Coherent Anti-Stokes Raman
Scattering (CARS) for Quantitative
Temperature and Concentration
Measurements in a High-Pressure Gas
Turbine Combustion Test Rig
Robert P. Lucht and Jay P. Gore
Purdue University, W. Lafayette, IN
Supersonics NRA Annual Review
Cleveland, OH January 27, 2010
Acknowledgments
•
Graduate students Mathew P. Thariyan (PhD),
Vijaykumar Ananthanarayanan (M.S., now at
Cummins), and Aizaz H. Bhuiyan (PhD), Senior
Research Engineer Scott E. Meyer, Senior Research
Associate Sameer V. Naik, Postdoc Dr. Ning Chai
•
Technical advice from Drs. Nader Rizk, William
Cummings, Mohan Razdan, Vic Oechsle, Dan
Nickolaus, M. S. Anand, and Duane Smith at Rolls
Royce Corporation in Indianapolis, Indiana
•
Funding from NASA Glenn under Cooperative
Agreement Number NNX07AC90A , technical
discussions with Drs. Yolanda Hicks, Clarence
Chang, and Randy Locke
Motivation
• To demonstrate dual-pump CARS
measurements of CO2, N2 and temperature
in the gas turbine combustor over a wide
range of simulated supersonic flight
conditions.
• To obtain high-quality data in the reacting
flow field downstream of the NASA lean
direct injection array for comparison with
advanced computational models.
Outline of the Presentation
• Optically Accessible Gas Turbine Combustor
Facility
• Dual-Pump CARS Measurements: Challenges
and Optical System
• Temperature Measurements: PDFs, Mean
Profiles, Standard Deviation Profiles
• Conclusions and Accomplishments
• Future Work
Purdue Gas Turbine Combustion Facility
(GTCF)
Maximum
Flow
Capacity
Max
Operating
Condition
Natural Gas
Heated High
Pressure Air
9 lbm/sec
700 psi /
500 deg C
Electric Heated
Air or Nitrogen
1 lbm/sec
600 psi /
600 deg C
Nitrogen
2 to 5 lbm/sec
1,500 psi
Liquid
Aviation Fuel
(Kerosene)
1 lbm/sec/tank
(2 tanks)
1,500 psi
Cooling Water
40 gpm
400 psi
High
Pressure Lab
System
NASA 9-Point LDI Assembly (Top-Hat)
• Nine simplex injectors arranged at throats of
nine converging-diverging venturis in a 3 x 3
arrangement.
• Axial swirlers with helical vanes at 60° impart
swirl to incoming heated air.
• Only central injector used for testing.
Purdue GTCF – Window Assembly
Window Assembly Details
Stagnant Air Gap
3"x3" Inner Cross Section
Coherent Anti-Stokes Raman
Scattering (CARS)
• Conventional
“Single-Pump” CARS
• Noninvasive
• Coherent Laser-Like
Signal
• Spatially and
Temporally Resolved
• Excellent Gas
Temperature Data
(especially at higher
temperatures)
pump
CARS
Stokes
pump
V
CARS
Stokes
Pump1
Pump1
Dual-Pump CARS of N2/CO2
Overall Experimental System
CARS System for GTCF Measurements
A: Aperture
BD: Beam Dump
CL: Camera Lens
IF: Interference
Filter
L: Lens
/2: Half-waveplate
