Final Report

UNDUCTED FAN ENGINE DESIGN

Embry-Riddle Aeronautical University

AE-440

Dr. Magdy Attia

04.26.2011

TEAM FUDD

Chris Burch

Helena Hobbs

Noelle Palmer

Ryan Dantis

Shaheryar Khan

Steven Bohlemann

Timothy Hauenstein

2

Executive Summary

This report covers the detailed analysis for the unducted propfan engine with variable pitch and counter

rotating blades to compete in the same thrust class as the CFM International CFM 56-7B24. The design

uses 13 blades for the forward propfan and 11 blades for the aft propfan and has a diameter of 4.04m.

Propfan 1 runs at 1708 RPM and propfan 2 runs at 1855 RPM at cruise conditions. At takeoff conditions,

propfan 1 and 2 operate at 1610 RPM. The variable pitch blades remove the need for thrust reversers

and save a large amount of weight compared to conventional turbofan configurations. The engine is

designed to cruise at .85M at 34,000ft altitude. Takeoff speed was assumed to be .212M. The engine

can produce the required 7402lbf of thrust, which amounts 40% of CFM56 7B24 takeoff thrust. The

cruise TSFC is 0.63 per hour which is comparable to .627 of the CFM56. The TIT is 1558K for cruise and

1672K for takeoff. The exhaust gas temperature (EGT) is 681.4K for cruise and 832.2K for takeoff. Core

mass flow is designed for a cruise value of 30kg/s at cruise and 65kg/s at takeoff. The first and second

propfan mass flows are 456.1 and 459.8 respectively at cruise. At takeoff the propfan mass flows change

to 164.2 for the first propfan then 219.0 for the second propfan.

3

Table of Contents

1. Introduction and Competitive Analysis ............................................................................................... 14

1.1 Problem Statement and Requirements ...................................................................................... 14

1.2 Detailed Analysis ......................................................................................................................... 15

1.3 Technological Innovations .......................................................................................................... 16

2. Cycle .................................................................................................................................................... 17

2.1 General Information ................................................................................................................... 17

2.2 Cycle at Design: Cruise ................................................................................................................ 18

2.3 Cycle at off-design: Take-off ....................................................................................................... 20

2.4 Key Engine Performance Values ................................................................................................. 22

2.5 Customer and Cooling Bleeds ..................................................................................................... 22

3. Intermediate Pressure Compressor (IPC) ........................................................................................... 23

3.1 IPC at Design Condition: Cruise ................................................................................................... 23

3.1.1 Key IPC design choices and criteria ..................................................................................... 24

3.1.2 Aerodynamic Analysis ......................................................................................................... 25

3.1.3 Thermodynamic analysis ..................................................................................................... 29

3.1.4 Geometric Analysis ............................................................................................................. 30

3.2 Off Design Condition: Takeoff ..................................................................................................... 33

3.2.1 IPC design criteria ............................................................................................................... 33

3.2.2 Geometry Analysis .............................................................................................................. 34

3.2.3 Key IPC trends ..................................................................................................................... 36

4. High Pressure Compressor (HPC) ........................................................................................................ 39

4.1 HPC at Design Conditions: Cruise ................................................................................................ 39

4.1.1 Aerodynamic Analysis ......................................................................................................... 39

4.1.2 Thermodynamic Analysis .................................................................................................... 45


4.2 HPC at Off Design Conditions: Takeoff ........................................................................................ 48

4.2.1 HPC Design Criteria ............................................................................................................. 48


4.2.3 Key HPC Trends ................................................................................................................... 51

5. Combustion Chamber ......................................................................................................................... 53

6. High Pressure Turbine (HPT) ............................................................................................................... 56

4

6.1 Aerodynamic Analysis ................................................................................................................. 57

6.2 Thermodynamic Analysis ............................................................................................................ 60

6.3 Geometric Analysis ..................................................................................................................... 61

7. Intermediate Pressure Turbine (IPT) ................................................................................................... 64




8. Power Turbine (PT) ............................................................................................................................. 74




9. Propfan ................................................................................................................................................ 90

9.1. Geometric Analysis ..................................................................................................................... 91

9.2. Aerodynamic Analysis ................................................................................................................. 97

9.3. Thermodynamic Analysis ............................................................................................................ 99

9.4. Performance ............................................................................................................................. 103

10. Inlet ................................................................................................................................................... 105

11. Ducts ................................................................................................................................................. 108

11.1 High Pressure Compressor Exit Diffuser ................................................................................... 108

11.1.1 Diffuser Thermodynamics ................................................................................................. 108

11.1.2 Diffuser Geometry ............................................................................................................ 109

11.2 Intermediate Pressure Compressor/Power Turbine Duct ........................................................ 109

11.2.1 Duct Thermodynamics ...................................................................................................... 109

11.2.2 Duct Geometry .................................................................................................................. 110

12. Materials ........................................................................................................................................... 111

12.1 Prop Fan .................................................................................................................................... 111

12.2 Compressor ............................................................................................................................... 112

12.3 Combustion Chamber ............................................................................................................... 112

12.3.1 Thermal Barrier Coating (TBC) .......................................................................................... 113

12.3.2 Anti Oxidation Coating ...................................................................................................... 114

12.4 Turbine ...................................................................................................................................... 114

12.5 Duct and Diffuser ...................................................................................................................... 115

5

12.6 Inlet and Exit Cone .................................................................................................................... 116

1. References ........................................................................................................................................ 117

2. Appendix ........................................................................................................................................... 118

6

Table of Figures

Figure 1: Unducted Propfan GE36 (NASA) .................................................................................................. 16

Figure 2: Total and Static Pressure for cruise conditions............................................................................ 18

Figure 3: Total and Static Temperature for Cruise Conditions ................................................................... 19

Figure 4: Mach Number Trend at Cruise ..................................................................................................... 19

Figure 5: Total and Static Pressure for Takeoff Conditions......................................................................... 20

Figure 6: Total and Static Temperature for Takeoff Conditions ................................................................. 21

Figure 7: Mach number Trend at Take-Off ................................................................................................. 21

Figure 8: IPC Isometric View ....................................................................................................................... 23

Figure 9: IPC Velocity Triangles at the Tip of the Second Stage.................................................................. 26

Figure 10: IPC Velocity Triangle at the Mid of the Second Stage ................................................................ 27

Figure 11: IPC Velocity Triangle at the Hub of Second Stage ...................................................................... 28

Figure 12: IPC h-s Diagram of the Second Stage in the absolute FoR ......................................................... 29

Figure 13: IPC Meridional View ................................................................................................................... 30

Figure 14: IPC Stagger ................................................................................................................................. 31

Figure 15: IPC Gap to Pitch Ratio ................................................................................................................ 32

Figure 16: IPC Number of Blades vs Stages ................................................................................................. 32

Figure 17: GE90-76B RPM at Take-Off and Cruise Conditions .................................................................... 35

Figure 18: IPC Flow Coefficient at Cruise and Take-Off .............................................................................. 36

Figure 19: IPC Pressure Ratio at Cruise and Take-Off ................................................................................. 36

Figure 20: IPC Work Coefficient at Cruise and Take-Off ............................................................................. 37

Figure 21: IPC Degree of Reaction at Cruise and Take-Off ......................................................................... 37

Figure 22: HPC Isometric View .................................................................................................................... 39

Figure 23: HPC Stage 3 Hub Velocity Triangles ........................................................................................... 42

Figure 24: HPC Stage 3 Mid Velocity Triangles ........................................................................................... 43

Figure 25: HPC Stage 3 Tip Velocity Triangles ............................................................................................. 44

Figure 26: HPC h-s Diagram for Stage 3 ...................................................................................................... 45

Figure 27: HPC Meridional View ................................................................................................................. 46

Figure 28: HPC Stage 1 Splitter Blade Detail ............................................................................................... 46

Figure 29:HPC Stagger for Stage 3 Rotor .................................................................................................... 47

Figure 30: HPC Gap to Pitch vs Blade Number ............................................................................................ 47

Figure 31: HPC Number of Blades vs Stage Number .................................................................................. 48

Figure 32: HPC Flow Coefficient at Cruise and Takeoff............................................................................... 51

Figure 33: HPC Pressure Ratio for Cruise and Takeoff ................................................................................ 51

Figure 34: HPC Work Coefficient at Cruise and Takeoff ............................................................................. 52

Figure 35: HPC Degree of Reaction at Cruise and Takeoff .......................................................................... 52

Figure 36: Combustion Chamber ................................................................................................................ 53

Figure 37: Combustion Chamber h-s Diagram ............................................................................................ 54

Figure 38: HPT Isometric View .................................................................................................................... 56

Figure 39: HPT Hub Velocity Triangle.......................................................................................................... 57

Figure 40: HPT Mid Velocity Triangle .......................................................................................................... 58

7

Figure 41: HPT Tip Velocity Triangle ........................................................................................................... 59

Figure 42: HPT h-s Diagram ......................................................................................................................... 60

Figure 43: HPT Meridional View ................................................................................................................. 61

Figure 44: Stagger of Rotor Blade ............................................................................................................... 62

Figure 45: Isometric View of IPT ................................................................................................................. 64

Figure 46: HPT-IPT Mid Velocity Triangle .................................................................................................... 65

Figure 47: HPT-IPT Hub Velocity Triangle ................................................................................................... 65

Figure 48: HPT-IPT Tip Velocity Triangle ..................................................................................................... 65

Figure 49: IPT Hub Velocity Triangle ........................................................................................................... 67

Figure 50: IPT Mid Velocity Triangle ........................................................................................................... 68

Figure 51: IPT Tip Velocity Triangle ............................................................................................................. 69

Figure 52: IPT h-s Diagram .......................................................................................................................... 70

Figure 53: IPT Meridional View ................................................................................................................... 71

Figure 54: IPT Stagger ................................................................................................................................. 72

Figure 55: Counter-rotating power turbine [AIAA-85-1190 The Unducted fan engine] ............................ 74

Figure 56: A 3D view of the power turbine (IGV/OGV-red; Rotors-blue; Unearthed Stators-black) .......... 74

Figure 57: Conventional Stage .................................................................................................................... 75

Figure 58: Counter-Rotating Stage.............................................................................................................. 75

Figure 59: Work Split across the Power Turbine ........................................................................................ 76

Figure 60: Work Coefficient of Rotors and Stators across the Power Turbine ........................................... 77

Figure 61: Velocity Triangle at Hub, Mid, and Tip; Rotor 1 Rotating Counter-Clockwise, Stator 1 Rotating

Clockwise .................................................................................................................................................... 80

Figure 62: Stack for the Power Turbine Rotor. ........................................................................................... 81

Figure 63: Stack for the Power Turbine Stator ........................................................................................... 81

Figure 64: Velocity Distribution across the Power Turbine ........................................................................ 82

Figure 65: Flow Coefficient across the Power Turbine ............................................................................... 82

Figure 66: Degree of Reaction for the Power Turbine Components .......................................................... 83

Figure 67: Meridional View of for Station 1, 2, 3 and 4 .............................................................................. 84

Figure 68: h-s Diagram UDF rotor in Relative FoR ...................................................................................... 84

Figure 69: h-s Diagram UDF rotor in Absolute FoR ..................................................................................... 85

Figure 70: Pressure Variation across Power Turbine .................................................................................. 86

Figure 71: Temperature Variation across the Power Turbine .................................................................... 86

Figure 72: The Meridional Flow Path of the Power Turbine ....................................................................... 88

Figure 73: The Number of Blades across the Power turbine ...................................................................... 89

Figure 74: Propfan Isometric View .............................................................................................................. 90

Figure 75: Propfan Airfoil ............................................................................................................................ 91

Figure 76: Propfan 1 snd 2 .......................................................................................................................... 93

Figure 77: Pitch Angles across Flight Conditions......................................................................................... 94

Figure 78: Angle of Attack Across Flight Conditions ................................................................................... 95

Figure 79: Advance Angle Across Flight Conditions .................................................................................... 96

Figure 80: Propfan Cruise Velocity Triangle ................................................................................................ 97

Figure 81: Propfan h-s Diagram .................................................................................................................. 99

8

Figure 82: Propfan Aero/Thermo Stations .................................................................................................. 99

Figure 83: Propfan Relative h-s Diagram .................................................................................................. 101

Figure 84: Propfan Aero/Thermo Stations for Relative Frame of Reference ........................................... 101

Figure 85: Detailed Meridional Inlet View with Capture Cones ............................................................... 105

Figure 86: h-s Diagram of Flow through Inlet Diffuser ............................................................................. 106

Figure 87: HPC Exit Diffuser Thermodynamics and h-s Diagram .............................................................. 108

Figure 88: HPC exit Diffuser Meridonial View ........................................................................................... 109

Figure 89: IPT/PT Thermodynamics and h-s Diagram ............................................................................... 109

Figure 90: Detailed Meridional View of IPT/PT Duct ................................................................................ 110

9

List of Tables

Table 1: Requirements for Cycle Analysis ................................................................................................... 14

Table 2: GE 36 UDF Data ............................................................................................................................. 15

Table 3: CFM 56-7B24 ................................................................................................................................. 15

Table 4: Stage Locations ............................................................................................................................. 17

Table 5: Pressure Ratio Values .................................................................................................................... 17

Table 6: Total and Static Pressure for Cruise Conditions Values ................................................................ 18

Table 7: Total and Static Temperature for Cruise Conditions Values ......................................................... 19

Table 8: Total and Static Pressure for Takeoff Conditions Values .............................................................. 20

Table 9: Total and Static Temperature for Takeoff Conditions Values ....................................................... 21

Table 10: Key Engine Thrust and TSFC ........................................................................................................ 22

Table 11: Bleed Effects ................................................................................................................................ 22

Table 12: IPC Design Choices ...................................................................................................................... 24

Table 13: IPC Design Values for each Stage ................................................................................................ 24

Table 14: IPC Design Values at Each Rotor and Stator ................................................................................ 24

Table 15: IPC Alpha and Beta Design Values ............................................................................................... 25

Table 16: IPC Tip Velocity Triangle Data ..................................................................................................... 26

Table 17: IPC Velocity Triangle Data at the Mid ......................................................................................... 27

Table 18: IPC Velocity Triangle Data at the Hub ......................................................................................... 28

Table 19: IPC h-s Diagram Values for the Second Stage ............................................................................. 29

Table 20: IPC Design Values at Off Design .................................................................................................. 33

Table 21: IPC Design Values at each Rotor and Stator at Off Design .......................................................... 34

Table 22: IPC Variable Stator Vane Deflection in Degrees .......................................................................... 34

Table 23: IPC Beta Error Entering the Rotors .............................................................................................. 35

