Sim Lizh1Kei1-9-5 Abstinvolflowsbreakvariabeen generspecikindsradicare cis siprovipropeobtaivariabubb KeywPlasm 1. In

mentsomestudielectrpollusurfabiomsynthsolut

presestudilargephasemodeair or[6-9]dischbecomperfoor plbubb

prope

mulation

hu Tong1 isoku Engine5 Uchikanda

tract: The plve various ps agitated by bkdown, dischaation, and so o

made on rated in bubblies taken in acs of ions, and cal, excited) sonsidered. Th

imulated usinided in COMSerties during tined. The effation in bubbble size on disc

words: Gas Bma, Moving B

ntroduction

Electrical dists and in lique cases also ied for a numbrical transmis

ution control, ace treatmen

medical treatmhesis, and ctions [1]. Discharges d

ented an inteies and potene surface areae for ease of del simulationsr injected gas ]. Since the harge, the plmes complica

ormed only folasma propert

ble size [8,9]. In this work, erties are cou

of the Pl

ering Systema, Chiyoda-ku

plasmas genephysical phenbubbles, high arges in bubbon. In this pathe simulati

les with the siccount includten kinds of n

species. 43 chhe time evoluting the movinSOL Multiphythe variation iffect of the dble size andcharge propert

Bubble, AtmoBoundary.

charges in gauids (primari

organic liquber of years fossion, chemic

chemical synt, biologica

ment, material chemical ana

directly insideresting case ntial applicat

as and the predischarge initias for dischargin bubbles ha

bubble sizelasma simulaated. Until nowor either bubblties ignoring

bubble dynaupled into a

asma Ge

m Co., Ltd. u, Tokyo 101

erated in wnomena suchelectric fields

bles with the saper, studies hion of plasmize variation. Te electrons, th

neutral (molechemical reactiion of bubble sng mesh metysics. The plasin bubble size duration for

d the maximties is examine

ospheric Press

as-liquid envirly water, butuids) have bor applicational destruction

ynthesis, polymal inactivatiand nanopart

alysis of liq

de bubbles hfor fundame

tions becauseesence of the ation [2-5]. So

ges within humave been repore varies dur

ation in bubbw the studies le dynamics [6the variation

amics and plasone-dimensio

enerated i

1-0047, Japan

ater h as s for size

have mas The hree cule, ions size thod sma are the

mum ed.

sure

ron-t in

been ns in n in mer ion, ticle quid

have ntal of gas

ome mid rted ring bles are

6,7] n in

sma onal

(aCpd

2

pavpsinvoinHaimsino

gpRd

win

A

in a Gas B

n, tong@kesc

1-D) bubble pand the moviCOMSOL Muproperties witdiscussed.

2. Numerical

Figure 1. Sch

The simuplasma modelatmospheric pvaried from 1 tprevious reseatudy is made n bubble rad

variation in buor 2.4 ms. Thenclude the io

H2O, H, OH, Has well as elempact collisiopecies are lnformation fo

our previous w1-D bubb

generated in bpower supplieRb are used. discharge curre

where V= - 1 kn this work.

The movArbitrary Lang

Bubble

co.co.jp

plasma model.ing mesh tecultiphysics arthin bubbles

l Model

hematic of 1-D b

ulations are pl in a 100%pressure. Theto 8.5 mm, wharch on bubblfor the first p

dius [6,7]. Thubble radius ise plasma spec

ons: H2O+, O2

H2, O(1D), O,ectrons. The ron and those isted in Tabr plasma mod

work [13,14]. ble plasma mobubbles is shod voltage V aVdc is discharent density. Vd

,

kV, Rb = 10 k

ving mesh tegrangian Eule

. The plasma chnique provie used. The

are presente

bubble plasma m

performed usin%H2O gas bub

e bubble radhich is taken fre dynamics [eriod of the vhe duration s chosen = 0cies taken in a2+, H2

+, the n, O2, O3, HO2

reactions of eof ions and

ble 1. The ddeling can be f

odel for the pown in Fig. 1and a ballast rge voltage adc is solved by

k. A is set 0

echnique, namerian (ALE) m

module ided in plasma

ed and

model.

ng 1-D bble at dius is

from the 7]. The ariation for the

0.8, 1.6, account

neutrals: 2, H2O2, electron neutral

detailed found in

plasmas 1. A dc resistor

and j is

(1)

.03 cm2

med as method,

Excerpt from the Proceedings of the 2013 COMSOL Conference in Boston

is use

Table

No.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

ed to trace the

e 1: The chemic

Reaction e− +H2O→ e−

e− +H2O→ e−

e− +H2O→ e−

e− +H2O→ 2ee− +H2→ e−

+

e− +H2→ e− +

e− +H2→ 2e−

e− +O2→ e− +

e− +O2→ e− +

e− +O2→ e−

+

e− +O2→ 2e−

e− +O→ e−

+

O(1D) → O 2O + O2 → OO + 2O2 → OH +O + H2 →H +O + H2O H +O2+ H2 →H +O2+ O2 →H +O2+ H2O H +OH+ H2 →H +OH+ O2 →H +O3 → OHH +O3 → O +H +HO2→H2

