
t
a
t
a
a
eNeNtN
0
0 ,11
)(
Attachment in air:
00 20 40 60
Time (ns)
0.010 20 40 60 80
Time (ns)
t
a
aeNNtN
0
0
1)(
close to close to exponential
Testing NO in buffer gasesTesting NO in buffer gases
0.20
1+1 Radar REMPI in NO at 226 nm
• N2 increases
0.10
0.15 NO 0.5Torr + N2 2TorrNO 0.5Torr + N2 2Torr + dry air 100TorrNO 0.5Torr + N2 2Torr + dry air 340TorrNO 0.5Torr + N2 2Torr + dry air 760Torr
Sig
nal
electron loss via recombination by suppressing diffusion
0
0.05
0 40 80 120
diffusion
• Dry air – faster decay due to electron
0.10
0.15
NO 0.5Torr + N2 2Torr
attachment to O2
• Humid air – further increase of losses due to higher
0.05
2NO 0.5Torr + N2 2Torr + humid air 97TorrNO 0.5Torr + N2 2Torr + humid air 752Torr
Sign
al due to higher
attachment rates in water
00 40 80 120
Time (ns)
Laser Designated Microwave IgnitionEExperimental Apparatus
ScreenCamera
Tuner (d)Waveguide
MagnetronSliding Short
Tuner (d)e
Seed Ionization
Laser Pulse
Circulator Collimated Nd:YAG (532 nm)
Laminar Premixed Flow
Microwave Field 3GHz 30kW peak power TE10 Mode
• Dpremixed = 1.9 cm• Uexit = 70 cm/s
14
TE10 Mode λguide = 11.2 cm Efield ~ 0.1Ebreakdown
Ps Laser-MW Evolution in AirPs Laser MW Evolution in AirLaser spot evolution
Laser + MW evolution
MW on
Ignition: Kernel growth comparisonSingle and multiple pulse microwave
0.0 ms 1.0ms 1.1 ms 1.9 ms 2.0ms 2.1 ms 2.9 ms
Laser
Micro-
PULSE 1
Microwave
IGNITION
6 mm
Single pulse
Micro-wave
PULSE 2
PULSE 3
triple pulse
PULSE 1
6 mm
1 msec intervals
Multi-point ignitionMulti point ignition
6mm6 mm
uexit
• Two 7mJ seed laser spots• 75 mJ MW pulse
70 cm/s
• 75 mJ MW pulse• φ = 0.7; Uexit = 70 cm/s• 3 ms after initial seed laser pulse• Flame kernel indicates ignition
200 Femtosecond Seed –180 μJ200 Femtosecond Seed 180 μJ
10 us 100 us 500 us 1000 us
6 mm
200 Femtosecond Seed –600 μJ200 Femtosecond Seed 600 μJ
10 us 100 us 500 us 1000 us
6 mm
Ignition of Methane/Air MixturesIgnition of Methane/Air Mixtures
• Seed ionization pulse7mJ; 200 ps, 780 nm
• MW heating pulse50mJ; 2 μs, 3GHz
λseed [nm] φ f [m] Elaser [mJ] *EMW [mJ]*
Observed Minimum Seed Laser Energies
800 (200 fs) 0.8 0.06 0.2 50
780 0.8 0.06 3 50
780 0.8 0.10 7 50780 0.8 0.10 7 50
780 0.7 0.10 7, 7 75
390 0.8 0.10 1.5 50
Fundamental Mechanisms, Predictive Modeling, d N l A A li ti fand Novel Aerospace Applications of
Plasma Assisted Combustion
Yiguang Ju
AFOSR MURI Ki k ff tiAFOSR MURI Kick off meeting
The Ohio State UniversityThe Ohio State UniversityNov 4, 2009
Team members:
Collaborators:
Team members: Wenting Sun, Sanghee Won, Mruthunjaya Uddi
Interactional: Fei Qi, University of Science and Tech. ChinaAFRL collaborators: Campbell Carter, Timothy Ombrello, Skip Williams
Collaborators:
Ju’s Group Primary Research Focus
Thrust 1. The effects of kinetic and transport of plasma assisted ignition– Task 1: Experimental measurements of minimum ignition energies
using a spherical bomb with different electrode geometriesTask 2: Experimental measurements of ignition/extinction limits by– Task 2: Experimental measurements of ignition/extinction limits by using counterflow flames
Thrust 2. Intermediate Species Measurements at Elevated Pressures pby Using a Plasma Assisted Jet Stirred Reactor with Molecular Beam Sampling
– Task 1: Development of plasma assisted a jet stirred reactorTask 2: Measurements of intermediate species of fuel oxidation– Task 2: Measurements of intermediate species of fuel oxidation
