NASA/CR—2003-212467
`
`Follow-On Technology Requirement Study
`for Advanced Subsonic Transport
`
`Bruce E. Wendus, Donald F. Stark, Richard P. Holler, and Merle E. Funkhouser
`United Technologies Corporation, Pratt & Whitney, West Palm Beach, Florida
`
`August 2003
`
`GE-1016.001
`
`

`
`The NASA STI Program Office . . . in Profile
`
`Since its founding, NASA has been dedicated to
`the advancement of aeronautics and space
`science. The NASA Scientific and Technical
`Information (STI) Program Office plays a key part
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`The Program Office is also NASA’s institutional
`mechanism for disseminating the results of its
`research and development activities. These results
`are published by NASA in the NASA STI Report
`Series, which includes the following report types:
`
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`
`•
`
`TECHNICAL PUBLICATION. Reports of
`completed research or a major significant
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`
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`
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`
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`
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`technical, or historical information from
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`often concerned with subjects having
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`
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`
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`
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`
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`
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` NASA Access Help Desk
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` 7121 Standard Drive
` Hanover, MD 21076
`
`GE-1016.002
`
`

`
`NASA/CR—2003-212467
`
`Follow-On Technology Requirement Study
`for Advanced Subsonic Transport
`
`Bruce E. Wendus, Donald F. Stark, Richard P. Holler, and Merle E. Funkhouser
`United Technologies Corporation, Pratt & Whitney, West Palm Beach, Florida
`
`Prepared under Contract NAS3–26618, Task XXXVIII
`
`National Aeronautics and
`Space Administration
`
`Glenn Research Center
`
`August 2003
`
`GE-1016.003
`
`

`
`Document History
`
`This research was originally published internally as AST005 in August 1995.
`
`Note that at the time of research, the NASA Lewis Research Center
`was undergoing a name change to the
`NASA John H. Glenn Research Center at Lewis Field.
`Both names may appear in this report.
`
`NASA Center for Aerospace Information
`7121 Standard Drive
`Hanover, MD 21076
`
`National Technical Information Service
`5285 Port Royal Road
`Springfield, VA 22100
`
`Available from
`
`Available electronically at http://gltrs.grc.nasa.gov
`
`GE-1016.004
`
`

`
`CONTENTS
`
`1. SUMMARY ........................................................................................................................................................... 1
`
`2. INTRODUCTION ................................................................................................................................................. 2
`
`3. ENGINE DESCRIP'TION ...................................................................................................................................... 3
`
`3.1. 1995 EIS TURBOFAN ENGINE .................................................................................................................. 3
`
`3.2. 2005 EIS ADP ENGINE ................................................................................................................................ 3
`
`3.2.1. Low Shaft Study ................................................................................................................................. 4
`
`3.2.2. Engine Description ............................................................................................................................. 6
`
`3.2.3. Component Description ...................................................................................................................... 8
`3.3. 1995 EIS TURBOFAN AND 2005 EIS ADP CYCLE COMPARISON .................................................... 12
`3.4. 1995 EIS TURBOFAN AND 2005 EIS ADP TSFC COMPARISON ........................................................ l3
`3.5. ADP AND TURBOFAN T3 AND T4 RATING COMPARISON ............................................................... 14
`3.6. 2005 EIS ADP ADVANTAGE ................................................................................................................... 24
`
`4. ECONOMIC BENEFIT ASSESSMENT ............................................................................................................ 25
`
`4.1. AIRCRAFT SIMULATION ........................................................................................................................ 25
`
`4.2. METHODOLOGY ...................................................................................................................................... 27
`
`4.3. PRIME ECONOMICS VARIABLE EVALUATION ................................................................................. 31
`
`4.3.1. Takeoff Gross Weight, Engine Thrust, and Fuel Burn ..................................................................... 31
`
`4.3.2. Engine Weight .................................................................................................................................. 34
`
`4.3.3. Engine Price ...................................................................................................................................... 35
`
`4.3.4. Engine Maintenance Cost ................................................................................................................. 35
`
`4.3.5. Airplane and Airframe Price ............................................................................................................. 37
`
`4.4. PERFORMANCE AND PRICE RELATED INFLUENCE FACTORS ..................................................... 37
`
`4.5. 2005 EIS ADP ECONOMIC ADVANTAGE ............................................................................................. 37
`
`5. CRITICAL TECHNOLOGIES ............................................................................................................................ 40
`
`6. CONCLUSIONS .................................................................................................................................................. 41
`
`APPENDIX A .......................................................................................................................................................... 42
`
`NASA/CR—2003-212467
`
`iii
`
`GE-1016.005
`
`

