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Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase Doppler Phase Doppler Particle AnalyzerParticle Analyzer
2007 TSI LDV/PDPA Workshop & Training
Presented by Joseph Shakal Ph.D.
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase Doppler Particle Phase Doppler Particle AnalyzerAnalyzer
• Light scattering principles and the phase Doppler method
• Measuring the phase of the scattered fringe pattern
• Validation techniques and error sources
• FlowSizer Software
• Measurement examples
Copyright© 2008 TSI Incorporated
TSI Incorporated
Light Scattering Principles Light Scattering Principles and the Phase Doppler and the Phase Doppler
MethodMethod• System Layout
• Fringe Patterns
• Reflective and Refractive Scatter
Copyright© 2008 TSI Incorporated
TSI Incorporated
ReceivingOptics
Optics
Fringes Move
Photo-detectors Signal Processor
FSA
Laser
Fiber-optic
Schematic of Phase Doppler Schematic of Phase Doppler OpticsOptics
C
BA
ReceivingAngle
FireWirePDM
FlowSizer
Slit
Particle
Copyright© 2008 TSI Incorporated
TSI Incorporated
Actual Fringe PatternsActual Fringe Patterns
At Crossing Away from Crossing
Copyright© 2008 TSI Incorporated
TSI Incorporated
Incident Beam (partially shown
for clarity)
Rainbow Angleat ~140 deg
m
Reflection p = 0
p = 2Refraction
p = 1
Light Scattering by a Light Scattering by a DropletDroplet
Different ComponentsDifferent Components
Rays scattered at ~30 deg
Copyright© 2008 TSI Incorporated
TSI Incorporated
Measuring the Phase of the Measuring the Phase of the Scattered Fringe PatternScattered Fringe Pattern
• Generation of Fringes by Droplets
• Fringe Spacing of the Scattered Light Pattern
• Reflective and Refractive Fringes
• Obtaining the Phase with a Three-Detector Receiver
• Detector Spacing
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase Shift of Light Phase Shift of Light Refracted Through a SphereRefracted Through a Sphere
• Two representative rays are pulled out of the crossing beams• Light rays enter the drop at different angles• Passing on different optical paths to reach an arbitrary point “P” results in a
phase shift between the two rays• Phase shift results in constructive and destructive interference
in the surrounding space
m
Ray 2
Ray 1
P
Enlarged View
Copyright© 2008 TSI Incorporated
TSI Incorporated
Scattered Fringe PatternScattered Fringe Pattern(small particle in the measuring volume)(small particle in the measuring volume)
Fringe pattern in the measuring volume, as seen by the receiver
Scattered fringe pattern
(No shift)
SABS
f
Copyright© 2008 TSI Incorporated
TSI Incorporated
Scattered Fringe PatternScattered Fringe Pattern(large particle in the measuring volume)(large particle in the measuring volume)
Scattered fringe pattern
(No shift)
SABS
f
Fringe pattern in the measuring volume, as seen by the receiver
Copyright© 2008 TSI Incorporated
TSI Incorporated
Signal A
Signal B
Signal C
Refraction
Signal C
Optimized Three Detector Optimized Three Detector ApproachApproach
Signal A
Signal B
Reflection
C
BA
Refr
act
ion
Reflect
ion
View into Front of Receiver
Intensity Pattern
Phase AB
Phase AC
Phase AB
Phase AC
Droplet is currently in the Beam Waist
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phas
e
Original Detector
Arrangement
Diameter
Optimized Three-Detector Optimized Three-Detector ApproachApproach
C
AB
AB)
AC)0
180
360
AC AB
C
ABOptimized
Detector Arrangemen
t
d1
Copyright© 2008 TSI Incorporated
TSI Incorporated
Optimized PDPA ReceiverOptimized PDPA Receiver
• No masks needed
• No planar phases measured
• Detector Areas same as Detection Areas
• Collimated light input to fibers
• Ideal fiber packing ratio
• Non-integer detector spacing ratio → leads to non-integer phase ratio
C
A
B
Copyright© 2008 TSI Incorporated
TSI Incorporated
Non-Integer Phase RatioNon-Integer Phase Ratio
C
B
A
View Into the Receiver
Detector Separation AC, DAC
Detector Separation AB, DAB
DAC / DAB is about 3.5 in RV series Receivers
~ 75 Fibers
Copyright© 2008 TSI Incorporated
TSI Incorporated
Error Sources and Validation Error Sources and Validation TechniquesTechniques
• Probe Volume Bias
• TSI’s 3rd Generation PVC Algorithm
• Mixed Mode Scattering
• Intensity Validation
• Phase Validation: “Diameter Difference”
Copyright© 2008 TSI Incorporated
TSI Incorporated
I
r
Sample Volume or Probe Sample Volume or Probe VolumeVolume
r(di)
A(di)A(di)
W
Defined by the Slit Defined by the Slit
dw
Copyright© 2008 TSI Incorporated
TSI Incorporated
1/2dw = ro
ID
I(di)m
2r(di)D
More in Next Slide
Probe Volume Probe Volume BiasBiasQuestion: Why does the sample volume depend on measured drop size?
