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Scientific Aspects of Weather Hazards for Aviation
Andreas PetzoldDLR, Institut für Physik der Atmosphäre
aerodays 2011 | madrid | 30 ‐ 31 march 2011
aerodays 2011 | madrid | 30 ‐ 31 march 2011 2
Atmospheric Hazards for Aviation
deep convection
volcanoes
dust storms
birds
aerodays 2011 | madrid | 30 ‐ 31 march 2011 3
http://www.radarvirtuel.com/ taken from BBC: Iceland volcano in maps
19 April 2010, 13:00 UTC - Mid-European Airspace Closed
aerodays 2011 | madrid | 30 ‐ 31 march 2011 4
ICAO Operator Risk Assessment Framework
Operator
establishes safety assessment process
uses all information including VAAC forecast
understands data and resolves conflicts
decides when and where to fly
aerodays 2011 | madrid | 30 ‐ 31 march 2011 5
1. Identify the hazards.a. Perform adequate research on the short and long term effects of volcanic ash
on the entire aircraft and their occupants.b. Conduct an in-depth risk analysis for the hazards of aircraft operation in VA.c. Establish generic engine ash tolerance levels based on actual data and
research for relevant ash parameters.
2. Identify the contaminated airspace.a. Improve modelling, measurement and/or sensing accuracy of ash particle size
and density in volcanic ash clouds.b. VAAC must deliver relevant data in an accurate, timely and robust way by
means of measurement, imaging, modelling and validation.c. The appropriate safety oversight authority shall establish a danger area.d. Uniform global criteria for closure of (parts of) airspace should be applied in
case of unacceptable hazardous ash concentrations (the no-fly black zone).
aerodays 2011 | madrid | 30 ‐ 31 march 2011 6
1. Identify the hazards.a. Perform adequate research on the short and long term effects of volcanic ash
on the entire aircraft and their occupants.b. Conduct an in-depth risk analysis for the hazards of aircraft operation in VA.c. Establish generic engine ash tolerance levels based on actual data and
research for relevant ash parameters.
2. Identify the contaminated airspace.a. Improve modelling, measurement and/or sensing accuracy of ash particle size
and density in volcanic ash clouds.b. VAAC must deliver relevant data in an accurate, timely and robust way by
means of measurement, imaging, modelling and validation.c. The appropriate safety oversight authority shall establish a danger area.d. Uniform global criteria for closure of (parts of) airspace should be applied in
case of unacceptable hazardous ash concentrations (the no-fly black zone).
RESEARCH NEEDED ON PARTICLE IMPACT ON AIRFRAME & ENGINE
RESEARCH NEEDS FOR THE DEVELOPMENT OF ON-BOARD INSTRUMENTATION
aerodays 2011 | madrid | 30 ‐ 31 march 2011 7
Glassy particles will melt in the combustion chamber, if high thrust rating is used.
Melted material will cool down in the turbine and deposit on the turbine vanes.
DLR Falcon flights
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particle diameter (m)
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_sd3_2010-04-19_150835-151535_f
_sd3_2010-05-02_151125-151435_f
Abrasive particles can erode compressor blades edges, reducing compressor performance.
