View
217
Download
1
Category
Tags:
Preview:
Citation preview
NASA Environmental Workshop
John G. Meier
Vinod Nangia
August 12, 1999
21-10790
21-10790
2
V9485-2
Environmental Impact of Small Engines Becoming Critical• Turbofans for Regional and Business Aviation, APUs have significant
environmental impact
– Frequent takeoffs and landings
– Widespread access to airports
– APU ground operation
• Strong projected market growth, increased use
– Growth in air travel
– Transition from turboprop to turbofan (Regional)
– Fractional ownership
• Greatest technology challenges
– Size effects
– Thermodynamic cycle trends
– ETOPS requirements for APUs
Technologies for noise and emission reduction in small turbine engines are unique
B
21-10790
3
V9485-3
Regional and Business Jets and APUs Under New Environmental Scrutiny
• Regional and Business Aviation aircraft operate from airports in >3,500 U.S. communities
Small engine environmental impact is the same as large engines
Commercial Transports
Business Aviation
0
3
6
9
12
15
0 3 6 9 12 15Engine Pressure Ratio
NO
x E
mis
sio
n I
nd
ex (
GM
/KG
M F
uel
)
Equivalent ‘96 ICAO
• Ground operation of APUs creates NOx emission above the equivalent ‘96 ICAO levels
• Regional & General Aviation Account for 40% of All Takeoffs & Landings
B
0
5
10
15
20
25
30
35
40
1991 1993 1995 1997 1999 2001 2003 2005 2007
Historical Forecast
Calendar Year
Ta
keo
ffs
& L
an
din
gs
, M
illi
on
s
Commercial Transport
Military
Regional
General Aviation
Source: FAA Air Traffic Activity
21-10790
4
V9485-4
Regional Jet Fleet Market Growth
• Turbofans replacing turboprops for customer comfort and safety
– Higher Pressure Ratios and Thrust ( emissions)
– Thrust and Fleet size ( Noise)
Turbofan market growth drives increased noise and emissions
U.S. Regional Fleet ForecastAircraft (Units)
2,000
1,800
1,600
1,400
1,200
1,000
800
600
400
200
01987 1992 1997 2002 2007
Year
Historic Forecast
Turbofans
B
Turboprops
21-10790
5
V9485-5
Fractional Ownership Game Changes Business Jet Market • Smaller companies flying to
smaller airports - more takeoffs and landings
• U.S.-based business aviation accounts for 75% of the overall market
Fractional ownership dramatically increases takeoffs and landings
PilatusIAI
Gulfstream(USA)
Learjet(USA)
Dassault
1998 Sales of New Turbine-Powered Aircraftto Business Aircraft Operators by Manufacturer
Boeing(USA) Socata/
Aerospatiale
Raytheon(USA)
Canadair
Cessna(USA)
C
21-10790
6
V9485-6
Auxiliary Power Unit Dependence Increasing
• Future aircraft standard for twin engine use requires APUs
– Extended Twin Engine Operations (ETOPS)
– APU use in engine-out situation
– Increased operating altitudes required
• Lack of facilities at small airports require APU usage for Regional and Business Jets
Increased use of APUs is an added source for noise and emissionsC
21-10790
7
V9485-7
Local Airports Driving Environmental Standards for Turbofans and APUs
*
Stockholm
*
*
Denmark
Zurich
Federal regulation will evolve from local restrictions
Proprietary
1996 ICAO
Class VClass VI
• Aircraft landing fees based on emissions and noise
• APU operating time, restrictions underway
A
21-10790
8
V9485-8
Regional Jets, Business Aviation, and APUs Face Unique Design Challenges
• Size Effects:
– Higher % cooling air
– Tolerance stacks
– No space for multi-dome concepts
• APUs - large ignition and blowout range
– Cold soak engine to sub-zero temperatures
– High-altitude start
Relative size comparison of Boeing 777 Combustors
APU 14 FuelNozzle Tips
Main Engine60 Fuel Nozzle Tips
Not the actual combustor
Physical size forces novel solutions for emissions and noiseB
21-10790
9
V9485-9
Technology Directions
Improved operability and low emissions needed for compact combustor
Fuel Staging Technology
Individual AtomizerControl and Spray
Advanced FlameStabilization
Single-dome, staged
Alt
itu
de
Flight Speed
IgnitionEnvelope
ETOPS
Single-dome, not staged
A
21-10790
10
V9485-10
Smaller Aircraft Face Stricter Noise Rules
Noise abatement technology is critical to smaller engines
70
80
90
100
Approach Takeoff Sideline
EP
NL
Stage 3
Transport (Airbus 319)Business Jet (Falcon 2000)
21-10790
11
V9485-11
100
110
120
130
140
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
APU Year of Introduction Into Service
To
tal
No
ise
(In
let
and
Ex
ha
us
t)P
WL
re:
10
^(-
12)
Wat
ts [
dB
]
10dB
APU Core Technology
Commercial APU Data Trend Future Goals, Anticipated Requirements
European Markets Push For Low APU Noise
• Current APU Operations being restricted due to noise
• Aircraft Manufacturers demand 5-10 dB noise reduction
• APU noise reduction research must intensify to support market needs
Airport workers and community residents REQUIRE lower ramp noise
21-10790
12
V9485-12
Technology Directions
A system approach is needed to globally reduce engine noise
Advanced Fan Designs
Advanced Nozzle Designs
Advanced Suppression
Measurement Technology
Variable Engine Cycle
A
Recommended