A SPECTROSCOPIC STUDY OF DISCHARGE SPECIES …mipse.umich.edu/files/MIPSE_GS2018_Engeling.pdf · O...

A SPECTROSCOPIC STUDY OF

DISCHARGE SPECIES PRODUCED IN

A PACKED BED DIELECTRIC

BARRIER DISCHARGE

Kenneth W. Engelinga, Maria C. Garciab, Juliusz

Kruszelnickia, Mark J. Kushnera, and John E. Fostera

[email protected], [email protected],

[email protected], [email protected], and

[email protected]

a)University of Michigan, Ann Arbor, MI, USAb)University of Cordoba, Cordoba, Spain

9th Annual MIPSE Graduate Symposium

*Work supported by the National Science Foundation and the DOE

Office of Fusion Energy Science

THE IMPORTANCE OF MICROPLASMAS

Spectroscopic Species and Packed Bed Reactors (PBRs)

• Non-thermal plasma production and propagation

• What are the reaction kinetic mechanisms?

• What surface properties enhance or limit plasma production in

microporous media?

• What variables are available to augment the plasma properties?

• Will the atmospheric plasma non-thermally interact with aggregate media?

Will they have non-destructive effects?

• How does surface morphology effect behavior and propagation (e.g.

catalysis, seeds)?

Micro-plasmas have the potential to advance chemical processing.

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University of Michigan

Institute for Plasma Science & Engr.

PACKED BED REACTOR DISCHARGES

• Introduction to PBRs

• Rod and mesh or film electrodes

• Dielectric aggregate of varying size, shape, and material

• Gas flow ports – feedstock gases, pollutants

• Various power sources (DC, AC, RF, pulsed)

• Applications

• Ozone generation

• Pollutant mitigation

• Dry-reforming of CH4

• Water reclamation

Seed as aggregate

Mesh ElectrodePlasma formation

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DETAILED APPROACH

• To visualize plasma propagation in PBRs, a 2D cell

investigation was developed

• 2D minimizes overlapping plasmas components and

optical analysis vs. 3D

• Time-resolved optical emission spectroscopy analysis

with ICCD camera and spectrometer

• Monitor electron energetics

• Investigate modes for dielectric-to-dielectric

plasma propagation

• Structured and randomly placed aggregate

• Modeling

• nonPDPSIM, ANSYS:Maxwell EM solver

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EFFECT OF DIELECTRICS

Dielectrics locally enhance the

electric field

Manipulation of media allows

for varying discharge

characteristics

Highest enhancement at

closest dielectric-dielectric

contact points

E/N scales with dielectric

constant

5 mm

ε/εo (26.6)

ε/εo (3.8)

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2D EXPERIMENTAL SETUP

• Nanosecond, pulsed

discharge: 20 kV

• Gas Parameters

• Room air composition

• 760 Torr

• ICCD image capture

• 10 Hz, 100 Hz

• Pulse Delay Generator

Timing

• Zirconia• ε/εo = (26.6)

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PREVIOUS EXPERIMENTAL FINDINGS

• Filamentary Microstreamers

(FM) to Surface Ionization

Waves (SIWs) to FMs as

plasma propagates in

different modes through PBR

• Discharges influenced by

strength of dielectric material

• Quartz and zirconia materials

studied

• Plasma localized at interstitial

locations and surfaces of

dielectric aggregate

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Model, nonPDPSIM

Experiment

1 ms, integrated

OPTICAL EMISSION SPECTROSCOPY

8

• Provides insight into the plasma

• Species produced

• Plasma properties

300 400 500 600 700 800

0

10000

20000

30000

Cu I, Mo I

Zone 1

Second Order

N2+ (1st neg)

N2 (2nd pos)

Gate Delay = 74 ns

Gate Width = 10 ns

gates/Exp = 1000

Acc = 1

I (a

.u.)

(nm)

• Investigations focused on

N2 (337 nm) emission

• Pi-Max3 Acton Spectrometer

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• Position (1)

• Placement between disks 1 and 2

• Data taken at 10 Hz, 100 Hz

• 4x Magnification of time-resolved imaging

• Tgas ≈ 345 K

9

0 20 40 60 80 100 120 140 160 180 200

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Position 1

N2 (337.1 nm)

10 Hz

100 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)

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0 20 40 60 80 100 120 140 160 180 200

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Position 1

N2 (337.1 nm)

10 Hz

100 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)

TIME-RESOLVED IMAGES: POSITION 1, 10 Hz

10

• 10 Hz

• 20 kV, 120 ns

pulse width

• 5 ns exposure

• 4x mag.

a) b) c) d)

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0 20 40 60 80 100 120 140 160 180 200

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Position 1

N2 (337.1 nm)

10 Hz

100 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)


11

• 100 Hz

• 20 kV, 120 ns

pulse width

• 5 ns exposure

• 4x mag.

a) b) c) d)

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0 20 40 60 80 100 120 140 160 180 200

0.00

0.02

0.04

0.06

0.08

0.10

0.12

POS 2 10 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)


• Position (2)

• Placement between disks 2 and 3

• Data taken at 10 Hz


• Tgas ≈ 345 K

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0 20 40 60 80 100 120 140 160 180 200

0.00

0.02

0.04

0.06

0.08

0.10

0.12

POS 2 10 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)

• 10 Hz

• 20 kV, 120 ns

pulse width

• 5 ns exposure

• 4x mag.