Properties and Impacts of Hazardous Particles
volcanic ashmineral dust
aerodays 2011 | madrid | 30 ‐ 31 march 2011 8
Volcanic Ash and Mineral Dust Particle Impact on Engines
Modelling Particle Trajectories at Cruise Condition
Particle Concentration:•2 – 4 x 10-4 g/m3
•Up to 4 x 10-3 g/m3 • Track inert particles• Melting temperature ~1050°C• Monitor particle temperature history
• Determine concentration and combustor passage factor
• Determine molten particle factor (potential accumulation/stick on turbine blades)
• Determine particle profile
• Find reasonable wall modelling
Particle Properties:•Density 2 g/m3
DLR Falcon flights
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particle diameter (m)
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_sd3_2010-04-19_150835-151535_f
_sd3_2010-05-02_151125-151435_f
adapted from S. Bake, R-R
aerodays 2011 | madrid | 30 ‐ 31 march 2011 9
Phase diagram for quartz – leucite – cordierite
Thornton et al. 1960, Am. J. Sci. 258, 664-684
A combination of minerals with high melting points can result in significantly lower melting points of the mixture
Dependency of Melting Point Temperature on Composition
by courtesy of K. Kandler, TU DarmstadtThornton et al. 1960, Am. J. Sci. 258, 664-684
aerodays 2011 | madrid | 30 ‐ 31 march 2011 10
Research Needs - VA impact on aircraft
Wide range of particle size in volcanic plumes (>1mm to <1µm), but only particles <20mm (strong plumes) and <1mm (weak plumes) reach the horizontally spreading current.
Melting properties of mixed particles are hardly to predict because a combination of minerals with high melting points can result in significantly lower melting points of the mixture; melting may start at 900 °C.
Impact of high pressures inside the engine and high water content on melting behaviour of VA particles is not clear.
Models are required for assessing the impact of large particles on aircraft engines, including the conditions inside a gas turbine combustor.
Agglomeration of VA particles is a key process influencing particle lifetime and particle size distribution, generating large uncertainties in atmospheric modelling and VA mass concentration forecast.
aerodays 2011 | madrid | 30 ‐ 31 march 2011 11
Properties and Impacts of Hazardous Particles
ice crystals
Super cooled drops form ice on cold surfaces of inlet, fan, and front of compressor
Ice crystals form ice on warm surfaces inside
the compressor
Supercooled liquid water accretion area inlet, spinner, fan, and first stages of the core
aerodays 2011 | madrid | 30 ‐ 31 march 2011 12
Ice Crystals Impact on Engines
J.‐F. Gayet (Univ. Clermont‐Ferrand)
aerodays 2011 | madrid | 30 ‐ 31 march 2011 13
Research Needs - Ice Crystal/SLD Impact on Aircraft
Formation conditions of dense ice crystal clouds not well known.
Impact of supercooled large droplets on aircraft engines is not clear.
Forecast of formation conditions for supercooled large droplets is nor sufficiently solved.
Research Needs - Weather Hazards
Forecast hazardous areas.
Identify hazardous areas.
Develop on-board measurement techniques for warning and for detection purposes.
Quantify hazardous potential.
aerodays 2011 | madrid | 30 ‐ 31 march 2011 14
IAGOS - Instrumented Civil Aircraft for Routine Observation of Atmospheric Composition, Aerosols and Clouds
www.iagos.org
©AI
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WEZARD – WP5: Scientific Support WBS & Content
March 2011CSA-SA on Weather Hazards for Aeronautics - WP5: Scientific Support
Task 5.0Supervision
and Roadmap
Task 5.1Atmospheric conditions causing air transport system
disruptions
Task 5.2Instrumentation for measuring
hazardous particles
Task 5.3Use of UAS
Task 5.4Reproduction of
hazardous particles
environments
Task 5.5Modelling, Tools and
Simulations
Identify research needs based on the gap analyses performed in Tasks 5.1 to 5.5 and build an integrated research roadmap as input to WP1
Review of the current status of knowledge concerning particles and ice crystals
Review and gap analysis of concepts and instrumentation available for the measurement of hazardous aerosol particles, SLD, mixed phase and ice crystals
Review and gap analysis of the use of UAS and development of UAS instrumentation for in situ measurements in hazardous weather conditions
Review the test facilities available in Europe for the identified studies and develop a test schedule for the identified studies
Review and gap analysis of models available for studying the impact of hazardous particles and icing on airframes, engines and systems
Formulate conclusive recommendations and the common roadmap as input to the strategic reports
WP5 : Scientific Support
aerodays 2011 | madrid | 30 ‐ 31 march 2011 16
Thank youThank you