`
`FIGURES
`
`Figure 1.
`
`2005 EIS ADP Low Shaft Torque Summary ........................................................................................ 5
`
`Figure 2.
`
`Low Shaft Material Capabilities Established for 2005 EIS ADP .......................................................... 6
`
`Figure 3.
`
`2005 EIS ADP Maximum Temperatures and Pressures ........................................................................ 7
`
`Figure 4.
`
`2005 EIS ADP General Engine Arrangement ........................................................................................ 7
`
`Figure 5.
`
`2005 EIS ADP With Six-Stage High-Pressure Compressor .................................................................. 9
`
`Figure 6.
`
`2005 EIS ADP With Eight-Stage High-Pressure Compressor ............................................................. 10
`
`Figure 7.
`
`2005 EIS ADP Has Significantly Lower TSFC Than 1995 EIS Turbofan .......................................... 13
`
`Figure 8.
`
`1995 EIS Turbofan and 2005 EIS ADP Takeoff to Climb Rating Comparison .................................. 14
`
`Figure 9.
`
`1995 EIS Turbofan and 2005 EIS ADP Rating Comparison Along Climb Path ................................. 15
`
`Figure 10. At Same T4, Turbofan and ADP Thrust Lapse Rates Are Different.. .................................................. 17
`Figure 11. At Same Rated Thrust, Turbofan and ADP T 3 and T 4 Are Different .................................................. 17
`Figure 12. Fan Pressure Ratio Effect on T3 and T4 ............................................................................................... 18
`Figure 13. Lower Fan Pressure Ratio ADP Nozzle Unchokes More at Takeoff ................................................... l9
`
`Figure 14. ADP Has Inadequate Surge Margin With Fixed Geometry Fan .......................................................... l9
`
`Figure 15. Fan Pitch Is Scheduled for ADP Surge Control.. ................................................................................. 20
`
`Figure 16. Changing Fan Pitch Impacts ADP LPC and HPC Operation ............................................................... 21
`
`Figure 17. Variable Geometry Low-Pressure Compressor Required for ADP ..................................................... 21
`
`Figure 18. Effect of Fan and LPC Variable Geometry on ADP T3 and T4 ............................................................ 22
`Figure 19. Airplane Thrust Requirements Impact Rating Differences .................................................................. 23
`
`Figure 20. ADP FPR and Variable Geometry Provide Thrust Growth Advantage ............................................... 23
`
`Figure 21. Fuel Burn Reflects Technology Effect on Aircraft Size ...................................................................... 33
`
`Figure 22. Takeoff Thrust Advantage of 2005 EIS ADP ...................................................................................... 33
`
`Figure 23. Effect of Thrust on Propulsion System Price ....................................................................................... 36
`
`Figure 24. Effect of Thrust on Engine Maintenance Cost.. ................................................................................... 36
`
`Figure 25. Typical Technology Development and Transition Path ....................................................................... 40
`
`NASA/CR—2003-212467
`
`iv
`
`GE-1016.006
`
`

`
`LIST OF TABLES
`
`Table 1.
`
`1995 EIS Turbofan and 2005 EIS ADP Component Comparison ......................................................... 3
`
`Table 2.
`
`1995 EIS Turbofan and 2005 EIS ADP Cycle Comparison ................................................................ 12
`
`Table 3.
`
`2005 EIS ADP TSFC Benefit ............................................................................................................... 13
`
`Table 4.
`
`1995 EIS Turbofan and 2005 EIS ADP Cycle Comparison ................................................................ 15
`
`Table 5.
`
`Cycle Effects on Rating Temperature .................................................................................................. 16
`
`Table 6. Aircraft Performance Requirements .................................................................................................... 25
`
`Table 7. Aircraft Characteristics ........................................................................................................................ 25
`
`Table 8. Aircraft Weight and Performance Summary ........................................................................................ 26
`
`Table 9.
`
`Long-Range Quad Economics Groundrules and Cost Calculation Summary ...................................... 28
`
`Table 10. Calculation of Interest Expenses .......................................................................................................... 30
`
`Table 11. Maximum Takeoff Gross Weight Composition ................................................................................... 31
`
`Table 12. Effect of Engine Technology on Airframe Weight and Price .............................................................. 37
`
`Table 13. Performance and Price Related Influence Factors ............................................................................... 37
`
`Table 14. Summary of 2005 EIS ADP Economics .............................................................................................. 38
`
`Table 15. Economic Analysis Input and Output Summary .................................................................................. 39
`
`Table 16. Year 2005 EIS Engine Overall Technology Study Summary .............................................................. 42
`
`Table 17. Recommended Technology Programs .................................................................................................. 45
`
`NASA/CR—2003-212467
`
`v
`
`GE-1016.007
`
`