13


a) b) c) d)

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0 20 40 60 80 100 120 140 160 180 200

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

POS 3

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

10 Hz

I (a

.u.)

Time Delay (ns)


• Position (3)

• Placement between disk 3 and planar electrode

• Data taken at 10 Hz


• Tgas ≈ 345 K

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0 20 40 60 80 100 120 140 160 180 200

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

POS 3

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

10 Hz

I (a

.u.)

Time Delay (ns)

• 10 Hz

• 20 kV, 120 ns

pulse width

• 5 ns exposure

• 4x mag.

15

pla

nar e

lectro

de

a) b) c) d)


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COMPARISON WITH MODEL

16

• Model (nonPDPSIM) predicts FM to SIW transition.

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0 20 40 60 80 100 120 140 160 180 200

0.0

0.2

0.4

0.6

0.8

1.0

1.2 POS 1

POS 2

POS 3

10 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)0 50 100 150 200

0.0

0.2

0.4

0.6

0.8

1.0

Normalized at max

10 Hz

GWidth= 10 ns

GDelay changing

Gates/exp = 1000

Acc = 1

I (a

.u.)

Time Delay (ns)

POS1

POS2

POS3

SUMMARY OF EMISSION vs POSITIONS

17

a) b)

• Intensity increases as discharge propagates through

PBR

• Evidence of restrike (double maximum)

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12

3

45

67

t = 0-5 ns t = 5-10 ns t = 10-15

nst = 15-20

ns

t = 20-25 ns t = 25-30 ns t = 30-35 ns t = 35-40

ns

5 mm

EOverall E-field

Direction

1

2

3

4

5

6

7

6 mm

ZIRCONIA: DISCHARGE PROPAGATION

THROUGH PBR

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• Explains time differences

in emission spectrum

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CONCLUDING REMARKS

• Evidence of restrikes seen with N2

• Double maximum in emission spectra

• N2 (337.1 nm) peak emission intensity was dependent upon location for this geometry

• Emission peaks at each location at some point in time showing the plasma propagation through the cell

• Likely tracking the density of electrons with energy above the excitation threshold

• Future Investigations:

• Active interrogation to find atomic N populations

• Expand the N2 emission study

• Compare emission spectrum with that using materials of various dielectric strengths

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QUESTIONS

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ADDITIONAL SLIDES

19Topic

270 275 280 285 290 295 300

0

500

1000

1500

2000

2500

3000

293.65 Mo I

289.96 Cu I291.53 Mo I

280.57 Cu I

280.98 Cu I

281.27 Cu I

281.36 Cu I

276.26 Cu I

276.30 Mo I

Cu I

N2 (2nd pos) 297.68 nm

Gate Delay = 74 ns GWidth = 10 ns

Gates/exp = 1000

Acc: 1

I (a

.u.)

(nm)

300 320 340 360

0

5000

10000

15000

20000

25000

30000

35000

346.07 Mo I

348.16 Cu I

N2 (2nd pos) 333.90 nm

317.16 Cu I

317.56 Cu I

319.27 Mo I

322.34 Cu I

324.31 Cu I

and many others

308.25 Cu I

308.04 Mo I

309.39 Cu I

310.13 Mo I

N2 (2nd pos)

350.05 nm

353.67 nm

357.60 nmN2 (2nd pos) 311.67 nm, 313.60 nm, 315.93 nm

N2 (2nd pos) 337.13 nm

Gate Delay = 74 nsGWidth = 10 ns

Gates/exp = 1000

Acc: 1

I (a

.u.)

(nm)

360 380 400 420

0

1000

2000

3000

4000

5000

6000

7000

N2+ (1st neg)

385.79nm

391.44 nm

N2 (2nd pos)

394.30 nm,

399.84 nm,

405.94 nm

N2 (2nd pos)

394.30 nm, 399.84 nm,

405.94 nm

N2 (2nd pos)

371.05 nm, 375.54 nm, 380.49 nm

Mo I

Gate Delay = 74 ns GWidth = 10 ns

Gates/exp = 1000

Acc: 1

I (a

.u.)

(nm)

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ADDITIONAL SLIDES

19

0 50 100 150 200

280

300

320

340

360

380

400

10 Hz

POS 1

Tg

as (

K)

Time Delay (ns)

0 50 100 150 200

290

300

310

320

330

340

350

360POS 2

10 Hz

T

gas (

K)

Time Delay (ns)

20 40 60 80 100

280

300

320

340

360

380

400

420

10 Hz

POS 3

Tg

as (

K)

Time Delay (ns)

MIPSE_2018



A SPECTROSCOPIC STUDY OF DISCHARGE SPECIES …mipse.umich.edu/files/MIPSE_GS2018_Engeling.pdf · O...

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