Post on 07-Feb-2016
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NON-THERMAL ATMOSPHERIC PRESSURE NON-THERMAL ATMOSPHERIC PRESSURE PLASMAS FOR AERONAUTIC PLASMAS FOR AERONAUTIC
APPLICATIONSAPPLICATIONS
Richard B. Miles,Richard B. Miles, Dmitry Opaits, Mikhail N. Shneider, Dmitry Opaits, Mikhail N. Shneider,
Sohail H. Zaidi - PrincetonSohail H. Zaidi - PrincetonSergey macheret – LockheedSergey macheret – Lockheed
Alexander Likhanskii – Penn State U.Alexander Likhanskii – Penn State U.
HAKONE XI HAKONE XI
Oleron Island Oleron Island
September 7-12, 2008September 7-12, 2008
OutlineOutline 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 Offset DBD Configuration for
Flow ControlFlow Control
Surface PlasmaSurface Plasma
Limitations of Sinusoidal Limitations of Sinusoidal Driven DBD Control Driven DBD Control
Breakdown occurs randomly during each Breakdown occurs randomly during each cyclecycle
There is a significant backward There is a significant backward component of the thrust during the cyclecomponent of the thrust during the cycle
Thrust is not generated equally in the Thrust is not generated equally in the positive and negative portion of the cyclepositive and negative portion of the cycle
The duty cycle is low – part of the time no The duty cycle is low – part of the time no thrust is being generatedthrust is being generated
Pulse Sustained, DC Driven DBD ConceptPulse Sustained, DC Driven DBD Concept
Dielectric material:kapton tapethickness 100 μm
Electrodes:copper foilwidth 25 mmspanwise 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
Main differences between pulses with arbitrary bias and sine voltage
Sine Voltage Pulses with Bias
Two functions simultaneously:Plasma generation andbody force on the gas
Bias produces the body force
on the gas
Pulses efficiently generate plasma
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
TerminologyTerminology
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 withPredicted Streamer Like Ionization with3kV, 4 nsec positive pulses and 1 kV positive DC 3kV, 4 nsec positive pulses and 1 kV positive DC
biasbias
Predicted Average Force with 3kV, 500kHz, 4 Predicted Average Force with 3kV, 500kHz, 4 nsec positive pulses and 1 kV positive DC nsec positive pulses and 1 kV positive DC
biasbias
Predicted Momentum Transfer Predicted Momentum Transfer with 4 nsec pulseswith 4 nsec pulses
Momentum, transfered to the gas
0.0E+00
2.0E-09
4.0E-09
6.0E-09
8.0E-09
1.0E-08
1.2E-08
1.4E-08
0.0E+00 4.0E-07 8.0E-07 1.2E-06 1.6E-06 2.0E-06
Time, s
Mo
men
tum
, N
*s/m
High-V neg. pulse
High-V pos. pulse
Low-V neg. pulse
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 Predicted Surface Jet Generated Vortex with pulse burstGenerated Vortex with pulse burst
Schlieren techniqueSchlieren techniquefor the DBD plasma actuator induced flowfor the DBD plasma actuator induced flow
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.
0.5 m/sec at 17 mm7 m/sec in the plasma region!
x
ResultsResultsDC Bias experimentsDC Bias experiments
Pulses:50 kHz - 20 μs between pulses500 pulses per burst - 10 ms per burst1000 pulses per period - 50 bursts per second
5kV pulse voltage
-2 kV.. +2 kV DC bias voltage
ResultsResultsSurface charge experiments Positive pulsesSurface charge experiments Positive pulses
10 s10 s
20 s20 s
60 s60 s
wipedwiped
0 kV 0 kV →→ +2 kV +2 kV
10 s10 s
20 s20 s
60 s60 s
wipedwiped
First runFirst run
0 kV Bias Voltage0 kV Bias Voltage +2 kV Bias Voltage+2 kV Bias Voltage
ResultsResultsBias switch experimentsBias 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 SurfaceCharge Build-up Along Surfacewith Sinusoidal Applied Voltagewith Sinusoidal Applied Voltage
3kHz, 10kV peak-to-peak 3kHz, 10kV peak-to-peak. .
