Velocity measurements of Sprays

En’Urga Inc.1201 Cumberland Ave., West Lafayette, IN 47906

Background

Several instruments available on the market

Single point measurements obtained using LDV, PDA, hot wire anemometry

For planar velocities, PIV is the most commonly used instrument (requires capture of images of

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1201 Cumberland Avenue, West Lafayette, IN 47906

used instrument (requires capture of images of individual particles)

Image correlation velocimetry does not require resolution of individual particles, but requires distinct patterns

Basic Arrangement

High speed camera

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1201 Cumberland Avenue, West Lafayette, IN 47906

Uniform background light

High speed camera

Spray

An Overview of Process Flow

Install camera with diffuse light source

Configure camera f-stop and focus

Calibrate millimeters to pixels conversion

Record reference frames with no spray

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1201 Cumberland Avenue, West Lafayette, IN 47906

Record reference frames with no spray

Configure settings in SPIV

Processing and post-processing

Statistical Pattern Imaging Velocimetry

Does not rely on capturing individual particles or distinct patterns

Requires large ensemble of images

Computes statistical correlation between patterns over the entire pixel range

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1201 Cumberland Avenue, West Lafayette, IN 47906

patterns over the entire pixel range

Image correlation velocimetry does not require resolution of individual particles

Sample Results (GDI Injector)

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1201 Cumberland Avenue, West Lafayette, IN 47906

Full Flow Field Mean Axial Velocity of GDI Injector

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1201 Cumberland Avenue, West Lafayette, IN 47906

Comparison of our SPIV with PDA

0

25

50

75

100

50

75

100

20 MPa, PDA 20 MPa, SPIV 12 MPa, SPIV 12 MPa, PDA 12 MPa, CFD

x = 5 mm

Axia

l ve

locity (m

/s)

x = 30 mm

GDI injector

PDA fails near injector due to high obscuration

10000 Hz camera

Good agreement at

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1201 Cumberland Avenue, West Lafayette, IN 47906

0 5 10 15 20 25 30 35

0

20

40

60

80

0

25

x = 50 mm

Distance (mm)

Axia

l ve

locity (m

/s)

Good agreement at lower positions

Full planar axial velocity available

Example results with low spray opacity

Raw DataProcessed Velocimetry Results

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1201 Cumberland Avenue, West Lafayette, IN 47906

Signal to noise of 1.1

Example results ensemble averaging 4ms spray bursts

E = 5 eventsE = 1 events

E = 10 events E = 30 events

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1201 Cumberland Avenue, West Lafayette, IN 47906

E = 10 events E = 30 events

Questions?

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1201 Cumberland Avenue, West Lafayette, IN 47906