Altitude Effects on Thermal Ice Protection System Performance; A Study of an Alternative Simulation Approach

Altitude Effects on Thermal Ice

Protection System Performance;

a Study of an Alternative

Simulation Approach

Gene Addy – NASA

Bill Wright – Vantage Partners, LLC

David Orchard & Myron Oleskiw – NRC - C

Presentation will include:

• Need for Study

• Initial test results

• Study Plan

• Development of alternate

scaling method

Ref Re-sc We-sc

• Flight scenarios

• Reference & Scaled test

conditions

Accreted Ice Mass, g

• Test Description & Results

Descent Wm Hld Cld Hld

• Summary

Need for Study

↓

Aircraft efficiency

Onboard power available ↓

Thermal IPS power ↓

Running wet vs. evaporative

Evaporative Running Wet

D evelop and test thermal IPS

at ground level icing facility

- Method to account for

NEED: altitude effects

- Validation data for

Computational tools

Power Required, W/in Descent Warm Hold

Example IPS power

Initial Study & 2012 Test

Leading Edge Inner Surface Temperatures Warm Hold - 7 min. Ridge Ice • Objectives:

– Study physics

Dry

– Test altitude scaling

Wet Temperature, Celcius square - ref

method (Re)

-10 triangle - sc -0.2 -0.1 0 0.1 0.2 s/c

• Outcomes

Heated Air Energy Loss

– Heat transfer scaled well

Reference

– Mass transfer did not

Scale qdot, W/sq. in.

– Water drops blown off

Warm Hold Dry Wet

surface?

0.400 , 0.300 Ref Icing Rate 0.200 Sc

AIAA 2013 - 2934

IPS/No IPS 0.100 Normalized 0.000

Study Plan

– Define scaling

method (alt/ grd )

[Icing Conditions] =

altitude

– Altitude Icing Wind

[Icing Conditions]

ground level

Tunnel (AIWT)

– NACA airfoil with

Heated Air IPS

– Various icing

scenarios

– IPS operated in

running wet mode

– Compare results: ice

accreted, surface

temps, heat rejection

– Assess scaling

method, insight on

processes

Thermal IPS Scaling Method

Parameters matched:

• Reynolds number Re = ρ Vd / μ , d=2xLE radius

• Water loading M = LWC ∙V∙ β

w

• Impingement K = f( Re )

0 droplet

• Recovery temperature T = T (1+r(( - 1)/2)M )

r s

Also matched: RHF, H , H , Nu, Sh , St, St

c g m

Not matched: ή , We

Alternate Thermal IPS Scaling Method

Parameters matched:

• Weber number We = ρ ∙ V ∙ d/ σ , d=2xLE radius

w

• Water loading M = LWC ∙V∙ β

w

• Impingement K = f( Re )

0 droplet

• Recovery temperature T = T (1+r(( - 1)/2)M )

r s

• Model leading edge surface temperatures*

Not matched: Re , ή , RHF, H , H , Nu, Sh , St, St

c g m

*Requires two steps: Re match run (dry) followed by

We match

Flight Scenarios for study

• Descent

• Cold Hold

• Warm Hold

Reference Conditions

Alt ., V , AOA, T , LWC, MVD, s o 3

Flight phase m kt deg C g/m μ m

Descent 3048 180 0 - 14 0.35 20

Cold Hold 4572 180 0 - 30 0.24 20

Warm Hold 4572 180 0 - 9 0.50 20

Altitude Thermal Scaling Study

Reference and corresponding scale conditions

Alt. V T LWC MVD Re - 2xr We - 2xr M T s w r o 3 6 6 2 o Flight phase m kt C g/m μ m x10 x10 g/m - s K C Descent (ref) 3050 180 - 14 0.35 19.6 1.58 4.30 20.3 1.37 - 10 (Re sc ) 130 - 12 0.49 24.0 1.58 2.24 20.3 1.37 - 10 (We sc ) 180 - 14 0.35 21.1 2.15 4.30 20.3 1.37 - 10 Cld Hld (ref) 4570 180 - 30 0.24 17.4 1.43 4.30 13.4 1.23 - 26 (Re sc ) 106 - 28 0.41 24.2 1.43 1.49 13.4 1.23 - 26 (We sc ) 180 - 30 0.24 19.5 2.35 4.30 13.4 1.23 - 26 Wm Hld (ref) 4570 180 - 8 0.54 17.7 1.26 4.30 30.3 1.24 - 5 (Re sc ) 106 - 6 0.91 24.5 1.26 1.50 30.3 1.24 - 5 (We sc ) 180 - 8 0.54 19.8 2.08 4.30 30.3 1.24 - 5

Facility

• NRC Canada Altitude

Icing Wind Tunnel (AIWT)

• Test Section: 57 cm x 57 cm

(22.5 in. x 22.5 in.)