`
`LIST OF ACRONYNMS and ABBREVIATIONS
`
`ADP
`NF
`Alt
`AST
`ATCC
`BPR
`CDT
`CET
`COD
`CORR
`DOC+l
`EGV
`EIS
`FPR
`HPC
`HPT
`IC
`ID
`IGV
`LPC
`LPT
`MTOGW
`OD
`OEW
`OPR
`Poly
`PR
`SL
`SLS
`SM
`Std
`TCA
`TCLA
`TOGW
`TSFC
`VAMP
`VJR
`
`Advanced Ducted Propulsor
`Airfoil
`Altitude
`Advanced Subsonic Transport
`Advanced Technology Common Core
`Bypass Ratio
`Compressor Discharge Temperature
`Combustor Exit Temperature
`Constant Outside Diameter
`Corrected
`Direct Operating Cost Plus Interest
`Exit Guide Vane
`Entry Into Service
`Fan Pressure Ratio
`High-Pressure Compressor
`High-Pressure Turbine
`Intermediate Case
`Inner Diameter
`Inlet Guide Vane
`Low-Pressure Compressor
`Low-Pressure Turbine
`Maximum Takeoff Gross Weight
`Outer Diameter
`Operating Empty Weight
`Overall Pressure Ratio
`Polytropic
`. Pressure Ratio
`Sea Level
`Sea Level Static
`Surge Margin
`Standard
`Turbine Cooling Air
`Turbine Cooling and Leakage Air
`Takeoff Gross Weight
`Thrust Specific Fuel Consumption
`Vehicle Analysis Modular Program
`Jet Velocity Ratio (Fan Duct/Engine Core)
`
`NASA/CR—2003-212467
`
`vi
`
`GE-1016.008
`
`

`
`AN2
`
`Btu
`F
`ft/min
`ftlsec
`ft
`hp
`in.
`K
`k
`ksi
`lbm
`lb
`lb/sec
`Mn
`N1
`N2
`nm
`N
`..Je
`p
`
`psi a
`PT
`R
`rpm
`T2
`T3
`T4
`TT
`u
`vi
`w
`Wae
`W/A
`We
`
`LIST OF SYMBOLS
`
`Turbine Exit Annulus Area x Rotor Speed Squared
`British Thermal Unit
`Fahrenheit
`Feet Per Minute
`Feet Per Second
`Feet
`Horsepower
`Inch
`Kelvin
`Thousands
`Thousands of Pounds Per Square Inch
`Pounds, Mass
`Pounds, Force or Weight
`Pounds Per Second
`Mach Number
`Low Spool Speed
`High Spool Speed
`Nautical Mile
`Corrected Speed
`
`Pressure
`Pounds Per Square Inch, Absolute
`Total Pressure
`Rankin
`Revolutions Per Minute
`Fan Inlet Total Temperature
`Compressor Discharge Total Temperature
`Combustor Exit Total Temperature
`Total Temperature
`Wheel Speed
`Jet Velocity
`Flow
`Core Air Flow
`Flow/Area
`Corrected Flow
`
`NASA/CR—2003-212467
`
`vii
`
`GE-1016.009
`
`

