A new DBD microplasma burner for measuring the effectof nanosecond discharge on burning velocity of CH4-Airflame at atmospheric pressureCitation for published version (APA):Elkholy, A. H. E., Nijdam, S., van Oijen, J. A., & de Goey, L. P. H. (2017). A new DBD microplasma burner formeasuring the effect of nanosecond discharge on burning velocity of CH4-Air flame at atmospheric pressure.Poster session presented at 6th EUCASS Thematic Workshop : Fundamentals of Aerodynamic Flow andCombustion Control by Plasmas, April 9-14, 2017, Saint Petersburg, Russia, Saint Petersburg, RussianFederation.

Document status and date:Published: 01/03/2017

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A new DBD microplasma burner for measuring the effectof nanosecond discharge on burning velocity of CH4/Airflame at atmospheric pressureA. Elkholy†, E. van Veldhuizen‡, S. Nijdam‡, J. van Oijen†, N. Dam† and P. de Goey†

†Department of Mechanical Engineering, Technische Universiteit Eindhoven, The Netherlands,

‡Department of Applied Physics,Technische Universiteit Eindhoven, The Netherlands.

MotivationNon-thermal and low temperature plasmas in air or gas mixturesat atmospheric pressure are very efficient sources of active species(radicals, excited species, charged particles, photons emission, etc.).

Figure 1: DBD microplasma burner

The main objective of this project is toinvestigate the effectiveness of usingnon-thermal plasma to enhance thecombustion characteristics throughthe following :

•Radical and species production•Thermal enhancement• Increasing burning velocity•Reducing emissions

DBD Microplasma Flow ReactorIn this work, we introduce a new geometry to generate a two layers ofa stable non-thermal plasma discharge in a DBD micro-holes structurefor gas flow applications at atmospheric pressure.

(a) P = 1 bar

(b) P = 0.1 bar

Figure 2: DBD microplasma reactor geometry

Experimental SetupThe schematic representation of the experimental setup is shown infigure 3.

Figure 3: Experimental setup

Experimental ResultsElectrical pulse characteristics

• A peak voltage and current of 4kV and 40A have been measured and a pulse energyof 1mJ has been calculated for plasma discharge at atmospheric pressure.

• Two power waves separated by 40ns are recorded, and they agree with the

spectroscopic measurements.

0 20 40 60 80 100Time [ns]

-2

0

2

4

6

Vol

tage

[kV

]-20

0

20

40

60

Cur

rent

[A]

Voltage [kV]Current [A]

0 20 40 60 80 100Time [ns]

0

50

100

150

200

Pul

se p

ower

[kW

]

0

0.5

1

1.5

2

Pul

se E

nerg

y[m

J]

Pulse power [kW]Pulse Energy[mJ]40 ns

First waveSecond wave

Figure 4: (Left) evolution of the current [A] and the applied voltage [kV] - (Right) calculatedinstantaneous power [kW] and the pulse energy [mJ] in air at atmospheric pressure

Discharge temperatures• Plasma discharge in microplasma reactor has a vibrational and rotational

temperatures of 3460 K and 550 K respectively at atmospheric pressure.• Temperature measurements done by comparing the broadening of the emission lines

of the second positive system for N2(C −B) with the Specair code.

• High level of non-equilibrium discharge has been reported.

368 370 372 374 376 378 380 382

Wavelength [nm]

0

0.2

0.4

0.6

0.8

1

Inte

nist

y [-

]

Experimental dataSpecair simulation at T(vib)=3460K

N2 C-B (0-2)

N2 C-B (2-4)

N2 C-B (1-3)

377 377.5 378 378.5 379 379.5 380 380.5 381

Wavelength [nm]

0

0.2

0.4

0.6

0.8

1

Inte

nist

y [-

]

Experimental dataSpecair simulation at T(vib)=550K

N2 C-B (0-2)

Figure 5: Experimental and simulated spectra of discharge in air at atmospheric pressure(left) using 1800 groove/mm grating (right) using 3600 groove/mm grating

Effect of plasma on burning velocity• Burning velocity measurements have been done by measuring the angle of a conical

flame.• The graph shows an increasing of the burning velocity as a result of plasma effect.

• In atmospheric pressure, most of the enhancement is due to thermal effect of the

discharge.

Figure 6: Effect of plasma discharge on burning velocity of CH4/Air flame at atmosphericpressure

Future Work• Using Raman spectroscopic technique to investigate the plasma discharge effect on

flame chemistry.• Studying the effect of pressure on the plasma emission and flame chemistry.

• Studying the effect of plasma discharge on NOx and CO emissions at different

working pressures.

/ Department of Mechanical Engineering - Multiphase and Reactive FlowsContact: Ahmed Elkholy , A.Elkholy@tue.nl