H +HO2→O2

H +HO2→ 2OO +O(1D)→ 2O(1D) +H2→O(1D) +O2→O(1D) +O3→O(1D) +O3→O(1D) +OH→O +HO2→OHO(1D) +HO2→O(1D) +H2O2

O(1D) +H2O→O(1D) +H2O→OH +O3→HO2OH →H2O2

OH +HO2→OOH +H2O2→2HO2 →H2O

e variation in s

cal reactions inc

− + H2O

− +

H+ OH

− + H2+ O(1D)

e− + H2O

+ + H2 + H + H + H2

+ + O2 + O + O + O + O(1D) + O2

+ O(1D)

O3 +O O3 +O2 → OH +H2 → OH +H2O

→ HO2 +H2 → HO2 +O2 →HO2 +H2O→H2O +H2 →H2O +O2

H +O2 + HO2

2O +O

2 +H2

OH 2O

→OH +H →O+ O2 →2O2 →2O + O2 → H+ O2 H +O2 →OH +O2

2→H2O +O2 → O +H2O → H2 +O2 O2 +O2

2 O2 +H2O

→ H2O +HO2

2+ O2

solved domain

cluded in the mo

Ref.

O

10 10 10 10 10 10 10 11 11 11 11 11 12 12 12 12

12 12

12 12

12 12 12 12 12 12

12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12

n.

odel.

Tiacrfracomcb

3

Fe

The method enan and Langra

capture the gresolution [15]

frames: a refera 1-D formulacoordinate. Thordinates whilemoving withconditions. Thby solving the

0.

3. Results

Figure 2. Electrelectric potential

njoys the advaangian frames eater deforma]. ALE methorence frame wation and a she reference e the spatial fr

h time, subhe mesh displfollowing equ

.

ron density, elel at the differen

antages of both of reference a

ation with theod comprises

with X coordinspatial frame frame has fix

frame has coorbject to bolacement is ouation

ectron temperatnt times for = 1

h Euler-and can

e higher of two

nate for with x

xed co-rdinates oundary obtained

(2)

ture, and 1.6 ms.

Excerpt from the Proceedings of the 2013 COMSOL Conference in Boston

electrdifferis enlsurfams, telectrappeatempcathosusta

The dtwo o

Figure 2 shron temperaturent times for larged, the ele

ace of cathodethe largest bubron density inars a large re

perature is locode during tains the behaviThe density odensities of Horders lower t

Figure 3

hows the eure, and electri = 1.6 ms. A

ectron density e to anode groubble size reachn the neighboreduction. The ated in the rethe whole dior of DC discof H2O

+ ion isH2

+ and O2+ ion

than H2O+, so

O

H2

3. Densities of c

electron densic potential at

As the bubble sextends from unded. At t = hes, in which rhood of cathhighest elect

egion close to discharge, whcharge. shown in Fig

ns are found tothat both are

O2

H2O+

hemical species

sity, the

size m the

0.8 the

hode tron the

hich

g. 3. o be not

pdanbfrospinnspO

s at the differen

presented herdistributions oaspect, i.e., thneighborhood bubble size, thfrom cathode aorders. After tolved domain

production efnside gas bub

noted that OH uch as oxid

pollutants, andOH obtained in

nt times for = 1

re. As showof neutral speche high densof cathode, bhe densities iare dramaticalt = 0.8 ms, dun, the densitiesfficiency of bble has beenradicals play ation, decom

d so on. The dn this work are

O3

H2O2

OH

1.6 ms.

wn in Fig. cies have a csities appear

but as the incrin the regionlly reduced ov

ue to the reducs start to rise uH2O2 for di

n reported [2,4some importa

mposition of densities of H2

e possessed of

3, the ommon in the

rease in n depart ver two ction of up. The scharge 4]. It is ant roles, organic 2O2 and f a high

Excerpt from the Proceedings of the 2013 COMSOL Conference in Boston

Figur= 0.8

Figurthe va = 1.

re 4. Electron dand 2.4 ms.

re 5. Electron ariations of bub.6 ms.

density at the d

density at the bble radius: 1~4

Radius: 1~

Radius: 1~

= 2

= 0

different times f

different times.8 and 1~6.7 mm

~6.7 mm

~4.8 mm

2.4 ms

0.8 ms

for

s for m at

leOnpbinOc

foTlotithioinvTmththin

4

gMisssbm

me

5

1PLW

2pcpP

3titr3

evel values, aO3 is found toneutral specieprevious reseabeen reported ncrease of H2O

