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TSI Incorporated Copyright© 2008 TSI Incorporated Phase Doppler Particle Analyzer 2007 TSI LDV/PDPA Workshop & Training Presented by Joseph Shakal Ph.D.

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Presentation on theme: "TSI Incorporated Copyright© 2008 TSI Incorporated Phase Doppler Particle Analyzer 2007 TSI LDV/PDPA Workshop & Training Presented by Joseph Shakal Ph.D."— Presentation transcript:

1 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Doppler Particle Analyzer 2007 TSI LDV/PDPA Workshop & Training Presented by Joseph Shakal Ph.D.

2 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Doppler Particle Analyzer 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

3 TSI Incorporated Copyright© 2008 TSI Incorporated Light Scattering Principles and the Phase Doppler Method System Layout Fringe Patterns Reflective and Refractive Scatter

4 TSI Incorporated Copyright© 2008 TSI Incorporated Receiving Optics Fringes Move Photo-detectors Signal Processor FSA Laser  Fiber-optic Schematic of Phase Doppler Optics C B A Receiving Angle FireWire PDM FlowSizer Slit Particle

5 TSI Incorporated Copyright© 2008 TSI Incorporated Actual Fringe Patterns At CrossingAway from Crossing

6 TSI Incorporated Copyright© 2008 TSI Incorporated Incident Beam (partially shown for clarity) Rainbow Angle at ~140 deg m Reflection p = 0 p = 2 Refraction p = 1 Light Scattering by a Droplet Different Components Rays scattered at ~30 deg

7 TSI Incorporated Copyright© 2008 TSI Incorporated Measuring the Phase of the Scattered 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

8 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Shift of Light Refracted 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

9 TSI Incorporated Copyright© 2008 TSI Incorporated Scattered Fringe Pattern (small particle in the measuring volume) Fringe pattern in the measuring volume, as seen by the receiver Scattered fringe pattern (No shift) S AB S f

10 TSI Incorporated Copyright© 2008 TSI Incorporated Scattered Fringe Pattern (large particle in the measuring volume) Scattered fringe pattern (No shift) S AB S f Fringe pattern in the measuring volume, as seen by the receiver

11 TSI Incorporated Copyright© 2008 TSI Incorporated Signal A Signal B Signal C Refraction Signal C Optimized Three Detector Approach Signal A Signal B Reflection C B A Refraction Reflection View into Front of Receiver Intensity Pattern Phase AB Phase AC Phase AB Phase AC Droplet is currently in the Beam Waist

12 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Original Detector Arrangement Diameter Optimized Three-Detector Approach C A B  AB )   AC )   AC  AB C A B Optimized Detector Arrangement d1d1

13 TSI Incorporated Copyright© 2008 TSI Incorporated Optimized 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

14 TSI Incorporated Copyright© 2008 TSI Incorporated Non-Integer Phase Ratio C B A View Into the Receiver Detector Separation AC, D AC Detector Separation AB, D AB D AC / D AB is about 3.5 in RV series Receivers ~ 75 Fibers

15 TSI Incorporated Copyright© 2008 TSI Incorporated Error Sources and Validation Techniques Probe Volume Bias TSI’s 3 rd Generation PVC Algorithm Mixed Mode Scattering Intensity Validation Phase Validation: “Diameter Difference”

16 TSI Incorporated Copyright© 2008 TSI Incorporated  I r Sample Volume or Probe Volume r(d i )  A(d i ) W Defined by the Slit dwdw

17 TSI Incorporated Copyright© 2008 TSI Incorporated 1/2d w = r o IDID I(d i ) m 2r(d i ) D More in Next Slide Probe Volume Bias Question: 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

18 TSI Incorporated Copyright© 2008 TSI Incorporated Bias is corrected for inside the Gaussian beam waist. All phase Doppler instruments suffer from probe volume bias. Probe Volume Bias 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

19 TSI Incorporated Copyright© 2008 TSI Incorporated Probe Volume Correction Technique 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 Normalized Counts E-051.0E-041.5E-042.0E-042.5E-043.0E Integrated

20 TSI Incorporated Copyright© 2008 TSI Incorporated Intensity 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

21 TSI Incorporated Copyright© 2008 TSI Incorporated Intensity Validation Settings 1/3 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

22 TSI Incorporated Copyright© 2008 TSI Incorporated Intensity Validation Settings D10 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

23 TSI Incorporated Copyright© 2008 TSI Incorporated Intensity Validation on LDV Count Intensity Rejects: Signals from large particles not tracking the flow Sub-range out points above a threshold, eg Arrow

24 TSI Incorporated Copyright© 2008 TSI Incorporated Refraction Reflection Receiver Reflection Refraction Mixed-Mode Scattering Droplet is moving into the page Reflection Internal Reflection

