© 2010, TSI Incorporated Global Sizing Velocimetry (GSV)

© 2010, TSI Incorporated

Global Sizing Velocimetry (GSV)


Global Sizing Velocimetry System


GSV System

• The system includes – Optical and mechanical components and – INSIGHT 3G GSV module

• For Global measurement of Size and VelocitySize and Velocity of spray droplets– Add GSV system components to a single camera PIV

system


Uniqueness of the GSV system

• InstantaneousInstantaneous Global measurements– Simultaneous droplet size and velocity measurements

• OptimalOptimal signal collection angle – Measures droplets of different refractive indices– Measures droplets with different characteristics

–

• GSV System can measure in wide rangewide range of test conditions– inhomogeneous droplets, reacting or burning droplets, and

droplets of unknown refractive index

• Simple and easy extension of a SINGLESINGLE camera PIV system– To measure size and velocity simultaneously


Uniqueness of the GSV system

• OptimalOptimal optical and image capture arrangement – Using a slit aperture allows maximum droplet concentration

• UniqueUnique processing algorithms – PM Windowed Algorithm for fringe analysis and velocity

tracking

• GSV system can be used with all POWERVIEW PlusPOWERVIEW Plus family of cameras

• SimultaneousSimultaneous display of size and velocity vector field

• CorrelationCorrelation of size and velocity


Spray Analysis

Global Spray Analysis Global Spray Analysis and Geometrical and Geometrical

PatternationPatternation

Macro analysis Macro analysis of spraysof sprays

Micro analysis Micro analysis of spraysof sprays

Global Sizing Global Sizing Velocimetry SystemVelocimetry System

GSVGSV


Application

• Detailed Spray Diagnostics

• Global velocity to global size and velocity measurements– Easy add on with the GSV system

• The complete system (PIV and GSV) – Capable for Spray patternation for dense spray– Macro and Micro diagnostics of sprays

• Expand to do other global measurements– PLIF for combustion analysis– Scalar property measurements


Features

• A global imaging system – To measure droplet size and velocity simultaneouslysimultaneously

• Employs – Generalized Scattering Imaging (GSI) approach based on

the Lorenz-Mie theory and the Finely Stratified Sphere Scattering Model for droplet size

• Applicable to – Both homogenous and inhomogenoushomogenous and inhomogenous (absorbing) droplets

with varying refractive index• Extension of a PIV system

– GSV system is an add onan add on to a complete PIV system


Principle for GSV system

• Light scattered by droplets – Characterized by strong angular oscillations

• Oscillation Pattern generates uniform angular spacing– Spacing - inversely proportional to the droplet diameter

• Defocused imaging provides– Angular spacing (sizing) information

• Image pairs with known time separation– Provides velocity measurement


Characteristics of the GSV system

• Optimum Orientation (60 deg collection angle)– For imaging of the oscillation spacing– Insensitive to change in refractive index – Provides highest visibility signals

• Use of a slit aperture to capture images – Generates narrow string image pattern – Reduces overlap of oscillation pattern – And increases the measured number concentration of the droplets

–

• Captures pairs of consecutive images – Operates as a PIV system to measure velocity

• Magnification obtained from calibration


PPOWEROWERVVIEW IEW CameraCamera

Slit apertureSlit aperture LensLens

Pulsed laserPulsed laserLight sheetLight sheet

Liquid sprayLiquid spray

System Configuration


Principle of Interferometric Oscillation


Image capture through the slit aperture

1-D Intensity profiles1-D Intensity profiles


Vertical scan

Burst detection

Freq analysis

GSV - PM Sizing Algorithm


Particle Identification in Two framesIPS Tracking: press mouse to start individual match; press keyboard to quit.

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IPS Tracking: press mouse to start individual match; press keyboard to quit.

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Velocity Measurement

• Two-frame tracking algorithm

• Uses both Size and Position – to match particles from the two image frames


GSV – Size measurements


Compensation for camera orientation

200 400 600 800 1000 1200 1400 16000.8

0.9

1

1.1

1.2

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mal

ized

siz

e

Position (pixel)

before correctionafter correction


Distribution of Measured Droplets


Measured Diameter Histograms

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0.1B

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0.1D

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0.1E

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0.1F

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0.1G

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Measured Diameter Histograms


Droplet distributionVariation with atomization pressure

Large droplet

Small droplet

Pan et. al (2005)


GSV – Spray Diagnostics

A

I

F


Velocity Distribution


Size-Velocity Correlation


GSV System

• InstantaneousInstantaneous Global measurements– Simultaneous droplet size and velocity measurements

• GSV System can measure in wide rangewide range of test conditions– inhomogeneous droplets, reacting or burning droplets, and

droplets of unknown refractive index

• Simple and easy extension of a SINGLESINGLE camera PIV system– To measure size and velocity simultaneously

© 2010, TSI Incorporated Global Sizing Velocimetry (GSV)

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