Bimodal SLD Ice Accretion on a NACA 0012 Airfoil Model

National Aeronautics and Space Administration

Bimodal SLD Ice Accretion on a NACA 0012

Airfoil Model

Mark Potapczuk

NASA John H. Glenn Research Center, Cleveland, Ohio, 44135 USA

Jen - Ching Tsao

Ohio Aerospace Institute, Cleveland, Ohio, 44135 USA

Laura King - Steen

HX5 Sierra, Cleveland, Ohio, 44135 USA Presented at 9th AIAA Atmospheric and Space Environments Conference Denver, CO June 5 - 9, 2017 www.nasa.gov 1 National Aeronautics and Space Administration

Outline

• Objectives

• Approach

• Background

 Facility

 Cloud Conditions

 Model

 Test Procedures

 Test Matrix

• Results

• Concluding Remarks

• Acknowledgements

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Objectives

1. Document the Ice Shapes Produced using the IRT

Bimodal Spray Conditions

2. Compare with Ice Shapes Produced using the Single

Nozzle Array ( Monomodal ) for Equivalent Cloud

Conditions

 Use previously produced ice shapes as reference

conditions

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Approach

1. Evaluate the IRT Bimodal Spray Ice Shapes

• At 130, 150, 200 & 250 knots

 

• At α = 0 , 4

2. Compare with Monomodal S pray Ice Shapes at

• 2 Ice Shape Repeatability Conditions

• 2 Ice Shape Condition from Scaling Work

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NASA Icing Research Tunnel

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2016 IRT Bimodal Spray

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Selected IRT Mod1 Spray Condition

Monomodal Distribution

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2016 IRT Bimodal & Monomodal Distributions

• FZDZ, MVD<40 1.0 – FAA App O distribution 0.9 – MVD=20 μ m – LWC between 0.29 and 0.44 g/m 0.8 • Bimodal 0.7 – Mod1 + Std nozzles 0.6 – Pair = 15 psig – Mod1 DeltaP = 80 psid 0.5 – Standard DeltaP = 7 psid 0.4 – Combined MVD = 20.8 μ m – Combined minLWC (@250 kts ) = 1.45 g/m 0.3 FZDZ, MVD < 40 • Monomodal 0.2 Mod1 (15, 30) Monomodal – Mod1 nozzles even Normalized Cumulative Volume 0.1 Cond 3 Mod1+Std Bimodal – Pair=15 psig even – DelP =30 psid 0.0 1 10 100 1000 – MVD=19.3 μ m Drop Diameter ( m m ) – minLWC (@250 kts ) = 0.37 g/m • Both IRT distributions were measured by spraying only even - numbered spray bars , as is typical for drop - sizing calibrations in Appendix C conditions in order to avoid coincidence error • LWC values are based on IRT calibration curves www.nasa.gov National Aeronautics and Space Administration

Test Model

21 - in chord NACA 0012 model, full span

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Test Procedures

• The tunnel temperature and velocity conditions were set.

• The spray bar air and water pressures were set.

• The tunnel was run at the set temperature and velocity conditions and the thermocouples on the model were monitored.

• When the model temperature matched the tunnel static air temperature, the model was considered to be sufficiently cold to initiate the spray.

• The spray was initiated and lasted for the prescribed time for the icing condition of that run.

• After the spray was stopped and the tunnel velocity was reduced to idle conditions, personnel entered the test section and performed the following tasks.

• Photographs of the ice on the model were taken from several pre - set locations around the model.

• A laser scanner system was used to obtain geometric data of the ice shape using the * method described by Lee, et al.

• Once the ice shapes were scanned, a 12 inch spanwise section of the ice shape was removed from the surface into a collection tray and weighed in order to obtain the accumulated mass.

• Following the removal of the mass, the model surface was cleaned of all remaining ice and prepared for the next test run .

* Lee , S., Broeren , A.P., Kreeger, R.E., Potapczuk, M., and Utt, L., “Implementation and Validation of 3 - D Ice Accretion Measurement Methodology,” AIAA 6th Atmospheric and Space Environments Conference, Atlanta, GA, June 16 - 20, 2014, AIAA Paper 2014 - 2613.