`
`GE-1016.010
`
`GE-1016.010
`
`

`
`1. SUMMARY
`
`A study was conducted to define and assess the critical or enabling technologies required for a year 2005 entry
`into service (EIS) engine for subsonic commercial aircraft, with NASA Advanced Subsonic Transport goals used
`as benchmarks. Two engines were selected for this study -
`a baseline current technology engine and an
`advanced technology engine. The baseline engine is a turbofan based on 1995/96 EIS technology, e.g., PW4084.
`The year 2005 EIS advanced technology engine is an Advanced Ducted Propulsor (ADP) engine.
`
`Performance analysis showed that the ADP design offered many advantages compared to the turbofan. The
`ADP' s lower fan pressure ratio (FPR) gives it a propulsive efficiency advantage resulting in lower thrust specific
`fuel consumption at cruise (14.6 percent), a thrust growth advantage, and the option to have a smaller size core
`engine. The ADP's fan drive gear combined with the variable geometry fan and low-pressure compressor (LPC)
`allows the fan, LPC, and low-pressure turbine to run at optimum speeds and efficiencies. The ADP' s reduced
`combustor exit temperature (T4) at takeoff, relative to a turbofan rated to similar thrusts, allows the ADP to have
`improved turbine airfoil life for the same climb T4 or allows the ADP to run a hotter climb T4 for the same
`turbine airfoil life.
`
`An airplane/engine simulation study using a long range quad aircraft quantified the effects of the ADP engine on
`the economics of typical airline operation. The economic figure of merit for this study was direct operating cost
`plus interest (DOC+!), which included both engine and aircraft related operating costs and ownership costs.
`Results of the economic analysis show the ADP propulsion system provides a 6.6 percent reduction in DOC+l
`with half the reduction resulting from fuel burn. Engine and airframe maintenance effects were small.
`
`Critical and enabling technologies for the year 2005 EIS ADP were identified and prioritized. Critical technology
`paths were defined.
`
`NASA/CR—2003-212467
`
`1
`
`GE-1016.011
`
`

`
`2. INTRODUCTION
`
`This study defined and assessed the critical or enabling technologies required for a year 2005 entry into service
`(EIS) engine for subsonic commercial aircraft, with NASA Advanced Subsonic Technology goals used as
`benchmarks. Two engines were defined and used to identify and evaluate technology features: a 1995/96 EIS
`baseline turbofan engine and a high technology Advanced Ducted Propulsor (ADP) engine. A performance
`analysis was performed to determine the advantages of a 2005 EIS ADP design over the conventional turbofan. A
`mission analysis was performed to quantify the effects of the ADP engine on the economics of typical airline
`operation. The economic figure of merit for this study was direct operating cost plus interest (DOC+I), which
`includes both engine and aircraft related operating costs and ownership costs. The class of aircraft chosen for this
`study was a long range quad (four engines) 470 passenger aircraft with today's three class seating standards.
`Propulsion system influence factors effecting thrust specific fuel consumption, drag, weight, maintenance cost,
`and engine price on DOC+ I were determined including the effects of airframe price assumptions on DOC+ I. The
`technologies that are critical or enabling in reaching the 2005 EIS ADP engine were prioritized and critical
`technology paths were defined.
`
`NASA/CR—2003-212467
`
`2
`
`GE-1016.012
`
`

`
`3. ENGINE DESCRIPTION
`
`Two engines were selected for use in Task XXXVill, a state-of-the-art turbofan engine and an Advanced Ducted
`Propulsor (ADP) engine. Section 3.0 provides descriptions of the selected engines and comparisons of the two
`cycles in terms of thrust specific fuel consumption (TSFC) and rating temperatures, i.e., compressor discharge
`and combustor exit temperatures.
`
`3.1. 1995 EIS TURBOFAN ENGINE
`
`The turbofan engine used as a basis for comparison in Task XXXVill is designated the STF1043. The STF1043
`represents a year 1995/96 entry into service (EIS) turbofan with PW4084 technology and bypass ratio (BPR). The
`fan diameter is 94 in., the takeoff thrust is 60,000 lb at sea-level static, and the cruise TSFC is 1 percent improved
`relative to a 1993 production engine. Component efficiencies are given in Table 1.
`
`3.2. 2005 EIS ADP ENGINE
`
`The ADP engine chosen for Task XXXVill is designated the STS1046. Two studies were conducted prior to the
`final definition of the STS 1046, a low shaft study and a high-pressure compressor (HPC) stage pressure ratio
`loading study. The results of the low shaft study are given in Section 3.2.1 and the HPC results are discussed in
`Section 3.2.3.3.
`
`Table 1. 1995 EIS Turbofan/2005 EIS ADP Component Comparison- Component Aero Point
`
`Aight Condition, Alt!Mn
`Power Setting
`Thrust, lb
`
`Efficiencies, %
`Fan OD Stage
`Fan ID + LPC Poly
`HPC Poly (Including IC and EGV)
`HPT
`LPT
`
`Burner Pressure Loss, % ~ PIP
`* Single stage based
`
`1995 EIS Turbofan
`STF1043
`35k/0.80
`Bucket
`9000
`
`2005EISADP
`STS1046
`35k/0.85
`42.5W/AFan
`7930
`5.4
`
`90.5
`90.8
`89.0
`90.6
`92.9
`
`Base
`Base
`Base
`Base
`Base
`
`3.8
`
`Base
`
`93.4
`90.4
`92.0
`87.5*
`93.5
`99.3
`24.0
`
`5.7
`
`+2.9
`-0.4
`+3.0
`-3.1 *
`+0.6
`
`+1.9
`
`The STS1046 represents a 50,000 lb sea-level static thrust category engine. The projected 10-year market for
`such an engine in the 2005 to 2014 time period is 3,600 engines. The STS1046 represents the combination of an
`advanced turbofan propulsion system and core, which would improve TSFC about 5 percent over the 1 0-year
`(1995 to 2005) time period, and the ADP concept, which would improve propulsive efficiency and reduce TSFC
`by approximately another 9 percent. Since the basic configuration and concept are not by themselves size limited,
`consideration of a particular market segment is academic and should not be considered as total market potential
`for an advanced core/ ADP configuration.
`
`NASA/CR—2003-212467
`
`3
`
`GE-1016.013
`
`

