effect of dissolve gas on luminescent spots induced by a cavitating jet

1Intelligent Sensing of Materials Lab., Department of Nanomechanics

Effect of Dissolve Gas on Luminescent Spots Induced by a Cavitating Jet

Hitoshi SOYAMA Department of Nanomechanics

Tohoku University

Flow

8th International Symposium on CavitationAugust 14 – 16, 2012, Singapore

Flow


Erosion Surface Modification

Cavitation PeeningCP

Shot Peening

Impact at Cavitation Bubble CollapseImpact at Cavitation Bubble Collapse

Cavitation Peening

H.Soyama and Y.Sekine, International Journal of Sustainable Engineering, Vol. 3, No. 1 (2010), pp. 25-32.

H.Soyama et al., Surface & Coatings Technology, Vol. 205 (2011), pp. 3167-3174.

-600

-400

-200

0

200

0 100 200 300 400

Res

idua

l str

ess

R

MP

a

Distance from surface z m

Not-peened tp = 0.25 s/mm

0.5

1

2 5

10

20

Introduction of compressive residual stress


Surface of solid Micro jet

NucleiCavitation bubble

Rebound

Shock wave

In water

Plastic deformationHigh speed /Low pressure Decrease of speed

L.A.Crum, J. Pys, C8-285 (1979).

100 374

1

218

Pre

ssu

re

p t

at

m

Temperature tw ℃

BoilingLiquid

Solid

Gas

Cavitatio

n

Hot SpotAdiabatic compression

Establishment of chemical reactor using a cavitating jet

ImpactCavitation peening

Schematic of cavitation bubblesSchematic of cavitation bubbles


Hydrodynamic cavitation andUltrasonic cavitation (Sonochemistry)

11 1010 101033101022 1010440.10.1

101022

101033

101044

101055

101066

101077

1010

11

0.10.1

Non-dimensional electric power to generate cavitation Non-dimensional electric power to generate cavitation

No

n-d

ime

ns

ion

al c

av

itat

ion

imp

ac

t en

erg

yN

on

-dim

en

sio

nal

ca

vit

atio

n im

pa

ct

ene

rgy

Material testing

Impa

ct e

nerg

y =

×F

orce

Impa

ct e

nerg

y =

×F

orce

22 ×O

ccur

renc

e fr

eque

ncy

×O

ccur

renc

e fr

eque

ncy

×100×100

Ultrasonic cleaning

UltrasonicUltrasoniccavitationcavitation

Limit of aggressivity of ultrasonic

Chemical reactorChemical reactorusing cavitationusing cavitation

Original technologyOriginal technologyUS patent No. 6,855,208 B1Japan patent No. 4240972

FlowFlow

FlowFlow

Venturi tubeVenturi tube

Hydrodynamic cavitationHydrodynamic cavitationCavitating jetCavitating jet

ASTM G32

ASTM G134ILS 2010-2013

Material testing


Severe erosive vortex cavitationRing vortex cavitation

Cloud cavitation

Vortex cavitation in shear layer

Impinging surface

Nozzle

High-speed water jet

Schematic diagram of cavitating jet Schematic diagram of cavitating jet

High speed photographHigh speed photographof cavitating jet of cavitating jet taken by Soyamataken by Soyama

WATER

Cavitating JetCavitating Jet H.Soyama ， J. Soc. Mater. Sci., Japan ， 47 (1998), pp. 381-387.


Residual bubbles

Erosion

specimen Cavitation cloud

Nozzle

outlet

View of the cavitation cloud and residual bubbles

0

0.01

0.02

0.03

0.04

8 8.5 9 9.5 10

Retention time t min

Inte

nsit

y V

mV

Room air

CO2

Residual cavitation bubbles

Magnified view of methane CH4 peak

p1= 200 MPa p2 = 0.2 MPa d = 0.35mm

Reduction of carbon dioxideReduction of carbon dioxide H.Soyama and T.Muraoka, Proc.20th Inter. Conf. Water Jetting, (2010), 259-267


H2O → H ・＋ OH ・

H ・＋ OH ・ → H2O

2 H ・ → H2

2 OH ・ → H2O2

2 OH ・ → O ・＋ H2O

2 O ・ → O2

½ O ・＋ 2 H ・ → H2O

O ・＋ H2O → H2O2

0

0.01

0.02

0.03

0.04

8 8.5 9 9.5 10


Inte

nsity

Vm

V

Room air

CO2


0

0.01

0.02

0.03

0.04

8 8.5 9 9.5 10


Inte

nsity

Vm

V

Room air

CO2


0

0.1

0.2

0.3

0.4

1 1.5 2 2.5 3


Inte

nsity

Vm

V

Room air

CO2


0

0.1

0.2

0.3

0.4

1 1.5 2 2.5 3


Inte

nsity

Vm

V

Room air

CO2


CH4

H2

CO2

CO2+4H2→CH4+2H2O

Reduction of carbon dioxideReduction of carbon dioxide

CH4 peak

H2 peak

Effect of Dissolve Gas on Luminescent Spots Induced by a Cavitating Jet

Purpose

Purpose


Pressurized water

Aspect of cavitating jet

Luminescent spots observed by EM-CCD camera

H. Soyama, Luminescent Spots Induced by a Cavitating Jet, Proc. ASME-JSME-KSME Joint Fluids Eng. Conf., (2011), AJK2011-33018.

