AeroMEMS

Date/reference/classification

AEROMEMS IIAdvanced Flow Control Using MEMSResults and Lessons Learned

Dr Clyde Warsop

Presented at 5th Community Aeronautical Days 2006

Advanced Technology Centre

Date/reference/classification/Slide NumberAdvanced Technology Centre

Objectives

y

Velocity

y

Velocityy

Velocity

y

Velocity

LaminarSeparation

Turbulent

TransitionWake

y

Velocity

y

Velocity

y

Velocity

y

Velocity

y

Velocity

y

Velocityy

Velocity

y

Velocity

y

Velocity

y

Velocity

y

Velocity

y

Velocity

LaminarSeparation

Turbulent

TransitionWake

- Control of turbulent boundary layers using active sub-boundary layer scale devices to achieve:

- Drag reduction- Flow separation control


Enablers - Microfabrication

1 Micron Features

Sandia

1 Micron Features

Sandia

BAE SYSTEMS

Accelerometer

BAE SYSTEMS

Accelerometer

Microelectronics = planar

Microengineering = 3-d sculpting

Integrate Sensors,

Actuators, Electronics

Microelectronics = planar

Microengineering = 3-d sculpting

Integrate Sensors,

Actuators, Electronics

BAE SYSTEMS

Gyroscope

BAE SYSTEMS


AEROMEMS II Overview

Application to High Lift,

Intakes, Fans compressors

Sub-BL Flow SeparationControl (Pulsed jets)

Pulsed jet, 100 - 200 m/s5-20% duty cycle

200µm dia

PZT cantilever actuator50-80µm displacement

1 - 2 KHz frequency

3mm

Pressurisedsupply (30-80 kPa)

MEMSSensors/Actuators High Re Demonstrations


Actuator Optimisation

Compare pulsed jets & synthetic jets with passive devices

High ReAdverse Press Grad.

• Hot wire• Skin friction• Steady/unsteady PIV

z/δ

y/δ

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.30

0.1

0.2

0.3

0.4

0.5

0.6 CtR jets VRe=3.1z/δ

y/δ

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.30

0.1

0.2

0.3

0.4

0.5

0.6 CtR Passive devices

z/δ

y/δ

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.50

0.1

0.2

0.3

0.4

0.5

0.6 u/ue1

0.9

0.8

0.7

0.6

0.5

0.4

0.3ue/4

CoR jets VRe=3.1z/δ

y/δ

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.50

0.1

0.2

0.3

0.4

0.5

0.6 u/ue1

0.9

0.8

0.7

0.6

0.5

0.4

0.3ue/4

Without actuator

u*0 0.2 0.4 0.6 0.8 1

0

0.2

0.4

0.6

u*0 0.2 0.4 0.6 0.8 1

0

0.1

0.2

0.3

0.4

0.5

0.6without actuatorCtR passive deviseCoR jets VR4CoR jets VR6CtR jets VR4CtR jets VR6


High-lift and Intake Distortion Tests

MThroat =0.6Unactuated Actuated

DC60 reduced by 40% for 0.05% engine mass flow bleed

Wind tunnel velocity = 30 m/s and wing incidence angle = 10.0 deg.

0.00

0.05

0.10

0.15

0.20

0.25

0.0 1.0 2.0 3.0 4.0 5.0

Velocity ratio

Cha

nge

in L

ift

coef

ficie

nt

10mmspacing

Actuated

NonActuated

Separation

Separation

TE

TE

LE

LE


Compressor surge tests

1.0111.0121.0131.0141.0151.0161.0171.018

2.5 3 3.5 4 4.5 5Corrected mass flow rate (kg/s)

Pres

sure

Rat

io (t

/t) No Control12jets,0.2bar(0.47%m)24jets,0.2bar(0.88%m)12jets,0.47bar(0.75%m)

0

5

10

15

20

0 0.5 1 1.5

Injected mass flow/compressor mass flow (%)

surg

e M

argi

n in

crea

se(%

)

10% increase in surge margin for

0.6% engine massflow


MEMS Flow Sensors

Polyimide 6µm

Silicon oxide 0.6µm

Low resistivity silicon 250µm


Tungsten resistor ~300nm Silicon nitride top layer 1µm

Resistor leads

Through wafer connections Membrane cavity

Polyimide 6µm


Low resistivity silicon 250µm



Resistor leads



Resistor leads


Designed for robustness, sensitivity, good frequency response10 x sensitivity of conventional stick-on hot film, 30 kHz cut-off


MEMS Pulse-Jet Flow Actuator


200µm diameter


200µm diameter

PZT cantilever actuator50-100 µm displacement

1-2kHz frequency

3mm

Pressurisedsupply

(30-80 kPa)

45 º skewed, 200µm dia hole

• Robust,• High authority (force & disp.),• Small footprint and thickness.

Modelling and simulation


MEMS Microvalve Development

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

0 200 400 600 800 1000

Frequency (Hz)

Jet v

oloc

ity (m

s-1)

30kPa50kPa80kPa100kPa

Top PZT layer

Titanium shim

Bottom PZT layer

Wax

PZT support for machining (2mm thick)

Top PZT layer

Titanium shim

Bottom PZT layer

Wax

PZT support for machining (2mm thick)

Microfabrication development


High Reynolds No. Demonstrations

Model 2D H8Y in NWB

Braunschweig

ONERA F1 Wind Tunnel

Reynolds number 6.5 x106

M=0.2


High Reynolds No. demonstrations

Flap TE

Flap LESeparation Separation

Flap TE

Flap LE

Flow Separation delayed from 30% to 90% off flap chord

URANS Simulation URANS Simulation

Unactuated Actuated


High-lift benefits

AOA (deg)

CL

Baseline TE Control TE+LE Control

π CL =0,2

Impact of applying pulsed jet actuation to LE and TE devices on an optimised civil transport wing derived from ONERA & DLR

test programmes


Summary of Achievements

- Demonstrated flow separation delay using active, distributed microsystems under flight scale conditions.

- Developed/demonstrated first-pass flush mounted flow sensors and high authority flow actuators

- Identified a number of relatively near-term applications

- Intakes- High Lift- Turbomachine compressors

- Developed/validated modelling capabilities for simple sub-boundary layer actuator concepts


Outstanding Issues

- Technology still relatively immature with regard to achieving all theoretically possible benefits

- However, limited application could be conceivable - perhaps for flow separation control

- high lift system performance improvement- Turbomachine compressors- Intake performance improvement- unconventional flight controls (compliant aerodynamics)

- Still need to address many practical issues regarding implementation:

- Robustness, system integration, maintenance & repair, cost/benefit assessment, certification.


Questions?

AeroMEMS

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