Pol: Polarizer
S: Shutter
TS: Translation
Stage
ZL: Zoom Lens
Window
608 nm
Assembly
Entrance
Translation
Stages
Exit
Translation
Stages
L4
BD
BD
BD
L5
Flow
L3
Probe
Volume
561 nm 532 nm
/2
Pol.
Main Leg
S
A
Pol.
Reference Leg
/2
S
SPEX
CL
/2
Pol.
IF
TS
S
ZL
TS
496 nm
BD
A
BD
BD
L2
Probe
Volume
L1
Use of Optical Parametric Oscillator/
Pulsed Dye Amplifier System
Optical Arrangement for Laser Beam
Generation
To Purdue GTCF
607
nm
BBDL
PDA 2
0
Mirror
355
nm
970
nm
BS
PDA 1
0
Mirror
ECDL
BS
Seeded Nd:YAG
532
nm
560
nm
OPO
BS
Dual-pump CARS System
Measurement Challenges in GTCF
• Translation of probe volume inside the flame
zone.
• Installation of pin-hole for spatial overlap of
CARS beams not possible, must use
referemce leg alignment.
• Measurement of non-resonant signal in the
reference leg for spectral normalization of
CARS signal.
• Safety of thin window, CARS beams are
focused tightly in the middle of the test
section.
CARS Probe Volume Translation
A: Aperture
BD: Beam Dump
CL: Camera Lens
IF: Interference
Filter
L: Lens
/2: Half-waveplate
Pol: Polarizer
S: Shutter
TS: Translation
Stage
ZL: Zoom Lens
Exit
Translation
Stages
Window
608 nm 561 nm 532 nm
Assembly
Entrance
Translation
Stages
L4
BD
BD
BD
L5
Flow
L3
Probe
Volume
Main Leg
/2
S
A
Reference Leg
SPEX
CL
/2
Pol.
Pol.
/2
S
Pol.
IF
TS
S
ZL
TS
496 nm
BD
A
BD
BD
L2
Probe
Volume
L1
Optical System near GTCF
CARS System Reference Leg
CARS System Reference Leg
A: Aperture
BD: Beam Dump
CL: Camera Lens
IF: Interference
Filter
L: Lens
/2: Half-waveplate
Pol: Polarizer
S: Shutter
TS: Translation
Stage
ZL: Zoom Lens
Window
608 nm
Assembly
Entrance
Translation
Stages
Exit
Translation
Stages
L4
BD
BD
BD
L5
Flow
L3
Probe
Volume
561 nm 532 nm
/2
Pol.
Main Leg
S
A
Pol.
Reference Leg
/2
S
SPEX
CL
/2
Pol.
IF
TS
S
ZL
TS
496 nm
BD
A
BD
BD
L2
Probe
Volume
L1
Probe Volume Translation
DP-CARS Detection Optics
Operating Conditions, Measurement
Locations and Sample DP-CARS Spectra
125 psia
(8.5 atm.)
■
150 psia
(10 atm.)
■
■
■
Φ=1.0
F = 0.6
P = 100 psi
DP/P = 4%
Comb. Pr. = 100 psia., Eq. Ratio = 0.8
Note: Distance between points along the centerline is 5 mm
+ 11 mm
+ 9 mm
+ 6 mm
10 mm
• Burner Inlet
Temperature: 850 0F (725 K)
• Fuel: Jet-A
• Normalized injector
pressure drop = 4%
■
+ 3 mm
- 3 mm
- 6 mm
- 9 mm
- 11 mm
(arb. units)
■
Φ=0.80
1/2
100 psia
(7.0 atm.)
Φ=0.59
(CARS Intensity)
Φ=0.4
75
65
55
T = 1325 K
CO2/N2 = 0.079
N2
Data
Theory
Residual
45
35
N2
25
CO2
15
5
-5
-15
1300
1320
1340
1360
Raman Shift (cm-1)
1380
1400
Purdue GTCF in Operation
Central injector operation
F= 0.45, Pcomb= 120 psia, Tinlet = 780° F
Flame Characteristics @ 100 psia
Φ =0.4
Φ =0.8
Φ =0.59
Φ =1.0
Data Analysis

