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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NON-THERMAL ATMOSPHERIC PRESSURE PLASMAS FOR AERONAUTIC APPLICATIONSRichard B. Miles,Dmitry Opaits, Mikhail N. Shneider, SohailH. Zaidi- PrincetonSergey macheret – LockheedAlexander Likhanskii – Penn State U.
September 7-12, 2008
thickness 100 μm
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
with arbitrary bias and sine voltage
Pulses with Bias
Two functions simultaneously:
Plasma generation and
body force on the gas
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 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.
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.
0.5 m/sec at 17 mm
7 m/sec in the plasma region!
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.
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
0 kV Bias Voltage
+2 kV Bias Voltage
0 kV → +2 kV
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
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.
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.
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!!
60 Hz sinusoidal
2.6 kV peak-to-peak voltage
4 kV positive bias voltage, 3 kV negative pulses
410 kHz PRR, 3 kV negative pulses