Table 24: HPC Design Choices ..................................................................................................................... 39

Table 25: HPC Design Values at Each Stage ................................................................................................ 40

Table 26: HPC Design Values at Each Rotor and Stator .............................................................................. 40

Table 27: HPC Design Values at each Aero/Thermo Station ....................................................................... 41

Table 28: HPC Stage 3 Hub Velocity Values ................................................................................................ 42

Table 29: HPC Stage 3 Mid Velocity Values ................................................................................................ 43

Table 30: HPC Stage 3 Tip Velocity Values .................................................................................................. 44

Table 31: HPC h-s Diagram Values for Stage 3 ............................................................................................ 45

Table 32:HPC Stagger for Stage 3 Rotor ..................................................................................................... 47

Table 33: HPC Off Design Values at Each Stage .......................................................................................... 48

Table 34: HPC Off Design Values at Each Blade .......................................................................................... 49

Table 35: HPC Variable Stator Vane Deflection .......................................................................................... 50

Table 36: HPC Error in Beta ......................................................................................................................... 50

Table 37: Combustion Chamber Inlet and Outlet ....................................................................................... 53

Table 38: Parameters of Jet-A Fuel ............................................................................................................. 54

Table 39: Combustion Chamber Fuel Parameters ...................................................................................... 55

Table 40: Combustion Chamber Specifics ................................................................................................... 55

10

Table 41: HPT Hub Velocity Triangle Values ............................................................................................... 57

Table 42: HPT Mid Velocity Triangle Values ............................................................................................... 58

Table 43: HPT Tip Velocity Triangle Values ................................................................................................. 59

Table 44: HPT h-s Diagram Values .............................................................................................................. 60

Table 45: HPT Radii Values .......................................................................................................................... 61

Table 46: HPT Airfoil Geometry Values ....................................................................................................... 62

Table 47: Key Values for the HPT ................................................................................................................ 63

Table 48: HPT-IPT Velocity Triangle Values................................................................................................. 66

Table 49: IPT Hub Velocity Triangle Values ................................................................................................. 67

Table 50: IPT Mid Velocity Triangle Values ................................................................................................. 68

Table 51: IPT Tip Velocity Triangle Values .................................................................................................. 69

Table 52: IPT h-s Diagram Values ................................................................................................................ 70

Table 53: IPT Radii Values ........................................................................................................................... 72

Table 54: IPT Airfoil Values ......................................................................................................................... 72

Table 55: IPT Key Values ............................................................................................................................. 73

Table 56: Counter-rotating Stage vs. Conventional Stage .......................................................................... 75

Table 57: Power Requirement .................................................................................................................... 76

Table 58: PT Aerodynamic characteristics at TIP ........................................................................................ 78

Table 59: PT Aerodynamic characteristics at MID ...................................................................................... 78

Table 60: PT Aerodynamic characteristics at HUB ...................................................................................... 79

Table 61: Thermodynamic Characteristics across Station 1, 2, 3 and 4 ..................................................... 85

Table 62: Geometry per Station across the Power Turbine ....................................................................... 87

Table 63: Geometry per Component across the Power Turbine ................................................................ 88

Table 64: Propfan Airfoil Data ..................................................................................................................... 91

Table 65: Radial Variation for Propfan ........................................................................................................ 92

Table 66: Propfan Key Geometric Values ................................................................................................... 92

Table 67: Propfan Cruise Velocity Triangle Values ..................................................................................... 98

Table 68: Propfan Cruise Thermodynamic Values .................................................................................... 100

Table 69: Propfan Relative Thermodynamic Values ................................................................................. 102

Table 70: Propfan Off Design Thermodynamic Values ............................................................................. 102

Table 71: Key Propfan Stage Thermodynamic Values- Off Design ........................................................... 103

Table 72: Propfan Cruise Performance ..................................................................................................... 103

Table 73: Propfan Takeoff and SLS Performance ...................................................................................... 104

Table 74: Areas at Locations of Interest Necessary for Inlet Design ........................................................ 105

Table 75: Thermodynamics through Inlet Diffuser at Cruise .................................................................... 106

Table 76: Thermodynamics through Inlet Diffuser at Takeoff .................................................................. 107

Table 77: Diffuser Thermodynamics ......................................................................................................... 108

Table 78: IPT/PT Thermodynamics ........................................................................................................... 109

Table 79: Composition of Ti-6Al-4V .......................................................................................................... 111

Table 80: Properties of Ti-6Al-4V compared with standard Alumina ....................................................... 111

Table 81: Composition of INCONEL® Alloy 706 ......................................................................................... 112

Table 82: Properties of INCONEL® Alloy 706 compared with standard Alumina ..................................... 112

11

Table 83: Composition of INCOLOY® alloy A-286 ..................................................................................... 113

Table 84: Properties of INCOLOY® alloy A-286 compared with standard Alumina .................................. 113

Table 85: Properties of YSZ ....................................................................................................................... 114

Table 86: Composition of MAR-M-247 ..................................................................................................... 114

Table 87: Properties of MAR-M-247 ......................................................................................................... 115

Table 88: Mechanical and Thermal Properties of Hastelloy alloy X ......................................................... 116

12

Nomenclature

GREEK

Symbol Definition

Δ Change α Absolute Flow Angle αP Angle of Attack

β Relative Flow Angle

βP Pitch Angle

σ Stagger Angle

η Efficiency

λ Work Coefficient, Excess Air

Flow Coefficient, Fuel to Air Equivalence Ratio

φ Specific Fuel Coefficient

φP Advance Angle

π Pressure Ratio

τ Temperature Ratio

Specific Heat Ratio

ζ Loss Coefficient

Ω Rotational Speed

ρ Density

LETTERS

Symbol Definition

A Cross-Sectional Area

AF Activity Factor

C Chord Length

Cp Specific heat at const pressure per unit mass

CP Coefficient of power

CQ Coefficient of Torque

CT Coefficient of Thrust

F Fan

h Specific enthalpy

HPC High Pressure Compressor

HPT High Pressure Turbine

IPC Intermediate Pressure Compressor

IPT Intermediate Pressure Turbine

J Advance Ratio

Mass flow rate

P Pressure

R Gas Constant

RPM Revolutions per minute

r Radius

s Specific Entropy

13

T Temperature

TO Takeoff

U Blade Speed

V Absolute Velocity

W Relative Velocity

Z Zweifel Coefficient

AR Aspect Ratio

FoR Frame of Reference

Ma Mach Number

TR Taper Ratio

SUBSCRIPTS

Symbol Definition

0 Total

ax Axial

h Hub-Span

LE Leading Edge

m Mid-Span

M Mechanical

P1 Propfan 1

P2 Propfan 2

rel Relative Frame of Reference

R1 Rotor 1

R2 Rotor 2

s Stator

ss Static to Static

TE Trailing Edge

t Tip-Span

ts Total to Static

tt Total to Total

u Radial Velocity

Rel Relative Frame of Reference

14

1. Introduction and Competitive Analysis

Growing reliance on the Gas Turbine Engine in the aviation industry is accompanied by dwindling energy

resources. Hiking fuel prices and increased environmental concerns require engineers to employ a

multidisciplinary approach, taking the engine’s environmental and economical impact into account.

Consequently, it is important to develop an engine with innovations which meet or surpass these

expectations. The engine with an unducted propfan(UDF) design has the innovations to surpass the

competition.

1.1 Problem Statement and Requirements The focus of this project is to create an engine comparable to that of the CFM International CFM 56-

7B24. The goal is to improve on the design with innovative features and adjustment to the detailed

design of the engine. The following is a table of requirements that must be met during the cycle analysis

of the engine.

Table 1: Requirements for Cycle Analysis

Cycle Analysis Requirements

ui TO 72 m/s ηM HPT and HPC 96%

Mi Cruise 0.85 ηss HCP to LPT Duct 93%

M7 (Combustor Inlet) 0.1 ηtt LPT 91%

M6 (HPC Diffuser) 0.3 ηM LPT and LPC 96%

Cruise Altitude 34000 ft. ηts Core Nozzle 93%

Cruise Trust ≥40% CFM TO Thrust ηtt Fan 1 92%

sa 10 J/kg*k ηtt Fan 2 92%

∆Po (a to 1) -1% γ 1.4

∆Po Inlet (1 to 2) Cruise: -1% γ(4) 1.39

TO: -1.5% γ(3->4) 1.395

∆Po Combustor (7 to 8) -1.50% γ(6) 1.38

π Overall <42 γ(4->6) 1.385

ηtt IPC 4 Stage: 90% γ(7->8) 1.355

3 Stage: 88% γ(8->12) 1.33

ηss ICP to HPC Duct 94% R 287 J/Kg*K

ηtt HPC 7 Stages: 89% R(CC) 259.8 J/Kg*K

6 Stages: 87% QR 43000000 J/kg

ηss HCP to Diffuser Duct 93% TITmax 2100 K

ηtt HPT 90%

Due to the engine’s innovative Unducted Propfan design, some of the requirements set previously do not apply for both the cycle analysis as well as the detailed fan design. There will be no ducted fan at the entrance of the engine. Instead, and unducted fan is installed at the end of the engine’s design. Further design specification of the unducted prop fan will be discussed in Chapter 9.

15

1.2 Detailed Analysis This design will be taking into comparison not only the CFM 56-7B24 but also the design of the GE-36

Unducted Fan. It will take into consideration some basic performance aspects of the CFM while

concentrating mainly on the GE-36 because of the similarities between the engine and the GE-36. The

engine will attempt to compare aspects such as the fan RPM and fan pressure ratio of the GE-36 while

taking into account characteristics such as the TSFC and Thrust of the CFM 56.

Table 2: GE 36 UDF Data

GE-36 UDF

SLS 25,000 Ibf

Cruise Trust 20.36% SLS Thrust

Fan RPM 1395

Fan Blade Numbers 8-8

Total Pressure Ratio 27

Fan Pressure Ratio 1.17

SFC at Cruise 0.52/hr

Fan Stages 2

IPC Stages 3

HPC Stages 7

HPT Stages 1

LPT Stages 1

Power Turbine 6

Fan Blade Tip Speed at Cruise 238 m/s

Fan Blade Tip Speed at TO 259 m/s

Turbine Inlet Temperature 1545 K

Table 3: CFM 56-7B24

CFM 56-7B24

Thrust TO 24200 lbf

Thrust Cruise 5480 lbf

SFC at Cruise 0.627

Bypass ratio 5.3

Mass Flow 354 kg/s

Turbine Inlet Temperature 1780 K

Total Pressure Ratio 32

Number of Spools 2

Fan Stages 1

LPC Stages 3

HPC Stages 9

HPT Stages 1

LPT Stages 4

16

1.3 Technological Innovations

The UDF was a modified turbofan engine with an attached open, counter–rotating fan blades. Its

advantage is that it offers the speed and performance of a turbofan, with the fuel economy of a

turboprop.

This technology has been proven to work and showed very promising results during its R&D and testing

stage in the 1970’s and 1980’s. NASA and GE collaborated to work on the GE36, while Pratt &Whitney-

Allison pursued the PW 578-DX Propfan. Figure 1 depicts the GE-36, a UDF similar to the engine

illustrated in this report.

The engine designed in this report has an aft mounted, pusher style, counter-rotating propfan. Initial

research shows a slight reduction of carbon and nitrogen oxides emissions and the UDF and saves fuel

when comparing the thrust produced. The UDF blades are variable pitch, which provides the reverse

thrust capability. This allows for reverse thruster mechanism on traditional turbofan engines to be

excluded from this engine, reducing overall weight of the engine. Counter-rotating fans allow recovery

of exit swirl and converting this to thrust, thus increasing efficiency. It is important to note that the

engine fan rotors do not deal with gearings thereby reducing weight, increasing reliability, and cutting

down maintenance costs. The HPC and IPC shafts are counter rotating and the rotation within the power

turbine for the UDF operates under a counter-rotating stage (rotor-rotor) design. A rotor-rotor design

has a work stage that is twice the amount of a conventional stage. This translates to lower stages for the

same work required, reducing the overall weight of the engine. All these factors combined produce an

engine which has high thrust to weight ratios, low specific fuel consumption and higher efficiencies.

Figure 1: Unducted Propfan GE36 (NASA)

17

2. Cycle

2.1 General Information

Cycle analysis was conducted for Cruise (34,000 ft and Mach .85) and Takeoff (Sea Level and Mach .212)

conditions.

Table 4: Stage Locations

Table 5: Pressure Ratio Values

Station Component

a Ambient

1 Inlet

2 Diffuser

3 IPC

4 HPC

5 HPC Diffuser

6 Combustion Chamber

7 HPT

8 IPT

9 IPT-PT Duct

10 Power Turbine

11 Core Nozzle

21 Propeller 1

22 Propeller 2

UDF

TO Cruise

π0 Core 25.24 28

π0F1 1.20 1.116

π0F2 1.18 1.114

π0 IPC 3.577 4

π0 HPC 7.056 7

a

21

7

8

9 10

11

1 2 5 6

3 4

22

Hauenstein, Palmer, Khan, Hobbs

18

2.2 Cycle at Design: Cruise

The pressure trend at cruise for the engine is shown in Figure 2 and the calculated values are shown in

Table 6. Pressure is increasing until the combustion chamber Inlet where the pressure begins to

decrease to the exhaust of the engine. The pressure across the fan stays almost constant.

Figure 2: Total and Static Pressure for cruise conditions

Table 6: Total and Static Pressure for Cruise Conditions Values

Ambient Inlet Diffuser IPC HPC

HPC Diffuser

Combustion Chamber

HPT IPT IPT/Power Turbine

Duct

Power Turbine

Core Nozzle

Po (Pa) 40198.1 39796.1 39398.2 156035.0 1072385.7 1084392.1 1068126.2 352686.4 200934.8 198614.6 39723.5 38395.4

P (Pa) 25064.0 28176.7 28403.2 128817.5 912910.2 1076942.6 978346.2 247190.9 166466.2 194874.9 38369.4 25064.0

The temperature trend at cruise for the engine is shown in Figure 3 and the calculated values are shown

in Table 7. Temperature is increasing until the HPT where the temperature begins to decrease to the

exhaust of the engine. The trend mimics that of the pressure across the engine.

0.0

200000.0

400000.0

600000.0

800000.0

1000000.0

1200000.0

Total and Static Pressure (Pa)

Po

P

19

Figure 3: Total and Static Temperature for Cruise Conditions

Table 7: Total and Static Temperature for Cruise Conditions Values


HPC Diffuser

Combustion Chamber

HPT IPT IPT/Power

Turbine Duct

Power Turbine

Core Nozzle

To(K) 252.8 252.8 252.8 393.3 719.7 719.7 1558.1 1226.6 1079.6 1079.6 757.5 757.5

T (K) 220.9 229.1 230.3 372.7 688.5 723.0 1524.5 1123.1 1030.3 1074.5 751.0 681.4

Below displays the Mach number trend throughout the engine at cruise.