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Test Matrix

5 proposed reference conditions

Test Conditions

V MVD LWC T T Time t s Reference Case α n Condition (kts) ( m m) (min)

(g/m ) ( ° C) ( ° C)

Ice Shape Repeatibility 1 4 200 20 0.55 -5.6 -10.8 7 0.52 Run 3 Ice Shape Repeatibility 2 4 130 22 1 -5.6 -7.8 6 0.34 Run 23 5-15-06/Run 14 3 0 150 30 1.34 -12.5 -15.5 5.5 0.49 5-15-06/Run 15 4 0 100 30 1.75 -13.5 -14.8 6.7 0.5 3-28-05/Run 6 5 0 250 26.8 0.56 -5.2 -13.4 8.5 0.46

Note: For scaling, two selected spray clouds are considered

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Test Matrix

Monomodal and bimodal test conditions based upon

scaling of reference conditions.

Mod-1 Mod-1 Std Std V MVD LWC T T Time t s Reference Run # α n p , Dp , p , Dp , (kts) ( m m) (min) 0 air air

(g/m ) ( ° C) ( ° C)

Condition psig psid psig psid -2.3 -10.5 AE2716 5.b 0 250 19.3 0.37 14 0.46 15 30 -2.8 -5 AE2717 2.b 4 130 19.3 0.55 11.5 0.34 15 30 -3.9 -9.2 AE2718 1.b 4 200 19.3 0.42 9.3 0.52 15 30 -9.9 -12.1 AE2719 2.a 4 130 20.8 2.15 2.9 0.34 15 80 15 7 -11.9 -20.2 AE2720 5.a 0 250 20.8 1.45 3.5 0.46 15 80 15 7 -15.2 -20.5 AE2721 1.a 4 200 20.8 1.64 2.3 0.52 15 80 15 7 -2.3 -10.5 AE2738 5.b 0 250 19.3 0.37 14 0.46 15 30 -2.8 -5 AE2739 2.b 4 130 19.3 0.55 11.5 0.34 15 30 -4.2 -7.2 AE2740 3.b 0 150 19.3 0.5 17 0.49 15 30 -9.9 -12.1 AE2741 2.a 4 130 20.8 2.15 2.9 0.34 15 80 15 7 -14.9 -17.9 AE2742 3.a 0 150 20.8 1.96 4.2 0.49 15 80 15 7

Note: a - Bimodal spray ; b - Monomodal spray

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Olsen Method for Scaling LWC

1. c = c

s r

2. V = V

s r

3. MVD = MVD

s r

4. Choose a LWC

s

5. Calculate the scale temperature T from n = n

st,s 0,s 0,r

6. Calculate the scale total temperature, T . If T is

tot,s tot,s

greater than - 2˚C, repeat steps 4, 5, and 6 with a larger

LWC

s

7. Calculate the scale accretion time from A = A , which

c,s c,r

leads to t = ( LWC ˣ t )/LWC

s r r s www.nasa.gov 13 National Aeronautics and Space Administration

Sample Photograph and Scan

Test Run #AE2741

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Test Results

Quantitative Data

Mass and volume measurements for the ice shapes

resulting from the scaled monomodal and bimodal

distribution icing conditions from this test program .

Test Results

Reference Mass Mass Volume Volume r r D r D m D m D Vol. D Vol.

eff,b eff,m eff i i Condition bimodal monomodal bimodal monomodal 3 3 3 3 3 (g) (g) (g) % in in in % g/in g/in % 1 163.1 131.2 31.9 24% 13.67 12.39 1.28 10.3% 11.9 10.6 12.7% 2 151.9 137.9 14 10% 14.3 11.28 3.02 26.8% 10.6 12.2 -13.1% 3 207.1 188 19.1 10% 18.46 15.49 2.97 19.2% 11.2 12.1 -7.6% 5 228.5 157.8 70.7 45% 19.52 13.56 5.96 44.0% 11.7 11.6 0.6% 3 3

Note: Density of ice at 0˚C is 0.9167 g/cm = 15.02 g/in

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Ice Shape Comparisons to Reference Shapes

