Hakone xi oleron island september 7 12 2008
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NON-THERMAL ATMOSPHERIC PRESSURE PLASMAS FOR AERONAUTIC APPLICATIONS Richard B. Miles, Dmitry Opaits , Mikhail N. Shneider , Sohail H. Zaidi - Princeton Sergey macheret – Lockheed Alexander Likhanskii – Penn State U. HAKONE XI Oleron Island September 7-12, 2008 Outline

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Hakone xi oleron island september 7 12 2008 l.jpg

NON-THERMAL ATMOSPHERIC PRESSURE PLASMAS FOR AERONAUTIC APPLICATIONSRichard B. Miles,Dmitry Opaits, Mikhail N. Shneider, SohailH. Zaidi- PrincetonSergey macheret – LockheedAlexander Likhanskii – Penn State U.

HAKONE XI

Oleron Island

September 7-12, 2008


Outline l.jpg
Outline APPLICATIONS

  • Dielectric Barrier Discharge (DBD) Configuration

  • Performance with Sinusoidal Driver

  • Modeling of Pulse Sustained DC Driven

  • Experimental Set up

  • Visualization technique

  • Surface Charge Effects

  • Surface Charge measurement

  • Bias Switching Experiments

  • Schlieren Movies and results

  • Thrust Stand Tests

  • New Electrode Configuration

  • Conclusions


Offset dbd configuration for flow control l.jpg
Offset DBD Configuration for APPLICATIONSFlow Control


Surface plasma l.jpg
Surface Plasma APPLICATIONS


Limitations of sinusoidal driven dbd control l.jpg
Limitations of Sinusoidal Driven DBD Control APPLICATIONS

  • Breakdown occurs randomly during each cycle

  • There is a significant backward component of the thrust during the cycle

  • Thrust is not generated equally in the positive and negative portion of the cycle

  • The duty cycle is low – part of the time no thrust is being generated


Pulse sustained dc driven dbd concept l.jpg
Pulse Sustained, DC Driven DBD Concept APPLICATIONS

Dielectric material:

kapton tape

thickness 100 μm

Electrodes:

copper foil

width 25 mm

spanwise dim. 50 mm

The circuit is designed so as to superimpose short pulses on a low frequency bias voltage without interference between the pulser and the low-frequency power supply. The pulses and the bias voltage are controlled independently


Slide8 l.jpg

Main differences between pulses APPLICATIONS

with arbitrary bias and sine voltage

Sine Voltage

Pulses with Bias

Two functions simultaneously:

Plasma generation and

body force on the gas

Pulses efficiently

generate plasma

Bias produces

the body force

on the gas

The parameters of pulse-bias configuration –

peak pulse voltage, pulse repetition rate, pulse burst rate, duty cycle,

and both the frequency and amplitude of the time-depended bias voltage –

can be varied independently,

greatly increasing flexibility of control and

optimization of the DBD actuator


Terminology l.jpg
Terminology APPLICATIONS

Terminology used in the paper for the pulse and bias voltage polarities. The encapsulated electrode is always considered to be at zero potential. The sign of potential of the exposed electrode relative to the encapsulated one determines the pulse and bias polarity.


Predicted streamer like ionization with 3kv 4 nsec positive pulses and 1 kv positive dc bias l.jpg
Predicted Streamer Like Ionization with APPLICATIONS3kV, 4 nsec positive pulses and 1 kV positive DC bias


Predicted average force with 3kv 500khz 4 nsec positive pulses and 1 kv positive dc bias l.jpg
Predicted Average Force with 3kV, 500kHz, 4 APPLICATIONSnsec positive pulses and 1 kV positive DC bias


Predicted momentum transfer with 4 nsec pulses l.jpg
Predicted Momentum Transfer with 4 APPLICATIONSnsec pulses

Blue and green lines correspond to the negative pulses with amplitudes -4.5 and -1.5 kV with positive bias of 0.5 kV, and the pink line corresponds to the positive pulses with 3 kV amplitude and positive bias of 1 kV. FWHM for all pulses is 4 ns.


Predicted surface jet generated vortex with pulse burst l.jpg
Predicted Surface Jet APPLICATIONSGenerated Vortex with pulse burst


Schlieren technique for the dbd plasma actuator induced flow l.jpg
Schlieren technique APPLICATIONSfor the DBD plasma actuator induced flow

0.5 m/sec at 17 mm

7 m/sec in the plasma region!

x

Schlieren technique, burst mode of plasma actuator operation, and 2-D fluid numerical model coupled together allow to restore the entire two-dimensional unsteady plasma induced flow pattern as well as the characteristics of the plasma induced force.