• Airspeeds: 10 – 194 kts

o o

• Air Temp: - 35 C to +40 C

• LWC: 0.1 to 3 g/m

• MVD: 8 to 100 μ m

• Altitude simulation: ground

level to 9100 m

Model

NACA 0018, 45.7 cm (18 in.) chord

• Simple design to study fundamentals

• Aluminum skin on aluminum spar and

rib frame

Heated Air IPS

• 2D flow

• Piccolo tube, single row of holes

Runback Ice - Descent

Alt P V T LWC MVD Tau Ice alt s o 3 m kPa kt C g/m μ m s g (Ref ) 3048 69.7 180 - 14.1 0.38 19.5 600 32.6

(Ref)

(Re - sc ) 453 96.0 130 - 12.4 0.50 24.3 600 57.2 (We - sc ) 775 92.3 180 - 14.2 0.36 21.5 600 30.6

(Re - sc)

(We - sc)

Dimensions in mm

Runback Ice - Descent

Leading Edge Inner Surface Temperatures Descent Case Dry Wet Temperature, Celcius squ - Ref QD2251 cir - Re scale QD2252 tri - We scale QD2253 -10 -0.2 -0.1 0 0.1 0.2 s/c

Runback Ice – Warm Hold

Alt P V T LWC MVD Tau Ice alt s o 3 m kPa kt C g/m μ m s g (Ref ) 4572 57.2 180 - 8.6 0.56 17.7 420 17.1

(Ref)

(Re - sc ) 314 97.6 106 - 6.1 0.83 24.5 420 91.2 (We - sc ) 828 91.8 180 - 8.4 0.56 19.8 420 28.6 Ice begins Ice ends Ice ends Ice begins

(Re - sc)

Ice ends Ice begins

(We - sc)

- No tracings

Runback Ice - Warm Hold

Leading Edge Inner Surface Temperatures Warm Hold 10 Dry

Heated Air Energy Input

Wet Temperature, Celcius 6 0 Ref squ - Ref QD2212 Re Sc cir - Re sc QD2215 tri - We sc QD2267 We Sc qdot, W/sq. in.

-10 -0.2 -0.1 0 0.1 0.2 s/c Dry Wet

Runback Ice – Cold Hold

Alt P V T LWC MVD Tau Ice alt s o 3 m kPa kt C g/m μ m s g (Ref ) 4572 57.2 180 - 30.0 0.24 17.4 600 13.3 (Re - sc ) 390 96.7 106 - 27.5 0.41 24.2 600 76.5

(Ref)

(We - sc ) 781 92.3 180 - 29.8 0.24 19.5 600 15.5* * Ice remaining after partial ice shed

(Re - sc)

(We - sc)

Dimensions in mm

Runback Ice – Cold Hold

Heated Air Temperatures

Leading Edge Inner Surface Temperatures Cold Hold squ - Ref QD2240 Reference cir - Re scale QD2263 tri - We Scale QD2264 Re - Sc grad - We scale QD2271 We - Sc We - Sc Temperature, Celcius Tin - dry Tout - dry Tin - wet Tout - wet Dry

Heated Air Energy Input - Cld Hld

Temperature, Celcius Ref Wet Re Sc -10 We Sc qdot, W/sq. in.

We Sc 2 -0.2 -0.1 0 0.1 0.2 s/c 0 0

Runback Ice Mass

• More ice accreted for

Ref Re-sc We-sc

Re - scaled conditions

• Mass of ice accreted

for We - scaled

conditions more

Accreted Ice Mass, g

similar to that

10 *

accreted at reference

Descent Wm Hld Cld Hld

(altitude) conditions

* Some ice shed

Summary

• Surface temperatures and heat rejection rates matched well

between reference and Re - scaled conditions

• Re - scaled conditions resulted in greater mass of ice accreted

• We - scaled conditions combined with T matching resulted in ice

surf

accretions more similar in mass and location of ice

• Greater convective cooling with We - scaling does affect freezing of

runback water

• Results indicate that surface water is being re - entrained in

airstream

• The two - step , Re & We scaling method produced ice accretions

more similar to those at the reference altitude conditions, but

differences in convective cooling warrant further investigation

• Model of water shedding being investigated

• Joint report being written

SAE 2015 International Conference on Icing of Aircraft, Engines, and Structures

June 22 - 25, 2015

Prague, Czech Republic

Backup Slides

Test Procedure

IPS settings Set Ref Tunnel and Spray ON & IPS determined; press & model to SS adjusted to tunnel OFF & temp w/IPS ON desired RB ice model cleaned Ice documented: Ice documented: Repeat at Re Photos, tracings, Photos, tracings, Run test Sc conditions thickness, mass thickness, mass Airspeed & Temp Ice documented: Spray ON at Set for We Sc ; IPS Photos, tracings, We Sc adjusted to Ref/Re thickness, mass conditions LE Temperatures

Nomenclature

c = model chord (18 in./45.7 cm) St = Stanton number d = twice the model leading edge radius St = Stanton number for mass transfer m T = recovery temperature H = convective heat transfer coefficient c r T = static temperature s H = convective mass transfer coefficient g V = true air speed IPS = ice protection system We = Weber number K = inertia parameter We sc = Weber number scaled conditions K = modified inertia parameter β = collection efficiency at stagnation LWC = liquid water content γ = ratio of specific heats for air M = Mach number Η = freezing fraction MVD = median volumetric diameter μ = air viscosity M = water loading w ρ = air density Nu = Nusselt number ρ = water density w σ = surface tension, water - air qdot = power density r = recovery factor Re = Reynolds number Re = Reynolds number based on droplet (droplet) diameter Re sc = Reynolds number scaled conditions Ref = Reference conditions RHF = Relative Heat Factor s = surface distance Sh = Sherwood number