ICING HAZARDS RESILIENCE BY DESIGN. Use or disclosure of the information contained herein is subject to specific written approval from CIRA

Transcription

1 ICING HAZARDS RESILIENCE BY DESIGN Use or disclosure of the information contained herein is subject to specific written approval from CIRA

2 RESILIENCE IN AIRCRAFT ICING THREATH AIRCRAFT ICING... is directly related to the variability of the inflight icing cloud conditions and to the frequency of catastrophic events to which the design of the aircraft ice protection and avoidance technologies have been adapted. Recently there is an increased interest toward the icing topic involving two key areas: SAFETY; PERFORMANCES; Use or disclosure of the information contained herein is subject to specific written approval from CIRA 2

3 Two completely different phenomena GROUND AND IN-FLIGHT ICING Ground icing: It is caused by moister collected on cold surface while aircraft is on the ground (usually wing/empennage upper surface) In flight icing: It is caused by water droplet impinging in flight on aircraft surfaces (usually wing/empennage leading edges, nacelle lip,..) Use or disclosure of the information contained herein is subject to specific written approval from CIRA 3

4 Ground icing Ground icing can be caused also by freezing precipitation or moisty air condensation on cold aircraft surface (typical is ice accumulation on integral tanks wing) No aircraft is allowed to take-off with contaminated surface (except in non-critical areas indicated in AFM) because even a small amount of ice can: Affect aircraft aerodynamics characteristics GROUND ICING Detach from the aircraft surface and either impact on other aircraft components or be ingested by engine causing flame-out Use or disclosure of the information contained herein is subject to specific written approval from CIRA 4

5 GROUND ICING Ground icing Ground icing contaminants can cause: Longer take-off Failure to liftoff Lift-off, but not climb capabilities Climb, but roll or pitch uncontrollability Engine power loss Use or disclosure of the information contained herein is subject to specific written approval from CIRA 5 5

6 IN-FLIGHT ICING The ice accretion physics Ice accretion is caused by the impact of supercooled water droplet on aircraft component surface Use or disclosure of the information contained herein is subject to specific written approval from CIRA 6

7 IN-FLIGHT ICING Aerodynamics performance degradation Ice can cause: a reduction of lift, a reduction of stall angle, an increase in drag, a modification in longitudinal stability. Rime ice, in some conditions, may also cause an increase in lift at low incidences. Even a small amount of roughness on airfoil leading edge can decrease stall characteristics. C l C m lift coefficent, moment coefficent, Glaze Mixed Rime Clean a) angle of attack b) angle of attack α (deg.) α (deg.) Glaze Mixed Rime Clean Glaze Mixed Clean C d drag coefficent, c) angle of attack α (deg.) Use or disclosure of the information contained herein is subject to specific written approval from CIRA 7

8 ICING: MOTIVATIONS SAFETY Following ATR Roselawns incident of 1984 and AIRBUS Rio de Janeiro incident of 2009 in 2014 new certification rules have been issued by FAA and EASA that require the presence of SLD: SuperCooled Large Dropets and Ice Crystals AT PRESENT TIME NO AVALIABLE MEANS OF COMPLIACE EXIST (NEITHER NUMERICAL NEITHER EXPERIMETAL) TO CORRECTELY SIMULATE SLD and ICE CRYSTALS Use or disclosure of the information contained herein is subject to specific written approval from CIRA 8

9 ICING: MOTIVATIONS SAFETY: SLD SLD: Have been recently included in certification envelop, can cause ice accretion behind aircraft protected area Use or disclosure of the information contained herein is subject to specific written approval from CIRA 9

10 CERTIFICATION Freezing Drizzle SLD cloud envelope extension (Appendix O) Freezing Rain (Ref. DOT/FAA/AR-09/10) Use or disclosure of the information contained herein is subject to specific written approval from CIRA 10

11 ICING: MOTIVATIONS SAFETY: ICE CRYSTALS Ice Crystal can cause ice accretion on probes and engine components and ice probes Lost of air data Engine flame-out Use or disclosure of the information contained herein is subject to specific written approval from CIRA 11

12 ICING: MOTIVATIONS SAFETY: ENGINE POWERLOSS air in engine is warm cold ice particles drive down the temperatures of surfaces to freezing temperatures some crystals melt and freeze on cooled surfaces ice breaks off and causes surge/stall/thrust loss, sheds into compressor and quenches flame (flameout), or builds up and chokes airflow (rollback) actual details are under investigation Super cooled drops form ice on cold surfaces of inlet, fan, and front of compressor Nonconvective Cloud Supercooled liquid water accretion area (inlet, spinner, fan, and first stages of the core) Convective/ Cumulonimbus Cloud Potential ice particle accretion areas Ice crystals form ice on warm surfaces inside the compressor Use or disclosure of the information contained herein is subject to specific written approval from CIRA 12 Fan (Souce of slide: Boeing) Core air travels downstream to the combustor