Thrust 3. Mechanism Reduction and Dynamic Multi-time Scale Modeling of Detailed Plasma-Flame Chemistryy– Task 1: Development of dynamic multi-timescale modeling– Task 2: Simulations of unsteady ignition and extinction of plasma
discharge with detailed kinetic mechanisms
Research Task Description,Methods and Preliminary ResultsMethods, and Preliminary Results
Thrust 1. The effects of kinetic and transport of plasma assisted ignition– Task 1: Experimental measurements of minimum ignition energies
using a spherical bomb with different electrode geometriesusing a spherical bomb with different electrode geometries
2.5
Qm
in
2Q
min
2
2.0
2.3
2.4on
pow
er,Q 1.5
onpo
wer
,Q 1.51.9
Le = 2.1
2.2
mun
igni
tio 1
mun
igni
tio 1
1.7
1.8 = Le2.0
1.9
1.8
Q ?
Min
im
0.5 Z = 10
Min
im
0.5Z = 13
1.4
1.6
1.51.4
1.71.6
1.5
Q ?
Cube of critical flame radius, RC3
0 500 1000 1500 2000 25000
Cube of critical flame radius, RC3
0 500 1000 1500 2000 25000
Experimental methods
(a) (b) (c)(a) (b) (c)Igniter configurations
Thrust 1. The effects of kinetic and transport of plasma assisted ignition– Task 2: Experimental measurements of ignition/extinction limits by
using counterflow flame w/wo non-equilibrium plasma dischargeusing counterflow flame w/wo non-equilibrium plasma discharge
2200
2000 Plasma+CH4/air
1600
1800
x, K
Th l i iti
1200
1400T max
1400 K1300 K
1200 K
Thermal ignition
1000
1200
850 K
1100 K1050 K
900 K
1025 K
950 K 1000 K
Kinetic ignition
8001 10 100 1000 10000
Strain, s-1
850 K 900 K
Thrust 1. The effects of kinetic and transport of plasma assisted ignition– Task 2: Experimental measurements of ignition/extinction limits by
using counterflow flame w/wo non-equilibrium plasma dischargeusing counterflow flame w/wo non-equilibrium plasma discharge
Nanosecond pulser: CarterLIF: OH, NO, CH2OTALIF: O, H
Laser beamLaser beamLaser beam
Thrust 2: High pressure JSR and MBMS experimental methods of intermediate species measurements
High pressure, high temperature chamberHigh pressure, high temperature chamberHigh pressure, high temperature chamber
MBMS analysisFuel
Preheated air
Mixing
MBMS analysisFuel
Preheated air
Mixing
MBMS analysisFuel
Preheated air
Mixing
1st T b 2nd Turbo1st T b 2nd Turbo
DBD dischargeJet stirred reactor
DBD dischargeDBD dischargeJet stirred reactor
Rea
ctor
exit
1st Turbopump
2 Turbopump
Mass analyzer
Rea
ctor
exit
1st Turbopump
2 Turbopump
Mass analyzer
Molecular beam
Rea
ctio
npr
oduc
ts
Skimmer
Charged
analyzer
Molecular beam
Rea
ctio
npr
oduc
ts
Skimmer
Charged
analyzer
0.1-5 atm
Quartznozzle
Chargedion separation
10-4
Torr10-6
Torr0.1-5 atm
Quartznozzle
Chargedion separation
10-4
Torr10-6
Torr
Three stage molecular beaming sample for high pressure
Equipment installation (EFRC program)
Comstock Time of flight (TOF) MB system: RTOF210: Mass resolution up to 5000g ( ) y p
Li and Qi, ACR, 2009m/Z
Thrust 3. Mechanism Reduction and Dynamic Multi-time Scale Modeling of Detailed Plasma-Flame Chemistry
– Task 1: Development of dynamic multi-timescale modeling approachapproach
– Task 2: Simulations of unsteady ignition and extinction of plasma discharge with detailed kinetic mechanisms
tt
KtimencomputatioTotal
%80
3
totalChem tt %80
C. K. Law and T. Lu, Energy and Combustion,2009
Multi Time Scale Method (MTS)
40
The Basic Idea of Multi-Time Scale Method: timescale changes!
