Task A-1.13: Experimental Measurement of Ice Accretion and ... shapes tubes.pdfProposal Comments • High level of risk involved in the development of this facility. To assist code

Dept. of Aerospace Engineering

Task A-1.13: Experimental Measurement of Ice Accretion and Shedding of Rotating Airfoils

Dr. Jose L PalaciosResearch Associate

[email protected]

ARMY Program Review

April 7, 2010

Yiqiang HanResearch Assistant

1


OutlineOutline

•• Background and MotivationBackground and Motivation

•• Research ObjectivesResearch Objectives

•• Technical ApproachTechnical Approach–– Facility Description and LimitsFacility Description and Limits

–– Facility Sensitivity Studies Facility Sensitivity Studies –– LWC LWC

–– Ice Shape Correlation to IRT/USAF TestsIce Shape Correlation to IRT/USAF Tests

–– Ice Shedding RigIce Shedding Rig

•• SummarySummary

2


Background and MotivationBackground and Motivation

Current 6.2 NRTC project: High Fidelity Icing Analysis and Validation for Rotors• Bell/Boeing/Sikorsky/NASA effort

• CFD Tool development – Penn State/Bell (NASA-NRA)

• Testing In NASA IRT starting 2011

• Goal: validate analytical tools for the prediction of rotor and fuselage ice accretion,

ice shedding from a rotating/oscillating blade, deice and anti-ice system performance

including transient heat transfer, and performance impact due to ice accretion.

• Rotorcraft qualification through full-scale tests is challenging and expensive

• Uncertainties in flight test data (conditions are difficult to control and measure)

• Need for well-validated analytical tools

• There are few test facilities that can accommodate rotating icing tests

• Ice accretion, shedding and performance degradation data collection required

Ultimate goal: All Weather Rotorcraft

Limited open access to ice shape database

accreted during rotation


Research ObjectivesResearch Objectives

• Finalize Construction of a Rig:

Adverse Environment Rotor

Tests Stand - AERTS

• Determine Capability and

Limitations of the facility

• Facility LWC Calibration

• Generate Ice Shape Database (NACA 0015)

• Generate Ice Shedding Database (Al., SS, TI, Ni) 4


Proposal CommentsProposal Comments

• High level of risk involved in the development of this facility. To assist code development

or icing physics studies, need to quantify and mitigate the uncertainties in the icing cloud.

• Develop an alternative airfoil section beyond the current elliptical section

• Tighten up the objectives and provide additional costs and items needed for calibration. Need a cost estimate for PIV and LWC needs, plus a risk reduction path which assumes a realistic level of funding.

Identify facility limitations, and determine facility unknowns (LWC)

1-in Cylinder and 3.75-in chord NACA 0015 currently used; Next test plan has been targeted at the NACA 0012 for calibration

The objective has been revised (oscillation accretion postponed) and attention will

be intensively paid on the facility validation, accretion correlation, analysis of coupled parameter impact and scaling method for realistic level of future research.


OutlineOutline



•• Technical ApproachTechnical Approach

–– Facility Description and LimitsFacility Description and Limits





6


AERTS Facility New Features AERTS Facility New Features

9 ft

Slip Ring

Collective ActuatorBell Housing w/ 6 Axis Load Cell

Weather Station

Creation of new capabilities at the AERTS- Low cost rotor icing facility - Collective and lateral cyclic rotor control – 9 ft. blades- Ice shape measurements system


LWC

• Controlled by MVD, nozzle configuration and temperature • NASA standard nozzles, controlled with feedback control loops for constant water and air

pressure

• Flexible nozzle control (0 to 15 nozzles)– Testing has shown that chamber saturation occurs at ∆P (water - air PSI) of >45 Psi– This promotes crystallization of water particles– Crystals erode ice shapes, generating spear-like geometries– Reduction of operational nozzles/water flow rate mitigates the issue

Environment Control Limitations

8

NACA 0012

View From Tip

Samples of Eroded Ice Shapes


5

10

15

20

25

30

35

40

45

50

0 25 50 75 100 125 150W ater Pressure - A ir Pressure, psid

Me

dia

n V

olu

me

Dia

me

ter,

µ

m

Air Pressure

psig

10 15 20 25 30 35 40 45 50 55 60

65

70

NASA Standard Nozzle

AERTS LIMIT

Adjustable Nozzle Control – total 15 Nozzles – Facility Ceiling View


25 Psi Air, 25 MVD, 500 RPM 30 Psi Air, 25 MVD, 500 RPM

Icing Experiments Performed at AERTSEroded Ice Shape

Tsao, J., Kreeger, R.,

AIAA 2009-4125

Ice shape Erosion

High number of nozzles,

High airline

Water droplet: Saturation,

Crystallization

Eroded “spear” ice shape 10

Collection Screen for Crystal Mitigation


Temperature LimitationTemperature Limitation

Temperature

• Chamber cooled by convection fans

• Fans must be shut down during operation to avoid ice accretion

• Currently, it limits the capability to maintain a desired temperature within 1°C to