`
`3.2.1. low Shaft Study
`A preliminary structural analysis conducted on a version of the ADP engine early in the low shaft technology
`study indicated that a properly designed low shaft could not fit within the bore dimensions of the high-pressure
`turbine disk. The earlier engine design incorporated a 120.9 in. variable pitch fan that resulted in an engine
`bypass ratio of 22.6 at cruise design conditions. Coupled with the fan was a five-stage low-pressure compressor
`with an inlet flow of 114.6 lb/sec and a pressure ratio of 4.04. The core was an 85 percent scale version of the
`Advanced Technology Common Core (ATCC) and incorporated a six-stage high-pressure compressor powered
`by a high work single stage high-pressure turbine. Powering the low spool was a five-stage low-pressure turbine
`with an expansion ratio of 14.36. Installed engine design tables of this configuration predicted a maximum low
`shaft torque of over 30,000 ft-lb at sea-level takeoff during hot day conditions. To transmit this torque and fit
`within the bore dimensional requirements of the scaled A TCC, a new shaft material with extremely high strength
`and high stiffness-to-weight capabilities was required. Specifically, material strength increases of 67 percent over
`current steel or 39 percent over Waspaloy were needed for a full-life design. Similar studies on the high-pressure
`turbine (HPT) disk also showed an overstressed condition if the bore diameter was increased to accommodate a
`larger low shaft. Material improvements necessary to reach full disk life were similar to what was needed for the
`low shaft. These material improvements were not considered reasonable for a 2005 EIS engine. Consequently, a
`low shaft study was conducted to guide the selection of a revised ADP cycle and component definition that
`would satisfy a 2005 EIS.
`
`The low shaft study started with a V2500 growth engine that had an overall pressure ratio (OPR) and BPR of 30
`and 4.8, respectively, at 0.8 Mn/35,000 ft maximum cruise condition. To determine the effects oflow shaft torque
`capability on engine cycle and rating schedules, the V2500 was modified step-by-step into a 55 OPR ADP with
`BPR ranging from 10 to over 22. For the low shaft study, the specific modifications to the V2500 engine were as
`follows:
`
`1. Replace the V2500 fan with a 1.4 pressure ratio, variable pitch fan (increases torque requirements as a
`result of slower fan tip speed and larger fan diameter).
`
`2.
`
`3.
`
`4.
`
`Introduce a gearbox into engine (reduces torque requirements through a low turbine speed increase).
`
`Increase fan inner diameter (ID) plus low-pressure compressor (LPC) pressure ratio from base to 3.93
`(increases torque requirements as a result of an increase in low spool power requirements).
`
`Introduce ADP engine thrust lapse characteristics (reduces maximum torque requirements relative to a
`required cruise thrust level).
`
`5. Modify low shaft wall thickness from 0.3 in. to 0.4 in. (impacts torque capability).
`
`6. Scale down core to reflect 55 OPR cycle (results in a smaller low shaft with less torque capabilities).
`
`7. Use advanced Waspaloy (PWA1112) low shaft materials and design procedures (increases torque
`capability).
`
`The above analysis resulted in a quantitative assessment of the various factors that make up the torque
`requirements of an 2005 EIS very high bypass ratio ADP and indicated that the gearbox was the greatest
`contributor to solving low shaft torque problems. Also of significance was the impact that ultra-high engine
`pressure ratios had on limiting the low shaft dimensions and hence torque capability. Increasing engine pressure
`ratios resulted in a smaller hot section with a corresponding smaller HPT disk and shaft diameters.
`
`NASA/CR—2003-212467
`
`4
`
`GE-1016.014
`
`

