Janusz Podliński, Artur Berendt, Jerzy Mizeraczyk

Centre for Plasma and Laser EngineeringThe Szewalski Institute of Fluid-Flow Machinery

Polish Academy of SciencesGdańsk, Poland

Multi‑DBD actuator with floating interelectrode

for aerodynamic control

Outline

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Dielectric Barier Discharge (DBD) plasma actuators

• Applications

• Design

Our investigations

• Electrode shape

• Electrode at floating potential

• Multi-DBD plasma actuator

Summary

Actuator ON Actuator ON

DBD plasma actuators

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Actuator OFF Actuator OFF

Flow visualisation in an aerodynamic channel

with a DBD plasma actuator

DBD plasma actuator for flow modification

Flow

DBD plasma actuators

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DBD plasma actuator placed on an aerodynamic element

can influence on:

• Boundary layer transition

• Wing tip vortex

• Leading and trailing flow separation

DBD plasma actuators can change parameters of the

airfoils

• Lift force increase

• Drag force decrease

• Noise reduction

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DBD plasma actuators

Cross-section of the „classic” DBD plasma actuator

Top-side view of the „classic” DBD plasma actuator

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Experimental set-up for DBD discharge parameters and flow measurements by PIV

Our investigations

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Our investigations

Up-p=24 kV; Ip=500 mA; f =1,5 kHz

Classic DBD plasma actuators

Without electrode gap With electrode gap 20 mm

Up-p= 48 kV; Ip=20 mA; f =1,5 kHz

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Saw-like electrodes for DBD plasma actuators

Example of saw-like electrode

Smooth electrode

DBD plasma actuators with smooth and saw-like electrodes

Electrode gap 20 mmUp-p = 52 kV,f = 1.5 kHz

The discharge for actuators with smooth and saw-like electrode

Effect of saw-like electrode

DBD starts at lower voltage

More uniform discharge along electrodes

Saw-like electrode

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Maximum flow generated by the actuators with smooth and saw-like electrodes

(d – distance between electrodes in mm)

Flow velocity field measured by PIV

Saw-like electrodes for DBD plasma actuators

Effect of saw-like electrode

Higher flow velocities generated by DBD

DBD plasma actuators with smooth and saw-like electrodes

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Multi-discharge plasma actuatorsSchematic design

Double DBD plasma actuator possible

‘Classic’ Multi-DBD for actuators

Multi-DBD with floating interelectrodes for actuators

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Multi-DBD actuator with floating interelectrodes Discharge visualisation - top view

Length of all electrodes: 80 mmHigh voltage electrode width: 10 mmHV to floating interelectrode distance: 0 mmGrounded (1) to HV electrode distance: 0 mm

Floating interelectrode width: 4 mmFloating to grounded (2) electrode distance: 4 mm Grounded electrode width: 3 mm High voltage: Upp = 32 kV, f = 1.5 kHz

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Length of HV and grounded electrodes: 50 mmLength of floating interelectrodes: 45 mmHigh voltage electrodes width: 15 mmHV and FL interelectrodes in optimum position

Floating interelectrodes width: 3 mmFloating to grounded electrode distance: 6 mm Grounded electrodes width: 3 mm Grounded to floating electrode distance: 13 mm

Dielectric: glass plate – 2 mm thick High voltage: Upp = 32 kV, f = 1.5 kHz

Airflow velocity m/s

Time-averaged streamlines of an airflow induced by the multi-DBD actuator with saw-like floating interelectrodes

Multi-DBD actuator with floating interelectrodes Time-averaged streamlines

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Experimental set-upfor leading edge flow separation control

Wind tunnel

Test section: 0.6 m x 0.46 m – 1.5 m long, Velocity 100 m/s, Turbulence level 0.1 %

NACA 0012 model:• Chord 200 mm

• Span 595 mm

• Multi-DBD actuator

with saw-like floating

interelectrode

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Plasma OFF – separated airflow Plasma ON - airflow reattachment

U0 = 15 m/s Chord: 200 mm

Incidence = 11o Re = 200 000

Multi-DBD plasma actuator with saw-like floating interelectrode for leading edge flow separation control

Applied HV: UHV = 15 kV fHV = 1.5 kHz

U0 = 15 m/s Chord: 200 mm

Incidence = 11o Re = 200 000

Leading edge flow separation control - results

Time-averaged flow velocity fields measured by PIV method

Summary

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The DBD with saw-like electrodes:

• Lower onset voltage,

• More uniform discharge along electrodes,

• Higher airflow velocities than the DBD with smooth electrodes.

The multi-DBD actuator with floating interelectrodes:

• Plasma generation on a large area of the dielectric surface,

• Maximum airflow velocity over 10 m/s ,

• Attractive for aerodynamic applications.