Reference Condition 1, V= 200 knots

3 3 MVD = 20 m m, LWC = 0.55 g/m , t = 7 min MVD = 20 m m, LWC = 0.55 g/m , t = 7 min 1 1 1 1 1 1 3 3 MVD = 20.8 m m, LWC = 1.64 g/m , t = 2.3 min MVD = 19.3 m m, LWC = 0.42 g/m , t = 9.3 min 1a 1a 1a 1b 1b 1b

Monomodal Distribution (b) Bimodal Distribution (a)

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Ice Shape Comparisons to Reference Shapes

Reference Condition 2, V = 130 knots

3 3 MVD = 22 m m, LWC = 1.00 g/m , t = 6 min MVD = 22 m m, LWC = 1.00 g/m , t = 6 min 2 2 2 2 2 2 3 3 MVD = 20.8 m m, LWC = 2.15 g/m , t = 2.9 min MVD = 19.3 m m, LWC = 0.55 g/m , t = 11.5 min 2a 2a 2a 2b 2b 2b

Monomodal Distribution (b) Bimodal Distribution (a)

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Ice Shape Comparisons to Reference Shapes

Reference Condition 3, V = 150 knots

3 3 MVD = 30 m m, LWC = 1.34 g/m , t = 5.5 min MVD = 30 m m, LWC = 1.34 g/m , t = 5.5 min 3 3 3 3 3 3 3 3 MVD = 20.8 m m, LWC = 1.96 g/m , t = 4.2 min MVD = 19.3 m m, LWC = 0.5 g/m , t = 17 min 3a 3a 3a 3b 3b 3b

Monomodal Distribution (b) Bimodal Distribution (a)

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Ice Shape Comparisons to Reference Shapes

Reference Condition 5, V = 250 knots

3 3 MVD = 26.8 m m, LWC = 0.56 g/m , t = 8.5 min MVD = 26.8 m m, LWC = 0.56 g/m , t = 8.5 min 5 5 5 5 5 5 3 3 MVD = 20.8 m m, LWC = 1.45 g/m , t = 3.5 min MVD = 19.3 m m, LWC = 0.37 g/m , t = 14 min 5a 5a 5a 5b 5b 5b

Monomodal Distribution (b) Bimodal Distribution (a)

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Bimodal Cloud Effects on Ice Shapes

I cing limits are further aft I cing limits are further aft Ref. 1 Ref. 2 2 4% more ice mass 10% more ice mass 10% more volume 27% more volume monomodal bimodal I cing limits are further aft I cing limits are further aft Ref. 5 Ref. 3 10% more ice mass 45% more ice mass 44% more volume 19% more volume www.nasa.gov 20 National Aeronautics and Space Administration

Ice Shape Repeatability

Reference Condition 2

3.6% ice mass difference 8.4% ice mass difference 5.9% volume difference 13.6% volume difference

Monomodal Distribution (b) Bimodal Distribution (a)

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Normalized Ice M ass Difference

𝑀 = 𝐿𝑊𝐶 ∙ 𝑉 ∙ 𝑡 ∙ 𝐴

𝑤 𝑝

∆ ෥ 𝑚 = ∆ 𝑚 / 𝑀

𝑖 𝑖 𝑤

A = projected area

p

D m = measured

i

mass difference

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Concluding Remarks

• Bimodal s pray i ce s hapes were created based upon the simultaneous

spray process of Steen and Ide

• Test conditions, using monomodal and bimodal spray distributions, were

developed for comparison to previously tested and recorded conditions

• For conditions that were the nominally the same, using the Olsen scaling

method, the bimodal ice shapes:

 Had a larger mass

 Had a greater volume

 Had icing limits further aft on the airfoil

• The ice mass difference seemed to increase with increasing velocity

• These differences seemed to be somewhat larger than repeatability

• More Evaluation Tests Recommended

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Acknowledgements

The authors would like to thank Quentin Schwinn and

Jordan Salkin of Alcyon Technical Services (ATS) JV, LLC

for their invaluable support in ice shape scanning and

post - processing.

The authors would also like to thank the IRT staff for their

support in advocating for this work and during the test

campaign.

This work was supported through the Aeronautics

Evaluation and Test Capabilities (AETC) Project.

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