PLASMA-ENHANCED AERODYNAMICS –
Download
1 / 44

- PowerPoint PPT Presentation


  • 259 Views
  • Uploaded on

PLASMA-ENHANCED AERODYNAMICS – A NOVEL APPROACH AND FUTURE DIRECTIONS FOR ACTIVE FLOW CONTROL. Thomas C. Corke Clark Chair Professor University of Notre Dame Center for Flow Physics and Control Aerospace and Mechanical Engineering Dept. Notre Dame, IN 46556.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '' - alsatia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Slide1 l.jpg

PLASMA-ENHANCED AERODYNAMICS –

A NOVEL APPROACH AND FUTURE DIRECTIONS

FOR ACTIVE FLOW CONTROL

Thomas C. Corke

Clark Chair Professor

University of Notre Dame

Center for Flow Physics and Control

Aerospace and Mechanical Engineering Dept.

Notre Dame, IN 46556

Ref: J. Adv. Aero. Sci., 2007.


Slide2 l.jpg

Presentation Outline:

  • Background SDBD Plasma Actuators

    • Physics and Modeling

    • Flow Control Simulation

    • Comparison to Other FC Actuators

  • Example Applications

    • LPT Separation Control

    • Turbine Tip-gap Flow Control

    • Turbulent Separation Control

  • Summary


Slide3 l.jpg

dielectric

exposed electrode

covered electrode

substrate

AC voltage source

Single-dielectric barrier discharge (SDBD)

Plasma Actuator

  • High voltage AC causes air to ionize

  • (plasma).

  • Ionized air in presence of electric

  • field results in body force that acts

  • on neutral air.

  • Body force is mechanism of flow

  • control.

The SDBD is stable at atmospheric pressure because it is self-limiting due to charge accumulation on the dielectric surface.

Ref:AIAA J., 42, 3, 2004


Slide4 l.jpg

t

Flow Response: Impulsively Started Plasma Actuator

Phase-averaged PIV

Long-time Average



Slide6 l.jpg

(x,t)

Y

Y

Y

Physics of OperationElectrostatic Body Force

D- Electric Induction

(Maxwell’s equation)

(given by Boltzmann relation)

solution of equation -

electric potential

Body Force



Slide8 l.jpg

xmax

dx/dt

Current/Light Emission ~ (x,t)

t/T

Voltage


Slide9 l.jpg

Electron Transport Key to Efficiency

a

c d

More Optimum

Waveform

b


Slide10 l.jpg

Steps to model actuator in flow

  • Space-time electric potential,

  • Space-time body force

  • Flow solver with body force added


Slide11 l.jpg

dielectric

exposed electrode

covered electrode

substrate

AC voltage source

Space-Time Lumped Element Circuit Model: Boundary Conditions on(x,t)

Electric circuit with N-sub-circuits

(N=100)

Ref:AIAA-2006-1206


Slide12 l.jpg

Space-time Dependent Lumped Element Circuit Model (governing equations)

air capacitor

dielectric capacitor

Voltage on the dielectric surface in the n-th sub-circuit

Plasma current


Slide13 l.jpg

x equations)max

dx/dt

Model Space-time Characteristics

Experiment

Illumination

Model Ip(t)


Slide14 l.jpg

Plasma Propagation Characteristics equations)

Effect of Vapp

dxp/dt vs Vapp

(xp)maxvs Vapp

Model

Model


Slide15 l.jpg

Plasma Propagation Characteristics equations)

Effect of fa.c.

dxp/dt vs fa.c.

(xp)maxvs fa.c.

Model

Model


Slide16 l.jpg

Numerical solution for equations)(x,y,t)

Model provides time-dependent B.C. for


Slide17 l.jpg

Body Force, f equations)b(x,t)

t/Ta.c.=0.2

Normalized fb(x,t)

t/Ta.c.=0.7


Slide18 l.jpg

Example: LE Separation Control equations)

Computed cycle-averaged body force vectors

NACA 0021 Leading Edge


Slide19 l.jpg

Example: Impulsively Started Actuator equations)

Velocity vectors

t=0.01743 sec

2 = -0.001 countours


Slide20 l.jpg

Base Flow equations)

Example: AoA=23 deg.

U∞=30 m/s, Rec=615K

Steady Actuator


Slide21 l.jpg

Comparison to Other FC Actuators? equations)

  • “Zero-mass Unsteady Blowing”

  • generally uses voice-coil system.

  • Current driven devices, V~I.

  • Losses result in I2R heating.

  • Flow simulations require actuator

  • velocity field (flow dependent).

  • SDBD plasma actuator is voltage driven, fb~V7/2.

  • For fixed power (I·V), limit current to maximize voltage.

  • Low ohmic losses.

  • Flow simulations require body force field (not affected by external flow, solve once for given geometry).


Slide22 l.jpg

Material equations)

Quartz 3.8

Kapton 3.4

Teflon 2.0

Imax

Imax

Imax

Imax

All previous SDBD flow control

Maximizing SDBD Plasma Actuator Body Force

At Fixed Power


Sample applications l.jpg
Sample Applications equations)

  • LPT Separation Control

  • Turbine Tip-Clearance-Flow Control

  • Turbulent Flow Separation Control

  • A.C. Plasma Anemometer


Slide24 l.jpg

LPT Separation Control equations)

  • Span = 60cm

  • C=20.5cm

Pak-B Cascade

Flow

Plasma

Side

Ref: AIAA J. 44, 7, 51-58, 2006

AIAA J. 44, 7, 1477-1487, 2006


Slide25 l.jpg

Plasma Actuator: x/c=0.67, Re=50k equations)

Ret.