Answer: Larger drops can pass through the beam anywhere and still produce enough light to be detected
Scattered Intensity:
Few mV up to 1000mV
This size and larger can be detected everywhere.
Typically 5 ~ 15um
Copyright© 2008 TSI Incorporated
TSI Incorporated
Bias is corrected for inside the Gaussian
beam waist.
All phase Doppler instruments suffer from
probe volume bias.
Probe Volume Probe Volume BiasBias
Bias can be corrected for
Small drops can only be detected in center region.
Only larger
particles detected
Bias can be corrected for
May not be detected
Copyright© 2008 TSI Incorporated
TSI Incorporated
Probe Volume Correction Probe Volume Correction TechniqueTechnique
• Large Drops: Probe volume defined by lower intensity limit
• Small Drops: Probe volume obtained from the cumulative distribution of path lengths
Path Length (m)
Path Length Distribution for 2 Runs
3.5E-04
Norm
aliz
ed C
ounts
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5.0E-05 1.0E-04 1.5E-04 2.0E-04 2.5E-04 3.0E-04
1011
Integrated
Copyright© 2008 TSI Incorporated
TSI Incorporated
Intensity ValidationIntensity Validation
But aren’t we throwing out good data? No.
Only TSI’s Intensity Validation can identify
the actual flow area:
A
B
C
B, C
A
Copyright© 2008 TSI Incorporated
TSI Incorporated
Intensity Validation Intensity Validation SettingsSettings
1/3 Dmax Method1/3 Dmax Method• Find Dmax from optics setup • Arrow indicates 1/3 of Dmax• Set slope of upper limit so
that it intersects saturation at 1/3 Dmax
• PMT voltage & laser power are adjusted so that the data comes close to upper limit
• Slope of Lower Limit is set to 1/10 Slope of Upper Limit
• This method is difficult to set up if only a small part of diameter range is being used
• See FAQ for more details• See Recent Support
presentation for more details
Copyright© 2008 TSI Incorporated
TSI Incorporated
Intensity Validation Intensity Validation SettingsSettings
D10 Stabilization MethodD10 Stabilization Method
• This method is particularly suitable when the system has an unusually wide diameter range and only a small part is being used
• See Manual for more details
D10
0
5
10
15
20
25
30
300 325 350 375 400 425 450 475 500 525 550 575
PMT Voltage
D1
0
Copyright© 2008 TSI Incorporated
TSI Incorporated
Intensity Validation on LDVIntensity Validation on LDVC
ount
Intensity
Rejects:Signals from large particles not tracking the flow
Sub-range out points above a threshold, eg Arrow
Copyright© 2008 TSI Incorporated
TSI Incorporated
Refraction
Reflection
Receiver
Reflection
Refraction
Mixed-Mode ScatteringMixed-Mode Scattering
Droplet is moving into the page
Reflection
InternalReflection
Copyright© 2008 TSI Incorporated
TSI Incorporated
Intensity ValidationIntensity Validation
Reflective Signals
Phase Wrap Region
MultipleParticlesRegion
Copyright© 2008 TSI Incorporated
TSI Incorporated
Reflected Signals from Large Reflected Signals from Large DropsDrops
• This issue often comes up with dense spray measurements
• Intensity validation may fail to reject these
• Their effect on mass flux is not significant
• Phase validation may be used to reject them via “Diameter Difference” check
Laser Beams
To Receiver
Gaussian Intensity Profile
y
z
Note that droplet is ‘large,’ non-uniformly illuminated,and just outside the waist
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase Validation: Phase Validation: Integer Integer Phase RatioPhase Ratio
Refraction
Reflection
Note that the ratio of Phase AC is 3x Phase AB