Figure 4: Mach Number Trend at Cruise

0.00

500.00

1000.00

1500.00

2000.00 Total and Static Temperature (K)

To

T

0

0.2

0.4

0.6

0.8

1

Mach Number

20

2.3 Cycle at off-design: Take-off

The pressure trend at take-off for the engine is shown in Figure 5 and the calculated values are shown in

Table 8. The pressure increases until the combustion chamber inlet where the pressure begins to

decrease to the exhaust of the engine.

Figure 5: Total and Static Pressure for Takeoff Conditions

Table 8: Total and Static Pressure for Takeoff Conditions Values

Ambient Inlet Diffuser IPC HPC HPC

Diffuser Combustion

Chamber HPT IPT

IPT/Power Turbine Duct

Power Turbine

Core Nozzle

Po (Pa) 104522.9 103477.7 101925.6 364636.3 2573014.5 2544118.8 2505957.1 698997.8 400344 394185.2 103740.4 103567.2

P (Pa) 101300.0 82286.1 81474.6 305881.6 2167150.5 2526641.4 2288149.6 614838.2 310991 384375.0 100894.4 101300.0

The temperature trend at take-off for the engine is shown in Figure 6 and the calculated values are

shown in Table 9. The temperature increases until the HPT inlet where the temperature begins to

decrease to the exhaust of the engine. The maximum temperature is higher at take off due to a higher

TIT takeoff.

0.0

500000.0

1000000.0

1500000.0

2000000.0

2500000.0

3000000.0

Total and Static Pressure (Pa)

Po

P

21

Figure 6: Total and Static Temperature for Takeoff Conditions

Table 9: Total and Static Temperature for Takeoff Conditions Values

Below is a figure representing the Mach number trend across the engine at takeoff.

Figure 7: Mach number Trend at Take-Off

0.00

500.00

1000.00

1500.00

2000.00Total and Static Temperature (K)

To

T

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Mach Number


HPC Diffuser

Combustion Chamber

HPT IPT IPT/Power

Turbine Duct

Power Turbine

Core Nozzle

To(K) 290.6 290.6 290.6 436.1 795.0 795.0 1672.9 1264.1 1117.2 1117.2 836.8 836.8

T (K) 288.0 272.2 272.6 415.2 758.3 793.5 1635.6 1224.5 1049.3 1110.2 831.1 832.2

22

2.4 Key Engine Performance Values

The key engine performance values from the cruise cycle design are tabulated in Table 10. All thrust

requirements were met with the cruise thrust at exactly 40% of the competitors take-off thrust. Both

the take-off and SLS thrust values match that of the CFM exactly. The thrust was chosen not to be

raised above the minimum constraints due to fuel savings. The conclusion was made that having a fuel

savings at cruise was more important than exceeding the thrust. As a result, the engine was able to

achieve a competitive cruise TSFC of the CFM 56-7B24.

Table 10: Key Engine Thrust and TSFC

Propfan Thrust

(lbs) Core Thrust

(lbs) Net Thrust

(lbs) Propfan Thrust

Percentage Core Thrust Percentage

TSFC (1/h)

Cruise 6362.0 1039.6 7401.6 86.0% 14.0% 0.630

Takeoff 14713.0 3791.0 18504.0 79.5% 20.5% 0.557

SLS 19400 4607.3 24200.0 80% 20% 0.434

2.5 Customer and Cooling Bleeds

A customer bleed of 5% was taken out of the HPC at station 10. A cooling bleed of 0.3% was taken out of

the HPC at station 15 behind the last stator. These stations were chosen to meet the criteria of having a

static pressure of 450 kPa for the customer bleed and using a station with 20 psi higher pressure than

the trailing edge of the cooled part. There is a slight loss in fuel savings when the bleeds are added as

well as uniform increase in work over all the components. These results were to be expected due to a

loss in mass flow.

Table 11: Bleed Effects

With Bleeds With Out Bleeds % Diff

ΔhO HPT (J/kg) 347064.7 329668.7 5.28

ΔhO LPT (J/kg) 153949.2 146232.7 5.28

ΔhO PT (J/kg) 337287.1 320381.2 5.28

TIT (K) 1558.1 1482.3 5.12

TSFC at Cruise (1/hr) 0.630 0.621 1.51

23

3. Intermediate Pressure Compressor (IPC)

The engine is equipped with a four stage intermediate pressure compressor as shown below in Figure 8.

It is equipped with a variable inlet guide vane and variable stator vanes.

3.1 IPC at Design Condition: Cruise

The key IPC design choices, design criteria, and the results from thermodynamics, aerodynamics, and

geometric analysis for the IPC at cruise are described in the subsections below.

Figure 8: IPC Isometric View

Hobbs, Burch

24

3.1.1 Key IPC design choices and criteria

The key design choices selected for the IPC and the design criteria that needed to be met are described

in this subsection. Table 12 below shows the design specifications selected to create the rotor and stator

blades.

Table 12: IPC Design Choices

RPM 13,800

AR – Rotors 2.2

AR – Stators 4

H/T 0.68

TR – Rotors 0.8

TR - Stators 1.2

Table 13, Table 14 and Table 15 show that none of the design criteria has been violated and that all of

the IPC detail design is within the limits stated. Please note that in Table 14 the columns highlighted are

the important values of interest. The Δ α requirement is only for the stator blades while the Δ β

requirement is for the rotor blades.

Table 13: IPC Design Values for each Stage

Stage 1 Stage 2 Stage 3 Stage 4 Criteria

Lambda ‘λ’ 0.207 0.195 0.171 0.181 <0.55

Phi ‘Φ’ 0.388 0.401 0.463 0.482 ----

R 0.901 0.868 0.779 0.705 ----

Table 14: IPC Design Values at Each Rotor and Stator

IGV Rotor 1 Stator 1 Rotor 2 Stator 2 Rotor 3 Stator 3 Rotor 4 Stator 4 Criteria

Diffusion Factor

DF tip 0.000 0.279 0.341 0.259 0.358 0.217 0.237 0.207 0.199 ----

DF mid 0.009 0.360 0.400 0.312 0.415 0.250 0.277 0.237 0.232 ----

DF hub 0.021 0.426 0.476 0.392 0.488 0.300 0.330 0.279 0.276 ----

DF Avg 0.010 0.355 0.406 0.321 0.420 0.256 0.282 0.241 0.236 <0.45

Delta Alpha (deg)

Tip 6.7 40.6 28.5 26.9 30.5 21.6 22.9 19.5 19.5 < 45

Mid 8.0 27.4 25.4 24.2 27.2 19.1 20.1 17.1 17.1 < 45

Hub 9.9 24.6 22.8 21.8 24.4 17.1 17.9 15.2 15.2 < 45

Delta Beta (deg)

Tip 4.9 6.8 9.3 9.3 9.7 10.4 6.7 12.3 7.2 < 45

Mid 2.3 4.2 4.7 5.5 5.4 7.4 4.0 9.2 4.5 < 45

Hub 2.4 1.7 2.7 3.6 3.3 5.7 2.6 7.2 3.0 < 45

25

Table 15: IPC Alpha and Beta Design Values

IGV Station 1

Station 2

Station 3

Station 4

Station 5

Station 6

Station 7

Station 8

Station 9

Criteria

Alpha (deg)

Tip 0 6.7 31.3 8.5 30.4 6.0 23.1 5.2 20.4 5.2 < 71

Mid 0 8 35.4 10 34.2 7 26.1 6 23.1 6 < 71

Hub 0 9.9 40.6 12.1 39.0 8.4 30.1 7.2 26.6 7.1 < 71

Beta (deg)

Tip 70.5 69.1 67.5 70.2 66.5 69.9 64.1 66.7 59.5 59.5 < 71

Mid 68.3 66.0 61.8 66.6 61.1 66.5 59.1 63.1 53.9 53.9 < 71

Hub 63.8 58.9 52.1 61.4 52.1 61.8 51.4 58.2 45.9 45.9 < 71

Important conclusions and observations:

The IPC meets all the design requirements. The work coefficients ‘λ’ per stage are less than 0.55 as

specified in the requirements. Lambda reaches a high value of 0.27 in stage one of the IPC, which means

the IPC is lightly loaded compared to the maximum limit since the HPC is responsible for most of the

compression work.

The average diffusion factor across the hub, mid, and tip of each blade is less than 0.45 which provides

the adequate surge margin required. All alpha and beta angles are less than 71 degrees. In addition,

delta alpha across the stator blades and delta beta across the rotor blades is less than 45 degrees as

specified.

3.1.2 Aerodynamic Analysis

The following figures and tables depict the values for the IPC stage 2 velocity triangles at the hub, mid

and tip. The beta angles are located between W and Vax while the alpha angles are located between V

and Vax.

26

Figure 9: IPC Velocity Triangles at the Tip of the Second Stage

Table 16: IPC Tip Velocity Triangle Data

TIP Rotor 2 Entrance Stator 2 Entrance Stator 2 Exit

U (m/s) 553.8 520.5 500.4

Vax (m/s) 189.6 180.2 176.6

V (m/s) 191.8 208.8 177.5

W (m/s) 558.5 452.3 513.2

Wu (m/s) 525.3 414.9 481.9

Vu (m/s) 28.4 105.6 18.5

Beta 70.2 66.5 69.9

Alpha 8.5 30.4 6.0

27

Figure 10: IPC Velocity Triangle at the Mid of the Second Stage

Table 17: IPC Velocity Triangle Data at the Mid

MID Rotor 2 Entrance Stator 2 Entrance Stator 2 Exit

U (m/s) 471.0 448.9 427.8

Vax (m/s) 189.6 180.2 176.6

V (m/s) 192.6 217.8 177.9

W (m/s) 476.9 372.9 442.8

Wu (m/s) 437.6 326.4 406.1

Vu (m/s) 33.4 122.4 21.7

Beta 66.6 61.1 66.5

Alpha 10 34.2 7

28

Figure 11: IPC Velocity Triangle at the Hub of Second Stage

Table 18: IPC Velocity Triangle Data at the Hub

Rotor 2 Entrance Stator 2 Entrance Stator 2 Exit

U (m/s) 388.3 377.3 355.1

VAX (m/s) 189.6 180.2 176.6

V (m/s) 193.9 231.7 178.5

W (m/s) 396.1 293.4 373.4

WU (m/s) 347.7 231.6 329.0

VU (m/s) 40.6 145.7 26.1

Beta 61.4 52.1 61.8

Alpha 12.1 39.0 8.4


The IPC aerodynamic geomerty is following its natural trend. Across the rotor in the relative frame of

reference W and beta are decrease while V and alpha are increasing in the absolute frame of reference.

The rotor blades are rotating clockwise and counter rotating in conjunction with the HPC.

29

3.1.3 Thermodynamic analysis

Below is the h-s diagram for the second stage of the IPC and the corresponding stage characteristic

values in the absolute FoR.

Figure 12: IPC h-s Diagram of the Second Stage in the absolute FoR

Below is the h-s table for the second stage of the IPC and the corresponding stage characteristic values.

Table 19: IPC h-s Diagram Values for the Second Stage

Rotor 2 Entrance Stator 2 Entrance Stator 2 Exit M 0.6 0.6 0.5

Po (Pa) 68655.4 100951.6 100236.9 P (Pa) 55101.6 78564.7 84968.4 To (K) 303.1 341.7 341.5 T (K) 284.7 318.1 325.8

ho (J/Kg) 304861.3 344075.6 344075.6 h (J/kg) 286319.0 320349.0 328253.5

CP (J/kg*K) 1005.8 1007.1 1007.5 γ 1.3993 1.3986 1.3983

ρ (kg/m3) 0.235 0.193 0.187

30


As shown above, the thermodynamics for the IPC follows the normal compression trend. Pressure is

increasing across the stage. Variable Cp is increasing across the IPC

3.1.4 Geometric Analysis

The meridional view of the IPC is show below. The stator blades shown in Figure 13 are turned slightly

to show the angle they are positioned at in reference to the rotor blades.

Figure 13: IPC Meridional View

31

Figure 14: IPC Stagger

Rotor 2 Stagger

TIP 68.3

MID 63.8

HUB 56.8

32

Figure 15 below is the gap to pitch ratio across the IPC.

Figure 15: IPC Gap to Pitch Ratio

Figure 16: IPC Number of Blades vs Stages

0.0000

0.0500

0.1000

0.1500

0.2000

0.2500

0.3000

0.3500

0.4000

0.4500

0 1 2 3 4 5 6 7 8 9

Gap

/S

Blade Number

Gap/S vs Stage

0

10

20

30

40

50

60

70

80

90

1 2 3 4 5

NO

B

Stages

Number of Blades per IPC Stage

Stators

Rotors

33


The reason for the unusual trend of blade numbers across the IPC is due to the variation in aspect ratio

across the rotors and stators. The aspect ratio across the rotors is 2.2 while the aspect ratio across the

stators is 4. Increasing the aspect ratio in the stators will increase the number of stator blades in each

stage. Although the best way to attain a smooth annulus is by altering the Vax and rmid these values could

no longer be altered at a certain point without affecting other key parameters. Instead it was chosen to

then alter the aspect ratio to keep the annulus as smooth as possible. The area of the IPC changes from

.328 at the entrance of the IGV to 0.122 at the exit of the last stator

3.2 Off Design Condition: Takeoff

The IPC, design criteria, and trend charts and design and off design for the IPC at cruise are described in

the subsections below.

3.2.1 IPC design criteria

The design criteria that the IPC needed to meet at off design are described in this subsection. Table 20 and Table 21 shows that none of the design criteria has been violated and that all of the IPC detail design at take-off is within the limits stated. Please note that in Table 21 the columns highlighted are the important values of interest. The Δ α requirement is only for the stator blades while the Δ β requirement is for the rotor blades.

