quantitative estimation of heat flux of atmospheric pressure plasma jet

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Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet Radiation Research Center, Osaka Prefecture University Hiroto Matsuura IC-PLANTS 2012 (2012/3/9 Inuya ma)

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Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet. IC-PLANTS 2012 ( 2012/3/ 9 、 Inuyama). Radiation Research Center, Osaka Prefecture University Hiroto Matsuura. Background. - PowerPoint PPT Presentation

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Page 1: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Radiation Research Center, Osaka Prefecture University

Hiroto Matsuura

IC-PLANTS 2012(2012/3/9 、 Inuyama)

Page 2: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Background

Atmospheric pressure plasma is now attractive for decontamination of environmental waste and medical technology, because of

low cast without vacuum pumping systemapplicability for biomaterial that does notis less tolerate vacuumlarge process speed

Although many production methods have been proposed, parameters of plasma produced with them are not well studied.

Electro static probe method has been widely used for low pressure discharge plasma. And even for Atmospheric pressure plasma, some literature reported its application as following.

O.Sakai et al.: J.Phys. D: Appl. Phys, 38, 431(2005).M.R.Talukder et al.: J.Appl.phys., 91, 9529(2002).H.Matsuura, et al.:AIP conf. Proc., 1084, 871(2008).

Key issue is the choice of probe tip material which tolerate plasma heat loadand analysis of I-V characteristic with collisional sheath effect.

Page 3: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

How about heat flux measurement?

http://www.jsap.or.jp/ap/2008/ob7704/cont7704.html

http://www.maximizingprogress.org/2010/02/plasma-medicine-disinfection.html

http://www.drexel.edu/research/img/mri_plasma.jpg

New J. Phys. 11 (2009) 115012

Are these guys insensitive?

Page 4: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Atmospheric Pressure Plasma Jet

Power supplyLHV-13AC(Logy Electric Co.LTD.) Input AC100V/2A Output 10KV/120mA RMS 9 ~ 12KHz Size 140×92×175 Weight 1.4kg

Page 5: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Plasma heat flux• Electron

positive bias• Ion

Negative bias• Metastable atom

Atmospheric He/Ar• Radical

Atmospheric N2/O2

• Surface recombination• Surface condensation

Is it possible to decompose these contribution? with bias? Tip material?

Page 6: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Measurement of target heat flux

Heat flux determination

Type-T TC Temperature gradient methodType-K TC Fitting/cut method

Electrically isolated

Easy to modify for Q-V characteristic

Material: Cu, Mo

Page 7: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Heat flux measurement

Page 8: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Reduction of TC noise

0 1000 2000 300010

20

30LF plasma(2011/12/22)

time[s]

Tem

p.[d

eg.C

]

During discharge, TC signal shows large fluctuations inspit of large thermal diffusion time. electro-magnetic noise? movement of jet column?

HR2500E Chart

Data aqusition with NI9211 and averagingDischarge control( flow, power, distance)

Relatively smooth TC signal is obtained.

Page 9: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Estimation of heat flux(Fitting)

0

4

8

12

16

20

1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

TC(center)

time[s]

TC[deg.]

Estimation with exponential fitting Q ( ~dT/t) = 0.5 [W]

12

4

0

0.5 0.17

Target moved

Heat flux depends upon measurement position.

dTdecay time t is obtained by fitting.

Page 10: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Estimation of heat flux(Cut)

0

2

4

6

0 500 1000 1500 2000 2500 3000

TC(center)

t ime[s]

TC[deg.]

0

2

4

6

2100 2200 2300 2400 2500 2600 2700 2800 2900 3000

TC(center)

time[s ]

TC[deg.]

Estimation with discharge cut Q ( ~jump of dT/dt) = 0.2 [W]

before

after

Page 11: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Effect on TC raw data of target bias

0 2000 400012

16

20

LF plasma(2012/2/14)

time[s]

Tar

get T

emp.

[deg

.C]

Although data is limited andAlthough data is limited and

Although data is limited, TC signal seems to depend upon bias voltage applied to target.

At positive bias, traget current becomes negative and TC signal shows large fluctuation.

Although discharge itself might be changed with biasing, positive bias seems to reduce heat flux.(Ion, surface reaction?)

Page 12: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Consideration

• If heat flux of 0.5W is composited only electron and ion contribution, particle flux ( equivalently 50mA ) must be flowed into the target depending on bias voltage. But by now, such a large current has not been observed.

• For previous work on DC discharge, electron saturation current of 1mA was observed with a small probe.

Page 13: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

DC atmospheric plasma data

With J.S.Chang's procedure, plasma density is about 1e17[m-3] for Ies=1[mA].

Page 14: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Consideration 2

• Heat from atmospheric plasma seems to be carried by mainly metastable or radical.( Different Q-V curve ?)

• To confirm this, plasma current must be measured preciously. But, since plasma jet is composed of so many micro plasma bullet, current measurement needs to some integration procedure to compare with heat flux measurement.

Page 15: Quantitative Estimation of Heat Flux of Atmospheric Pressure Plasma Jet

Conclusion

• Heat flux from atmospheric plasma jet was measured with target TC data and thermal probe analysis, as like as for low pressure plasma.

• Considering heat flux value and its response to bias, heat flux contribution from charged particles seems small.

• Present plasma jet has smaller density compared with DC discharge.