1
3
Phase AB
Phase AC
360
360
00
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase AB
Phase AC
360
360
00
Refraction
Reflection
Note that the ratio of Phase AC is now 3.5x Phase AB
1
3.5
Phase Validation: Non-iPhase Validation: Non-integer nteger Phase RatioPhase Ratio
Copyright© 2008 TSI Incorporated
TSI Incorporated
Phase ValidationPhase Validation
Phase AB
Phase AC
360
360
00
Indicated measurements would appear outside our 7% limit
Actual Data
Mismatch Limit, Typ 7%
Copyright© 2008 TSI Incorporated
TSI Incorporated
FlowSizer 2.0 SoftwareFlowSizer 2.0 Software
New Fitting Routines
Copyright© 2008 TSI Incorporated
TSI Incorporated
Measurement Case StudiesMeasurement Case Studies
• Pulsed Bio-Diesel and Common Rail diesel spray (2 cases)• Flux Profile of a DI Gasoline spray• Condensing flow at a turbine outlet• Mach 2 scramjet engine flow• Aircraft based hurricane measurements• Turbine engine combustor• Nasal Inhaler Spray
Copyright© 2008 TSI Incorporated
TSI Incorporated
PDPA Measurements by PDPA Measurements by FSA 4000FSA 4000
Pulsed Diesel Injector
100% Bio-Diesel Fuel
Copyright© 2008 TSI Incorporated
TSI Incorporated
High Density Diesel SprayHigh Density Diesel Spray
Velocity 1 Realtime
0 2.00x10 -3 4.00x10 -3 6.00x10 -30
24
48
72
96
120
Time Ch. 1 (sec)
Veloc
ity C
h. 1 (
m/se
c)
Courtesy CMT – Polytechnic Univ. ValenciaTSI-64
Particle Diameter Distribution
0 16 32 48 64 80
0.4
1.8
3.2
4.6
6.0
Diameter (um)
No
rma
lize
d D
iam
ete
r C
ou
nt
(%/u
m)
0
100
200
300
400
500
600
Pa
rticle
Co
nc
en
tratio
n 1
/(cc
*um
)
Uncorrected DiameterCorrected DiameterCorrected AreaCorrected VolumeParticle Con. per Bin
Copyright© 2008 TSI Incorporated
TSI Incorporated
Diameter Statistics
High Density Diesel SprayHigh Density Diesel Spray
Courtesy CMT – Polytechnic Univ. Valencia
PVC SpatialD10 (um)D20 (um)D30 (um)D32 (um)D43 (um)PhaseAB Mean (degree)PhaseAB RMS (degree)PhaseAC Mean (degree)PhaseAC RMS (degree)Size Data Rate (Hz)Size Valid CountEpsilon ExceptionDiameter ExceptionIntensity Invalid
16.41 16.07 16.3917.51 17.19 17.6018.55 18.25 18.7020.82 20.57 21.1123.05 22.7970.5430.04-18.78121.0451425000455405286
Extended Diameter Statistics
xqLWC (g/m3)Volume Flux X (cc/cm2 s)Volume Flux Y (cc/cm2 s)Volume Flux Z (cc/cm2 s)Volume 1 (%)Volume 10 (%)Volume 50 (%)Volume 90 (%)Volume 99 (%)Total Particle Conc.(1/cc)
23.643.9531.07760.05860.00000.00007.3913.3721.5429.1934.799762.7988
Copyright© 2008 TSI Incorporated
TSI Incorporated
Flux Profile of a G-DI SprayFlux Profile of a G-DI Spray
Excellent Repeatability
Copyright© 2008 TSI Incorporated
TSI Incorporated
Flux Profile of a Coolant Flux Profile of a Coolant SpraySpray
X Y Flux( )
A New Method for Minimizing Volumetric Flux Errors Associated with PDPA Measurements in the Dilute Region of Full Cone Pressure Swirl Atomizers, ICLASS 2006, Paper # 06-163
Copyright© 2008 TSI Incorporated
TSI Incorporated
High Density Condensing High Density Condensing FlowFlow
Diameter Measurement Statistics Raw PVCD10 (um) 1.35 2.08 D20 (um) 1.57 2.11 D30 (um) 2.14 2.26 D32 (um) 3.97 2.59
Coinc. Size Data Rate (Hz) 5737 Particle Conc.(1/cc ) 1,175,879
Waist Size 16umLaser Power ~4W
Copyright© 2008 TSI Incorporated
TSI Incorporated
High Speed FlowHigh Speed FlowGatetime 1 Histogram
0 0.467 0.933 1.4000
1000
2000
3000
4000
Gate Time Ch. 1 (usec)
Ga
te T
ime
Co
un
t C
h. 1
Diameter Histogram
0 13 27 400
50
100
150
200
Diameter (um)
Dia
met
er C
ou
nt
Vmean = 595m/sFreqmean = 118.8MHzValid Vel = 100%Valid Dia = 91.7%