Table 20: IPC Design Values at Off Design

Stage 1 Stage 2 Stage 3 Stage 4 Criteria

Lambda ‘λ’ 0.311 0.192 0.157 0.151 <0.55

Phi ‘Φ’ 0.325 0.353 0.355 0.393 ----

R 0.891 0.761 0.742 0.690 ----

34

Table 21: IPC Design Values at each Rotor and Stator at Off Design

IGV Rotor 1 Stator 1 Rotor 2 Stator 2 Rotor 3 Stator 3 Rotor 4 Stator 4 Criteria

Diffusion Factor

DF tip -0.029 0.425 0.466 0.280 0.363 0.221 0.226 0.191 0.149 ----

DF mid -0.021 0.514 0.536 0.344 0.428 0.256 0.274 0.216 0.187 ----

DF hub -0.011 0.178 0.603 -0.049 0.552 -0.031 0.337 -0.019 0.238 ----

DF Avg -0.020 0.372 0.535 0.192 0.448 0.149 0.279 0.129 0.191 <0.45

Delta Alpha

Tip 6.7 37.3 26.1 21.1 27.2 15.8 20.1 12.7 17.0 < 45

Mid 8 40.0 27.4 22.2 29.2 17.1 22.1 14.1 19.1 < 45

Hub 9.8 42.8 28.3 22.9 31.1 18.5 24.5 15.8 21.7 < 45

Delta Beta

Tip 2.7 1.2 2.7 4.0 2.5 5.3 1.4 6.3 1.5 < 45

Mid 3.7 4.0 5.6 6.4 5.0 7.1 2.9 8.0 3.0 < 45

Hub 4.0 13.3 13.5 11.8 11.0 10.3 6.1 10.8 5.9 < 45


The IPC meets all the design requirements at off design. The work coefficients ‘λ’ per stage are less than

0.55 as specified in the requirements. Lambda reaches a high of 0.311 in stage one of the IPC which

means the IPC is moderately loaded compared to the maximum limit since the HPC is doing most of the

compressive work. The average diffusion factor across the hub, mid, and tip of each blade is less than

0.45 which provides the adequate surge margin required.

3.2.2 Geometry Analysis

At off design the stator geometry of the IPC changes slightly. The RPM decreases from 13,800 at cruise

to 13,330 at take-off approximately a 3.4% decrease. The IPC has three variable stator vanes as well as a

variable IGV. Table 22 below shows the angle change on the variable stators and IGV. Table 23 shows

the Beta error values entering the rotor blades of the IPC.

Table 22: IPC Variable Stator Vane Deflection in Degrees

IGV Stator 1 Stator 2 Stator 3 Stator 4 VSV Deflection 2.4 13 9 5 0

35

Table 23: IPC Beta Error Entering the Rotors

Rotor 1 Rotor 2 Rotor 3 Rotor 4 Criteria

TIP 0.78 1.23 0.03 -0.74 2<β<2

MID -0.2 0.92 -0.4 -1.1 2<β<2

HUB 2.0 -0.13 -1.3 -1.8 2<β<2


Although the design criteria for change of RPM between take-off and cruise is 3% and the engine is at

3.4 % it is not uncommon for engines to have a higher percent increase/decrease between takeoff and

cruise conditions. After reviewing several FAA Type Certificate Data Sheets, it was observed that there

are similar engines in service that operate with a higher percent increase/decrease. Shown below in

Figure 17, the GE90-76B has a nine percent decrease between take-off and cruise conditions. The three

variable stator vanes were used to decrease the difference in beta angles between cruise and take-off

on the leading edge of the rotors. All errors in beta are within the allowed clearance of two degrees.

Figure 17: GE90-76B RPM at Take-Off and Cruise Conditions

36

3.2.3 Key IPC trends

Some key trends of the IPC at cruise and take-off are shown below.

Figure 18: IPC Flow Coefficient at Cruise and Take-Off

Figure 19: IPC Pressure Ratio at Cruise and Take-Off

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0 1 2 3 4 5

# of stage

Flow Coefficient 'φ'

Cruise

T.O.

00.20.40.60.8

11.21.41.61.8

2

0 1 2 3 4 5

# of stage

Pressure Ratio 'π'

Cruise

T.O.

37

Figure 20: IPC Work Coefficient at Cruise and Take-Off

Figure 21: IPC Degree of Reaction at Cruise and Take-Off

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0 1 2 3 4 5

# of stage

Work Coefficient 'λ'

Cruise

T.O.

0.000

0.200

0.400

0.600

0.800

1.000

0 1 2 3 4 5

# of stage

Degree of Reaction 'R'

Cruise

T.O.

38


The trends between design and off design are fairly similar. The Flow coefficient graph follows the

proper trend which should look like a relatively flat straight line. The flow coefficient graph increases by

less than a tenth of a point. The pressure ratio between take-off and cruise has a downward trend as

does the work coefficient. Although, the work coefficient at cruise has more of a shallow trend than that

at take-off.

39

4. High Pressure Compressor (HPC)

The engine is equipped with a seven stage HPC as shown below in Figure 22.

Figure 22: HPC Isometric View

4.1 HPC at Design Conditions: Cruise

4.1.1 Aerodynamic Analysis

Table 24 below shows the design selection used to create the rotor and stator blades.

Table 24: HPC Design Choices

RPM 14,775

AR – Rotors 2

AR – Stators 2

H/T 0.7

TR – Rotors 0.8

TR - Stators 1.25

Burch, Hobbs, Dantis

40

Table 25, Table 26, and Table 27 show the design criteria and design values for the HPC detail design.

Please note that in Table 26 the columns highlighted are the important values of interest. The Δ α

requirement is only for the stators while the Δ β requirement is for the rotors.

Table 25: HPC Design Values at Each Stage

Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Stage 6 Stage 7 Criteria

Lambda ‘λ’ 0.586 0.420 0.373 0.365 0.364 0.363 0.387 λ<.55

Phi ‘Φ’ 0.508 0.559 0.628 0.628 0.653 0.679 0.692 .25<φ<.75

R 0.818 0.664 0.546 0.572 0.562 0.586 0.686 .1<R<1

Table 26: HPC Design Values at Each Rotor and Stator

ROTOR 1 STATOR 1 ROTOR 2 STATOR 2 ROTOR 3 STATOR 3 ROTOR 4 STATOR 4

DIFFUSION FACTOR

DF AVG 0.55 0.52 0.50 0.38 0.43 0.45 0.43 0.47

DELTA ALPHA

TIP 47.30 31.94 30.46 22.29 22.62 22.34 22.62 24.32

MID 52.06 34.56 32.06 23.56 23.25 23.25 23.18 25.18

HUB 57.77 37.42 33.65 24.88 23.80 24.18 23.70 26.07

DELTA BETA

TIP 11.88 8.42 13.74 8.07 15.85 14.26 15.24 15.16

MID 18.97 15.33 18.38 12.64 19.52 18.50 18.39 18.90

HUB 32.50 28.49 25.47 19.82 24.35 24.19 22.37 23.68

ROTOR 5 STATOR 5 ROTOR 6 STATOR 6 ROTOR 7 STATOR 7 CRITERIA

DIFFUSION FACTOR

DF AVG 0.41 0.45 0.12 0.45 0.17 0.45 < 0.45

DELTA ALPHA

TIP 22.36 25.09 22.77 28.42 25.91 31.65 < 45

MID 22.92 25.92 23.32 29.32 26.59 32.59 < 45

HUB 23.45 26.77 23.87 30.26 27.29 33.58 < 45

DELTA BETA

TIP 15.94 15.38 15.73 15.66 14.75 15.96 < 45

MID 18.45 18.36 17.64 18.10 16.35 17.94 < 45

HUB 21.47 21.99 19.87 20.97 18.19 20.21 < 45

41

Table 27: HPC Design Values at each Aero/Thermo Station

STATION 1 2 3 4 5 6 7 8

ALPHA

TIP -5.11 42.20 10.26 40.72 18.43 41.05 18.67 41.30

MID -6.00 46.06 11.50 43.56 20.00 43.25 20.00 43.22

HUB -7.27 50.49 13.07 46.73 21.85 45.65 21.43 45.15

BETA

TIP -65.31 -53.43 -61.86 -48.11 -56.18 -40.33 -54.61 -39.39

MID -61.97 -43.00 -58.33 -39.95 -52.59 -33.07 -51.49 -32.98

HUB -57.80 -25.30 -53.79 -28.32 -48.14 -23.79 -48.00 -25.65

STATION 9 10 11 12 13 14 15 CRITERIA

ALPHA

TIP 16.98 39.49 14.32 37.16 8.65 34.63 2.90 <71

MID 18.00 40.94 15.00 38.36 9.00 35.63 3.00 <71

HUB 19.07 42.54 15.76 39.64 9.38 36.68 3.11 <71

BETA

TIP -54.53 -38.16 -53.78 -37.89 -53.75 -38.86 -54.99 <71

MID -52.01 -33.49 -51.93 -34.20 -52.39 -35.95 -53.98 <71

HUB -49.31 -27.85 -49.82 -29.96 -50.91 -32.72 -52.92 <71

42

Figure 23 below shows the hub velocity triangle followed by Table 28 with the numerical values

Figure 23: HPC Stage 3 Hub Velocity Triangles

Table 28: HPC Stage 3 Hub Velocity Values

Rotor 3 Entrance Stator 3 Entrance

Stator 3 Exit

U (m/s) 329.11 333.46 335.54 VAX (m/s) 216.94 227.79 223.24 V (m/s) 233.74 325.88 239.81 W (m/s) 325.09 248.95 333.63 WU (m/s) 242.11 100.42 247.94 VU (m/s) 87.00 233.04 87.60

β 48.14 23.79 48.00 α 21.85 45.65 21.43

43

Figure 24 below shows the mid velocity triangle followed by Table 29 with the numerical values

Figure 24: HPC Stage 3 Mid Velocity Triangles

Table 29: HPC Stage 3 Mid Velocity Values

Rotor 3 Entrance

Stator 3 Entrance

Stator 3 Exit

U (m/s) 329.11 333.46 335.54 Vax (m/s) 216.94 227.79 223.24

V (m/s) 233.74 325.88 239.81 W (m/s) 325.09 248.95 333.63

Wu (m/s) 242.11 100.42 247.94 Vu (m/s) 87.00 233.04 87.60

Beta 48.14 23.79 48.00 Alpha 21.85 45.65 21.43

44

Figure 25 below shows the tip velocity triangle followed by

Table 30 with the numerical values.

Figure 25: HPC Stage 3 Tip Velocity Triangles

Table 30: HPC Stage 3 Tip Velocity Values

Rotor 3

Entrance Stator 3 Entrance Stator 3 Exit

U (m/s) 396.10 391.76 389.68 VAX (m/s) 216.94 227.79 223.24 V (m/s) 228.67 302.05 235.64 W (m/s) 389.77 298.82 385.46 WU (m/s) 323.82 193.40 314.24 VU (m/s) 72.28 198.36 75.43

β 56.18 40.33 54.61 α 18.43 41.05 18.67

Important conclusions and observations

The work coefficient for stage 1 is the highest in the HPC and is held to a greater limit than the other

stages due to its added splitter blades. The Diffusion Factor for highly loaded compressors can range

from .52 to .58 according to Dickens and Day from reference [3].

45

4.1.2 Thermodynamic Analysis

Below is the h-s diagram for the third stage of the HPC and the corresponding stage values.

Figure 26: HPC h-s Diagram for Stage 3

Table 31: HPC h-s Diagram Values for Stage 3

STAGE 3 1 2 3

M 0.557 0.739 0.536

γ 1.385 1.382 1.379

R [J/kg*K] 287 287 287

CP [J/kg*K] 1033.1 1039.0 1044.0

PO [kPa] 750989.6 1011297.4 1002414.3

P [kPa] 609690.1 706467.9 826527.1

TO [K] 548.4 601.9 599.0

T [K] 517.6 545.1 568.1

V [m/s] 252.5 343.5 254.2

hO [J/kg] 566585.7 625403.2 625403.2

ρ [kg/m3] 4.105 4.515 5.069

46

Important conclusions and observation

The thermodynamic table shows increasing static pressure across the stage but a decrease in total

pressure across the stator, which should be expected. Similarly there is a total temperature drop across

the stator even though total enthalpy does not change due to the variable Cp.


Figure 27: HPC Meridional View

Figure 28: HPC Stage 1 Splitter Blade Detail

0.15

0.17

0.19

0.21

0.23

0.25

0.27

0.29

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22 0.24 0.26 0.28

47

Figure 29:HPC Stagger for Stage 3 Rotor

Table 32:HPC Stagger for Stage 3 Rotor

Stagger

TIP 48.3

MID 42.8

HUB 36.0

Figure 30: HPC Gap to Pitch vs Blade Number

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 2 4 6 8 10 12 14 16

# of Stage

Gap to Pitch

48

Figure 31: HPC Number of Blades vs Stage Number


The gap to pitch at station 10 does not follow the same trend as the other stations, because the gap at

that station is doubled to allow for the customer bleed to be extracted. There is no second doubled gap

to pitch for the HPT stator bleed because that bleed is taken just aft of Stator 7 so no blade gap is

needed. The number of blades of Rotor 1 is high because the solidity of the rotor was doubled to

account for the splitter blades that were added to that rotor. These splitter blades were added to

extract more work from the flow while still mitigating flow separation issues.

4.2 HPC at Off Design Conditions: Takeoff

4.2.1 HPC Design Criteria

Table 33: HPC Off Design Values at Each Stage

Stage 1 Stage2 Stage3 Stage4 Stage5 Stage6 Stage7 Criteria

Lambda ‘λ’ 0.466 0.413 0.417 0.354 0.390 0.422 0.440 λ<.55

Phi ‘φ’ 0.637 0.700 0.736 0.782 0.764 0.741 0.719 .25<φ<.75

R 0.741 0.647 0.553 0.425 0.517 0.661 0.766 .1<R<1

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7

Number of Blades

Rotors

Stators

49

Table 34: HPC Off Design Values at Each Blade

ROTOR 1 STATOR 1 ROTOR 2 STATOR 2 ROTOR 3 STATOR 3 ROTOR 4 STATOR 4

DIFFUSION FACTOR

DF AVG

0.48 0.47 0.40 0.38 0.40 0.47 0.30 0.48

DELTA ALPHA

TIP 0.23 0.26 0.26 0.48 0.48 0.78 0.78 0.96

MID 177.63 154.80 157.49 117.91 158.68 144.54 134.39 147.34

HUB 26.67 63.41 60.24 47.01 48.26 49.39 47.00 46.78

DELTA BETA

TIP 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

MID 38.56 32.56 30.56 21.56 26.25 23.25 20.22 23.22

HUB 83.62 71.05 88.05 65.85 100.11 98.71 103.18 102.30

ROTOR 5 STATOR 5 ROTOR 6 STATOR 6 ROTOR 7 STATOR 7 CRITERIA

DIFFUSION FACTOR

0.35 0.45 0.41 0.43 0.45 0.41 < 0.45

DELTA ALPHA

0.96 0.26 0.26 0.07 0.07 0.00 < 45

148.02 159.71 160.51 174.23 167.24 167.29 < 45

46.75 50.44 48.50 52.35 50.44 50.03 < 45

DELTA BETA

5.04 0.00 0.00 0.00 0.00 0.00 < 45

23.94 26.94 27.86 30.86 30.63 30.63 < 45

96.00 80.53 72.60 64.49 52.88 53.78 < 45


At off design the high pressure shaft moves from 14775rpm to 15520rpm, which is an increase of 5%.

