Download - PIEZOELECTRIC SHEAR WAVE INDUCED ANTI-ICING SYSTEM

Rotorcraft Center of Excellence Department of Aerospace Engineering

PIEZOELECTRIC SHEAR WAVE INDUCED ANTI-ICING SYSTEM

PIs: Dr. Edward C. Smith, Professor of Aerospace EngineeringDr. Joseph L. Rose, Professor of Engineering Mechanics

Graduate Students: Jose L. Palacios

Huidong Gao

Rotorcraft Center of ExcellenceThe Pennsylvania State University, PA 16802

April, 2005

ROTORCRAFT CENTER OF EXCELLENCE

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The icing tanker provides simulated test conditions throughout the test

envelope required for icing certification (Sikorsky Artificial Icing Tests)

Glaze Ice Encountered During Test(Icing Research Tunnel NASA Glenn)

•Liquid Water Content: 0.1 to 3 g/m3

•Temperature: = 00 C to -200 C

Background

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Rime Ice: Low water vapor concentration (0.5 – 1.0 g/m3) Water droplets freeze on impact Smooth streamlined, white opaque layers High surface roughness

Glaze Ice: High water concentrations (1.5 – 3.0 g/m3)Water droplets do not freeze upon contact: travel back in the chord direction Has a stronger influence on the lift and drag Irregular ice horns structures created on the leading edge

Rotorcraft Aerodynamics in Icing Conditions•High collection efficiency of rotor:

Higher rotor velocity collects more water droplets per second (ice accretes under icing conditions)

•Vibrations due to mass unbalance•Ice shedding •Premature transition & Separation of flow around the blade•Change in the profile drag over very short periods of time torque required increase •Undesired vibrations and changes in the handling of the vehicle flight conditions critically dangerous

Rotorcraft Icing

a) Rime Ice

b) Glaze Ice

Temperature, airspeed or liquid water content

increase

AIRFOIL

AIRFOIL

Typical Rotor Blade Ice Fragments found in the

Ground

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ELECTROTHERMAL DE-ICING• Heavy system • Large electrical power consumption • Melted ice may flow aft and refreeze further • Qualified by the FAA and the Dod• Fast erosion of metallic leading-edge protections caps

Substitution by erosion resistant composite plastic leading-edge• Plastic materials have low thermal conductivity

Not suitable to work with thermal de-icing systems due to melting and delamination of the material

PNEUMATIC DE-ICING• Light weight • Inexpensive • High engine torque

requirement• Negligible electrical power requirements • Fast erosion of the blade

leading edge boots

ICE REMOVAL DURINGBOOT INFLATION

Other Methods Explored:• FLUID ANTI-ICING• ELECTRO-IMPULSE DE-ICING• ELECTRO-VIBRATORY DE-ICING• HIGH FREQUENCY MICROWAVE ANTI/DE-ICING

Anti/De-Icing Solutions For Rotorcraft

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Anti/De-Icing Solutions For Rotorcraft

Electro-Thermal Fluid Pneumatic Electro-

Impulse Vibratory

Application to Date In Production Flight Tested Being

EvaluatedFeasibility

StudyUnder

Development

Weight (lbs) 162 194 54 120 120

Ice Accretion Yes No Yes Yes Yes

KW Power Requirement 26 Negligible Negligible 3.0 1.3

Performance Effects

10% Torque Increase No Penalty

10% Torque Increase

10% Torque Increase

10% Torque Increase

Runback Potential Yes No No No No

Detached Ice Impact Yes No Yes Yes Yes

Bell Model412 (6800 lb)

Ice Thickness

0.3 in.

Ref: Coffman, H.J., “Helicopter Rotor Icing Protection Methods”

Limited by Fluid on Board

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Anti-Icing Leading Edge Shear Actuator Conceptual Designs

Substitute with Shear Piezoelectric Tube

• Segments poled along longitudinal direction, P2

• Electric field applied in the width direction, E1

a’

Ω a’

a’

Dead Leading Edge Mass (10 – 20% Weight of the Blade)

a a’ a

Insert Embedded Shear Actuators

1 2

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2 Frequency Ranges to Study:

Frequency Ranges to Study

1) Standing wave vibration: 0 Hz up to fifth natural frequency of the system

2) Shear horizontal waves (SHW): 18 KHz up to 20 MHz

Frequency (Hz)

Am

plitu

de R

espo

nse

(Deg

.)

300 Volts input

Analytical Model and Experimental Results 144 in. AL. Tube

Analytical EOMExperimental

Dispersion Curves for a 1mm. Think ice layer on an Aluminum Plate

Theoretical calculations (Rose et al): SHW create interface shear stresses of 0.5GPa.