1000 to 2000 spectra collected at each measurement
location.

Spectra with low average N2 signal counts and droplet
interferences rejected.

Square-root of background corrected normalized CARS
spectra analyzed using Sandia CARSFT code in the
batch processing mode.

N2 spectra analyzed for optimal temperature, horizontal
and vertical shift, instrument function etc.

Spectra with low peak CO2 counts rejected. CO2 part of
the spectrum analyzed for CO2/N2 concentration ratio.
Data Processing
Corrected
Averaged
Background
Final Image
Corrected
Non-Resonant
Stokes
Corrected
Image
Blocked
Signal
Image
Raw
Temp PDFs Along Centerline
Combustor Pressure: 104 psia, Equivalence Ratio: 0.4
Temperature PDF: Z = 10 mm, R = 0 mm
Temperature PDF: Z = 15 mm, R = 0 mm
100
160
Mean Temp. = 2020 K
Std. Dev. = 370 K
(a)
Mean Temp. = 1820 K
Std. Dev. = 340 K
(b)
120
60
Counts
Counts
80
140
40
100
80
60
40
20
20
0
1000
0
1500
2000
2500
3000
1000 1250 1500 1750 2000 2250 2500 2750
Temperature (K)
Temperature (K)
Temperature PDF: Z = 25 mm, R = 0 mm
Temperature PDF: Z= 50 mm, R= 0 mm
100
80
Mean Temp. = 1595 K
Std. Dev. = 267 K
(a)
Mean Temp. = 1340 K
Std. Dev. = 180 K
80
Counts
Counts
60
40
60
40
20
0
1000
20
0
1200
1400
1600
1800
Temperature (K)
2000
2200
2400
1000
1200
1400
1600
Temperature (K)
1800
2000
Temp PDFs at Different Locations
Combustor Pressure: 104 psia., Equivalence Ratio: 0.4
Temperature PDF: Z = 10 mm, R = 9 mm
Temperature PDF: Z = 10 mm, R = 6 mm
120
140
Mean Temp. = 1835 K
Std. Dev. = 340 K
(b)
120
100
Counts
80
60
60
40
40
20
20
0
0
1000
1000 1250 1500 1750 2000 2250 2500 2750
1500
2000
2500
3000
Temperature (K)
Temperature (K)
Temperature PDF: Z = 20 mm, R = 6 mm
Temperature PDF: Z = 20 mm, R = 9 mm
80
80
Mean Temp. = 1520 K
Std. Dev. = 235 K
(e)
60
(f)
Mean Temp. = 1405 K
Std. Dev. = 265 K
800
1000 1200 1400 1600 1800 2000 2200
60
Counts
Counts
Counts
100
80
Mean Temp. = 1760 K
Std. Dev. = 410 K
(c)
40
40
20
20
0
0
1000
1200
1400
1600
Temperature (K)
1800
2000
Temperature (K)
2200
(a)
Z = 10 mm
Z = 20 mm
Z = 45 mm
2000
Temperature (K)
Mean
Temperature &
Temperature
Standard
Deviation
Profiles
1800
1600
1400
1200
0
2
4
6
8
10
12
Radial Distance (mm)
Equivalence
Ratio: 0.4
Relative Temp. Std. Dev. (%)
Combustor
Pressure: 104
psia
40
Z =10 mm
Z = 20 mm
Z = 45 mm
(b)
35
30
25
20
15
10
0
2
4
6
8
Radial Distance (mm)
10
12
Mean Temperature Profiles
F = 0.4
100 psia
2100
F = 0.8
F= 0.4
2000
Mean Tempearture (K)
Mean Tempearture (K)
2200
1800
1600
1400
150 psia
100 psia
2000
1900
1800
1700
1600
1500
1400
1200
10
15
20
25
30
35
40
Axial Distance (mm)
45
50
1300
10
15
20
25
30
35
40
Axial Distance (mm)
45
50
Mean Temperature Profiles
Z = 20 mm, 150 psia, F = 0.4
Mean Tempearture (K)
1800
1700
1600
1500
1400
1300
1200
-12
-8
-4
0
4
8
Vertical Distance (mm)
12
Temperature and CO2/N2 PDFs
Combustor Pressure: 104 psia., Equivalence
Ratio: 0.4
Temperature PDF: Z = 30 mm, R = 3 mm
Temperature PDF: Z = 25 mm, R = 0 mm
80
100
Mean Temp. = 1595 K
Std. Dev. = 267 K
(a)
Mean Temp. = 1515 K
Std. Dev. = 205 K
(b)
80
Counts
Counts
60
40
60
40
20
20
0
1000
0
1200
1400
1600
1800
2000
2200
1000
2400
1200
2200
Mean CO2/N2 = 0.0546
Std. Dev. = 0.019
(d)
30
30
Counts
Counts
2000
40
Mean CO2/N2 = 0.0625
Std. Dev. = 0.0212
40
1800
CO2/N2 Conc. Ratio PDF: Z = 30 mm, R = 3 mm
CO2/N2 Conc. Ratio PDF: Z = 25 mm, R = 0 mm
(c)
1600
Temperature (K)
Temperature (K)
50
1400
20
20
10
10
0
0.02
0.04
0.06
0.08
0.10
CO2/N2 Concentration Ratio
0.12
0.14
0
0.00
0.02
0.04
0.06
0.08
0.10
CO2/N2 Concentration Ratio
0.12
Temperature and CO2/N2 Scatter
Combustor Pressure: 104 psia., Equivalence Ratio: 0.4
Temp. vs CO2/N2 Correlation: Z = 25 mm, R = 0 mm
Temp. vs CO2/N2 Correlation: Z = 30 mm, R = 3 mm
0.12
CO2/N2 Concentration Ratio
CO2/N2 Concentration Ratio
0.12
0.10
0.08
0.06
0.04
0.02
0.00
1000
0.10
0.08
0.06
0.04
0.02
0.00
1200
1400
1600
Temperature (K)
1800
1000
1200
1400
Temperature (K)
1600
1800
Accomplishments and Conclusions

GTCF has been operated at wide range of simulated
supersonic flight conditions. The optically accessible
GTCF has been operated up at pressures up to150 psia,
single-shot dual-pump CARS measurements obtained at
all operating conditions.

Approximately 500,000 single-shot spectra were
acquired in a test campaign conducted during the
summer of 2009. These spectra are being processed to
obtain temperature and CO2/N2 concentration ratio
values at various equivalence ratios at multiple axial and
vertical positions downstream of the LDI injector.
Accomplishments and Conclusions

A new OPO/PDA system was used to generate the 560nm pump beam in the dual-pump CARS system.
Considerable care in allignment was required for all
beams to obtain good beam quality in the combustor
test cell.