Justification for this rpm increase was covered in the IPC design. Table 35 below shows the deflection of

the Variable Stator Vanes (VSVs) where a positive angular deflection is in the clockwise direction. The

error in beta entering the rotor is presented in Table 36 seen below.

50

Table 35: HPC Variable Stator Vane Deflection

VSV

Deflection

Stator 1 Stator 2 Stator 3 Stator 4 Stator 5 Stator 6 Stator 7

11.5 10 8 9 9 6 0

Table 36: HPC Error in Beta

Beta Error Rotor 1 Rotor 2 Rotor 3 Rotor 4 Rotor 5 Rotor 6 Rotor 7 Criteria

TIP 0.23 0.26 0.26 -0.34 -0.34 -0.78 -0.78 -2<β<2

MID 0.24 -0.39 -0.39 -0.99 -0.99 -1.28 -1.28 -2<β<2

HUB 0.26 -1.46 -1.46 -1.96 -1.96 -1.92 -1.92 -2<β<2


Six VSVs were utilized at off design to normalize the beta values on the leading edge of the

rotors to cruise values. Rotational speed varied by 5%, which is higher than recommended but

is within range for the CFM-56-7B. All errors in beta are within the mandated 2 degrees.

51

4.2.3 Key HPC Trends

Some key trends of the HPC at cruise and take-off are shown below.

Figure 32: HPC Flow Coefficient at Cruise and Takeoff

Figure 33: HPC Pressure Ratio for Cruise and Takeoff

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6 7 8

# of Stage

Flow Coeffecient

CRUISE

TAKEOFF

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 1 2 3 4 5 6 7 8

# of Stage

Pressure Ratio

CRUISE

TAKEOFF

52

Figure 34: HPC Work Coefficient at Cruise and Takeoff

Figure 35: HPC Degree of Reaction at Cruise and Takeoff


The trends for off design are more jagged when compared to the design points trends, which is to be

expected, but the values still fall into acceptable ranges.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8

# of Stage

Work Coeffecient

CRUISE

TAKEOFF

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8

# of Stage

Degree of Reaction

CRUISE

TAKEOFF

53

5. Combustion Chamber

The combustion chamber is an annular combustor that is made from INCOLOY® alloy A-286. The combustion chamber is explained in detail in the tables below.

The given inlet conditions and the required outlet conditions are as referenced in the tables below. The combustion chamber had to perform as per the given criteria.

Table 37: Combustion Chamber Inlet and Outlet

Inlet Conditions Outlet Conditions

P0 1084392.12 Pa P0 1068126.24 Pa

T0 719.72 K T0 1558.08 K

M 0.1 M 0.36

Figure 36: Combustion Chamber

Dantis, Palmer

54

The figure above refers to the h-s diagram of the process that takes place in the combustion chamber. As can be seen from the figure, the upwards arrow indicates the compression done in the HPC. This compression takes us to pressure gradient P07. However, the total pressure migrates onto the P08 line. This is due to the addition of Jet-A fuel which is ignited with the compressed air, raising the temperature but causing a drop in the total pressure. As per the design constraint, the drop in the pressure is 1.5% to total pressure entering the combustion chamber. The arrow from P08 to P09 signifies the further drop in pressure as we proceed through the HPT.

An important parameter to be taken into account during the calculations for the combustion chamber is the type of fuel used. Today, the most common fuel used today is the Jet-A fuel. Table 38 highlights the pertinent properties of the fuel.

Table 38: Parameters of Jet-A Fuel

Criteria Jet A Fuel

Flashpoint (K) 311

Auto-Ignition Temperature (K) 483

Open Air Burning Temperature (K) 560

Specific Energy (MJ/kg) 42.8

Figure 37: Combustion Chamber h-s Diagram

55

The combustion chamber is designed completely at cruise. Based on the current mass flow and the cycle analysis, the following parameters were calculated.

Table 39: Combustion Chamber Fuel Parameters

Criteria Value

(kg/s) 28.41

(kg/s) 5.89

(kg/s) 15.97

f 0.0207

fprimary zone 0.0368

fst 0.131

Φ (fuel/air equivalence ratio) 0.9512

λ (% excess air) 256.4

From the above calculations, it is determined that there is a fuel lean mixture in the combustion chamber. This ensures that all the fuel is burnt. Hence the combustion chamber is parametrically efficient. From the amount of air mass flow through the combustion chamber, the appropriation of air through the primary zones, secondary zones and dilution holes need to be determined. The values after calculation are given as follows.

Table 40: Combustion Chamber Specifics

Criteria Value

(kg/s) 15.97

(kg/s) 5.59

(kg/s) 6.85

Diameter of Primary Zone (mm) 38

Diameter of Secondary Zone (mm) 10

Diameter of Dilution Holes (mm) 18

Number of Primary Nozzles 18

Number of Secondary Zones 164

Number of Dilution Holes 98

Length of Combustion Chamber (m) 0.195

Outer Diameter of Combustion Chamber (m) 0.239

Inner Diameter of Combustion Chamber (m) 0.15

56

6. High Pressure Turbine (HPT)

The High Pressure Turbine (HPT) uses one stage with a stator then rotor configuration. This component

rotates counterclockwise with the High Pressure Compressor. This is counter rotating with respect to

the Intermediate Shaft that is spinning clockwise. The HPT has an inlet temperature of 1557.4K and only

the stator requires a cooling circuit provided to the High Pressure Turbuine. Further information about

this component is given below.

Figure 38: HPT Isometric View

Hauenstein, Khan, Bohlemann

57

HUB

6.1 Aerodynamic Analysis

The following figures display the velocity triangles and their respective values at the hub mid and tip

sections at station two of the HPT.

Figure 39: HPT Hub Velocity Triangle

Table 41: HPT Hub Velocity Triangle Values

Station 2 3

Mabs 0.977 0.747

Mrel 0.651 1.28

U(m/s) 321.6 304.5

Vax(m/s) 278.4 292.3

V(m/s) 723.3 523.9

Vu(m/s) 667.6 434.8

W(m/s) 444.1 794.9

Wu(m/s) 346.0 739.3

α(deg) 67.4 56.1

β(deg) 51.2 68.4

Δαhub (deg) 123.45 Δβhub (deg) 119.61

58

MID

Figure 40: HPT Mid Velocity Triangle

Table 42: HPT Mid Velocity Triangle Values

Station 2 3

MREL 0.549 1.26

U(m/s) 354.7 365.4

VAX(m/s) 278.4 292.3

V(m/s) 666.2 465.5

VU(m/s) 605.2 362.3

W(m/s) 374.5 784.2

WU (m/s) 250.5 727.7

α(deg) 65.3 51.1

β(deg) 42.0 68.1

Δαmid 116.41

Δβmid 110.10

59

TIP

Table 43: HPT Tip Velocity Triangle Values

Important Conclusions and Observations

The velocity triangles and corresponding values above display the proper trends of absolute and relative

velocities across the rotor of the HPT. These trends show a decrease in absolute velocity while there is

an increase in relative velocity. Both Mach Number constraints, absolute and relative, have been met by

being lower than 1 and 1.45 respectively.

The alpha and beta constraints have been met by staying under 71˚.

Station 2 3

MREL 0.475 1.27

U(m/s) 387.8 426.2

VAX(m/s) 278.4 292.3

V(m/s) 619.6 426.5

VU(m/s) 553.5 310.6

W(m/s) 323.9 792.7

WU (m/s) 165.7 736.8

α(deg) 63.3 46.7

β(deg) 30.8 68.4

Δαtip 110.04

Δβtip 99.12

Figure 41: HPT Tip Velocity Triangle

60

6.2 Thermodynamic Analysis

The thermodynamic characteristics of the HPT are described below in the absolute frame of reference in

Table 44. The h-s diagram illustrated in Figure 42 also demonstrates these characteristics.

Figure 42: HPT h-s Diagram

Table 44: HPT h-s Diagram Values

Station 1 2 3

MABS 0.365 0.977 0.747

Po (Pa) 1068126.2 1061182.1 352724.3

P (Pa) 978385.8 588746.3 247270.6

To (K) 1558.1 1558.1 1226.7

T (K) 1524.5 1346.2 1123.2

ΔTo (K) --------------- --------------- 331.4

ho (J/kg) 1631565.3 1631565.3 1284500.6

h (J/kg) 1596423.0 1409678.1 1176138.8

Δho (J/kg) --------------- --------------- 347064.7

Δ so (J/kg*K) --------------- --------------- 37.4

Δ s (J/kg*K) --------------- --------------- 37.4

A (m2) 0.044 0.062 0.117

ρ (kg/m3) 2.47 1.68 0.85

61


As seen above in the table, both adiabatic expansion as well as expansion with work extraction

takes place across the HPT. This trend is seen as well in the area increase and density decrease. The

absolute Mach number, although high at station 2, does not exceed one which meets the criteria.

Looking at the static temperature trend, the stator is needed to be cooled from the station 15 of

the HPC. Due to the high acceleration of the flow across the stator, the static temperature was reduced

at the leading edge of the rotor to below 1350 K so no cooling was needed.

6.3 Geometric Analysis

The following figure display a meridional of the HPT as well as Table 45 and Table 46 which are

tabulated geometric values found during the design process.

Table 45: HPT Radii Values

Station 1 2 3

rM (m) 0.223 0.229 0.236

rH (m) 0.207 0.208 0.197

rT (m) 0.238 0.251 0.275

bavg (m) 0.037 0.061 0.079

Figure 43: HPT Meridional View

62

Table 46: HPT Airfoil Geometry Values

Stator Rotor

C Hub (m) 0.043 0.044

Stagger Hub (deg) 33.68 -8.62

Cax Hub (m) 0.036 0.044

C Mid (m) 0.046 0.040

Stagger Mid (deg) 32.65 -13.07

Cax Mid (m) 0.039 0.039

C Tip (m) 0.050 0.037

Stagger Tip (deg) 31.65 -18.80

Cax Tip (m) 0.043 0.035

Aspect Ratio 0.8 1.5

Taper Ratio 1.2 0.8

NOB 34 43

The following shows the stagger variation between hub mid and tip sections of the rotor. The stator

stagger overlay is not shown due to the low difference in stagger between the sections. As seen above

there is approximately only one degree difference in stagger.

Below in Table 47 are the key performance factors and other important values that are key to analyzing

the HPT.

Figure 44: Stagger of Rotor Blade

63

Table 47: Key Values for the HPT

Key Values

λ 2.6

Φ 0.8

TIT (K) 1558.1

Δho (J/kg) 347064.7

ηtt (%) 88.5

τoHPT 0.7873

πoHPT 0.3302

CP (J/kg*K) 1047.2

γ 1.33

RPM 14775

Degree of Reaction (hub) 0.636

Degree of Reaction (mid) 0.676

Degree of Reaction (tip) 0.722

Zweifel Coefficient 0.8


The performance factors in the table above including the work coefficient and flow coefficient are

reasonable values that are well within the given criteria. The degree of reaction (R) values given are also

within the given limits of above 0.1 and below 1 and their trend from hub to tip is correct with the

highest being at the tip.

64

7. Intermediate Pressure Turbine (IPT)

The Intermediate Pressure Turbine is spinning in the clockwise direction, opposite of the HPT allowing it

to utilize the swirl from the HPT rotor and use a single rotor configuration with no stator. This

configuration is used due to the small amount of work the IPC requires.

Figure 45: Isometric View of IPT

Hauenstein, Khan, Bohlemann

65

Hub


Below are the velocity triangles showing the exit of the HPT and the inlet of the IPT at hub mid and tip.

Take note in the ways the velocity vectors are directed representing the counter rotation. The values for

these triangles can be found on the following page.

Tip

Mid

Figure 47: HPT-IPT Hub Velocity Triangle Figure 46: HPT-IPT Mid Velocity Triangle

Figure 48: HPT-IPT Tip Velocity Triangle

66

Table 48: HPT-IPT Velocity Triangle Values

Hub Mid Tip

U (m/s) 304.5 365.4 426.2

U' (m/s) 284.5 341.6 398.7

Vax (m/s) 292.3 292.3 292.3

V (m/s) 523.9 465.5 426.5

Vu (m/s) 434.8 362.3 310.6

W (m/s) 794.9 784.2 792.7

Wu (m/s) 739.3 727.7 736.8

W' (m/s) 407.7 292.7 292.7

Wu' (m/s) 150.2 20.4 88.6

α (deg) 56.1 51.1 46.7

β (deg) 68.4 68.1 68.4

β' (deg) 27.2 3.99 16.9

The velocity triangles and tables of values below will show the aerodynamic trends across the IPT rotor.

It is important to note that the inlet values of relative velocity and beta angles are the same as the prime

values shown in the above triangle.

67

Table 49: IPT Hub Velocity Triangle Values

Station 1 2

MREL 0.654 0.722

U (m/s) 284.5 289.5

VAX(m/s) 292.0 318.3

V(m/s) 523.6 335.0

VU(m/s) 434.7 104.6

W(m/s) 407.7 430.3

WU(m/s) 150.2 394.1

α (deg) 56.1 18.2

β (deg) 27.2 51.1

ΔαHub (deg) 74.78

ΔβHub (deg) 78.99

HUB

Figure 49: IPT Hub Velocity Triangle

68

Table 50: IPT Mid Velocity Triangle Values

Station 1 2

MREL 0.470 0.915

U (m/s) 341.6 358.2

VAX(m/s) 292.0 318.3

V(m/s) 465.1 329.3

VU(m/s) 362.0 84.6

W(m/s) 292.7 545.3

WU(m/s) 20.4 442.7

α (deg) 51.1 14.9

β (deg) 3.99 54.3

ΔαMid(deg) 66.32

ΔβMid(deg) 59.05

MID

Figure 50: IPT Mid Velocity Triangle

69

Table 51: IPT Tip Velocity Triangle Values


As seen in the triangles representing counter rotation and the corresponding data table shows the exit

alpha of the HPT is 51˚ at the mid. With this high alpha angle, the IPT rotor is able to take advantage of

the swirl from the HPT allowing there to be no inlet stator needed. All velocity trends meet criteria for

this component as well as the angle requirements.

