development of combined dual- pump vibrational and pure- rotational coherent anti-stokes raman...
DESCRIPTION
Introduction to CARS 3 CARS is a third order, four-wave mixing, parametric process Time resolved and Spatially resolved Species specific and Transition specific Relatively insensitive to collisions Roy et al., “Recent advances in CARS spectroscopy: Fundamental developments and applications in reacting flow”, Prog. Energy and Comb. Sci., 2010.TRANSCRIPT
Development of Combined Dual-Pump Vibrational and Pure-
Rotational Coherent anti-Stokes Raman Scattering Technique
Aman Satija and Robert P. Lucht
Motivation and Background
• CARS in reacting flows primarily used for temperature and species concentration measurements
2
• High Accuracy and Precision in Complex Environments• Multiple Species
Introduction to CARS
3
• CARS is a third order, four-wave mixing, parametric process
•Time resolved and Spatially resolved •Species specific and Transition specific•Relatively insensitive to collisions
CARS p St pr
CARS p St prk k k k
Roy et al., “Recent advances in CARS spectroscopy: Fundamental developments and applications in reacting flow”, Prog. Energy and Comb. Sci., 2010.
Comparison between CARS and known Temperature in a
Calibration Burner
0.25 0.50 0.75 1.00 1.251000
1250
1500
1750
2000
2250
2500
Adiabatic Temperature VCARS Temperature Difference
Equivalence Ratio
Fla
me
Tem
pera
ture
(K)
-30
-25
-20
-15
-10
-5
0
5
10
Tem
pera
ture
Diff
eren
ce
Two-beam PRCARS
Probe 3
Signal 4
Pump 1 + Stokes 2
1 2
3 4
k3, 3 k1, 1
k2, 2 k4, 4
k1 + k3 = k2 + k4
4 = 1 - 2 + 3
Combined VCARS and PRCARS System
6
Two-Beam ns-PRCARS demonstrated by Satija and Lucht, Opt. Lett. (2013)
BLUE: 473 nm (N2 VCARS SIGNAL)GREEN: 532.2 nm + 528 nm (PRCARS SIGNAL)
Energy Level Diagrams
8
DPVCARS first demonstrated by Lucht , Opt. Lett. (1987)
Combined DPVCARS and PRCARS System
9
200 Shot Averaged PRCARS Spectra
50 75 100 125 150 175
10
15
20
25
30
S(22)
S(10)
S(18)
S(14) Temp. = 613 K
(Inte
nsity
)1/2 (a
rb. u
nits
)
Raman Shift (cm-1)
Experiment Theory
75 100 125 150 175 200
2
4
6
8
10S(22) S(18)
S(14)
S(10)
Temp. = 1189 K
Experiment Theory
(Inte
nsity
)1/2
(arb
. uni
ts)
Raman Shift (cm-1)
CARSFit code from Cutler and Magnotti. J. Raman Spec., (2011).
60 80 100 120 140 160 180
20
40
60
80
100
S(22)
S(18)
S(8) S(10)
S(14) Temp. = 295 KO2/N2 = 0.266
(In
tens
ity)1/
2 (arb
. uni
ts)
Raman Shift (cm-1)
Experiment Theory
75 100 125 150 175 200
5.0
7.5
10.0
12.5
15.0
17.5
S(22)
S(10)
S(18) S(14) Temp. = 911 K
(Inte
nsity
)1/2 (a
rb. u
nits
)
Raman Shift (cm-1)
Experiment Theory
200 Shot Averaged DPVCARS Spectra
2200 2250 2300 2350 2400 2450 25000
10
20
30
40
50
60 N2
CO2
O2
(Inte
nsity
)1/2 (a
rb. u
nits
)
Raman Shift (cm-1)
Temp. = 681 KO2/N2= 0.23
CO2/N2= 0.11
Experiment Theory
2200 2225 2250 2275 2300 2325 2350
2
4
6
8
H2 S(5)
Temp. = 2081.5 KH2/N2= 0.07
Raman Shift (cm-1)
(In
tens
ity)1/
2 (arb
. uni
ts)
Experiment Theory
CARSFit code from Cutler and Magnotti. J. Raman Spec., (2011).
2220 2250 2280 2310 2340 2370 2400 24300
1
2
3
4
Temp. = 2441.7 K
Raman Shift (cm-1)
(In
tens
ity)1/
2 (arb
. uni
ts) Experiment
Theory
2250 2300 2350 2400 24500
25
50
75
100
125
150
175
200
Temp. = 295 KO2/N2 = 0.265
Inte
nsity
1/2 (a
rb. u
nits
)
Raman Shift (cm-1)
Data Theory
Single-shot Precision of the Combined CARS System
0 400 800 1200 1600 20002
3
4
5
6
7
8
9
Temp PRCARS Temp DPVCARS N2/O2 PRCARS N2/O2 DPVCARS
Prec
isio
n (%
)
Temperature (K)
1900 2000 2100 2200 2300 24000
50
100
150
200
250
300
Num
ber o
f Las
er S
hots
Temperature
Temperature
Std. Deviation of 3% . Average Temperature = 2087 K
2175 2200 2225 2250 2275 2300 2325 2350 23750
2
4
6
8
Temp. = 2107.56 KH2/N2= 0.089
Raman Shift (cm-1)
(Inte
nsity
)1/2 (a
rb. u
nits
)
Experiment Theory
Measurements and 1-D Simulations in Laminar Premixed
Flames
Mechanism Giovangigli’s GRI 3.0 San Diego
Number of species 16 53 63
Number of steps 46 325 297
Typical computation time 20 minutes 3 hours 2.5 hours
•Comparison of various chemical mechanisms against CARS measurements.•Assess influence of fuel composition and strain rate on flame structure.•Assess Influence of transport properties such as thermal diffusion on flame structure.•Assess Influence of radiation model on flame structure.
Satija et al., Int. J. Hydrogen. Energy, (2015)
1-D Numerical Solution of Premixed Flame Structure
Major and important minor species at Eq. Ratio = 1.4 using San Diego chemical mechanism
0 2 4 6 8 10 120.00
0.05
0.10
0.15
0.20
0.25
0.30
CH4 CO CO2 H2 H2O N2 / 3.0 O2
CH x 105
OH x 3.2 x 102 San Diego Temp
NO x 1.6 x 103Distance from the bottom nozzle (mm)
Mol
e fr
actio
n
300
600
900
1200
1500
1800
2100
Tem
pera
ture
(K)
CH4/Air Premixed Flame with varying Equivalence Ratios
0 2 4 6 8 10 12
500
750
1000
1250
1500
1750
2000
2250
Flam
e Te
mpe
ratu
re (K
)
Distance from the Fuel Nozzle (mm)
DPVCARS Temp. PRCARS Temp. San Diego
0 2 4 6 8 10 12
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Distance from the Fuel Nozzle (mm)
H2 VCARS H2 SD O2 VCARS O2 SD
0.00
0.05
0.10
0.15
0.20
O
2 M
ole-
Frac
tion
H2
Mol
e-Fr
actio
n
Comparison of Flame temperature for Eq. ratio = 1.31
Comparison of H2 and O2 mole-fraction for Eq. ratio = 1.31
1.2 1.3 1.4 1.5
0.04
0.06
0.08
0.10
0.12
0.14
0.16
DPVCARS Adiabatic Flame H2 Caln.
Mol
e-Fr
actio
n of
H2
Equivalence Ratio
Other DPVCARS Possibilities
