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Propulsion TechnologyDirection
Wesley LordTechnical Fellow – System Architecture Functional Design
Pratt & Whitney
3rd UTIAS International Workshopon Aviation and Climate ChangeToronto May 2, 2012
© 2012 United Technologies Corporation
Flt Crew14%
Fuel49%
A/F Maint.8%
Engine Maint.6%
Cash A/C Related
IOC23%
Medium range aircraft, $3/gal
Twofold Pressure to Improve Performance
$$$ CO2
IATA
© 2012 United Technologies Corporation
Aggressive Technology Goals Have Been Defined
Vehicle Level Metrics for Fuel Burn Reduction
∆ Fuel Burn Time Frame
NASA N+2ACARE Vision 2020
NASA N+3Flightpath 2050
-50% 15 yrs
-60 to -75% 20-40 yrs
© 2012 United Technologies Corporation
Short/Medium RangeIn Service
BPR 5Fuel Burn Reference
2013-16BPR ~12
-15%
Longer TermBPR 15~18-20~30%
How Much ∆ Fuel Burn from the Propulsion System?
Propulsion Trend to Big Fans/ Small Cores
© 2012 United Technologies Corporation
ICAO/CAEP Fuel Burn Workshop –London, England, 25-26 March 2009
Fan Drive Gear SystemPlanetary- 5 PlanetsCompact High Efficiency Power Transmission
Low-PR FanLow Tip Speed
High-Speed Low SpoolCompact 3-stage LPC, LPT
New High-OPR coreLow-Emissions Combustor
GTF Engine Architecture – 2013 ConfigurationBPR ~ 12
© 2012 United Technologies Corporation
0.1
0.40.3
0.2
0.60.5
High BPR~ 5-10
LHVVTSFC
overall
0
×=η
35K/ 0.80/ ISA/ uninstalled
Ultra-HighBPR
Fuel Efficiency Drives Thermodynamic CycleThermal efficiency- production of power from fuel heat release → higher OPRPropulsive efficiency- conversion of power to thrust → lower FPR
© 2012 United Technologies Corporation
0.45
0.5
0.55
0.6
0.65
0.7
20 30 40 50 60 70 80OPR cruise
Ther
mal
Effi
cien
cy
NN+1
35K/0.80 Mach/ISA/uninstalled
25K Thrust Size
Thermal Efficiency Trend with Overall Pressure Ratio
N+3Challenges:
▪High-Temp Materials▪Component ηat Small Core Size
© 2012 United Technologies Corporation
5.7 core 3.0 core
“Core Size” Design Issue for High-OPR Engines
OPR
FPR
RelativeCore Size
(const thrust)
1.0
0.60.25
Compressor exit corrected flow ~ “core size”δθW
© 2012 United Technologies Corporation
Current Engines “N”Centrifugal Rear Stage
Current Engines “N”All Axial HPC
Material Limit
Architecture Limit
Material Limit
20
30
50
10
100
OverallPressureRatio(OPR)Max Climb
Core Size (lbm/s)1 2 5 10
N+1
OPR-CS Design Space ChartTechnology trend to higher OPR/ smaller CS challenges material capability and architecture
© 2012 United Technologies Corporation
FPR
Propulsive Efficiency Trend with Fan Pressure Ratio
FanηP
internal losses in fan stream
Ideal fan ηP is only a function of FPRand flight Mach
Flight Mach = 0.80fan
0NfanPfan SHP
VF=η
GTF Engine design spaceFPR ~ 1.2 – 1.5
© 2012 United Technologies Corporation
Current 5:1 BPR
Advanced 18:1 BPR
Current 5:1 BPR Future 18:1 BPR
Installation Challenge for Low-FPR/ High-BPR Engines
RelativeFan Diameter(const thrust)
FPR
© 2012 United Technologies Corporation
ReferenceV2500
1988 EIS
Adv GTFTM
Engine+30% EffEIS 2020-2025
PW1000G GTFTM Engine+16% EffEIS 2013-2015
UnconventionalInstallations
2015 2020 2025 2030
Gen 3 GTFTM Engine+45% EffEIS 2030-2035
Unconventional Installations Considered for N+2, N+3
© 2012 United Technologies Corporation
N+2 Boeing BWB Installation UHB Ducted Engine
BPR ~ 18 Engine∆ Fuel Burn for the Propulsion Systemestimated at -18% relative to PW4090/777
Significant reduction in jet noisefor the low-FPR engine
Combine with airframe shielding offan noise and airframe noise reductionto meet N+2 noise goals
UHB Engine vs Legacy (PW4090) Noise
© 2012 United Technologies Corporation
N+3 D8 (Double-Bubble) Configuration180 Passengers, 3000 nmi Range
From: M Drela, MIT
• Double bubble lifting fuselage
• Engines flush-mounted above aft fuselage
• Engine noise shielding and extended rearward liners
• Reduced cruise Mach number with unswept wings,
• Optimized cruise altitude 45kft (13.7 km)
© 2012 United Technologies Corporation
• Entire upper fuselage BL ingested by propulsor bypass stream
• Exploits aft fuselage static pressure field to condition flow– Fuselage's potential flow has local M = 0.6 at fan face– No additional required diffusion into fan– No generation of streamwise vorticity and secondary flow
Contoured aft fuselageEngines ingesting full upper surface boundary layer
Fuselage Boundary Layer Ingestionfor Increased Propulsive Efficiency
From: M Drela, MIT© 2012 United Technologies Corporation
Reduced Emissions/ Combustor Technology
• For aviation gas turbines, key issues are:– Landing and Take-Off (LTO) NOx => impacts on local airport
operations– Cruise NOx and particulate matter (PM) => man-made pollutants
at altitude• P&W combustor technology
– World-class TALON rich-quench-lean (RQL) technology• Significant reductions in LTO NOx (over 50% reduction compared to
CAEP 6 for the TALON X in a GTF)• Similar reductions in cruise NOx• Swirler technology to reduce smoke and PM
– Continued exploration of novel combustor concepts• Seeking very low NOx and PM• Robust configurations• Working with NASA, AFRL, Navy
© 2012 United Technologies Corporation
Propulsion Technology Direction - Summary
▪ -15% fuel burn by mid-decade enabled by new technology engines(PW1524G, PW1133G) on single-aisle aircraft
▪ Longer term goal -20 to -30% (2025+)
▪ Future propulsion design challenges involve small cores and big fans-alternative architectures at engine and vehicle level may be required
© 2012 United Technologies Corporation