Station 1 2

MREL 0.793 0.893

U (m/s) 398.7 426.8

VAX(m/s) 292.0 318.3

V(m/s) 426.0 326.1

VU(m/s) 310.1 71.0

W(m/s) 494.2 532.4

WU(m/s) 88.6 497.8

α (deg) 46.7 12.6

β (deg) 16.9 57.4

ΔαTip(deg) 59.54

ΔβTip(deg) 41.34

Figure 51: IPT Tip Velocity Triangle

TIP

70

7.2 Thermodynamic Analysis

Below in Figure 52 and Table 52 represents the absolute frame of reference thermodynamic

characteristics of the IPT.

Table 52: IPT h-s Diagram Values

Station 1 2

MABS 0.746 0.553

PO (Pa) 352686.4 200945.0

P (Pa) 247421.8 164831.6

TO (K) 1226.6 1079.6

T (K) 1123.3 1027.8

ΔTO (K) ----------------- 146.7

hO (J/kg) 1284471.4 1130522.2

h (J/kg) 1176321.7 1076295.8

ΔhO (J/kg) ----------------- 153652.9

Δ sO (J/kg*K) ----------------- 15.3

Δ s (J/kg*K) ----------------- 15.3

A (m2) 0.117 0.148

ρ (kg/m3) 0.85 0.62

Figure 52: IPT h-s Diagram

71


As seen above in the table, both adiabatic expansion as well as expansion with work extraction

takes place across the IPT. This trend is seen as well in the area increase and density decrease. The

absolute Mach number, although high at station 2, does not exceed one which meets the criteria. This

single rotor stage requires no cooling due to an inlet temperature below 1350 K.

7.3 Geometric Analysis

Below displays the meridional view of the IPT rotor along with corresponding tables containing

geometric data for the stage.

Figure 53: IPT Meridional View

72

Table 53: IPT Radii Values

Station 1 2

rm 0.236 0.248

rh 0.197 0.199

rt 0.276 0.296

bavg 0.088 0.097

Table 54: IPT Airfoil Values

C Hub (m) 0.045

Stagger Hub (deg) 11.930

Cax Hub (m) 0.044

C Mid (m) 0.044

Stagger Mid (deg) 25.149

Cax Mid (m) 0.039

C Tip (m) 0.044

Stagger Tip (deg) 37.144

Cax Tip (m) 0.035

Aspect Ratio 2

Taper Ratio 0.8

The following will show the stagger overlay of the blade to show the stagger of the hub mid and tip

sections.

Figure 54: IPT Stagger

73

Below in Table 55 are the key values and performance coefficients for the IPT that are used in analyzing

the component.

Table 55: IPT Key Values

λ 1.20

Φ 0.889

Δho (J/kg) 153949.2

ηtt (%) 92.00

τoHPT 0.880

πoHPT 0.570

Cp (J/kg*K) 1047.2

γ 1.33

RPM 13800

Degree of Reaction (hub) 0.323

Degree of Reaction (mid) 0.662

Degree of Reaction (tip) 0.717

Number of Rotors 47

Zweifel Coefficient 0.8


The above performance characteristics show a work coefficient of 1.2 which is low compared to the

range given between 2 and 2.8. This low work coefficient is due to the low power balance between the

IPT and IPC. The degree of reaction trend follows the correct trend of highest at tip and lowest at the

hub while also staying within the range of 0.1 to 1.

74

8. Power Turbine (PT)

The power turbine for the Unducted Propfan is a six-stage counter-rotating turbine. The flow is

introduced into the turbine through the high slope transition duct and an inlet guide vane (IGV). The exit

flow is turned axial through outlet guide vane (OGV). 12 turbine blade rows make up a six-stage power

turbine with each alternate row rotating in the opposite direction. Each stage has a pair of counter-

rotating rotors. As the turbine rotors rotate on a shaft, the turbine stators rings are unearthed and free

to move on a rotating cowling. This mechanism allows for stage-to stage counter-rotation throughout

the six-stage power turbine as illustrated in Figure 55. A total of six rotors rotating counter-clockwise are

connected to and operate the aft propfan while the other set of clockwise rotating turbine stators are

connected to and operate the front propfan.

Figure 55: Counter-rotating power turbine [AIAA-85-1190 The Unducted fan engine]

Figure 56: A 3D view of the power turbine (IGV/OGV-red; Rotors-blue; Unearthed Stators-black)

Khan, Bohlemann, Dantis, Palmer

75

Conventional Turbine vs Counter-rotating Turbine

In comparison to a conventional turbine, a counter-rotating turbine provides a comparable stage loading at lower rpm with a similar number of blade rows. This allows the counter-rotating power turbine to run the propfans at the required low rpm range of 1500-2000 within a reasonable no of six stages and without the requirement for a gearbox.

A comparative study between a conventional and a counter-rotating turbine stage highlighted the added thermodynamics advantages achieved through counter rotation. These are listed in Table 56 along with the respective stage configuration represented in Figure 57 and Figure 58

Figure 57: Conventional Stage

Figure 58: Counter-Rotating Stage

Table 56: Counter-rotating Stage vs. Conventional Stage

Conventional Stage Counter-Rotating Stage

Efficiency (%) 89 89

Work Coefficient 2.78 2.58

Delta h (J/kg) 27912 55960

Pressure Ratio 1.14 1.30

Temp Ratio 1.03 1.06

76

As a stator is replaced by a rotor rotating in the opposite direction, the counter-rotating stage provides a higher capacity to do work with a comparatively similar work coefficient to that of a conventional Stage. It also provides a higher temperature and pressure ratio across the stage. Thus, counter-rotation allows for an optimum turbine design required to operate the Propfans.

Turbine Power Requirement

The power required from the turbine to operate the Propfans is listed in Table 57. The clockwise rotating rotors running the front fan will be referred to as Stators from this point onwards for the sake of simplicity and clarification.

Table 57: Power Requirement

Fan 1 Fan2

RPM 1708 1855

Power(HP) 6319 6311

Stators Rotors

η % 96

Mass flow rate(kg/s) 29.07 29.07

Δh(J/kg) 168856 168653

The work split across the rotors and stators for the power turbine is as follows.

Figure 59: Work Split across the Power Turbine

Blade rows, moving from front to aft, constitute a higher diameter and therefore perform more work.

The load factor on each rotating blade across PT is demonstrated through its work coefficient in Figure

60.

27700

27800

27900

28000

28100

28200

28300

28400

1 2 3 4 5 6

Tota

l En

thal

py

(kg/

J)

Stages

Work split across PT

Rotors

Stators

77

Figure 60: Work Coefficient of Rotors and Stators across the Power Turbine

The work coefficient for the rotors and stators increases progressing to the later stages. The rotors have

an average work coefficient of 2.37 compared to the stators with an average work coefficient of 2.79.

This difference in loadings can be attributed to the difference in component RPMs based on propfan

requirement where the stators are generating a higher amount of work with lower RPMs than the rotors

as seen in Table 57.

The results from thermodynamics, aerodynamic and geometric analysis for the Power Turbine Design are described in the following sections.


The power turbine with its six stages plus an IGV and OGV, is comprised of 15 stations. The aerodynamic

characteristics in the absolute and relative FoR for the power turbine at its Aero/Thermo stations 2, 3

and 4 are listed in Table 58, Table 59 and Table 60. These stages are a good representation of the

characteristics throughout the PT. The velocity triangles illustrated Figure 61 in demonstrates these

characteristics.

0

0.5

1

1.5

2

2.5

3

R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

Wo

rk C

oe

ffic

en

t

PT Components

Work Coefficient across PT

Rotor

Stator

78

Table 58: PT Aerodynamic characteristics at TIP

Rotor 1 Stator 1

Station 2 3TE

3LE

4

Vax

(m/s) 105.11 107.22 107.22 108.82

V(m/s) 168.05 161.38 161.38 161.47

Vu(m/s) 131.12 120.62 120.62 119.30

W(m/s) 107.10 255.43 107.22 264.52

Wu(m/s) 20.56 231.84 -1.18 241.10

U(m/s) 110.56 111.22 121.80 121.80

α(°) 51.28 48.37 48.37 47.63

β(°) 11.07 65.18 -0.63 65.71

Mar 0.18 0.43

Ma 0.28 0.27

Δ β(°) 76.25 65.08

Stagger(°) 27.05 33.17

Table 59: PT Aerodynamic characteristics at MID

Stator 1 Rotor 1

Station 2 3TE

3LE

4

Vax

(m/s) 105.11 107.22 107.22 108.82

V(m/s) 178.83 162.07 162.07 163.31

Vu(m/s) 144.68 133.88 133.88 133.45

W(m/s) 114.13 257.47 110.09 265.65

Wu(m/s) 44.47 234.09 25.00 242.33

U(m/s) 100.20 100.20 108.88 108.88

α(°) 54.00 48.58 48.58 48.22

β(°) 22.89 55.86 13.12 55.98

Mar 0.19 0.43

Ma 0.29 0.27

Δ β(°) 78.75 69.10

Stagger(°) 16.5 21.43

79

Table 60: PT Aerodynamic characteristics at HUB

Rotor 1 Stator 1

Station 2 3TE

3LE

4

Vax

(m/s) 105.11 107.22 107.22 108.82

V(m/s) 192.58 184.72 184.72 186.47

Vu(m/s) 161.36 150.42 150.42 151.42

W(m/s) 127.14 262.50 120.25 270.26

Wu(m/s) 71.52 239.61 54.46 247.38

U(m/s) 89.84 89.18 95.96 95.96

α(°) 56.92 54.52 54.52 54.30

β(°) 34.23 65.89 26.93 66.26

Mar 0.21 0.44

Ma 0.32 0.31

Δ β(°) 100.13 93.18

Stagger(°) 15.83 19.56

80

Figure 61: Velocity Triangle at Hub, Mid, and Tip; Rotor 1 Rotating Counter-Clockwise, Stator 1 Rotating Clockwise

81

Figure 61 demonstrates an increasing stagger flow leaving the IGV and entering the CCW rotating rotor

at station 2. Swirl is added to the flow in the relative FoR (W) and removed in the absolute FoR(V). This

flow enters CW rotating Stator 1 at station 3. The flow in the relative FoR (WLE) attains a new direction

due to counter-rotation and swirl is induced to it across the stator.

The increase of V (V3LE < V4) across Stator 1 (Station 3TE-4) in spite of the expected decrease

demonstrates the additive effect of counter-rotation as the V continues to increase through the PT and

eventually contributed to the thrust from the core.

The aero/thermo hub for a stator indicated in Figure 61 corresponds to its geometric tip and vice versa

since its rotating on the cowling. Regardless of the geometry, the stagger and the camber follow the

expected trend from the aero/thermo hub to tip; the stagger increases and the camber decreases from

hub to tip.

Figure 62: Stack for the Power Turbine Rotor.

Figure 63: Stack for the Power Turbine Stator

82

The aerodynamic trend across the PT is demonstrated in Figure 64

Figure 64: Velocity Distribution across the Power Turbine

The flow is accelerating throughout PT in the axial direction, the absolute and the relative FoR. Ma_Wo

represents relative velocity(W) before the effect of counter-rotation, and Ma_Wc represent W after

counter-rotation as W attains a new direction.

The highest Mach in the relative FoR is 0.59 and therefore within the design criteria of 1.45 Mach.

This acceleration of flow across the PT is characterized through the increase in flow coefficient across

the PT as illustrated in Figure 65.

Figure 65: Flow Coefficient across the Power Turbine

0

0.1

0.2

0.3

0.4

0.5

0.6

R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

Mac

h N

um

be

r

PT Components

Velocity Distribution across PT

Ma_Vax

Ma_Wc

Ma_V

Ma_Wo

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.2

1.25

1.3

R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

Flo

w C

oe

ffic

ien

t

PT Components

Flow Coefficientacross PT

83

The flow coefficient generally increases across the turbine. The rotors have a lower coefficient

compared to the stators due to lower RPMs for comparatively the same amount of work.

The Degree of reaction for the PT rotors and stators is illustrated in Figure 66

Figure 66: Degree of Reaction for the Power Turbine Components

The reactions are significantly high and positive indicating a decrease in pressure throughout the turbine. There is no danger of pressure rise. With the exception of R1, the components follow an expected trend of a decrease in reaction from tip to hub.

8.2 Thermodynamic Analysis The thermodynamic characteristics in the absolute and relative FoR for the power turbine at its

Aero/Thermo stations 1, 2, 3 and 4 are listed in Table 61. The h-s diagrams illustrated in Figure 68 and

Figure 69 demonstrate these characteristics.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

DO

R

PT Components

Degree of Reaction

HUB Reaction

MID Reaction

TIP Reaction

84

Figure 67: Meridional View of for Station 1, 2, 3 and 4

Figure 68: h-s Diagram UDF rotor in Relative FoR

85

Figure 69: h-s Diagram UDF rotor in Absolute FoR

Table 61: Thermodynamic Characteristics across Station 1, 2, 3 and 4

Station P0 P T

0 T h0 h V W

1 198669.2 194928.8 1078.9 1073.8 1116686.2 1124372.3 103.1 2 198483.5 187401.3 1078.9 1063.6 1116686.2 1113697.3 178.8 3 177254.5 168891.4 1052.2 1039.7 1088774.1 1088641.8 162.1 4 157815.5 150064.0 1025.6 1012.8 1060828.3 1060493.7 163.3 2r 191857.85 187401.3 1069.8 1063.6 1120210.6 1113697.3 114.1

3rTE 190591.84 168891.4 1071.3 1039.7 1121787.36 1088641.8 257.4

3rLE 172712.68 168891.4 1045.4 1039.7 1094701.99 1088641.8 110.0 4 171223.92 150064.0 1046.5 1012.8 1095777.57 1060493.7 265.6 Figure 69 demonstrates the IGV, Rotor 1 and Stator 1 in an absolute FoR. The IGV exhibits adiabatic

expansion with no work and thus a Δh0 = 0. Rotor 1 and Stator 1 exhibit adiabatic expansion with work

done across Rotor 1 being h03 - h02 and Stator 1 being h04 - h03.

86

Figure 68 demonstrates Rotor 1 and Stator 1 in a relative FoR. Each blade behaves like a stator and

exhibits adiabatic expansion with h02r=h03rTE and h03rLE=h04r . h03rLE < h03rTE and W3LE < W3TE exemplifies

counter-rotation in the PT where W3LE leading into Stator1 acquires a new direction and a lower

magnitude compared to W3TE leaving rotor 1. The temperature and pressure distribution across the PT is described in Figure 70 and Figure 71. The pressure ratio across the PT is 0.2 and the temperature ratio in 0.7.