13 CERTIFICATION Proposed cloud envelope extension (Appendix D) Temperature-altitude envelope (heavy purple) determined by EHWG from engine events Some events now outside envelope (esp. considering air-data events) (Adapted slide courtesy of E. Duvivier, EASA) Realities - Currently we have some limitations in: Unsubstantiated environmental definition (i.e. App D) Basic understanding of the physics of accretion. Test facility capabilities to demonstrate compliance. Current proposed rule and guidance recognizes today s realities but lays the ground work for future advances in knowledge and capability. Use or disclosure of the information contained herein is subject to specific written approval from CIRA 13

14 CERTIFICATION Engine Harmonization Working Group has defined a Technical Plan with overarching goal of the flight campaigns (executed within the HAIC and HIWC international projects) to acquire a benchmark database of the atmospheric environment that causes engine & air data sensor failures that threatens air transportation safety. The strategy includes: Set new design and certification standards for engines and sensors to operate within this environment Develop HIWC detection methods (onboard, ground-based, space-based) and weather diagnostic & forecast tools to enable threat avoidance Develop engine ice models/simulations and guide future experimental activities for means of compliance & fundamental ice growth studies Understand the fundamental cloud microphysical processes that cause High IWC to occur and, by doing so, improve the ability to forecast or detect it Use or disclosure of the information contained herein is subject to specific written approval from CIRA 14

15 CERTIFICATION New certification requirements CS 16 and CS 4, Published in March 2015 ICING ENVIRONMENT expanded for CS large airplanes and CS-E (turbine engines) CS 25@Amdt 18, Published in June 2016 Introduce the Comparative Analysis as an acceptable Mean of Compliance to (SLD requirement) Proper implementation of the new regulations requires: Further Development of Means of Compliance (appendix P + O) Appendix O detection means for the detection and avoidance certification strategy Use or disclosure of the information contained herein is subject to specific written approval from CIRA 15

16 ICING: MOTIVATIONS HELICOPTERS AND OTHER CHALLANGES 1. Ice accretion on rotating elements => Engine components 2. Ice accretion on rotors => unsteady ice accretion and ice shedding 3. Increase wind turbine operativity => Ice accretion on wind turbine 4. Propeller icing: propeller ice evaluation and ice protection NACA 0012 R = 6.7 R = 8.5 R = 9.2 Panel MultiStep R=8.5 Euler 3m R=8.5 Y/C X/C Use or disclosure of the information contained herein is subject to specific written approval from CIRA 18

17 CIRA ICING NUMERICAL CAPABILITIES Ice Accretion and Ice Protection o Ice accretion simulation o Ice protection systems simulation o Aerodynamic degradation due to ice accretion Use or disclosure of the information contained herein is subject to specific written approval from CIRA 19

18 SUMMARY OF CIRA ICING SOFTWARE 2D ice Accretion code MULTIICE Coupled with both panel methods and field methods Fully validated User friendly interface Lagrangian approach 3D ice Accretion code HELICE Lagrangian approach Coupled with both panel methods and field methods IMPIN 2D and 3D Eulerian approach for water impingement calculation coupled with ice accretion CIRA ICING NUMERICAL CAPABILITIES Eulerian approach by immersed boundary TERMO: Thermal ice protection systems Use of Open source or commercial software for ice accretion and ice protection simulation Use or disclosure of the information contained herein is subject to specific written approval from CIRA 20

19 Lamb-wave ice protection/ice detection CIRA: ICE PROTECTION Theoretical and numerical modeling of the PZT de-icing system Identification of the optimal design parameters: frequencies of excitation, PZT dimensions. Simulation (FE modeling) of the system performance transmitted shear action at the icestructure interface structure PZT ice z 0 h (i) h (s) x Piezoelettrico Struttura 21 Ghiaccio Use or disclosure of the information contained herein is subject to specific written approval from CIRA 21

20 Idrophobic-coatings Development of idrophobic coating (passive ice protection) and/or integrated passive/active ice Tools and procedure for coating performance evaluation CIRA: ICE PROTECTION PASSIVE Test Room with environmental controlled parameters Camera conditions scoreboard (pressure control by vacuometer and temperature control by thermocouple) Optical path: Led light + analyzer + polarizer + diffuser screen 22 Sample Holders with micrometric handling on 3 axes Digital high resolution camera (magnifications up to 200X) Development of idrophobic coating Use or disclosure of the information contained herein is subject to specific written approval from CIRA 22

21 CIRA: ICING WIND TUNNEL - IWT A EUROPEAN CORE SPECIALIZED ASSET World largest in size World highest speed World widest test envelope World largest icing instrumentation stock Use or disclosure of the information contained herein is subject to specific written approval from CIRA 23