O3 presentsconcentration r

Figure 4 for the variatioThe electron dower than thaime of small bhat longer onizations soncreased at

variations in bThe bubble ramm. As the redhe electron dehe bulk of disn the region fa

4. Conclusion

The simulagas bubbleMultiphysics 4s coupled foimulation. Thpecies, such a

beneficial to mmental applica

The presenmethod to stuespecially in w

5. Reference

1. V.I. ParvulPlasma ChemiLiquids, WileWeinheim, Ge

2. K.Y. Shih, protrusion lengconductivity apulsed electricPolym., 6 (11),

3. K. Yasuoka,ive pulsed plreatment”, Int

3 (1), 22-27 (2

as shown in Fo be five ordes, which isarches, e.g., thto be dramatiO concentratioa very low rises up to onlshows the res

on in bubble sidensity at =at at = 2.4 mbubble size. T

discharge to that the = 2.4 ms. The

bubble radius adius varies wduction of maensity becomecharge. The dar from cathod

ns

ation of the pis performed

4.3a. The movfor the first he obtained das OH, H2O2,

many further reations. nt research pdy plasmas g

water.

s

lescu, M. Maistry and Cat

ey-VCH Verlermany (2012)

B.R. Locke, gth, pre-existiand temperatucal discharge, 729–740 (20

, K. Sato, “Delasmas in gat. J. Plasma En009).

ig. 3. The deners lower thas similar tohe density of ically reducedon and the den

value whenly 6% [9]. sults for the dize of 0.8 and

= 0.8 ms is dims, especially

This could be dtimes cause electron dene results for dare given in

with 1~4.8 andximum bubble

es relative unidamping phenode is remitted.

lasma generatd using COving mesh tec

time with densities of ch

and so on, wesearches on e

provides an egenerated in b

agureanu, P. talysis in Gaslag & Co. .

“Effects of eling bubbles, sure, on liquide”, Plasma P09).

evelopment ofs bubbles fornviron. Sci. Te

nsity of an other o some

O3 has d as the nsity of n H2O

duration 2.4 ms.

istinctly for the

deduced more

nsity is different

Fig. 5. d 1~6.7 e radius, form in omenon

ted in a OMSOL chnique plasma

hemical would be environ-

efficient bubbles,

Lukes, ses and KGaA,

lectrode solution d phase Process.

f repeti-r water echnol.,

Excerpt from the Proceedings of the 2013 COMSOL Conference in Boston

4. L. Němcová, A. Nikiforov, C. Leys, F. Krcma, “Chemical efficiency of H2O2 production and decomposition of organic compounds under action of DC underwater discharge in gas bubbles”, IEEE Trans. Plasma Sci., 39 (3), 865-870 (2011).

5. M. Kurahashi, S. Katsura, A. Mizuno, “Radical formation due to discharge inside bubble in liquid”, J. Electrostatics, 42, 93-105, (1997).

6. J.A. Cook, A.M. Gleeson, R.M. Roberts, “A spark-generated bubble model with semi-empirical mass transport”, J. Acoust. Soc. Am., 101 (4), 1908-1920 (1997).

7. X.P. Lu, “One-dimensional bubble model of pulsed discharge in water”, J. Appl. Phys., 102, 063302(4pp) (2007).

8. N.Y. Babaeva, M.J. Kushner, “Structure of positive streamers inside gaseous bubbles immersed in liquids”, J. Phys. D: Appl. Phys., 42, 132003 (5pp) (2009).

9. N. Takeuchi, Y. Ishii, K. Yasuoka, “Modelling chemical reactions in dc plasma inside oxygen

bubbles in water”, Plasma Sources Sci. Technol., 21, 015006 (8pp) (2012).

10. LXcat, http://www.lxcat.laplace.univ-tlse.fr

11. COMSOL Multiphysics 4.3a- Model library for Plasma Module.

12. D.X. Liu, P. Bruggeman, F. Iza, M.Z. Rong, M.G. Kong, “Global model of low-temperature atmospheric-pressure He+H2O plasmas”, Plasma Sources Sci. Technol. 19 (2), 025018 (2010).

13. L.Z. Tong, “Effect of gas flow rate and gas composition in Ar/CH4 inductively coupled plasmas”, COMSOL Conference 2011 Boston, USA (2011).

14. L.Z. Tong, “Numerical study of the effect of gas flow in low pressure inductively coupled Ar/N2 plasmas”, Central European Journal of Physics 10 (4), 888-897 (2012).

15. K.B. Deshpande, “Validated numerical modelling of galvanic corrosion for couples: Magnesium alloy (AE44)–mild steel and AE44–aluminium alloy (AA6063) in brine solution”, Corrosion Sci. 52, 3514–3522 (2010).

Excerpt from the Proceedings of the 2013 COMSOL Conference in Boston