Figure 70: Pressure Variation across Power Turbine

Figure 71: Temperature Variation across the Power Turbine

As expected, the temperatures and pressures across PT decrease from front to aft of the engine with the

total pressures and temperatures higher than the static pressures and temperatures.

0

50000

100000

150000

200000

250000In

let

IGV R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

OG

V

Pre

ssu

re(P

a)

PT Components

Pressure Variation across PT

P0

P

0

200

400

600

800

1000

1200

Inle

t

IGV R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6

OG

V

Tem

pe

ratu

re(K

)

PT Components

Temperature Variation across PT

T0

T

87

8.3 Geometric Analysis The geometric characteristics of the power turbine are listed in Table 62 and Table 63 and demonstrated

in the detailed meridional view illustrated in Figure 72. The PT’s areas expand from front to aft with

constant mid radius.

Table 62: Geometry per Station across the Power Turbine

Station Area rh rm rt 1 0.404 0.503 0.560 0.618 2 0.408 0.502 0.560 0.618 3 0.434 0.499 0.560 0.622 4 0.468 0.494 0.561 0.627 5 0.522 0.486 0.561 0.635 6 0.559 0.481 0.561 0.640 7 0.615 0.473 0.561 0.648 8 0.671 0.465 0.561 0.656 9 0.736 0.456 0.561 0.665

10 0.807 0.446 0.561 0.675 11 0.900 0.433 0.561 0.689 12 0.992 0.420 0.561 0.702 13 1.068 0.410 0.561 0.712 14 1.158 0.397 0.561 0.725 15 1.267 0.381 0.561 0.741

88

Rotor

Stator IGV/OGV

Table 63: Geometry per Component across the Power Turbine

Avg Span Mid Chord AR TR IGV 0.115 0.052 2.2 1.2 R1 0.120 0.034 3.5 0.8 S1 0.128 0.037 3.5 1.2 R2 0.141 0.040 3.5 0.8 S2 0.153 0.055 2.8 1.2 R3 0.167 0.048 3.5 0.8 S3 0.183 0.052 3.5 1.2 R4 0.200 0.057 3.5 0.8 S4 0.219 0.063 3.5 1.2 R5 0.242 0.081 3 0.8 S5 0.268 0.077 3.5 1.2 R6 0.292 0.083 3.5 0.8 S6 0.316 0.083 3.8 1.2

OGV 0.344 0.132 2.6 1.2

The merdional view shows the flow entering the IGV, followed by 12 rows of counter-rotating rotors and

unearthed stators and exiting through the OGV to the exhaust nozzle.

Figure 72: The Meridional Flow Path of the Power Turbine

89

The number of blades for the Power Turbine is listed in Figure 73.

Figure 73: The Number of Blades across the Power turbine

82 90

102

86 94

74 72 62 60

66

50 44 46

70

0

20

40

60

80

100

120

IGV R1 S1 R2 S2 R3 S3 R4 S4 R5 S5 R6 S6 OGV

No

of

bla

de

s

PT Components

No of blades

90

9. Propfan

Most of the propulsive power for this engine comes from the two counter-rotating profans in the rear of the engine. The propfans have the ability to change their pitch through a computer controlled hydraulic system which alters the pitch of the blade to ensure maximum thrust generation at different flight conditions. The two sets of propfan blades are each attached to the corresponding components in the powerturbine. These powerturbines spin the propfan blades. Both propfan and the corresponding stages of the powerturbine spin at the same RPM.

Figure 74: Propfan Isometric View

The results from thermodynamic, aerodynamic and geometric analysis for the fan design are described and more details of the engine are given in following sections.

Bohlemann, Khan, Hauenstein

91

9.1. Geometric Analysis

When designing the propfan blades it is very important to select the correct airfoil as this will allow for high performance. For this design the Lockheed C-141 BL761.11 was chosen for its high CLmax angle as well as its low camber and thin shape. The characteristics of the airfoil chosen are listed below in Table 64.

Table 64: Propfan Airfoil Data

The low camber and thin characteristic is expected for a high speed airfoil. The CLmax angle of attack is

very important in respect to maximizing thrust. Thrust for this airfoil is highest at the CLmax value of 15˚.

Thus, for the propfan design it is important to attempt to keep angle of attack as close as possible to 15˚

to maximize thrust generation.

The chord lengths chosen for the propfan blade designs were reverse engineered from the GE-36. The

same chord values were used for propfan 1 and propfan 2. The chord lengths are shown in the Table 65

below in radial locations (r/R) intervals of 10%.

Airfoil Data

Thickness: 10.50%

Camber: 1.80%

Trailing edge angle: 18.3o

Lower flatness: 70.30%

Leading edge radius: 2.30%

Max CL: 1.15

Max CL angle: 15

o

Max L/D: 41.709

Max L/D angle: 6.5

Max L/D CL: 0.995

Stall angle: 6.5

Zero-lift angle: -2o

Figure 75: Propfan Airfoil

92

Table 65: Radial Variation for Propfan

r/R Propfan 1 & 2

Chord (m)

βP1

(deg)

βP2

(deg)

αP1

(deg)

αP1

(deg)

0.0 0.427 97 99 --- ---

0.1 0.447 98 99 13.3 14.8

0.2 0.447 93 95 13.7 14.9

0.3 0.447 89 91 13.8 15.0

0.4 0.439 85 87 13.9 15.0

0.5 0.419 82 84 13.9 15.0

0.6 0.391 78 80 13.9 14.9

0.7 0.363 75 77 13.7 14.8

0.8 0.334 72 74 13.4 14.4

0.9 0.286 69 71 13.3 14.3

1.0 0.193 65 67 13.1 14.0

The above values are set at cruise conditions. The pitch angle, the angle between axis of rotation and

the chord line, is determined based on the angle of attack, meaning the pitch angle is adjusted in order

to ensure angle of attack is at the desired value. In the table the corresponding angle of attacks are

given, and it can be observed that they are all close to their max allowed value of 15˚. If the angle of

attack exceeds 15˚, the lift is cut off and the propfan blade now experiences a reduction in its lift ability

which negatively impacts the thrust produced.

Table 66: Propfan Key Geometric Values

The tip speed for propfan 1 and 2 are mach 1.1 and 1.2, respectively. These speeds are obviously too

high therefore sweep is introduced to the blades, as can be seen in the above tables. This is done for

noise reductions. Tip speeds are the higher than the rest of the blade speeds. When these tip speeds

approach the critical Mach number, flow issues arise and these flow issues and shock formation cause

the creation of intense unwanted noise and vibration. To minimize the noise the blades are swept back

to allow for these tips to have high speeds but not all the noise and flow problems that come with high

speed. It is important to note the amount of sweep for the blades was determined at cruise condition,

because in this flight condition the tips speeds were the highest.

Key Values Propfan 1 Propfan 2

NOB 13 11

Blade Height (m) 1.197 1.151

Fan Diameter (m) 2.394 2.302

Sweep 45° 48°

93

Also it is important to note that the diameter of propfan 2 is slightly smaller than propfan 1. This

difference in diameter helps in reducing noise. A significant amount of the noise generated in an

unducted fan design engine comes from the viscous interactions between the propfan blades. Basically

when the front propfan vortices interact with the aft propfan, noise is generated, and to avoid excessive

interaction between the vortices, a simple solution of reducing the diameter of the aft causes a

reduction in the interaction of the two. The diameter of the GE-36 engine fan blades is about 7.7ft, and

the engine design in this report is about 7.8ft.

The GE-36 Unducted Fan was used as a basis for this engine design, but with respect to the number of

blades based on research this design was modernized. It has been shown to reduce to noise, if the

number of blades is different, the resonance affect is reduced. More experimental data needs to be

gathered to completely verify this, but it has been shown to put more blades in the front propfan to

reduce noise. Thus, based on research showing a 12x10 configuration, it was decided to go with a 13x11

configuration to ensure sufficient thrust without exceeding tip speeds by having to increase RPM too

much.

*All lengths are in meters, and they are axial lengths not true lengths*

Figure 76: Propfan 1 snd 2

94

Figure 77: Pitch Angles across Flight Conditions

The pitch trend is correct as in propellers the pitch angle decreases from hub to tip to keep the angle of

attack mostly constant at it CLmax angle across the blade to maximize thrust.

50

60

70

80

90

100

110

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Pit

ch A

ngl

e (

de

g)

Radial Location r/R

Pitch Angle (Blade Twist)-Cruise Propfan 1

Propfan 2

30

40

50

60

70

80

90

100

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Pit

ch A

ngl

e (

de

g)

Radial Location r/R

Pitch Angle- TO Propfan 1

Propfan 2

20

30

40

50

60

70

80

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Pit

ch A

ngl

e (

de

g)

Radial Location r/R

Pitch Angle - SLS

Propfan 1

Propfan 2

95

Figure 78: Angle of Attack Across Flight Conditions

The angle of attack is mostly constant in all stages of flight. In the TO and SLS stages the angle is not

completely stable especially in the sections close to the hub, which is still acceptable, since when

analyzing propellers the sections close to hub are often ignored since they contribute very little to the

thrust.

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ao

A (

de

g)

Radial Location r/R

Angle of Attack -Cruise

Propfan 1

Propfan 2

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ao

A (

de

g)

Radial Location r/R

Angle of Attack -TO

Propfan 1

Propfan 2

0

5

10

15

20

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ao

A (

de

g)

Radial Location r/R

Angle of Attack -SLS

Propfan 1

Propfan 2

96

Figure 79: Advance Angle Across Flight Conditions

The advance angle for all stages of flight share the same trend of decreasing from hub to tip. This makes

sense as pitch angle is decreasing while angle of attack remains almost constant, therefore advance

angle has to decrease as a well.

0

10

20

30

40

50

60

70

80

90

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ad

van

ce A

ngl

e (

de

g)

Radial Station r/R

Advance Angle - Crz

Propfan 1

Propfan 2

0

10

20

30

40

50

60

70

80

90

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ad

van

ce A

ngl

e (

de

g)

Radial Station r/R

Advance Angle - TO

Propfan 1

Propfan 2

0

10

20

30

40

50

60

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Ad

van

ce A

ngl

e (

de

g)

Radial Station r/R

Advance Angle - SLS

Propfan 1

Propfan 2

97

9.2. Aerodynamic Analysis

The results for the Aerodynamic analysis for both propfan 1 and propfan 2 are analyzed below. The analysis is completed at 80% chord length, since propellers are usually analyzed at about 70-80% chord length. This is done since most thrust is generated towards the tips of propellers and at the hub a lot of aerodynamic flow problems occur and very little thrust is generated in this region; therefore propellers are analyzed on average at 75% chord. The values obtained in the data analysis where taken at 10% intervals, thus 80% was the reasonable choice. The aerodynamic characteristics for the propfan at cruise flight condition are shown below in Table 67.

Figure 80: Propfan Cruise Velocity Triangle

98

Table 67: Propfan Cruise Velocity Triangle Values

Important Observations and Conclusions

Advance angle, φp , is the angle formed between the rotation axis, and a tangent to the blade helix. The advance angle of the two blades is different as expected since the RPM and Velocity of the two propfans are different. The angle of attack, αp, is seen to be close to 15˚ which is what is desired to maximize thrust.

The effects of counter-rotation are also exhibited. The increase of V (V1 < V2) across Rotor 1 (Station 1 – 2) describes swirl induction. Employing counter-rotation in propfan 2 (Station 3 - 4 ), this swirl is expelled as V is turned axial again, without the expected reduction in V (V4 > V3) typical of swirl expulsion. This demonstrates how counter-rotation recovers exit swirl between blades and converts this to thrust.

Station 1 2 3 4

Vax

(m/s) 253.1 279.5 279.5 302.2

Vu

(m/s) ------- 60.3 60.3 5.3

V (m/s) 253.1 286.0 286.0 302.2

M 0.85 0.95 0.95 1.00

Wu (m/s)

171.3 111.0 246.4 191.3

W (m/s) 305.6 300.7 372.6 357.7

MRelative 1.03 1.00 1.24 1.19

UP (m/s)

171.3 186.0 ------- -------

φP (deg)

55.9 48.6 ------- --------

αP (deg) 13.4 14.4 ------- --------

βP(deg) 71.9 73.8 ------- -------

β (deg) 34.1 21.6 41.4 32.3

α (deg) 0 12.2 12.2 1.0

99

9.3. Thermodynamic Analysis

Figure 81 demonstrates Propfan 1 and Propfan 2 in an absolute FoR. Each blade exhibits adiabatic

compression with work done across blade 1 being h02 - h01 and Rotor 2 being h04 - h03.

The figure below describes the thermo stations used to describe the flow through the propfans.

Figure 81: Propfan h-s Diagram

Figure 82: Propfan Aero/Thermo Stations

100

Table 68: Propfan Cruise Thermodynamic Values

Figure 83 demonstrates Propfan 1 and Propfan 2 in a relative FoR. Each blade behaves like a stator and

exhibits adiabatic compression with h01r=h02rTE and h02rLE=h04r . h02rTE < h02rLE and W2TE < W2LE

exemplifies counter-rotation in the propfan where W2LE leading into propfan 1 has a new direction and

a higher magnitude compared to W2LE leaving propfan 1. This phenomenon has a big part to play in the added work being done across a counter rotating fan compared to a conventional fan.

Station 1 2 3

Mach # 0.85 .938 1.01

γ 1.4 1.4 1.4

R (J/Kg*K) 287 287 287

Cp (J/Kg*K) 1004.5 1004.5 1004.5

P0 (Pa) 40198.1 44862.7 49990.0

P (Pa) 25064.0 25441.4 25962.1

T0 (K) 252.8 263.1 273.3

T (K) 220.9 223.7 226.6

h0 (J/Kg) 253957.7 264290.4 274525.8

ρ (Kg/m3

) 0.395 0.396 0.399

A (m2

) 4.50 4.33 4.17

V(m/s) 253.1 286.0 302.2

Propfan 1 Propfan 2

π0 1.116 1.114

τ0 1.041 1.039

Δh0 (J/Kg) 10332.6 10235.4

Δs0 (J/Kg*K) 8.55 7.11

Δs0 (J/Kg*K) 8.55 7.11

Total Δh0 (J/Kg) 20568.0

101

The figure below describes the thermo stations used to describe the flow through the propfans.