25
30
35
40
ecie
s
t = 0.1 ms t = 0.2 ms t = 0.3 ms
FastestG
ΔtF
k
t
KY
10
15
20
Num
ber o
f speGroup
Medial Groups
ΔtM
kkk eKY
-1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -130
5
Log10
(characteristic time / s)
SlowestGroup
ΔtS
Diagram of multi time scale scheme
Δt i th ti t f th f t t Δt i th ti t f th di l
0Time
Δt1 2
ΔtF is the time step of the fastest group, ΔtM is the time step of the medial group, and ΔtS is the time step of the slowest group
Validation by homogeneous ignition Ignition in
n-decane/Air 121 species (M. Chaos, IJCK,2007)
ghomogeneous
mixture
105
2 42.62.8
CO2
K)
temperature
1.5
2.0
(ms)
VODE MTSHMTS
1atm
10
10-5
100
1 82.02.22.4
OH
s fra
ctio
n
ODEMTS atur
e (1
000K
0.5
1.0
20 tdela
y tim
e ( HMTS
10-20
10-15
10-10
1 21.41.61.8
C10H22
Mas
s MTS HMTS
Tem
pera
0 5 0 6 0 7 0 8 0 9-0.5
0.0
20atm
Igni
tion
0 1 2 3 4 51020 1.2
Time (0.1 ms)
0.5 0.6 0.7 0.8 0.91000/Initial temperature (1/K)
Temperature and species profiles Ignition delay time for n-decane-air
Computation efficiency vs. Mechanism size
CPU Time(s)No. Mechanism
Base Time
Initial Pressure
Initial Temperature RTOL ATOL
CPU TimeNo. Mechanism Time
Step(s) Pressure
(atm) Temperature
(K) RTOL ATOL
VODE MTSTime
Saving a1 H2 1.0E-6 1 1200 1.0E-4 1.0E-13 0.28 0.13 53.6% a2 H 1 0E 7 1 1200 1 0E 4 1 0E 13 2 58 1 31 49 2%a2 H2 1.0E-7 1 1200 1.0E-4 1.0E-13 2.58 1.31 49.2% a3 H2 1.0E-8 1 1200 1.0E-4 1.0E-13 24.9 7.56 69.6% a4 H2 1.0E-9 1 1200 1.0E-4 1.0E-13 260 18.4 92.9% b1 CH 1 0E 6 1 1400 1 0E 4 1 0E 13 123 25 79 7%b1 CH4 1.0E-6 1 1400 1.0E-4 1.0E-13 123 25 79.7% b2 CH4 1.0E-7 1 1400 1.0E-4 1.0E-13 1269 181 85.7% b3 CH4 1.0E-8 1 1400 1.0E-4 1.0E-13 14639 1029 93.0% c1 C10H22 1.0E-6 1 1400 1.0E-4 1.0E-13 86 14 83.7% c2 C10H22 1.0E-7 1 1400 1.0E-4 1.0E-13 773 125 83.8% c3 C10H22 1.0E-8 1 1400 1.0E-4 1.0E-13 7609 1049 86.2%
A path flux analysis method for model reduction
0.01detail
T0=1200 K ig
(s)
detail DRG PFA
50 60 70 80 90
1E-3 1 atm
1E-3
ig (s
)
50 60 70 80 901E-4
20 atm
N b f i i k l l h i
15
Number of species in skeletal mechnism
Modeling of flame front trajectories of spherical propagating flames using MTSp p p g g g