3.5 minutes, as warm air, water and kinetic friction of the rotor increase the

temperature in the chamber

DURIPRequested to install conduction cooling lines to maintain

temperature during testing


Icing Test Capability:MVD/LWC

MVD: Calculated from NASA calibration tables (10 to 100 µm)

- Not directly or indirectly measured during testing

LWC:

Changing with water cloud, coupled with: MVD, Local Velocity,

Aerodynamics (circulation at the tip - ), etc., temperature

Also, sensors not applicable:

- LWC sensors required a minimum velocity component

- Rotation of sensors is not possible

LWC MUST BE EXPERIMENTALLY DETERMINED

12


• A LWC tracing back method based on experimental ice thickness was developed

• Validation based on experimental data from:

• A LWC tracing back method based on experimental ice thickness was developed

• Validation based on experimental data from:

LWC Calculation Code

13

40 cases for airfoil from “Evaluation and Validation of the

Messinger Freezing Fraction,” Anderson D., and Tsao, J.,

NASA/CR—2005-213852, AIAA–2003–1218,

14 cases for cylinder from “Evaluation of Constant-Weber-Number

Scaling for Icing Tests,” Anderson, David N., AIAA-96-0636 and

NASA TM 107141

NASA confirms LWC values in the IRT by checking ice thickness on grids

In our case, we measure ice thickness, and calculate freezing fraction

and corresponding LWC


14


LWC Calculation Code Validation

• From experimental LWC and ice thickness presented in literature:

determine if code can predict LWC from ice thickness

“Evaluation and Validation of the

Messinger Freezing Fraction,”Anderson D., and Tsao, J.,

NASA/CR—2005-213852

“Evaluation of Constant-Weber-

Number Scaling for Icing Tests,”Anderson, David N., AIAA-96-0636

and NASA TM 107141


Some of the data shows Discrepancy

Code Validation: Code Validation: Result Comparison

16

“Evaluation and Validation of the

Messinger Freezing Fraction,”

Anderson D., and Tsao, J.,

NASA/CR—2005-213852, AIAA–

2003–1218,

“Evaluation of Constant-Weber-

Number Scaling for Icing Tests,”

Anderson, David N., AIAA-96-0636

and NASA TM 107141

Code Prediction


0.08 (45%) difference in

freezing fraction

0.8 (200%) difference in

LWC

0.005 inch difference in

ice thickness0.43g/m3 difference in

LWC

Uncertainty Analysis andMeasurement Tolerance

AERTS Experiments


AERTS LWC Sensitivity StudiesAERTS LWC Sensitivity Studies

CALIBRATION CONDITIONS Total: 21 Test Cases

RPM 400 500 600

MVD (µm) 20 25 30

Temperature (°C) -5 -10 -15

Airline (psi) 20 25 30

18

Tip speed 180 ft/sec

Bottom View Rotor

with Accreted Ice


500 RPM, 25 Psi Air, 25 MVD, 3 min.

0.8

0.9

1

1.1

1.2

1.3

1.4

0.5 0.6 0.7 0.8 0.9 1

Rotor Span (r/R)

Ice

Th

ick

ne

ss

(in

.)Icing Experiments Performed at AERTS

Thickness VS. Temperature

-100C, LWC 2.35 g/m3

-150C, LWC, 2.55 g/m3

-50C, LWC 2.29 g/m3


-100C, LWC 2.35 g/m3

-150C, LWC, 2.55 g/m3

-50C, LWC 2.29 g/m3


500 RPM, 25 Psi Air, -15 Deg. C

1

1.05

1.1

1.15

1.2

1.25

1.3

1.35

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Rotor Span (r/R)

Ice T

hic

kn

ess (

in.)

20 MVD

30 MVD

Linear (30 MVD)

Linear (20 MVD)

LWC = 2.4 gr/m3

LWC = 2.2 gr/m3

Icing Experiments Performed at AERTSThickness VS. Temperature

Thickness VS. MVD


Thickness VS.RPM

25 Air line, 25 MVD, -5 Deg C.

0.8

0.9

1

1.1

1.2

1.3

1.4

0.5 0.6 0.7 0.8 0.9 1

Span Location (r/R)

Ice T

hic

kn

ess (

in.)