22 CIRA: ICING WIND TUNNEL - IWT Engine Flow Simulation IWT LAY-OUT Fan System Parking hall Control room Air Station HX Electrical Room Cooling station Transformer building Use or disclosure of the information contained herein is subject to specific written approval from CIRA 24

23 CIRA: ICING WIND TUNNEL - IWT HXs IWT AEROLINES Fan TEST DIMENSION SPEED TEMP SECTION (m) (Mach) ( C) MAIN 2.25x < t < +40 SECONDARY 1.15x < t < +40 ADDITIONAL 3.60x < t < +40 OPEN-JET 2.25x < t < +40 SBS Test Sections Use or disclosure of the information contained herein is subject to specific written approval from CIRA 26

24 CIRA: FUTURE PLANS CIRA FUTURE MACRO OBJECTIVES Increase and extend productivity Increase and extend capabilities Development of new technologies To reach the objective the following areas have been identified: Area 1 : Facilities for ice accretion simulation Area 2 : Icing instrumentation Area 3 : Ice accretion simulation Area 4 : Development of Technologies for ice protection Area 5 : Technological demonstrator Use or disclosure of the information contained herein is subject to specific written approval from CIRA 27

25 CIRA: FUTURE PLANS Area 1 : Facilities for ice accretion simulation Improvements of productivity and of the actual icing envelop with improvement on the existing facility CIRA technical objectives: Extension/improvements of IWT capabilities to freezing drizzle conditions New nozzles New calibrations Study and small demonstrator of Spray-bar for SLD New spray-bar system Improvement thermal IWT envelope New SBS calibration X (mm) Use or disclosure of the information contained herein is subject to specific written approval from CIRA 28 Skewness TC# 10 Y=0mm Z=152.4mm ADA small TC# 10 Y=0mm Z=228.6mm ADA small

26 CIRA: FUTURE PLANS Area 2 : Icing instrumentation Improvement of icing instrumentation to reduce measurements uncertainties, to implement new certification requirements and to increase IWT competitiveness and productivity New techniques for particle sizing (assessment/intercomparison) Droplet temperature measurements CIRA technical objectives: New techniques for remote ice shape measurements New techniques for cloud uniformity measurement and characterization High speed camera for ice shedding studies Use or disclosure of the information contained herein is subject to specific written approval from CIRA 29

27 CIRA: FUTURE PLANS Area 3 : Ice accretion simulation CIRA technical objectives: Improve numerical simulation capabilities to provide an extend offer that include both numerical and experimental activities Improvement and maintenance of ice accretion tools (SLD, 3D, rivulets, ) Improvements and maintenance of ice protection simulation tools Degradation of aerodynamics performances Ice shedding simulation (shedding and trajectories debris) (with possibility of PT1 simulation for debris characterization and test article manufacturing with 3D printing) SEASIDE (PROTON/GKN) Courtesy Use or disclosure of the information contained herein is subject to specific written approval from CIRA 30

28 CIRA: FUTURE PLANS Area 4 : Development of technologies for ice protection Continue development of both passive and active ice protection system and identify new innovative ice protection concepts Passive systems (coatings, hybrid passive active systems) Lambda wave concepts Electro thermal systems CIRA technical objectives: Integrated ice detection ice protection New concept (integrated Laminar flow control and ice protection) Use or disclosure of the information contained herein is subject to specific written approval from CIRA 31

29 CIRA: FUTURE PLANS CIRA technical objectives: Area 5 : Technological demonstrator Development and test in CIRA IWT new demonstrators representatives of UAV, Regional aircraft and helicopters Demonstrate technologies for ice accretion; Validate ice accretion and ice protection numerical simulation tools; Verify CIRA IWT capabilities improvement. AG2: Pol. Milano Courtesy 2D demonstration (SMOS) Oscillating airfoil demonstration 3D demonstration Typical UAV demonstration Typical regional aircraft demonstration (conventional and innovative leading edge) Helicopter test rig Use or disclosure of the information contained herein is subject to specific written approval from CIRA 32

30 CONCLUSIONS AIRCRAFT IN-FLIGHT ICING CHALLENGES Lighter, more efficient / low power and easy to integrate and operate (maintenance, reparability) breakthrough Ice Protection Technologies High performance and high durability Hydro/Icephobic coating and combination with Ice Protection Technologies Validated & verified Engineering Tools (numerical tools, test facilities) with special focus to SLD & Glaciated and Mixed Phase icing conditions Ice Accretion & Ice Protection System performance prediction Ice shedding, Ice block trajectory & Impact Aerodynamic performance degradation & Handling Quality Ice detection and ice protection integration Use or disclosure of the information contained herein is subject to specific written approval from CIRA 33