Cavitation clouds observed by CCD camera with flash lamp

Luminescent Spots Induced by Cavitating JetLuminescent Spots Induced by Cavitating Jet


Experimental Apparatus and Procedures Experimental Apparatus and Procedures

Acoustic noise : Hydrophone (20 kHz ～１ 00 kHz)

High speed video camera

Electron Multiplication Cooled Charged-Coupled Device camera (EM-CCD camera)

Luminescence Analyzer (Photomultiplier Tube) 50 - 108 photons/cm2/s (1 count = 50 photons)

Figure 1: Test loop of cavitating jet

Nozzle

Flow

Flow

Target

ChamberNozzleholder

Specimen holder

Figure 2: Test chamber of cavitating jet apparatus


= 0.005

(a) Overall view (b) Magnified view

0 40 mm

= 0.014

= 0.020

= 0.005

(a) Overall view (b) Magnified view

0 40 mm

= 0.014

= 0.020

Flow

Luminescent Spots Induced by Cavitating JetLuminescent Spots Induced by Cavitating Jet

Figure 4: Luminescent spots of cavitating jet

11

(a) Original images (b) Bth8 = 10 (c) Bth8 = 100 (d) Bth8 = 200Figure 5: Luminescent spot induced by cavitating jet as a function of cavitation number and threshold level (p1 = 30 MPa, Oxygen)

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 0.005 0.01 0.015 0.02 0.025

Cavitation number σ

Bth8 = 10

101

10-1

10-2

100

Area larger than threshold level Ath mm2/s

103

102

50

100

150 200

Figure 6: Effect of threshold level on area ofluminescence spot (p1 = 30 MPa, Oxygen)

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 50 100 150 200 250

Threshold level Bth8

Figure 7: Effect of cavitation number ondistribution of area of luminescence spot (p1 = 30 MPa, Oxygen)

0.016101


102

100

103

= 0.012

0.02

0.008

10-1

10-2

0.005


1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

0 50 100 150 200 250

Ar

101

10-1

10-2


102

100

O2

Air

N2

Threshold level Bth8

Figure 8: Effect of dissolved gas ondistribution of area of luminescence spot (p1 = 30 MPa, = 0.016)

Figure 9: Effect of dissolved gason area of luminescence spot (p1 = 30 MPa, Bth8 = 150)

1.E-02

1.E-01

1.E+00

1.E+01

0 0.005 0.01 0.015 0.02 0.025


AirO2

N2

101

10-1

10-2


100 Ar


0

2

4

6

8

10

0 0.005 0.01 0.015 0.02 0.025Intensity of luminescence CL count/s


×105

Ar

O2Air

N2

Figure 10: Effect of dissolved gas on intensity of luminescence (p1 = 30 MPa)



Figure 11: Effect of dissolved gas on spectrum of luminescence (p1 = 30 MPa)

0

5

10

15

20

25

300 400 500 600 700Wave length λ nm

Intensity of luminescence CL counts

×103

Ar

O2

Air

N2


1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

0 5 10 15 20101

102

104

Threshold level Pth Pa

103

= 0.016

0.007

105

107

106

Acoustic energy EA Pa2/s

0.01

0.022

0.019 0.013

Figure 12 : Pulse height distribution of acoustic energy (p1 = 30 MPa, Air)


1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E+07

0 0.005 0.01 0.015 0.02 0.025101

102

104

Cavitation number

103

105

107

106


Figure 13 : Acoustic energy changing with cavitation number (p1 = 30 MPa, Air)

pth = 1 Pa

3

6

9

12

0

3

6

9

0 0.5 1 1.5 2 2.5



Figure 14 : Correlation between acoustic energy and area of luminescent spot (p1 = 30 MPa, Air)

Approximate line



ConclusionsConclusions

The luminescent spots were observed in the cavitating jet by EM-CCD camera.

The intensity of the luminescence spots was changing with cavitation number, and it had a maximum at certain cavitation number. The optimum cavitation number was the same as that of acoustic energy.

The intensity was changing with the dissolved gas of the water.


Energy of individual impactEnergy of individual impact EEii

EEii = = I Ii i τ τi i AAi i IIii ：： Acoustic energyAcoustic energy

ττii ：： Impact durationImpact duration

A A i i ：： Affective area of each Affective area of each

impactimpactAcoustic energyAcoustic energy IIii

IIii = = P Pii 2 2 ／２／２ ρ ρ C C PPi i ：： Amplitude of pulseAmplitude of pulse

ρρ ：： DensityDensityC C ：： Acoustic speedAcoustic speed

Individual impact forceIndividual impact force FFii

FFii = = P Pii A Ai i

UnknownUnknown ：：PPii ，， ττii

[Assumption[Assumption ］］ PPii ∝∝ FFii

ττii = = constantconstant

EEii== F Fii P Pii ττii ／２／２ ρ ρ CC

ΣΣEEii ∝∝ ΣΣFFii 2 2ΣΣEEii ∝∝ ΣΣFFii

2 2

Measured by Measured by PVDF sensorPVDF sensor

H.Soyama et al., H.Soyama et al., J. Fluids EngJ. Fluids Eng., ., Trans. ASMETrans. ASME, , 120 (1998), pp. 120 (1998), pp. 712-718.712-718.

H.Soyama and H.Kumano, H.Soyama and H.Kumano, J. J. Testing and Testing and EvaluationEvaluation, , 30 (2002), pp. 30 (2002), pp. 421-431.421-431.

effect of dissolve gas on luminescent spots induced by a cavitating jet

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