Chu et al: typical adhesive shear strength of glaze ice is 0.4MPa

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Initial Approach Standing Wave Vibration

a’

Ω a’

PZT Actuator

Aluminum Tube

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20 Psi Pressurized Air Liquid Nitrogen Bath

Cooper Coil

Super Cooled Air Radiator

PZT Shear Actuator

Aluminum Tube

Motivation Icing Static Test

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Piezoelectric Actuator


Frequency (Hz)

Am

plitu

de (D

eg.) FRF: W1 = 436 Hz

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Generate a model to efficiently experimentally test the prototype under icing conditions in future work

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• Introduction of a new shear induced rotorcraft anti-icing conceptual design – Low weight penalty– No heat degradation of plastic/composite materials

• Conduction of icing environment motivation experiments (Vibration Range):– 6’’ Aluminum tube actuated by Shear Tube– Temperature: - 250 C– Ice accretion was prevented by actuator (System 1st natural frequency, standing wave

range)– Input voltage of 300 Volts– Strains generated up to 90 μ-strains (Shear Stress of 2.6 MPa)

• Formulation and experimental validation of an analytical tool to model the system (Vibration Range)

– Uncoupled EOM do not predict the actuators behavior: 1st natural frequency predicted 70% errors

– Electrical – mechanical coupled EOM accurately predict the behavior of the actuator

• Development of analytical tools for SHW ultrasonic ranges

Summary of Preliminary Studies

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• Experimental validation of predicted ultrasonic shear horizontal wave (SHW) behavior – SHW generate 2 orders of magnitude higher shear stress than standing waves (Vibration Range)– Objective:

• Induce horizontal shear waves on a plate using a shear piezoelectric patch• Experimentally observe the generated waves using Electromagnetic Transducers (EMAT)

• Experimental selection of optimum frequency and phase velocity for anti-icing purposes

– Theoretical calculations predicts that for ice layer thicknesses from 0.3 mm to 0.8 mm, the 2nd mode of the SHW will generate high shear stresses (0.5 GPa), sufficient to affect the ice bounding

– Objective:• Form accreted ice to a substrate plate using the liquid nitrogen cooling radiator• Observe the effects of SHW to the ice bounding strength via ice detection system (visual, infrared system, or

ultrasonic guided wave (Rose 1999))

• Measurement of generated shear stresses at the ice-substrate interface

• Implementation of presented ultrasonic anti-icing system to composite and plastic protection leading edge caps

• Cold wind tunnel and hover stand icing testing on proposed ultrasonic induced shear anti-icing system

– Cold Chamber with rotor stand at Penn State

• Fatigue integrity tests– Delamination of composite rotors– Depoling of shear actuators at larger number of cycles (greater than 2 x 108 cycles)

Proposed Future Work

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Shear horizontal ultrasonic waves in a solid isotropic elastic media formal solution

X1

X2 X3

Ice

Fe

o

Wave propagation

∑=

−+=2

1

)(2

31

k

ctxxikk

keBu α

∑=

−+=2

1

)(32

31)(k

ctxxikkk

keikB αμασ

Ultrasonic SHW Theory

2u

32σ

kα

Displacement Field

Stress Field

Eigen values obtained from Christoffel’s Equation

kB Undetermined Coefficients for the Partial Waves

K Wave number along the x1 direction

Corresponding Phase Velocity of the Wave

cSolved from Bc’s

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ICE

d15 Shear Motion

+

-THERMOMETER

SUPERCOOLED AIR FROM LIQUID NITROGEN

RADIATOR

Proposed Initial Approach Shear Horizontal Waves

Poling Direction

Width Applied Voltage

EMAT SENSOR

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Contact: Edward C. Smith

[email protected]

http://www.psu.edu/


• Coffman, H.J., “Helicopter Rotor Icing Protection Methods,” Bell Helicopter Textron Inc., Fort Worth Texas. Journal of the American Helicopter Society 1987

• Gent, R.W., Dart, N.P., and Candsdale, J.T., “Aircraft Icing,” Defense Evaluation and Research Agency, Farnborough, Hampshire GU14 OLX, UK, The royal Society, 2000

• Flemming, R.J., “The Past Twenty Years of Icing Research and Development at Sikorsky Aircraft,” 40th AIAA Aerospace Sciences Meeting, January 14th 2002

• M.C. Chu, and R.J.Scavuzzo, Adhesive Shear Strength of Impact Ice, AIAA Journal, Vol. 29, No. 11, November (1991), 1921-1926

• Bragg, M.B., Bassar, T., Perkins, W. R., Selig, M. S., Voulgaris, P. G., and Melody, J. W., “Smart Icing Systems for Aircraft Icing Safety,” AIAA Aerospace Science Meeting January 14th 2002

• J. L. Rose and Lvis E. Soley, “Ultrasonic guided wave for anomaly detection in aircraft components”, Material Evaluation, Sep. 2000, 1080-1086

• J. L. Rose, D. D. Hongerholt, G.. Williams, “Ultrasonic In-Flight Ice Detection,”

• J. L. Rose, Ultrasonic waves in solid media, Cambridge university press, Cambridge, (1999).

Related References

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