LWC 2.4 gr/m3

LWC 3 gr/m3

600 RPM

500 RPM


OutlineOutline








•• SummarySummary23


Icing Experiments Performed at AERTSReproduction of Literature Ice shapes

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5

X Dimension (in.)

Y D

ime

nsi

on

(in

.)

Reference

Cylinder

Experimental

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5

X Dimension (in.)

Y D

ime

nsi

on

(in

.)

Reference

Cylinder

Experimental1 in Tube

27 MVD 490 RPM 0.91 r/R59.2 m/sec

-120C

Ref: Anderson, D., “Rime-, Mixed-, and Glaze-Ice Evaluations of Three Scaling

Laws,” NASA Technical Memorandum 106461, AIAA-94-07-18, AIAA 32nd

Aerospace Sciences Meeting and Exhibit, Reno, Nevada January 10-13, 1994.


ResultsResults

25

25 MVD

510 RPM

0.875 r/R

58 m/sec-11.70C

Ref: Anderson, D., “Rime-, Mixed-, and Glaze-Ice Evaluations of Three Scaling

Laws,” NASA Technical Memorandum 106461, AIAA-94-07-18, AIAA 32nd

Aerospace Sciences Meeting and Exhibit, Reno, Nevada January 10-13, 1994.


ResultsResults

26

Ref: Ruff, G., “Analysis and Verification of the Icing Scaling

Equations,” Air force Technical Report AEDC-TR-85-30,

November 1985


ResultsResults



November 1985


Summary Summary

Ice Shape Validation ResultsIce Shape Validation Results

28

It is believed that increases of temperature

during testing beyond the desired

comparison value are the main cause for

shape deviations



November 1985


OutlineOutline






–– Ice Shape Correlation to IRT/Ice Shape Correlation to IRT/AirforceAirforce TestsTests



29


Shedding Rotor Shedding Rotor

Expected Behavior

4.5 ft.

Strain Gauge Location

Design by – Ed Brouwers

Construction/Testing – Jose Palacios

Ref: Stallabrass, J., Price., R., “On the

Adhesion of Ice to Various Materials” 1962


Ice Shedding RotorIce Shedding Rotor

Post Shedding Photo


Sample ResultSample Result

3.8

3.9

4

4.1

4.2

4.3

4.4

4.5

4.6

4.7

0 100 200 300 400 500

Time (Sec.)

Voltage A

mplit

ude (

V)

Icing Cloud ON

Shedding

Rotor OFF

350 RPM 0 RPM


ConclusionsConclusions

• Facility construction finalized

• Capability to spin up to 9 ft. diameter rotors

• Limitations of facility identified

• Capability of performing desired icing tests in AERTS confirmed

• Generally satisfying correlation of experimental ice shape comparisons

• Correlations between IRT and AERTS stagnation ice thicknesses are excellent, with less than 2% discrepancy between tests

• Impingement limits deviated at the AERTS facility by increases of up to 16% of stagnation thickness

• It is believed that increases of temperature during testing beyond the desired comparison value are the main cause for these discrepancies


• Calibration table, complete database

• Continue ice shape correlations – Airfoils

• Investigate circulation and CF effects unique to AERTS

• Implement ice shape laser measuring system

• Test stability and repeatability

• Start data base creation (NACA 0015, shedding)

Future WorkFuture Work

34


AERTS LAB FundingAERTS LAB Funding

AERTS ConstructionHuntsville, AL

DURIPFreezerMotor

CF Rig

PIV for Rotor and MVD Measurement DURIP

Laser LWC DURIP

QH-50 HubIcing Nozzles

Glenn

35

MVD, LWC Measurement & Cooling System

DURIP?

PSU


External InteractionsExternal Interactions

• NASA (Eric Kreeger) – Task Monitor• AATD (Dr. Louis Centolanza, Nelson Ciron)

• Boeing (Andy Peterson)

• Goodrich (Galdemir Botura)

Glaze Ice (60 µm)

36

PapersPapers

Palacios, J., Brouwers, E, Han, Y, Smith , E., “ADVERSE ENVIRONMENT ROTOR TEST STAND

CALIBRATION PROCEDURES AND ICE SHAPE CORRELATION” – 2010 AHS

Brouwers, E., Palacios, J., Smith, E., Peterson, A., “THE EXPERIMENTAL INVESTIGATION OF

A ROTOR HOVER ICING MODEL WITH SHEDDING” – 2010 AHS, 2010 AHS, LitchtenLitchten Competition Paper, Competition Paper,

2010 NASA AHS Intern Award Winner2010 NASA AHS Intern Award Winner


QuestionsQuestions……??

37

Documents

Task A-1.13: Experimental Measurement of Ice Accretion and ... shapes tubes.pdfProposal Comments • High level of risk involved in the development of this facility. To assist code