Results dc bias experiments l.jpg
Results APPLICATIONSDC Bias experiments

Pulses:

50 kHz - 20 μs between pulses

500 pulses per burst - 10 ms per burst

1000 pulses per period - 50 bursts per second

5kV pulse voltage

-2 kV.. +2 kV DC bias voltage


Results surface charge experiments positive pulses l.jpg
Results APPLICATIONSSurface charge experiments Positive pulses

0 kV Bias Voltage

+2 kV Bias Voltage

10 s

10 s

20 s

20 s

60 s

60 s

wiped

wiped

0 kV → +2 kV

First run


Results bias switch experiments l.jpg
Results APPLICATIONSBias switch experiments

Switching the polarity of the bias voltage has a dramatic effect on the DBD operation: much faster jets and vortices are generated compared with the constant-bias cases

Reason - accumulation of surface charge on the dielectric


Charge build up along surface with sinusoidal applied voltage 3khz 10kv peak to peak l.jpg
Charge Build-up Along Surface APPLICATIONSwith Sinusoidal Applied Voltage 3kHz, 10kV peak-to-peak.

  • Non-contacting Trek Model 247-3 Electrostatic Voltmeter with Trek Model 6000B-13C Electrostatic Voltmeter Probe.

  • Fast response time (less then 3 ms for a 1kV step)

  • Operating range from 0 to +/- 3 kV DC or peak AC.

  • Spatial resolution of ~1 mm.


Surface charge build up with 2kv dc bias and 4kv pulses at 20 khz l.jpg
Surface Charge Build up with 2kV DC bias APPLICATIONSand 4kV pulses at 20 kHz


Charge build up rate l.jpg
Charge Build-up Rate APPLICATIONS


Charge bleed off rate l.jpg
Charge Bleed Off Rate APPLICATIONS


Slide22 l.jpg

Single Sided Versus Double APPLICATIONS

Positive pulses

Although some of the pulse bursts do not create a strong wall jet, they still play an important role in the DBD operation. Their task is to discharge/recharge the dielectric surface and thus to increase the efficiency of the other bursts.


Slide23 l.jpg

Single Sided Versus Double APPLICATIONS

Negative pulses

In the absence of the pulse burst during the other half-cycle, the induced wall jet speed becomes 2-3 times lower. The wall jets induced by negative pulses evolve into two-vortex formations whereas the ones from the positive pulses do not.


Slide25 l.jpg

Results APPLICATIONSSinusoidal bias experiments

Pulses:

50 kHz - 20 μs between pulses

208 pulses per burst - 4.16 ms per burst

416 pulses per period - 120 bursts per second

5kV peak voltage

Totally different from conventional sinusoidal profile!!

Bias:

60 Hz sinusoidal

2.6 kV peak-to-peak voltage


Slide26 l.jpg

Results APPLICATIONSPulse Repetition Rate Positive pulses

20 kHz

50 kHz

100 kHz


Slide27 l.jpg

Results APPLICATIONSPulse Repetition Rate Negative pulses

30 kHz

50 kHz

70 kHz


Slide28 l.jpg

Results APPLICATIONSPulse Voltage Positive pulses

3.3 kV

5.0 kV

7.4 kV


Slide29 l.jpg

Results APPLICATIONSPulse Voltage Negative pulses

3.3 kV

5.0 kV

7.4 kV


Slide30 l.jpg

Results APPLICATIONSBias Voltage Positive pulses

5 kV

10 kV

13 kV


Slide31 l.jpg

Results APPLICATIONSBias Voltage Negative pulses

5 kV

10 kV

13 kV





Shielded thrust stand l.jpg
Shielded Thrust Stand APPLICATIONS


Thrust measurements with high voltage pulses and oscillating bias voltage waveforms l.jpg
Thrust Measurements with APPLICATIONSHigh Voltage Pulsesand Oscillating Bias Voltage Waveforms



Slide38 l.jpg
Thrust Dependence with Positive Pulses APPLICATIONSCommon point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at 25kHz


Slide39 l.jpg
Thrust Dependence with Negative Pulses APPLICATIONSCommon point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at 25kHz



Low voltage region l.jpg
Low Voltage Region APPLICATIONS


New dbd design with exposed lower electrode l.jpg
New DBD Design APPLICATIONSwith Exposed Lower Electrode


Thrust scaling with new design l.jpg
Thrust Scaling with New Design APPLICATIONS

4 kV positive bias voltage, 3 kV negative pulses

410 kHz PRR, 3 kV negative pulses


Conclusions l.jpg
Conclusions APPLICATIONS

  • Offset dielectric barrier discharges can generate strong surface jets for aerodynamic control

  • Using AC to drive the offset DBD is not optimal

    • Reverse thrust component

    • Low duty cycle

    • Uncontrolled plasma formation

  • A new voltage waveform, consisting of high-voltage nanosecond repetitive pulses superimposed on a DC voltage was proposed

  • The experiments showed that the charge build-up on the dielectric surface shields both the applied DC and AC electric field

  • Charge build up was overcome with high voltage pulse sustained plasma and

    • A high-voltage low-frequency sinusoidal or square wave bias voltage

    • A partially covered electrode configuration operating with a DC bias

  • Bias voltage is the most important parameter for thrust generation


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