Actuator

Location

Sep.

Steady Actuator


Slide26 l.jpg

f L equations)s /Ufs=1

Plasma Actuator: x/c=0.67, Re=50k

Base Flow

Unsteady Plasma Act.

Deficit Pressure

Loss Coeff. vs Re

200%

20%


Slide27 l.jpg

Turbine Tip-Clearance-Flow Control equations)

Objective:

  • Reduce losses associated with

  • tip-gap flow

Approach:

  • Document tip gap flow behavior.

  • Investigate strategies to reduce pressure-

  • losses due to tip-gap-flow.

    • Passive Techniques: How do they work?

    • Active Techniques: Emulate passive effects?

Ref: AIAA-2007-0646


Slide28 l.jpg

Experimental Setup equations)

Pak-B blades:

4.14” axial chord

Flow


Slide29 l.jpg

Under-tip Flow Morphology equations)

g/c=0.05

Separation line:

Receptive to active flow control.

t/g =2.83

t/g =4.30

Tip-flow Plasma Actuator


Slide30 l.jpg

No Plasma equations)

0

0.1

0.2

y/pitch

0.3

0.4

0.5

0.8

0.9

1

Unsteady Excitation Response

Re=500k

z/span

Shear Instability: 0.01<F+<0.04, U = maximum shear layer velocity, l = momentum thickness

Viscous Jet Core: 0.25<F+<0.5, U = characteristic velocity of jet core, l = gap size, g


Slide31 l.jpg

Cp equations)

No Plasma

F+

= 0.03, (f = 500 Hz)

F+

= 0.07, (f = 1250 Hz)

t

0.8

0

0

0

0.7

0.1

0.1

0.1

0.6

0.5

0.2

0.2

0.2

y/pitch

0.4

0.3

0.3

0.3

0.3

0.2

0.4

0.4

0.4

0.1

0.5

0.5

0.5

0

-0.1

0.8

0.9

1

0.8

0.9

1

0.8

0.9

1

z/span

Unsteady Excitation Response: Selected F+

Cpt/Cptbase=0.95

Cpt/Cptbase=0.92


Slide32 l.jpg

C equations)pt and Loss Efficiency


Slide33 l.jpg

Turbine Tip-Clearance-Flow Control equations)

Future Directions

Suction-side Blade “Squealer Tip”

“Plasma Squealer”

Active Casing Flow Turning

“Plasma Roughness”

Rao et al.

ASM GT 2006-91011

“Plasma Winglet”


Slide34 l.jpg

Turbulent Flow Separation Control equations)

Wall-mounted hump model used in NASA 2004 CFD validation.

Ref: AIAA-2007-0935


Slide35 l.jpg

R equations)

S

S

Baseline: Benchmark Cp and Cf

k- SST best up to x/c=0.9

k- best for (x/c)ret



Slide37 l.jpg

Aggressive Transition Ducts equations)

BWB Inlet with 30% BLI

Low-Speed

Separated

Flow Region

Plasma Actuator

Reattached

Flow Region

Turbulent Separation Control:

Future Applications

  • Flight control without moving surfaces

Miley 06-13-128 Simulation

AIAA-2006-3495,

AIAA-2007-0884


Slide38 l.jpg

Plasma Flow Control equations)

Summary

  • The basis of SDBD plasma actuator flow control is the

  • generation of a body force vector.

  • Our understanding of the process leading to improved plasma

  • actuator designs resulted in 20x improvement in performance.

  • With the use of models for ionization, the body force effect can

  • be efficiently implemented into flow solvers.

  • Such codes can then be used as tools for aerodynamic designs

  • that include flow control from the beginning, which holds the

  • ultimate potential.


Slide40 l.jpg

A.C. Plasma Anemometer equations)

Originally developed for mass-flux measurements in high Mach number, high enthalpy flows.

Principle of Operation:

  • Flow transports charge-carrying ions downstream from electrodes.

  • Loss of ionsreduces current flow across gap- increases internal resistance – increases voltage output.

  • Mechanism not sensitive on temperature.

  • Robust, no moving parts.

  • Native frequency response > 1 MHz.

  • Amplitude modulated ac carrier gives excellent noise rejection.

Flow


Slide41 l.jpg

ac carrier at equations)

fc = ~2 MHz

RF Amplifier

Plasma

Sensor

fc

fc - fm

fc + fm

electrode

Velocity Fluctuations

at frequency, fm

electrode

Plasma Sensor Amplitude Modulated Output

Amplitude Modulated

Output

Frequency Domain

Output


Slide42 l.jpg

Real Time Demodulation equations)

FPGA-based digital acquisition board allows host based demodulation in real time.

GnuRadio

Modulated signal recovered


Slide43 l.jpg

Real-time Measurement of Blade Passing Flow equations)

Video

Jet

f=1-2kHz


Slide44 l.jpg

T.C. wire forms electrode equations)

pair with gap = ~0.005”

Plasma Anemometer

Future Applications

  • Engine internal flow sensor:

  • - Surge/stall sensor

  • - Casing flow separation sensor

  • - Combustion instability sensor