Preliminary Results From a Heavily Instrumented Engine Ice Crystal Icing Test in a Ground Based Altitude Test Facility

National Aeronautics and Space Administration

Preliminary Results from a Heavily

Instrumented Engine Ice Crystal Icing Test in

a Ground Based Altitude Test Facility

Ashlie B. Flegel Michael J. Oliver NASA Glenn Research Center AIAA Aviation Atmospheric and Space Environments Conference June 13-17, 2016 www.nasa.gov National Aeronautics and Space Administration

Motivation

Engine Ice Crystal Icing events have led to increased need of understanding the mechanisms of engine icing.

NASA Advanced Air Transport Technology (AATT) Project key technology area is to develop engineering model and icing risk assessment tools and improve understanding of the physics of ice crystal icing through fundamental and engine testing.

• Enable analysis of ice crystal icing effects on turbofan engines.

• Provide guidance for safe operation of current and future N+2/N+3 propulsion systems.

Propulsion Systems Laboratory is developing its engine icing capability to ensure PSL can simulate high ice water content cloud conditions experienced in nature to the degree required to simulate engine failure modes by FY20.

• Understand the differences between PSL Cloud and natural environment ingested in the engine.

• Instrumentation to measure IC Cloud upstream and inside test hardware flow path.

• Characterize PSL Cloud • Standardize PSL Icing Test Methodology National Aeronautics and Space Administration 3

LF11 Test Approach and Objectives

• Document ice accretion in a full scale engine at altitude conditions.

• Develop advanced instrumentation to characterize the cloud entering the core flowpath and measure accretion characteristics.

• Replicate full rollback from LF01 Honeywell flight test and PSL tests.

• Duplicate key test points from the LF01 test plan in order to document and characterize the flow path, engine performance, and ice that builds up leading to the loss of thrust events.

• Further develop test methodologies and capability of PSL-3 facility.

• Simulate high and low altitude ice crystal cloud environments as well as specific aircraft/engine operating profiles.

• Investigate sensitivities of ice build up to various engine and facility parameters.

National Aeronautics and Space Administration 4

Propulsion Systems Laboratory (PSL)

Specification Min Max Engine / Rig Dia. (in | cm) 24 | 60 _72 | 180 Air Flow Rate (lbm/s | kg/s) 10 | 5_ 330 | 150 Altitude, pressure (kft | km) -_ 4 | 1.2 50 | 15 Total Temp (°F | °C) -60 | -50 50 | 10 Mach Number 0.15 0.80 TWC (g/m ) 0.5 8.0 * # MVD (um) 15 >100 * Evidence that probe under-measured # Particles larger than ~ 90 microns are NOT fully glaciated PSL-3 Icing Operating Envelope National Aeronautics and Space Administration 5

Test Article: ALF502-R5 Engine

From 1988 through 1997 the Lycoming

ALF502-R5 experienced 12 rollback field

events .

Root Cause Investigation Conducted

• Computer models, alt. chamber rig tests, and flight test.

• Rollback event duplicated in flight test

• Investigation found ice accretion on the

EGVs the cause of the rollback incidents

Engine Details Parameter Value Bypass Ratio 5.7:1 Fan Diameter 40.25 in Engine Length 64 in Maximum Thrust 6970 lbf Fan (# of stages) 1 Booster (# of stages) 1 Axial Compressor (# of stages) 7 Centrifugal HPC (# of stages) 2 High Pressure Turbine (# of stages) 2 Low Pressure Turbine (# of stages) 2 Source: Goodwin, R.V., Dischinger, D. G., AIAA Atmospheric and Space Environments National Aeronautics and Space Administration 6 Conference, AIAA–2014–2895

Instrumentation

• Engine Instrumentation (total and static pressures and thermocouples): ˗ Bypass Stator and Strut ˗ IGV and EGV ˗ Core Strut • Capture HPC Response to ice shedding: ˗ Kulites • Facility Instrumentation: ˗ Inlet total pressure ˗ Inlet total temperature ˗ Humidity sensors ˗ Eight external cameras observing the plenum and inlet of the test section National Aeronautics and Space Administration 7

Instrumentation

• Detect and Characterize Ice:

˗ Humidity sensors

˗ Four internal engine cameras

˗ Tomography (inlet)

˗ NASA Ice/water sensor

˗ Light Extinction Probes

˗ NRC Ultrasound Ice Accretion sensor

˗ Surface temperature thermocouples

Light Extinction Probe Planes Tomography Plane Metal Temperature Camera Region of Ice/Water sensors and camera views .