The Zaber translation stages performed well, alignment
was maintained over the entire spatial region of interest
during the test.

The reference leg was invaluable for alignment and for
frequent recording of the nonresonant signal.
Alignment was maintained before and after translation of
the large 2-inch prisms.
Accomplishments and Conclusions

Data analysis is still in progress. Filtering techniques to
remove spectra with signals that were too low have
been developed and are still being optimized. .

Experimental results will be compared with
computational results obtained from, for example, the
National Combustion Code (NCC). The data will be
provided in a form decided in collaboration with NASA
personnel.
Accomplishments and Conclusions

Estimated uncertainty in temperature measurements :
 Accuracy: 1-2%
 Precision: 2-3%

Uncertainty in CO2/N2 ratio measurements :
 Very dependent on CO2 concentration and on the
temperature, approximately 10% relative standard
deviation in the range of 5% CO2 concentation around
1500 K.

Probe volume dimensions:
 500 μm along the laser propagation direction.
 50 μm perpendicular to the laser direction.
Papers and Presentations
1. Mathew P. Thariyan, Aizaz H. Bhuiyan, Sameer V. Naik,
Jay P. Gore, and Robert P. Lucht, “Temperature and CO2
Concentration Measurements in a High-Pressure, Lean
Direct Injector Combustor using Dual-Pump CARS,”
paper submitted to the 33rd Combustion Symposium.
2. Mathew P. Thariyan, Aizaz H. Bhuiyan, Scott E. Meyer,
Sameer V. Naik, Jay P. Gore, and Robert P. Lucht,
“Optically Accessible, High-Pressure Gas Turbine
Combustion Facility and Dual-Pump CARS System,”
paper in preparation for submission to Measurement
Science and Technology.
Papers and Presentations
3. M. P. Thariyan, V. Ananthanarayanan, A. H. Bhuiyan, S. E. Meyer, S.
V. Naik, J. P. Gore and R. P. Lucht, “Dual-Pump CARS Temperature
and Major Species Concentration Measurements in Laminar
Counterflow Flames and in a Gas Turbine Combustor Facility,”
Paper AIAA-2009-1442, presented at the 47th Aerospace Sciences
Meeting, Orlando, Florida, January 5-8, 2009.
4. M. P. Thariyan, A. H. Bhuiyan, N. Chai., S. V. Naik, R. P. Lucht, and
J. P. Gore, “Dual-Pump CARS Temperature and Major Species
Concentration Measurements in a Gas Turbine Combustor Facility,”
Paper AIAA 2009-5052, 45th AIAA/ASME/SAE/ASEE Joint
Propulsion Conference & Exhibit, Denver, Colorado, 2-5 August
2009.
5. M. P. Thariyan, A. H. Bhuiyan, N. Chai, S. V. Naik, R. P. Lucht, and
J. P. Gore, “Dual-Pump CARS Measurements in a Gas Turbine
Combustor Facility Using the NASA 9-point LDI Injector,” Paper
AIAA-2010-1401, presented at the 48th Aerospace Sciences
Meeting, Orlando, Florida, January 4-7, 2010.
Typical Dual-Pump CARS spectra
T = 1274 K
(arb. units)
100
Data
Theory
80
80
T = 1414 K
40
20
0
1300
60
1315
1330
1345
1360
1375
40
20
0
1300
1315
(arb. units)
Data
Theory
1/2
50
40
(CARS Intensity)
(arb. units)
1/2
(CARS Intensity)
70
T = 1528 K
30
20
10
0
1300
1315
1330
1345
1330
1345
1360
1375
Raman Shift (cm-1)
Raman Shift (cm-1)
60
Data
Theory
1/2
60
(CARS Intensity)
(CARS Intensity)
1/2
(arb. units)
Pressure: 100 psia. @ F = 1.0, 40 mm Center-line
1360
Raman Shift (cm-1)
1375
25
T = 2198 K
Data
Theory
20
15
10
5
0
1300
1315
1330
1345
1360
Raman Shift (cm-1)
1375
Modified Combustor Window Assembly
(CWA) for RRC Injector

Cross section increased from 3"x3“ to 4.2"x4.2". The
modified CWA is fabricated from Hastelloy-X instead of
stainless steel. Brazing has been eliminated. Film cooling air
passages are incorporated in the injector assembly rather
than in the CWA. Thermal barrier coatings are being applied
to the window assembly inner surfaces.

Upstream spool section has been redesigned to
accommodate the larger injectors and to ensure uniform flow
into the injector.

Downstream spool sections redesigned for larger flow cross
section.
Modified Combustor Window Assembly
(CWA) for RRC Injector
Modified Combustor Window Assembly
(CWA) for RRC Injector