25 TSI Incorporated Copyright© 2008 TSI Incorporated Intensity Validation Reflective Signals Phase Wrap Region Multiple Particles Region

26 TSI Incorporated Copyright© 2008 TSI Incorporated Reflected Signals from Large Drops 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

27 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Validation: Integer Phase Ratio Refraction Reflection Note that the ratio of Phase AC is 3x Phase AB 1 3 Phase AB Phase AC

28 TSI Incorporated Copyright© 2008 TSI Incorporated Phase AB Phase AC Refraction Reflection Note that the ratio of Phase AC is now 3.5x Phase AB Phase Validation: Non-integer Phase Ratio

29 TSI Incorporated Copyright© 2008 TSI Incorporated Phase Validation Phase AB Phase AC Indicated measurements would appear outside our 7% limit Actual Data Mismatch Limit, Typ 7%

30 TSI Incorporated Copyright© 2008 TSI Incorporated FlowSizer 2.0 Software New Fitting Routines

31 TSI Incorporated Copyright© 2008 TSI Incorporated Measurement 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

32 TSI Incorporated Copyright© 2008 TSI Incorporated PDPA Measurements by FSA 4000 Pulsed Diesel Injector 100% Bio-Diesel Fuel

33 TSI Incorporated Copyright© 2008 TSI Incorporated High Density Diesel Spray Courtesy CMT – Polytechnic Univ. Valencia TSI-64

34 TSI Incorporated Copyright© 2008 TSI Incorporated Diameter Statistics High Density Diesel Spray Courtesy CMT – Polytechnic Univ. Valencia Extended Diameter Statistics

35 TSI Incorporated Copyright© 2008 TSI Incorporated Flux Profile of a G-DI Spray Excellent Repeatability

36 TSI Incorporated Copyright© 2008 TSI Incorporated Flux Profile of a Coolant Spray 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 #

37 TSI Incorporated Copyright© 2008 TSI Incorporated High Density Condensing Flow Diameter Measurement Statistics Raw PVC D10 (um) D20 (um) D30 (um) D32 (um) Coinc. Size Data Rate (Hz) 5737 Particle Conc.(1/cc ) 1,175,879 Waist Size16um Laser Power~4W

38 TSI Incorporated Copyright© 2008 TSI Incorporated High Speed Flow V mean = 595m/s Freq mean = 118.8MHz Valid Vel = 100% Valid Dia = 91.7% Gate Time mean = 110nsec Data Rate: Ch 1 = 55.8kHz, Ch 2 = 26kHz Courtesy Dr. Kuo-Cheng Lin This work was sponsored by AFRL/Propulsion Directorate at Wright-Patterson Air Force Base

39 TSI Incorporated Copyright© 2008 TSI Incorporated PDPA Measurements in Supersonic Wind Tunnel (Jet in Crossflow) Mach 1.94 d 0 =0.5 mm q 0 =7 GLR=5% x/d 0 =200 Lin, K.-C., Kennedy, P.J., Jackson, T.A., “Structures of Water Jets in a Mach 1.94 Supersonic Crossflow,” AIAA Paper , January This work was sponsored by AFRL/Propulsion Directorate at Wright-Patterson Air Force Base

40 TSI Incorporated Copyright© 2008 TSI Incorporated PDPA Measurement of a Spray in an Acoustic Field Courtesy Prof. R.I.Sujith and K. Gurubaran, Dept. of Aerospace Engineering, IIT-Madras, India See AIAA paper for more details. Water Spray Dual Speakers Resonance Chamber

41 TSI Incorporated Copyright© 2008 TSI Incorporated PDPA Measurements in a Lean Low-NOx Aircraft Combustor Courtesy of Jonathan Colby and Georgia Institute of Technology SMD with Combustion Lean Low NOx Combustor (GE CFM 56 Engine)

42 TSI Incorporated Copyright© 2008 TSI Incorporated Fuel Rate = 0.75g/s Eq. Ratio = 0.4 Tair = 380K Twall = 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 Combustor

43 TSI Incorporated Copyright© 2008 TSI Incorporated PDPA Measurements in Hurricane NOAA research aircraft N43RF Courtesy of Prof. Bill Asher and Trina Litchendorf, APL, Univ of Washington Hurricane Jeanne 9/25/04

44 TSI Incorporated Copyright© 2008 TSI Incorporated Nasal Inhaler Spray Measurements Measurements were made in externally triggered mode 100ms200ms300ms400ms Time-averaged diameter

45 TSI Incorporated Copyright© 2008 TSI Incorporated Transient Measurements When an electronically triggered device is being measured, it is often interesting to look at time histories. You can use the “Sync Pulse” 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 Comments Use of a Traverse It is easy to create and run scans through the flow, with the Traverse GUI in FlowSizer. Scans can be saved, and edited in Excel.

46 TSI Incorporated Copyright© 2008 TSI Incorporated Conclusions 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


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