Document
CD–10–83242 at Lewis Field Page 1 Gene Addy, NASA Glenn Peter Struk, NASA Glenn William Wright, Vantage Group, LLC Tadas Bartkus, Ohio Aerospace Institute Recent Advances in the LEWICE Icing Model Icing Branch
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National Aeronautics and Space Administration at Lewis Field Page 2 Outline Comparison with Thermal Scaling Data Comparison with RatFac Data – – Thermal Model Modifications Thermal Model Validation Conclusions from Thermal Analysis Mixed Phase Additions Mixed Phase Calibration Conclusions From Ice Crystal Analysis • • • • • • Icing Branch
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k x V 5*10 a w at Lewis Field w 2 c h We w k x G Page 3 a V a h x G We h 3 x c Thermal Model Additions We w We h We x in , Chilton-Colburn analogy underestimates evaporation rate by 30% t h shed – Myers Water Film Model Surface Water Shedding Model (calibrated) Enhanced Evaporation m runback m • • • Icing Branch
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at Lewis Field 0.38 h x d Page 4 0.22 h n z d Process for Comparison 0.004 Re Pr Nu All Cases Use Same Coefficients – Determine Internal Heat Transfer Coefficient from Dry Cases External Heat Transfer Coefficient is Forced Laminar Where There is No Ice Run All Dry Cases To Ensure Correlation Matches Run Wet Cases for Validation • • • • Icing Branch
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t(min) 7 7 7 7 10 10 AOA 0 0 0 0 0 0 MVD 20 27.8 20 24.5 20 27.8 LWC 0.5 0.85 0.15 0.21 0.15 0.25 at Lewis Field T(K) 264.5 266.9 253.1 254.9 247.4 245.5 Page 5 V(m/s) 92.7 54.3 92.7 66.8 92.7 54.6 P(Pa) 57295 98525 69981 97422 57295 98318 Conditions Used For Thermal Comparison Case Warm Hold(Ref) Warm Hold(Scale) Descent(Ref) Descent(Scale) Cold Hold(Ref) Cold Hold(Scale) Icing Branch
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at Lewis Field Page 6 Warm Hold (Ref) - Dry Icing Branch
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at Lewis Field Page 7 Warm Hold (ref) - Wet Icing Branch
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at Lewis Field Page 8 Warm Hold (Ref) Ice Shape Comparison Icing Branch
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at Lewis Field Page 9 Warm Hold (Re Scale) - Dry Icing Branch
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at Lewis Field Page 10 Warm Hold (Re Scale) - Wet Icing Branch
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at Lewis Field Page 11 Warm Hold (Re Scale) Ice Shape No Ice from Experiment nor from LEWICE • Icing Branch
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at Lewis Field Page 12 Descent (Ref) Icing Branch
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at Lewis Field Page 13 Ice Growth in Impingement Direction Descent (Ref) Ice Growth Normal to Surface (Default) Icing Branch
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at Lewis Field Page 14 Descent (Re Scale) Icing Branch
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at Lewis Field Page 15 Descent (Re Scale) Icing Branch
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at Lewis Field Page 16 Cold Hold (Ref) - wet Icing Branch
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at Lewis Field Page 17 Cold Hold (Ref) Icing Branch
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at Lewis Field Page 18 Cold Hold (Re Scale) - wet Icing Branch
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at Lewis Field Page 19 Cold Hold (Re Scale) Icing Branch
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at Lewis Field Page 20 Observations from Thermal Analysis Peak Ice Thickness Higher for LEWICE Peak Thickness Higher for LEWICE, Especially Upper Surface – – Temperature Prediction is Very Good to Excellent for Most Cases Warm Hold Cases Show Predicted Runback Ice Forward of Experiment Descent and Cold Show Predicted Runback Ice Forms Slightly Behind Experiment Ice in Experiment Grows Toward Leading Edge While LEWICE always grows Ice Normal to Surface Further Refinement of Runback Model May Be Necessary External Heat Transfer Coefficients for Residual Ice Shapes Need to Be Separately Validated • • • • • • Icing Branch
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1.5
imp
cos
at Lewis Field TWC
imp V
1979.167
= 0.14 for TWC > 0.12
Page 21 7.5*10 and
TWC
0.57 Ice Breakup Model
imp
47.292
d
cos 0.45 sin For TWC < 0.12 kg/m
0.1425
– Breakup Threshold (Hauk) Sticking Efficiency (Currie) imp b o V m m • • Icing Branch
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t(m) 3 3.5 3.5 3 AOA -6 -6 -6 0 IWC 4.4 6.9 7.3 4.9 LWC 1.4 1.3 1.9 0.6 at Lewis Field Sh 8.3 5.6 5.2 5.9 T 12.7 4.3 3.8 7.2 Page 22 V 87.4 83.9 84.1 86.2 P 6.5 10 10 6.5 Scan# 889 996 1003 796 Conditions for Ice Crystal Comparison Airfoil Wedge Wedge Wedge NACA 0012 Icing Branch
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at Lewis Field Page 23 Ice Shape Prediction for Scan 996 Icing Branch
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at Lewis Field Page 24 Ice Shape Prediction for Scan 1003 Icing Branch
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at Lewis Field Page 25 Particle Sizes Sticking Efficiency on Wedge at Various Icing Branch
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at Lewis Field Page 26 (NACA0012) Ice Thickness Prediction for Scan 796 Icing Branch
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at Lewis Field Page 27 Additional Erosion Effects may be Needed Improved Model for Reimpingement of Ice Crystals Observations from Ice Crystal Comparison – – Peak Thickness is Over Predicted by LEWICE while Extent is Under Predicted Additional Data is Needed to Complete Model • • Icing Branch