Document
National Aeronautics and Space Administration
Evaluation of Alternative Altitude Scaling
Methods for Thermal Ice Protection System
in NASA Icing Research Tunnel
Sam Lee
Vantage Partners, LLC
Harold E. Addy, Jr. , retired
Andy P. Broeren
NASA Glenn Research Center
David M. Orchard
National Research Council Canada www.nasa.gov 1 National Aeronautics and Space Administration
Outline
• Introduction
• Experimental Methods
• Results and Discussion
• Conclusion
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Introduction
Motivation for Study
• Most thermal Ice Protection System (IPS) development and
testing done in atmospheric icing tunnels that cannot
simulate altitude effects.
• Altitude s caling is required to test IPS in atmospheric wind
tunnels.
• Re - based scaling methods with empirical corrections
typically used.
• A more robust scaling methods desired for development of
current and future generation aircraft
• Joint NASA and NRCC research program conducted to
study the issue.
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Introduction
NRC AIWT Tests (2012, 2014, 2015)
• 18” chord NACA 0018 model with simple heated air IPS
• Re - based scaling method found to be inadequate
• Airfoil surface temperatures well matched between
altitude and ground conditions .
• Accreted ice mass much larger than reference
• Ice formed farther downstream than reference
• Visual evidence of water re - entrainment into air flow.
• Two Weber number based method for scaling investigated .
• One method matched We (water density based)
DW
• Other method matched We (air density based) and
DA m /m (defined as Pi3).
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Introduction
AIWT Tests (2012, 2014, 2015 )
• We - based scaling methods produced ice accretions much
closer in size and location to altitude reference conditions than
Re - based scaling method.
• Provided means of altitude scaling based on primary physics
and not empirical corrections.
Reference Re Scaling WePi3 Scaling
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Introduction
2016 IRT Test
• Compared different scaling methods with a much larger
business jet airfoil model.
• Ice protection system more similar to what is used on
commercial aircraft.
• IRT cannot simulate altitude conditions.
• Results of different scaling methods can be compared to one
another and trends compared to AIWT results.
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Experimental Procedure
• Test conducted in Icing
Research Tunnel at NASA
Glenn Research Center.
• 60 in. chord model
representative of modern
business jet.
• Piccolo tube IPS.
• Built for 2006 Wichita State
University IPS analysis and
modelling study.
• Extensively instrumented with
temperature and pressure
sensors.
0 10 20 30 40 50 60 x (in) www.nasa.gov 7 National Aeronautics and Space Administration
Experimental Procedure
• Surface temperatures (32 TCs)
• 4 TCs in piccolo tubes (Inlet T)
• 4 TCs in diffuser liner (Outlet T)
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Reference Conditions
Altitude V a T T LWC MVD
s t
Flight Phase
(ft) (kts) (deg) (deg C) (deg C) ( m m)
(g/m )
Descent 10000 180 -1 -14.2 -10 0.35 19.1
Cold Hold 15000 180 3 -20.1 -15.8 0.24 17.5
Warm Hold 15000 180 3 -8.6 -4.3 0.49 17.4
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Scaling Parameters
Scaling Parameters Held Constant
Scaling Method
Re Re m K T
2r w 0 r
WePi3 WeDA Pi3 K T
0 r
WeDW WeDW m K T
w 0 r
• Required 2 step process to obtain scaled conditions
• Run at Re - scaled conditions to obtain L.E. temperatures.
• Run at We - scaled conditions with IPS adjusted to match the
L.E. temperatures obtained at Re - scaled conditions.
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Descent Scenario
T m s w Re LWC WeDW MVD Ice Mass Scale 2r Alt (ft) V (kts) WeDA Pi3 2 3 6 ( m m) (g) Method (deg C) (g/m ) (x10 ) (g/m s) (x10 ) Referenc 10000 180 -14.2 0.35 19.1 17.6 0.224 5814 1.6 6.21 N/A Re 1066 133 -12.7 0.48 22.8 17.6 0.224 4315 2.24 3.38 20 WePi3 1439 159 -13.5 0.35 19.4 14.4 0.265 5814 1.62 4.84 8.5 WeDW 1782 180 -14.2 0.34 21.6 17.6 0.297 7769 1.88 6.21 12.7
Re Scaling WePi3 Scaling WeDW Scaling
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Descent Scenario
LE Surface Temperature Re Dry Re Wet WePi3 Dry WePi3 Wet WeDW Dry WeDW Wet T (deg C) -10 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 s/c www.nasa.gov 12 National Aeronautics and Space Administration
Descent Scenario
Heated Air Energy Input Heated Air Temp.