1. EGV1 LE, Pressure Side 2. EGV1 TE, Suction Side 3. EGV2 LE, Suction Side 4. EGV2 TE, Pressure Side National Aeronautics and Space Administration 8

Sample Test Conditions

RS-5 RS-3 FLT855 (Cold E) RS-1 (Warm E) FLT850 RS-6 • Research Altitude Points not shown • Sweeps of TWC, MVD, N1, and ambient temperature were conducted for each condition tested.

National Aeronautics and Space Administration

Results National Aeronautics and Space Administration Your Title Here 10

Repeatability of Similar Engines

• FLT850 Full Rollback Condition

LF01

LF11

N2

Load N1

Average Load (lbf)

Temps

Temperature (F), %N, Cloud Cloud ON Cloud OFF Time EGV1LE LF11 EGV1LE LF01 EGV1TE LF11 EGV1TE LF01 EGV2LE LF11 EGV2LE LF01 EGV2TE LF11 EGV2TE LF01 cloud LF11 cloud LF01 N2 LF11 N2 LF01 OS_AVG LF11 OS_AVG LF01 N1 LF11 N1 LF01 Load LF11 Load LF01 National Aeronautics and Space Administration 11

Daily Engine Repeatability

• Add text

% N1 Temperature (F)

Fan Speed

EGV1 TE Temp

Time Time Rdg 108 Rdg 178 Rdg 179 Rdg 194 Rdg 227 Rdg 270 Rdg 356 Rdg 108 Rdg 178 Rdg 179 Rdg 194 Rdg 227 Rdg 270 Rdg 356

• FLT850 Anchor Point

) initial

• Run nearly every test day

• Performance degradation

observed throughout the test

Load

Normalized Load (Load/Load Time Rdg 108 Rdg 178 Rdg 179 Rdg 194 Rdg 227 Rdg 270 Rdg 356 National Aeronautics and Space Administration 12

Effects of Icing National Aeronautics and Space Administration Your Title Here 13

Effects of Icing: Metal Temperatures

• Average Metal temperatures in five axial locations

• FLT850 called rollback condition

• Water Run back observed, leads to strong evaporative cooling in outer shroud

metal temperatures

• Leading edges of the EGVs are cooled due to ice/water impingement

FLT850 Called Rollback Condition Ice/water particle Initial stronger evaporative cooling Water Runback impinging cooling Prior to Cloud ON Cloud ON Cooling from runback water Cloud ON for 2 Sec Average Metal Temperature (F) FLOW Called Rollback EGV2 TE 0 1 2 3 4 5 6 EGV1 LE EGV1 TE EGV2 LE Outer Shroud Core Flowpath Location National Aeronautics and Space Administration 14

Effects of Icing: Metal Temperatures

• Average Metal temperatures in five axial locations

• FLT850 non-rollback conditions

• Similar axial temperature behavior is observed from the CRB condition

• Temperatures do not decrease as much and reach similar temperatures

• Ice and water observed for the non-rollback condition

FLT850 Non-Rollback Condition (+5% N1) Prior to Cloud ON Cloud ON EGV2 Cloud ON for 2 Sec EGV2 EGV2 Average Metal Temperature (F) FLOW FLOW 0 1 2 3 4 5 6 EGV1 TE EGV2 TE Outer Shroud EGV1 LE EGV2 LE National Aeronautics and Space Administration 15 Core Flowpath Location

Facility Response Due to Rollback

• FLT850 “Fast” Rollback Condition

7% ) f Called Rollback Line /s) and Avergae Load (lb m Temperature (F), Pressure (psia), Cloud Mass Flow (lb Airflow conditions set to these parameters Time P0 P2 PS1 TPL Cloud ON Load Mass Flow National Aeronautics and Space Administration 16

Influences on Rollback National Aeronautics and Space Administration Your Title Here 17

Influences on Rollback: TWC Effects

• 60 second sweeps at six TWC conditions.

