impact of jet engines ingesting dust

1. UNIVERSITY OF ATHENS
SCHOOL OF PHYSICS, DIVISION OF ENVIRONMENT AND METEOROLOGY
ATMOSPHERIC MODELING AND WEATHER FORECASTING GROUP
DUST INGESTION BY AIRCRAFT JET
ENGINES
Theodore Lekas1, George Kallos2, Jonilda Kushta2, Stavros Solomos2
1Dpt. of aerodynamics and flight mechanics, Hellenic Air Force Academy
2University of Athens, School of Physics, AMWFG, Athens, Greece

2. OBJECTIVES
THE MAJOR OBJECTIVE IS TO DRAW ATTENTION ON A SERIES OF
POTENTIAL PROBLEMS THAT MIGHT BE ASSOCIATED WITH THE FLIGHT OF
AIRCRAFTS IN DUST LOADED AREAS

3. PREREQUISITES
THE OPERATIONAL PROCEDURES MUST TAKE INTO ACCOUNT
QUANTITATIVE PREDICTIONS OF THE DUST AIR MASSES ALONG THE
ROUTES AND ESPECIALLY NEAR APPROACHING AND TAKING OFF
THE QUANTITATIVE PREDICTION OF DUST MASS IN THE ATMOSPHERE IS
AVAILABLE DESPITE THE UNCERTAINTIES ASSOCIATED TO IT
BY UTILIZING SUCH PREDICTIONS THE AREA,TIMING AND THE AMOUNT OF
INGESTED DUST CAN BE CALCULATED ALONG THE FLIGHT PATH

4. DUST MODEL
PHYSICAL PROCESS INITIATED AND
FAVORED BY CERTAIN METEROLOGICAL
CONDITIONS
LAND USE INFORMATION TO CHARACTERIZE
POSSIBLE DUST SOURCES
COMBINE SURFACE GEOPHYSICAL
CHARACTERISTICS WITH THE
METEOROLOGICAL FEATURES TO QUANTIFY
THE DUST MASS MOBILIZED AND THE
SPATIOTEMPORAL PATTERNS OF ITS
TRANSPORT
FORECASTING OF DUST EVENTS AS
PARALLEL PORCESS IN WEATHER
FORECASTING SYSTEMS

5. VISIBILITY
DUST FORECASTING IS UTILIZED:
DIRECTION INFORMATION ON THE PRESENT DUST
CONCENTRATIONS FOR THE ASSESSMENT OF THE
NUMBER OF PARTICLES INJECTED INTO THE ENGINE
INDIRECT INFORMATION ON VISIBILITY AND
METEOROLOGICAL CONDITION OF THE FLYING
SECTORS
Surface visibility
Aerosol Optical Depth
Visibility at 2km

6. CONCERNED GEOGRAPHICAL AREAS
DESERT AREAS ARE THE MAIN SOURCE OF DUST AND SAND IN THE
ATMOSPHERE
DESERT COVER A CONSIDERABLE AMOUNT OF LAND
DESERT DUST IS A MAJOR SOURCE OF PARTICULATE IN THE
ATMOSPHERE WITH SEVERAL IMPLICATIONS
DUE TO ATMOSPHERIC CIRCULATION THE PROBLEMS ASSOCIATED
WITH DESERT DUST BECOMES GLOBAL
OF COURSE THERE ARE OTHER SOURCES OF DUST SUCH AS THE
VOLCANIC ERUPTIONS OR VENTING SO2

7. SAHARAN DUST
DUST OVER
NORTH SEA
DUST OVER EUROPE
DUST OVER GREECE &
MEDITERRANEAN
Pictures taken from NASA/GSFC satellite

8. THE PROBLEM
DESERT DUST CAN CAUSE SIGNIFICANT PROBLEMS IN AVIATION SUCH AS:
REROUTING DUE TO POOR VISIBILITY
DISTURBANCES IN AIRPORT OPERATIONS
MECHANICAL PROBLEMS SUCH AS EROSION AND CORROSION
IN THIS PRESENTATION WE WILL DISCUSS ONLY ABOUT SOME
MECHANICAL PROBLEMS

9. JET ENGINE

10. EROSION
SAND PARTICLES IMPACT AND BOUNCE ON COLD AERAS OF THE ENGINE
CAUSING SURFACE DAMAGES AND GAP SIZE AUGMENTATION LEADING
TO GAS FLOW DETERIORATION AND GRADUAL LOSS OF PERFORMANCE
OF THE ENGINE

11. CORROSION
IF HOT SAND PARTICLES IMPACT ON HOT SURFACES (
COMBUSTOR WALLS, TURBINE BLADES…) THEY CAN FORM A DEPOSIT
WITH A ROUGH SURFACE WHICH MAY LEAD TO A RAPID LOSS OF
PERFORMANCE (POTENTIAL RISK DURING TAKE-OFF OR LANDING
OPERATIONS) BY DISTURBING THE FLOW FIELD.
THIS DEPOSIT MAY ALSO LEAD TO THERMAL CORROSION OF A
COMPONENT OF THE ENGINE BY BLOCKING ITS COOLING HOLES.