`
`Figure 1 summarizes the results of the study for an engine BPR of 16.3 and an OPR of 55. Along the horizontal
`axis are the seven changes that were studied while the vertical axis is a parameter called Low Shaft Degree of
`Difficulty. A degree of difficulty of 2.0 indicates a torque level 100 percent above what is allowed for a full-life
`part and represents an unacceptable design. Likewise a degree of difficulty of 1.0 results in a full-life design
`while less than 1.0 represents excess life. Note in Figure 1 that for a full-life shaft with a 0.3 in. wall thickness
`and the indicated engine cycle (55 OPR, 16.3 BPR), the material torque capability must be increased to 56
`percent better than what was used in the base V2500. This particular low shaft used AMS6304, which is a
`conventional steel alloy, in addition to a design stress margin that was very conservative. The major part of the
`improvement needed by the ADP at 16.3 BPR and 55 OPR can be easily accommodated by incorporating the low
`shaft design philosophies and material (PWA1112) of the recently qualified PW4084. The remaining
`improvement comes from a 10 percent increase in the yield strength of the PWA1112 Waspaloy material and is
`considered a moderate risk development program for the 2005 EIS time frame. The new material, called
`advanced Waspaloy, was used to define the ADP low shaft used in this study. Figure 2 compares the material
`characteristics of both AMS6304 and PWA1112 along with the stress margins used in the two referenced
`operational engines.
`
`PW1112 Plus 10% Strength Allowable
`0.3 in. Wall Thickness and No Stress Margin
`
`5.0
`
`4.5
`
`.?!- 4.0
`:;
`.g 3.5
`i5
`0 3.0
`~ Ol 2.5
`0 1ii 2.0
`..c
`(/) 1.5
`
`(J)
`
`(J)
`
`~ 1.0
`
`0.5
`
`0
`
`2
`
`5
`4
`3
`Material or Mechanical Feature
`
`6
`
`7
`
`67426.cdr
`
`Figure 1. 2005 EIS ADP Low Shaft Torque Summary
`
`NASA/CR—2003-212467
`
`5
`
`GE-1016.015
`
`

`
`110,000
`
`100,000
`
`en 90,000
`en
`~
`Ci5
`....
`al 80,000
`Q)
`.s:::
`(/)
`X
`al
`:::;:: 70,000
`
`60,000
`
`50,000
`
`ADP
`PWA1112
`Plus 10%
`Yield Strength
`
`PW4084
`Current
`PWA1112 at
`0.2% Yield
`Strength
`
`AMS6304 at
`0.2% Yield
`Strength
`
`V2500AMS
`6304
`
`3
`2
`Material and/or Design Criteria
`
`4
`
`67427.cdr
`
`Figure 2. Low Shaft Material Capabilities Established for 2005 EIS ADP
`
`The results of the analysis were then applied specifically to a derivative of the full sized ATCC that had a
`corrected flow of 6.35 lb/sec exiting the high-pressure compressor. Design studies indicated that the largest
`diameter low shaft that could fit this core and also satisfy critical speed margin had a radius of 1.75 in. and a wall
`thickness of 0.3 to 0.4 in. The material selected was an improved PWA1112 (advanced Waspaloy) that had a
`projected 0.2 percent yield strength of 98.4 ksi. Based on the above assumptions, the maximum torque allowable
`in the 2005 EIS ADP engine at sea-level takeoff hot day conditions was approximately 490,000 in-lb. These
`results helped define the final ADP engine.
`
`3.2.2. Engine Description
`
`The STS 1046 is an Advanced Ducted Propulsor engine configuration that combines an ultra-high bypass ratio,
`variable pitch fan with a derivative of the Advanced Technology Common Core. Engine OPR and bypass ratio
`are 55 and 16.7, respectively, at 0.85 Mn/35,000 ft (T2=471"R) maximum climb rating conditions where installed
`thrust is 10,538 lb. Sea-level (0.2 Mn) takeoff thrust is 43,200 lb during hot day conditions that establishes many
`of the temperature and speed limits of the ·engine shown in Figure 3. The variable pitch fan is followed by a
`six-stage variable geometry low-pressure compressor, both of which are powered by a six-stage low-pressure
`turbine through a 4.2:1 gearbox. The core is a derivative of the ATCC and is composed of a six-stage high(cid:173)
`pressure compressor powered by a single stage turbine. Figure 4 illustrates overall engine arrangement as well as
`selected component inlet pressures, temperatures, and corrected airflows at maximum climb flight conditions.
`Technologies and materials selected are consistent with an EIS date of2005.
`
`NASA/CR—2003-212467
`
`6
`
`GE-1016.016
`
`