• TWC based on bulk calculations

FLT850 Run TWC Comparisions

Avg. Load (Lbf)

TWC 1.0 g/m TWC 2.3 g/m

%N1

TWC 6.8 g/m TWC 5.4 g/m TWC 3.3 g/m TWC 4.3 g/m

Time

Rdg 119 %N1 Rdg 121 %N1 Rdg 122 %N1 Rdg 123 %N1 Rdg 124 %N1 Rdg 126 %N1 Rdg 119 Load Rdg 121 Load Rdg 122 Load Rdg 123 Load Rdg 124 Load Rdg 126 Load Rdg 119 Cloud Rdg 121 Cloud Rdg 122 Cloud Rdg 123 Cloud Rdg 124 Cloud Rdg 126 Cloud National Aeronautics and Space Administration 18

Influences on Rollback: MVD Effects

• FLT850

• Strong Accretion condition

MVD 43 μ m MVD 19 μ m %N Load (lbf) MVD 82 μ m Time Rdg 128 Load Rdg 130 Load Rdg 131 Load Rdg 128 %N1 Rdg 130 %N1 Rdg 131 %N1 Rdg 128 Cloud Off Rdg 130 Cloud Off Rdg 131 Cloud Off National Aeronautics and Space Administration 19

Influences on Rollback: MVD Effects

• Warm E

MVD 17 μ m

• Threshold Condition

MVD 24 μ m MVD 70 μ m %N Load (lbf)

• MVD does not have an

effect until 70 μ m

Time Rdg 289 Load Rdg 291 Load Rdg 293 Load Rdg 289 %N1 Rdg 291 %N1 Rdg 293 %N1 Rdg 293 Cloud Off

• Cold E

• Threshold Condition

MVD 16 μ m

• Increasing MVD decreases

%N Load (lbf)

CRB time

MVD 70 μ m MVD 24 μ m Time Rdg 330 Thrust Rdg 332 Thrust Rdg 334 Thrust Rdg 330 %N1 Rdg 332 %N1 Rdg 334 %N1 National Aeronautics and Space Administration 20 Rdg 330 Cloud Off Rdg 332 Cloud Off Rdg 334 Cloud Off

Influences on Rollback: N1 Effects

1.1 1.08

• FLT850

1.06 N1+10% N1+5% 1.04 1.02

• Increasing N1 provides more

0.98

energy into the flow suppressing

0.96 N1− 5% 0.94 Normalized Load rollback.

N1− 10% 0.92 N1 0.9 Time Rdg 197 Load Rdg 196 Load Rdg 198 Load

• Ice/water present during N1

Rdg 195 Load Rdg 182 Load Rdg 197 Cloud Off Rdg 196 Cloud Off Rdg 198 Cloud Off increases.

• Little to no water runback observed

while decreasing N1.

Average Metal Temperature (F) 0 1 2 3 4 5 6 Core Flowpath Location N1-10% N1-5% N1 N1+5% N1+10% National Aeronautics and Space Administration 21

Other Observations

• Observed build and shed in the videos and metal temperature measurements.

• Spinner and IGV A/I Heat was turned off to explore the effects of the

additional heat sources.

• Descent operation point was explored in PSL.

• Demonstrated ability to perform peak sensitivity study during a single test

entry.

• Performed altitude research points

Ice Accretion at 5 Kft Research Point and FLT850 at Respective CRB Times EGV2 FLT850 CRB 5 Kft Research Point EGV2 EGV2 EGV2 EGV2 EGV2 FLOW FLOW National Aeronautics and Space Administration 22

Conclusions

• Tested a Heavily Instrumented ALF502R-5 engine in PSL • Repeated FLT850 full rollback point with good repeatability • Repeated key revenue service called rollback points with good agreement.

• Although performance degradation occurred during the test, daily anchor points show facility and engine conditions were very repeatable.

• Cameras were installed downstream of the EGV’s to observe accretion. Videos can be correlated to the metal thermocouples and icing sensors.

• For each condition tested, sweeps of the TWC, MVD, N1, and ambient temperature were conducted.

National Aeronautics and Space Administration Your Title Here 23

Conclusions

• TWC has the largest effect on the onset of icing.

• MVD had secondary effect, however for strong accretion conditions, MVD had no effect.

• Decreasing the fan speed promotes stronger cooling leading to an increased rate of accretion • Additional heat sources are not needed for rollback to occur.

• PSL facility demonstrated the ability to simulate peak TWC intensities during a single spray and performed a flight descent • Data generated during this test is being used to validate in-house icing prediction and risk mitigation computational tools • Data enables the assessment and development of the advanced instrumentation and expands the capabilities of the Propulsion Systems Laboratory National Aeronautics and Space Administration Your Title Here 24

Acknowledgements

• Advanced Air Transport Technology Project (AATT) • Aeronautics Evaluation and Test Capabilities Project (AETC) • NASA Engine Icing Research Team • NASA PSL Staff • Honeywell • National Research Council Canada (NRC) • Ice Crystal Consortium (ICC) National Aeronautics and Space Administration Your Title Here 25

National Aeronautics and Space Administration Glenn PowerPoint Template 26