-2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28-200
0
200
400
600
800
1000
1200
1400
1600
Su
rfac
e p
oten
tial,
V
Distance, mm
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 Surface Charge Build up with 2kV DC bias and 4kV pulses at 20 kHzand 4kV pulses at 20 kHz
0 5 10 15 20 25-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
Sur
face
pot
entia
l, kV
Distance, mm
Positive biasZero biasNegative bias
Positive pulses
0 5 10 15 20 25
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Negative pulses
Su
rfa
ce p
ote
ntia
l, kV
Distance, mm
Positive bias Zero bias Negative bias
0 5 10 15 20 25-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
Sur
face
pot
entia
l, kV
Distance, mm
Positive biasZero biasNegative bias
Positive pulses
0 5 10 15 20 25
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Negative pulses
Su
rfa
ce p
ote
ntia
l, kV
Distance, mm
Positive bias Zero bias Negative bias
Charge Build-up RateCharge Build-up Rate
-5 0 5 10 15 20
0.0
0.5
1.0
1.5
2.0
Su
rfa
ce p
ote
ntia
l, V
Distance, mm
1 pulse 10 pulses 100 pulses 1000 pulses
Positive pulsesPositive bias
-5 0 5 10 15 20
0.0
-0.5
-1.0
-1.5
Positive pulsesNegative bias
Sur
face
pot
entia
l, m
m
Distance, mm
1 pulse 10 pulses 100 pulses 1000 pulses
-5 0 5 10 15 20
0.0
0.5
1.0
1.5
2.0
Negative pulsesPositive bias
Su
rfa
ce p
ote
ntia
l, m
m
Distance, mm
1 pulse 10 pulses 100 pulses 1000 pulses
-5 0 5 10 15 20
0.0
-0.5
-1.0
-1.5
-2.0
Negative pulseNegative bias
Su
rfa
ce p
ote
ntia
l, V
Distance, mm
1 pulse 10 pulses 100 pulses 1000 pulses
Charge Bleed Off RateCharge Bleed Off Rate
-5 0 5 10 15 20 25 30
0.0
0.5
1.0
1.5
2.0
2.5
0 min 5 min 10 min 15 min 20 min 25 min 30 min
Sur
face
pot
entia
l, kV
Distance, mm
4 kV Negative pulses2 kV Positive bias
-5 0 5 10 15 20 25 30
0.0
-0.5
-1.0
-1.5
-2.0
4 kV Negative pulses2 kV Negative bias
Sur
face
pot
entia
l, kV
Distance, mm
0 min 5 min 10 min 15 min 20 min 25 min 30 min
Single Sided Versus DoubleSingle Sided Versus DoublePositive pulsesPositive 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.
Single Sided Versus DoubleSingle Sided Versus DoubleNegative pulsesNegative 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.
ResultsResultsSinusoidal bias experimentsSinusoidal bias experiments
Bias:60 Hz sinusoidal2.6 kV peak-to-peak voltage
Pulses:50 kHz - 20 μs between pulses208 pulses per burst - 4.16 ms per burst416 pulses per period - 120 bursts per second5kV peak voltage
Totally different from conventional sinusoidal profile!!
ResultsResultsPulse Repetition Rate Positive pulsesPulse Repetition Rate Positive pulses
20 kHz20 kHz
50 kHz50 kHz
100 100 kHzkHz
ResultsResultsPulse Repetition Rate Negative pulsesPulse Repetition Rate Negative pulses
30 kHz30 kHz
50 kHz50 kHz
70 kHz70 kHz
ResultsResultsPulse Voltage Positive pulsesPulse Voltage Positive pulses
3.3 kV3.3 kV
5.0 kV5.0 kV
7.4 kV7.4 kV
ResultsResultsPulse Voltage Negative pulsesPulse Voltage Negative pulses
3.3 kV3.3 kV
5.0 kV5.0 kV
7.4 kV7.4 kV
ResultsResultsBias Voltage Positive pulsesBias Voltage Positive pulses
5 kV5 kV
10 kV10 kV
13 kV13 kV
ResultsResultsBias Voltage Negative pulsesBias Voltage Negative pulses
5 kV5 kV
10 kV10 kV
13 kV13 kV
Scaling with Pulse Repetition Rate
Scaling with Pulse Voltage
Scaling with Bias Voltage
Shielded Thrust StandShielded Thrust Stand
Thrust Measurements withThrust Measurements withHigh Voltage PulsesHigh Voltage Pulses
and Oscillating Bias Voltage Waveformsand Oscillating Bias Voltage Waveforms
0
5
10
Positive pulses Negative pulses Average abs value
of bias voltage, a.u.