12. WHAT IS NEEDED?
UNDERSTANDING OF THE PHYSICS OF SAND EROSION AND CORROSION
IN ORDER TO ADEQUATELY MODIFY :
- THE ENGINE DESIGN
- MAINTENANCE PROCEDURES
- ROUTING AND APPROACHING PROCEDURES

13. PROPOSED STUDY METHODOLOGY
EXPERIMENTAL
THEORETICAL
BOTH APPROACHES ARE COUPLED

14. OBJECTIVE
ONCE THE DUST PARTICLE CONCENTRATION IS KNOWN THE ERODED
AREA AND THE SHAPE OF THE DEPOSIT WHICH MAY BE FORMED CAN BE
FOUND
THIS KNOWLEDGE IS IMPORTANT IN ORDER TO DETERMINE THE CRITICAL
AREAS OF THE ENGINE AS WELL AS PARAMETERS LEADING TO AN
ENGINE LOSS OF PERFORMANCE IN A SHORT OR LONG TERM

15. EXPERIMENTAL APPROACH
ADVANTAGES
POSSIBILITY OF REALISTIC SIMULATION OF THE PHYSICAL PHENOMENA
DISADVANTAGES
NEED FOR COMPLEX AND RATHER EXPENSIVE EQUIPMENT
CURRENT STATUS
THERE ARE SPECIALIZED RESEARCH CENTERS ABLE TO SIMULATE DUST
STORMS OF VARIOUS INTENSITIES AND WITH VARIOUS DUST PARTICLES
DIAMETERS

16. THEORETICAL APPROACH
ADVANTAGES
PHYSICAL APPROACH AS GOOD AS THE EFFICIENCY OF THE MATHEMATICAL
MODEL IN USE
NO NEED FOR IMPORTANT INFRASTRUCTURE
DISADVANTAGES
SIGNIFICANT NUMERICAL PROBLEMS MAY OCCUR
COMPUTATIONAL TIME CAN BE PROHIBITIVE
CURRENT STATUS
THE CONTINOUSLY INCREASING COMPUTATIONAL POWER ALLOWS FOR VERY
ACCURATE COMPUTATION OF THE FLOW FIELD AND DUST PARTICLES
TRAJECTORIES AROUND AN OBSTACLE WITH COMPLEX GEOMETRY

17. STEPS OF THE THEORETICAL APPROACH
DESCRIPTION OF THE GEOMETRY OF A GIVEN OBSTACLE (AIRCRAFT)
COMPUTATION OF THE FLOW FIELD AROUND THE OBSTACLE
COMPUTATION OF SAND PARTICLE TRAJECTORIES DUE TO THE FLOW
FIELD AROUND THE OBSTACLE
DETERMINATION OF IMPACT POINTS
KNOWLEDGE ABOUT THE CONTAMINATED AREA AND THE SHAPE OF THE
DEPOSIT ON THE OBSTACLE

18. GEOMETRY

19. TRAJECTORIES

20. SAND MASS INGESTED
Total dust mass injected for a 1 hour period as a function of the angle of attack in kg/hr

21. SAND MASS INGESTED
Total dust mass injected for a 1 hour period as a function of the particle size in kg/hr

22. ANOTHER PROBLEM
SIMILAR PROBLEMS SHOULD BE ENCOUNTERED IN AIRPORTS ADJACENT
TO COASTAL AREAS DUE TO THE INGESTION OF SEA SALT PARTICLES
FROM EVAPORATION OF WATER DROPLETS PRODUCED BY WAVE
BREAKING
VOLCANIC ASH IS AN ADDITIONAL SOURCE OF NATURAL PARTICLES IN
THE ATMOSPHERE

23. CONCLUSIONS (1/2)
NATURAL PARTICLES AFFECT AVIATION BY DETERIORATING THE
FLIGHT CONDITIONS (REDUCED VISIBILITY, FOG FORMATION)
THEY CAN DECREASE ENGINE PERFORMANCE BY THE ROSION AND
CORROSION PROCESSES
IMPORTANT ASSET FOR THE SOUTHERN EUROPE COUNTRIES FOR
FORECASTING DUST STORM EVENTS.
EARLY PREDICTION CAN LEAD TO BETTER AIR TRAFFIC MANAGEMENT
AND INPROVED FLIGHT SAFETY

24. CONCLUSION (2/2)
WITH A DETAILED PREDICTION OF THE DUST CONCENTRATIONS DURING THE FLIGHT
ROUTE OF AN AIRCRAFT IT IS POSSIBLE TO:
CALCULATE THE TOTAL EXPOSURE OF THE ENGINE TO DUST
MODIFY MAINTENANCE PROGRAMMING TAKING INTO ACCOUNT THE ENGINE
PERFORMANCE DETERIORATION DUE TO THE DUST MASS INGESTED DURING THE
FLIGHT
ESTIMATE A POSSIBLE IMMEDIATE LOSS OF ENGINE PERFORMANCE
IMPROVE THE EFFICIENCY OF AIR TRASPORTATION