Gate Timemean = 110nsecData Rate: Ch 1 = 55.8kHz, Ch 2 = 26kHz
Courtesy Dr. Kuo-Cheng LinThis work was sponsored by AFRL/Propulsion Directorate at Wright-Patterson Air Force Base
Copyright© 2008 TSI Incorporated
TSI IncorporatedPDPA Measurements in PDPA Measurements in Supersonic Wind Tunnel Supersonic Wind Tunnel
(Jet in Crossflow)(Jet in Crossflow)
Mach 1.94
• d0=0.5 mm
• q0=7
• GLR=5%
• x/d0=200
Lin, K.-C., Kennedy, P.J., Jackson, T.A., “Structures of Water Jets in a Mach 1.94 Supersonic Crossflow,” AIAA Paper 2004-0971, January 2004.This work was sponsored by AFRL/Propulsion Directorate at Wright-Patterson Air Force Base
Copyright© 2008 TSI Incorporated
TSI Incorporated
PDPA Measurement of a PDPA Measurement of a Spray in an Acoustic Spray in an Acoustic
FieldField
Courtesy Prof. R.I.Sujith and K. Gurubaran, Dept. of Aerospace Engineering, IIT-Madras, India
See AIAA paper 2008-1046 for more details.
Water Spray
Dual Speakers
Resonance Chamber
Copyright© 2008 TSI Incorporated
TSI Incorporated
PDPA Measurements in a PDPA Measurements in a Lean Low-NOx Aircraft Lean Low-NOx Aircraft
CombustorCombustor
Courtesy of Jonathan Colby and Georgia Institute of Technology
0 0.5 1 1.5 2 2.5 3 3.5 4
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
X / Ro
Y /
Ro
D32
/ D
o
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
SMD with Combustion Lean Low NOx Combustor (GE CFM 56
Engine)
Copyright© 2008 TSI Incorporated
TSI Incorporated
Fuel Rate = 0.75g/sEq. Ratio = 0.4Tair = 380KTwall = 540K
Courtesy of Jonathan Colby, Georgia Institute of Technology
Lean Low NOx Combustor (GE CFM 56 Engine)
Cold Flow
Combustion
Courtesy of Jonathan Colby, Georgia Institute of Technology
LDV Measurements in PPL LDV Measurements in PPL CombustorCombustor
Copyright© 2008 TSI Incorporated
TSI Incorporated
PDPA Measurements in PDPA Measurements in Hurricane Hurricane
NOAA research aircraft N43RF
Courtesy of Prof. Bill Asher and Trina Litchendorf, APL, Univ of Washington
Hurricane Jeanne 9/25/04
Copyright© 2008 TSI Incorporated
TSI Incorporated
Nasal Inhaler Spray Nasal Inhaler Spray MeasurementsMeasurements
Measurements were made in externally triggered mode
100ms200ms300ms400ms
Diameter Histogram
0 10 20 30 400
50
100
150
200
Diameter (um)
Dia
met
er C
ou
nt
Realtime Diameter
0
20
40
60
80
100
120
0.00 0.10 0.20 0.30 0.40 0.50
Time (s)
Dia
me
ter
(um
)
Running Mean
Realtime Axial Velocity
0
1
2
3
4
5
6
0.00 0.10 0.20 0.30 0.40 0.50
Time (s)
Ve
loc
ity
(m
/s)
Running Mean
Time-averaged diameter
Copyright© 2008 TSI Incorporated
TSI Incorporated
Transient MeasurementsWhen an electronically triggered device is being measured, it is often interesting to look at time histories. You can use the “SyncPulse” input to act as an OPR signal with FlowSizer 2.0 and current FSA’s. EB option and OPR input is the best way to trigger FSA though.
Other CommentsOther Comments
Use of a TraverseIt is easy to create and run scans through the flow, with the Traverse GUI in FlowSizer. Scans can be saved, and edited in Excel.
Copyright© 2008 TSI Incorporated
TSI Incorporated
ConclusionsConclusions
• We have seen how the droplet scatters light• Fringe pattern is detected from three angles, resulting in
phase difference• Phase is linearly related to diameter• Intensity Validation works with Probe Volume
Correction (PVC) to give reliable results, even flux• Phase Validation provides backup to Intensity Validation• PDPA systems used in many applications, worldwide