Th
rust
, m
N/m
Thrust Dependence on Thrust Dependence on Square Wave Duty Cycle Square Wave Duty Cycle
0 20 40 60 80 1000
2
4
6
8
10
12
Positive pulses Negative pulses
Thr
ust,
mN
/m
Positive bias duty cycle, %
Thrust Dependence with Positive Thrust Dependence with Positive PulsesPulses
Common point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at Common point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at 25kHz25kHz
Thrust Dependence with Negative Thrust Dependence with Negative PulsesPulses
Common point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at Common point: 10kV peak to peak square wave bias, 100Hz, 3kV pulses at 25kHz25kHz
2.0 2.5 3.0 3.50
2
4
6
8
10
12
Thr
ust,
mN
/m
Pulse voltage, kV
0 10 20 30 40 500
2
4
6
8
10
12
14
16
Thr
ust,
mN
/m
PRR, kHz
0 2 4 6 8 10 120
2
4
6
8
10
12
14
16
18
Thr
ust,
mN
/m
Bias voltage, peak-to-peak, kV
1 10 1000
2
4
6
8
10
12
Thr
ust,
mN
/m
Bias frequency, Hz
Summary of Thrust Summary of Thrust MeasurementsMeasurements
0 20 40 60 800
20
40
60
80
100
120
140Sinusoidal voltage profile
6 mil Kapton, 4.4 kHz 4 mil Kapton, 5 kHz 1/4" Quartz, 1 kHz 1/4" Quartz, 2 kHz 1/4" Quartz, 4 kHz 1/4" Quartz, 8 kHz Glass plate, 5 kHz, Thickness unknown
Pulses plus bias voltage profile 1/16" MACOR, 100 Hz square bias
50 kHz 4.5 kV negative pulses 4 mil Kapton, 100 Hz square bias
50 kHz 3.0 kV negative pulses Modified DBD plasma actuator,
4 mil kapton, DC positive bias,10 kHz 3 kV negative pulses
Thr
ust,
mN
/m
Voltage, peak-to-peak, kV
Low Voltage RegionLow Voltage Region
0 5 10 15 20 25 300
10
20
30
40 Sinusoidal voltage profile 6 mil Kapton, 4.4 kHz 4 mil Kapton, 5 kHz 1/4" Quartz, 1 kHz 1/4" Quartz, 2 kHz 1/4" Quartz, 4 kHz 1/4" Quartz, 8 kHz Glass plate, 5 kHz, Thickness unknown
Pulses plus bias voltage profile 1/16" MACOR, 100 Hz square bias
50 kHz 4.5 kV negative pulses 4 mil Kapton, 100 Hz square bias
50 kHz 3.0 kV negative pulses Modified DBD plasma actuator,
4 mil Kapton, DC positive bias,10 kHz 3 kV negative pulses
Thr
ust,
mN
/m
Voltage, peak-to-peak, kV
New DBD Design New DBD Design with Exposed Lower with Exposed Lower
ElectrodeElectrode
Thrust Scaling with New Thrust Scaling with New DesignDesign
0 10 20 30 400
2
4
6
8
10
12
14
16
18
Th
rust
, mN
/m
PRR, kHz0 1 2 3 4 5 6 7 8
0
2
4
6
8
10
12
Th
rust
, mN
/mBias voltage, kV
4 kV positive bias voltage, 3 kV negative pulses 410 kHz PRR, 3 kV negative pulses
ConclusionsConclusions
• 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