8 Re Re WePi3 WePi3 80 WeDW WeDW ) T (deg C) qdot (W/in Inlet Dry Outlet Dry Inlet Wet Outlet Wet Dry Wet www.nasa.gov 13 National Aeronautics and Space Administration
Cold Hold Scenario
T m LWC WeDW Re s w MVD Scale Ice Mass 2r Alt (ft) V (kts) Pi3 WeDA 2 3 6 ( m m) Method (g) (deg C) (g/m ) (x10 ) (g/m s) (x10 ) Reference 15000 185 -20.1 0.31 14.6 13.4 0.193 5147 1.06 6.54 N/A Re 976 109 -16.4 0.52 20.1 13.4 0.193 3065 1.87 2.27 54.2 WePi3 1495 149 -16 0.28 16.9 9.5 0.253 5147 1.06 4.22 5.0 WeDW 2087 185 -15.7 0.27 18.9 13.3 0.31 8346 1.37 6.54 16.4*
Re Scaling WePi3 Scaling WeDW Scaling
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Cold Hold Scenario
LE Surface Temperature Re Dry Re Wet WePi3 Dry WePi3 Wet WeDW Dry WeDW Wet T (deg C) -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 s/c www.nasa.gov 15 National Aeronautics and Space Administration
Cold Hold Scenario
Heated Air Temp. Heated Air Energy Input Re Re WePi3 WePi3 WeDW WeDW ) T (deg C) qdot (W/in Dry Wet Inlet Dry Outlet Dry Inlet Wet Outlet Wet www.nasa.gov 16 National Aeronautics and Space Administration
Warm Hold Scenario
T m Re LWC WeDW s w 2r Scale MVD Ice Mass WeDA V (kts) Alt (ft) Pi3 3 6 Method ( m m) (g) (deg C) (g/m s) (g/m ) (x10 ) (x10 ) Reference 15000 185 -8.6 0.39 18.3 20.0 0.186 4922 1.74 6.55 N/A Re 1336 109 -6.3 0.66 25.4 20.0 0.186 2923 3.09 2.26 207.5 WePi3 1814 147 -7.3 0.36 19.6 13.6 0.241 4922 1.74 4.12 64.5 WeDW 2454 184 -8.6 0.37 22 20.0 0.299 8005 2.24 6.55 138.8
Re Scaling WePi3 Scaling WeDW Scaling
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Warm Hold Scenario
LE Surface Temperature Re Dry Re Wet WePi3 Dry WePi3 Wet WeDW Dry WeDW Wet T (deg C) -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 s/c www.nasa.gov 18 National Aeronautics and Space Administration
Warm Hold Scenario
Heated Air Temp. Heated Air Energy Input 120 10 Re Re WePi3 WePi3 80 WeDW WeDW ) T (deg C) qdot (W/in Inlet Dry Outlet Dry Inlet Wet Outlet Wet Dry Wet www.nasa.gov 19 National Aeronautics and Space Administration
Conclusion
• Test conducted at NASA Icing Research Tunnel to evaluate
new altitude scaling methods for thermal ice protection
systems.
• Two Weber number - based scaled methods developed during
a series of joint NASA and NRCC tests at AIWT.
• Results from IRT generally agreed with and supported the
results from previous tests in NRCC.
• We - based scaling methods resulted in smaller ice accretion
that formed farther upstream than the Re - based scaling
methods.
• Additional tests required in altitude capable tunnels using full -
scale models to better define the limits of physical
relationships used to develop these scaling methods.
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Extra Slides
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WSU Warm Hold Scenario
T m s w LWC WeDW Re MVD Scale Ice Mass 2r Alt (ft) V (kts) Pi3 WeDA 3 6 (deg C) ( m m) Method (g) (g/m ) (x10 ) (g/m s) (x10 ) Reference 15000 205 -9.4 0.5 20 31.1 0.205 6065 1.73 8.04 N/A Re 1312 126 -6.3 0.82 27.2 31.1 0.205 3769 2.98 3.01 236.5 WePi3 1835 164 -7.6 0.43 24 21.0 0.264 6065 1.73 5.13 68.9 WeDW 2446 205 -9.2 0.5 22.4 31.1 0.324 9715 2.23 8.04 266.2 1191 115 -9.4 0.87 29 30.8 0.192 3229 3.03 2.53 483.3 WSU Model Re WePi3 y (in) WeDW WSU -2 -4 0 2 4 6 8 10 12 14 x (in) www.nasa.gov 22 National Aeronautics and Space Administration
WSU Warm Hold Scenario
Re Scaling
WePi3 Scaling
WSU Scaling
WeDW Scaling
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WSU Warm Hold Scenario
Heated Air Temp.
Re 140 LE Surface Temp.
WePi3 WeDW WSU Re Dry Re Wet WePi3 Dry T (deg C) WePi3 Wet WeDW Dry WeDW Wet WSU Dry WSU Wet Inlet Dry Outlet Dry Inlet Wet Outlet Wet T (deg C) Heated Air Energy Input Re WePi3 WeDW -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 WSU ) s/c qdot (W/in Dry Wet www.nasa.gov 24