`
`SU0.2Mn/Hot Day
`T2 = 90"F
`
`Fan
`
`DEGV -
`
`141•F
`20.2 psia
`
`1,2so·F
`732 psia
`
`2,075•F
`189 psia
`
`1,o5o•F
`17.5 psia
`
`~06'F
`1~6.4psia
`
`(
`
`N2 Max = 21 ,000 rpm
`N, Max= 7,631 rpm
`
`3,1oo·F
`691 psia
`
`69437.cdr
`
`Figure 3. 2005 EIS ADP Maximum Temperatures and Pressures
`
`0.8Mn/35,000 ft- Max Climb
`
`We= 1,0951b/sec
`PT = 7.72 psia
`TT = 523"R
`
`We= 2,9151b/sec
`PT = 5.53 psia
`TT=471°R
`
`Fan
`
`TT= 1340•R l
`
`We = 62.5 lb/sec
`PT= 5.4 psia
`
`Six-stage
`LPT
`
`N2 Max = 20,563 rpm
`N1 Max = 7,290 rpm
`
`We = 35.6 lb/sec
`Pr = 34.2 psia
`TT = 844°R
`
`~0
`
`PT= 77.8 psia
`TT= 2,423°R
`P T = 288.5 psia
`We= 5.11b/secr = 3443.R
`PT = 305 psia
`T
`'
`TT= 1,60TR
`
`69438.cdr
`
`Figure 4. 2005 EIS ADP General Engine Arrangement
`
`NASA/CR—2003-212467
`
`7
`
`GE-1016.017
`
`

`
`3.2.3. Component Description
`
`Component efficiencies for the STS1046 ADP are listed in Table 1. The ADP component efficiency levels reflect
`Pratt & Whitney estimates for 2005 EIS.
`3.2.3. 1. Variable Pitch Fan
`
`The high efficiency, variable pitch fan has a diameter of 118.8 in. and an inlet hub-to-tip radius ratio of 0.4. Low
`noise and high efficiency are as a result of several features incorporated into the design including advanced
`aerodynamic blading, low corrected rotor tip speed, and noise acoustic treatments. The fan tip and root pressure
`ratios are 1.32 and 1.08, respectively, at the fan aerodynamic design point (0.85 Mn/35,000 ft cruise). At the
`same flight point, fan rotor tip efficiency is 95.1 percent with an inlet specific flow of 42.5 lb/sq ft and a
`corrected tip speed of 850 ft/sec. The fully reversible variable pitch fan consists of 18 blades and 40 duct exit
`guide vanes that are located 1.6 chord lengths behind the fan rotor for acoustic reasons. The component
`efficiency of 93.4 percent in Table 1 includes 0.5 percent for exit guide vane pressure loss.
`
`The level of fan tip speed is made possible by the ADP fan drive gear system. The reduction ratio of 4.2 was
`selected to optimize both the low shaft and the fan speeds to maximize efficiencies of the fan, LPC, and low(cid:173)
`pressure turbine (LPT). The level falls within design range for a planetary type gear system consisting of a ring
`gear and five planets. The system was sized for a maximum input shaft horsepower (hp) of 42,000 at takeoff and
`has an efficiency level at cruise of 99.3 percent.
`3.2.3.2. Low-Pressure Compressor
`
`Coupled to the high speed side of the gearbox is a six-stage LPC that has an inlet flow and pressure ratio of
`130.8lb/sec and 4.83:1 respectively, at the aerodynamic cruise design point. The average pressure ratio per stage
`is 1.3: 1. AU stages have variable stators to maximize efficiency and provide stall free operation. The inlet tip
`speed is 1,306 ft/sec with physical rotor speed set by the low turbine AN2 limit. The flowpath was determined at
`the front by the fan root and exit guide vane dimensions as well as the high speed gearbox and, at the rear, by the
`inlet size of the high-pres