Figure 83: Propfan Relative h-s Diagram

Figure 84: Propfan Aero/Thermo Stations for Relative Frame of Reference

102

Table 69: Propfan Relative Thermodynamic Values

Table 70: Propfan Off Design Thermodynamic Values

Station 1 2 3

Before P1 Between P1 and P2 Aft P2

M 0.21 0.35 0.46 γ 1.4 1.4 1.4 R 287 287 287 cp 1004.5 1004.5 1004.5 Po 104522.4 125342.1 148080.8 P 101300.0 115146.7 128062.5 To 290.6 333.7 366.5 T 288.0 325.7 351.6 ho 291896.0 335196.4 368103.4 h 289296.0 327168.9 353140.9

ρ (kg/m3) 1.226 1.232 1.269

u (m/s) 72.1 126.7 173.0 A (m

2) 4.50 4.33 4.17

Loc P0

(Pa) P (Pa) T0

(K) T (K)

1 40198.1 25064.0 252.8 220.9

2 44862.7 25441.4 263.1 223.7

3 49990.0 25962.1 273.3 226.6

1r 48914.7 25064.0 267.4 220.9

2TEr 48331.9 25441.4 268.8 223.7

2LEr 66598.3 25441.4 292.8 223.7

3r 59626.3 25962.1 290.3 226.6

Loc h0 (J/Kg) h (J/Kg) Mach V(m/s) W(m/s)

1 253957.7 221894.1 0.85 253.1

2 264290.4 224748.7 0.95 286.0

3 274525.8 227659.1 1.00 302.2

1r 268604.8 221894.1 1.03

305.6

2TEr 269975.2 224748.7 1.00 300.7

2LEr 294164.0 224748.7 1.24 372.6

3r 291624.6 227659.1 1.19 357.7

103

Table 71: Key Propfan Stage Thermodynamic Values- Off Design

In the table above, as in the Cruise Thermo values, Cp is constant. It is determined that Cp is constant as

there a very small temperature change across the propfans.

9.4. Performance In the tables below some key performance characteristics of each propfan in different flight conditions

are listed.

Table 72: Propfan Cruise Performance

Summary-Cruise Propfan 1 Propfan 2


RPM 1708 1855

NOB 13 11

Velocity (m/s) 253.14 278.19

AF/blade 187 195

CT 0.19 0.17

CP 0.89 0.84

CQ 0.14 0.13

J 3.71 3.91

η PROP

0.78 0.81

P (HP) 6319.34 6311.68

P (Watts) 4712330.02 4706617.82

∆ho (J/Kg) 10332.63 10235.39

π0 1.116 1.114

mass flow (kg/s) 456.1 459.8

T(lb) 3278 3084

Total ∆ho (J/Kg) 20568

Total P (HP) 12631

Total T(lb) 6362

Propfan 1 Propfan 2

π0 1.20 1.18

τ0 1.15 1.10

Δh0 (J/Kg) 43300.4 32907.0

Δs0 (J/Kg*K) 86.8 46.2

Δs0 (J/Kg*K) 86.8 46.2

Total Δh0 (J/Kg) 76207.5

104

In cruise condition the RPM was set to 1708 for propfan 1 and 1855 for propfan 2. These RPM were

chosen based on obtaining the correct amount of thrust as well as matching the HP of each propfan

since this was necessary for the power turbine. The velocity propfan two sees is the velocity which

comes off propfan 1. The activity factor for both blades is good, as they both are higher than the

comparable engine, GE-36 whose blades have an AF of 148. The advance ratio values of 3.71 and 3.91

are both values which represent a good forward motion of the engine for its revolution rate. The

pressure ratio across each propfan is relatively low compared to a fan but this is very characteristic for a

propeller style propulsive unit.

Table 73: Propfan Takeoff and SLS Performance

For TO and SLS condition, as can be seen in Figure 77 in the geometric section, the pitch of the propfans

were changed to acquire the desired thrust and power values. Pitch angle could not exceed 15˚ due to

the airfoil, thus, RPM was also changed to control the desired thrust and power.

Summary-SLS Propfan 1 Propfan 2


RPM 2000 2010

NOB 13 11

Velocity (m/s) 0 20.60

AF/blade 187 195

CT 0.16 0.16

CP 0.28 0.33

CQ 0.044 0.053

J 0.00 0.27

η PROP

0.00 0.13

P (HP) 10305.7 10280.0

P (Watts) 7684995.9 7665804.8

∆ho (J/Kg) 132493.1 92213.3

mass flow (kg/s) 58.0 83.1

T(lb) 12791 10647

Total ∆ho (J/Kg) 224,706

Total P (HP) 20,586

Total T(lb) 23,439

Summary-TO Propfan 1 Propfan 2


RPM 1610 1690

NOB 13 11

Velocity (m/s) 72 119.6

AF/blade 187 195

CT 0.16 0.14

CP 0.50 0.52

CQ 0.078 0.083

J 1.12 1.84

η PROP

.36 0.5

P (HP) 9534.0 9662.7

P (Watts) 7109489.5 7205480.2

∆ho (J/Kg) 43300.4 32907.0

mass flow (kg/s) 164.2 219

T(lb) 7958.1 6754.9

Total ∆ho (J/Kg) 76207.5

Total P (HP) 19196.7

Total T(lb) 14713

105

10. Inlet

The goal of the Inlet is to allow the appropriate amount of upstream air to be capture and swallowed by

the engine while minimizing inlet lip losses. Similarly, the goal of the Diffuser is to minimize viscous

losses in between the inlet lip and the first stage of the IPC by allowing the air to decelerate smoothly

from one point to the other. Both the Inlet and Diffuser were designed simultaneously using CATIA

V5R20 educational software. The table below shows the radius and area for the locations of interest.

Table 74: Areas at Locations of Interest Necessary for Inlet Design

Location Area (m2) Outer Diameter (m)

Takeoff Capture Area .735 .968

Cruise Capture Area .300 .618

Inlet .320 .639

Diffuser .328 .883

Finally, the start of the IPC was placed at a distance of .46m in the opposite direction from the capture

areas. A spline command in the Generative Shape Design workbench was used to connect each circle.

Two splines were used, one passing through what will be the top of the inlet and one passing through

what would be the bottom of the inlet. By manipulating the distance between inlet and capture area, a

smooth annulus was created by attempting to superimpose the cruise funnel on the takeoff funnel,

which allows for minimal losses at each flight condition.

Figure 85: Detailed Meridional Inlet View with Capture Cones

The flow through the diffuser can be described as adiabatic compression with no work. The process

from the Inlet to the IPC Entrance is modeled on the h-s Diagram in Figure 86 below.

Palmer

106

Table 75: Thermodynamics through Inlet Diffuser at Cruise

Inlet Diffuser

M 0.720 0.700

γ 1.4 1.4

R 287 287

cp (J/kg*K) 1004.5 1004.5

Po (Pa) 39796.1 39398.2

P (Pa) 28176.7 28403.2

To (K) 252.8 252.8

T (K) 229.1 230.3

ho (J/kg) 253957.7 253957.7

h (J/kg) 230100.9 231291.2

ρ (kg/m3) 0.429 0.430

u (m/s) 218.4 212.9

A (m2) 0.320 0.328

φ (m) 0.639 0.646

Δs (J/kg*K) 25.1 25.4

hO 1,2

h2

h1

s1 s2

PO1 PO2

P2

222

P1

1

2 ½ V1

2

½ V22

Figure 86: h-s Diagram of Flow through Inlet Diffuser

107

Table 76: Thermodynamics through Inlet Diffuser at Takeoff

Inlet Diffuser

M 0.582 0.575

γ 1.4 1.4

R 287 287

cp (J/kg*K) 1004.5 1004.5

Po (Pa) 103477.7 101925.6

P (Pa) 82286.1 81474.6

To (K) 290.6 290.6

T (K) 272.2 272.6

ho (J/kg) 291896.4 291896.4

h (J/kg) 273397.4 273804.1

ρ (kg/m3) 1.05 1.04

u (m/s) 192.35 190.22

A (m2) 0.32 0.33

φ (m) 0.64 0.65

Δs (J/kg*K) 2.88 4.34

108

11. Ducts

Engine ducts and diffusers are meant to guide the while at the same time accelerate or decelerate the

flow to an acceptable level for the next component. The engine has a total of 2 ducts. They range in size

based on their location throughout the engine. All Ducts were designed using CATIA V5R20 visualization

software. In order to design these components the components which they connected must be finalized

first. The duct length was determined by adjusting the spacing between the two components until the

steepest angle in the duct was no greater than 45° if the flow is accelerating or 30° if the flow is

decelerating.

11.1 High Pressure Compressor Exit Diffuser

11.1.1 Diffuser Thermodynamics

The flow from the HPC to the Combustion chamber is adiabatic compression with no work. Below is

pictured the enthalpy-entropy diagram and the table to the right of it shows all thermodynamic values

of interest.

Table 77: Diffuser Thermodynamics

Diffuser Entrance

Diffuser Exit

M 0.488 0.100

γ 1.38 1.38

R 287.0 287.0

cp (J/kg*K) 1042.3 1042.3

Po (Pa) 1072385.7 1084392.1

P (Pa) 912910.2 1076942.6

To (K) 719.7 719.7

T (K) 688.5 723.0

ho (J/kg) 750142.5 750142.5

h (J/kg) 717611.9 753533.4

ρ (kg/m3) 4.62 5.23

u (m/s) 255.1 53.5

A (m2) 0.02 0.10

φ (m) 0.18 0.36

Δs (J/kg*K) 77.73 3.48

Figure 87: HPC Exit Diffuser Thermodynamics and h-s Diagram

hO 1,2

h2

h1

s1 s2

PO1 PO2

P2

222

P1

1

2 ½ V1

2

½ V22

Palmer

109

11.1.2 Diffuser Geometry

Figure 88: HPC exit Diffuser Meridonial View

11.2 Intermediate Pressure Compressor/Power Turbine Duct

11.2.1 Duct Thermodynamics

The flow from the IPT to the PT is adiabatic compression with no work. The enthalpy-entropy diagram

pictured in Figure 89 depicts the process.

Table 78: IPT/PT Thermodynamics

Duct Entrance Duct Exit

M 0.538 0.169

γ 1.33 1.33

R 259.8 259.8

cp (J/kg*K) 1047.1 1047.1

Po (Pa) 200934.8 198614.6

P (Pa) 166466.2 194874.9

To (K) 1079.6 1079.6

T (K) 1030.3 1074.5

ho (J/kg) 1130414.1 1130414.1

h (J/kg) 1078844.7 1125095.1

ρ (kg/m3) 0.62 0.70

u (m/s) 321.2 103.1

A (m2) 0.15 0.40

φ (m) 0.44 0.72

Δs (J/kg*K) 12.47 3.02

Figure 89: IPT/PT Thermodynamics and h-s Diagram

hO 1,2

h2

h1

s1 s2

PO1 PO2

P2

222

P1

1

2 ½ V1

2

½ V22

110

11.2.2 Duct Geometry

Figure 90: Detailed Meridional View of IPT/PT Duct

The mean angle on the top surface of the duct is 28.9°. The bottom surface of the duct’s mean angle is

26.7°. These angles meet the design requirement of less than 30° in a duct with decelerating flow.

FLOW DIRECTION

111

12. Materials

A working engine is just an engine half done. To get the engine presentable and lucrative to the customer, the various components of the engine must prove that they will perform and exceed expectations in terms of life, durability and reliability. The materials used in the FUDD are top grade aerospace materials that guarantee long life and reliability of the engine.

12.1 Prop Fan

The propfan is about 13 feet in diameter and spins around 1800 rpm. The material that is chosen to create it should be strong enough to take rotational stresses and light enough to not add too much weight to the engine. The material chosen for the propfan is Titanium Aluminum Vanadium alloy (Ti-6Al-4V). The propfan is going to have a unique material design namely the titanium alloy sandwiches a titanium honeycomb structure. The main reason this is done is to save weight while not compromising on performance and reliability. Table 79 provides the composition of the alloy.

Table 79: Composition of Ti-6Al-4V

Element % Comp Element % Comp Element % Comp Element % Comp Element % Comp

Ti 90 Al 5.99 V 3.99 Fe >0.25 O >0.2

The thermal and mechanical properties of the alloy are represented in the table below.

Table 80: Properties of Ti-6Al-4V compared with standard Alumina

Criteria Ti-6Al-4V Alumina

Young’s Modulus (GPa) 119.3 70

Bulk Modulus (GPa) 153.1 76

Tensile Strength (GPa) 1.268 0.125

Endurance Limit (GPa) 0.64 0.172

Density (g/cc) 4.43 2.7

Melting Point (K) 1672 2277

Maximum Service Temp. (K) 623 2033

Thermal Expansion Coefficient ( strain/ K)

9.1 8.1

Thermal Conductivity (kW/m.K) 7.31 30

Titanium is relatively difficult to work with. However, the blade is created using patented Rolls Royce® technology which involves sandwiching and then air inflation till it reaches prime size. Rolls Royce® has used this technology on the Trent 900 and Trent 1000 already.

Dantis

112

12.2 Compressor The compressor consists of two parts namely the IPC and the HPC. The material used for both compressors is INCONEL® nickel-iron-chromium alloy 706. The alloy is a precipitation-hardenable alloy that provides high mechanical strength in combination with good fabrication ability. Table 81 provides the composition of the alloy.

Table 81: Composition of INCONEL® Alloy 706

Element % Comp. Element % Comp. Element % Comp. Element % Comp. Element % Comp.

Ni 39-44 Cr 14.5-17.5 Co 1 Nb 2.5-3.3 Ti 1.5-2

Al 0.4 C 0.06 Cu 0.3 Mn 0.35 Si 0.35

S 0.015 P 0.02 B 0.016 Fe rest

The INCONEL® alloy maintains its high strength and creep rupture resistance up to 980 K. This is due to the heat treatment process it undergoes during fabrication. Table 82 lists the mechanical and thermal properties of the alloy.

Table 82: Properties of INCONEL® Alloy 706 compared with standard Alumina

Criteria INCOLOY® Alloy 706 Alumina





Density (g/cc) 8 2.7




12.5 8.1


As stated before, the alloy is highly machineable and is very easy to manufacture. It is easily available in the form of rods, plates, billets, wires, forgings and strips. Another reason to use a strong material for the compressor is to provide added strength and reliability to the blisk in the HPC.

12.3 Combustion Chamber

The combustion chamber is the hottest part of the engine and hence the material should be hard,

sturdy, heat resistant and durable. The material used for the combustion chamber is INCOLOY® alloy A-

286. It is an iron-nickel-chromium alloy with additions of molybdenum and titanium. The alloy maintains

good strength and exceptional oxidation resistance at high temperatures. The high strength and

excellent fabrication characteristics of INCOLOY® alloy A-286 make the alloy useful for various

components of aircraft and industrial gas turbines. It is also used for fastener applications in automotive

113

engine and manifold components subject to high levels of heat and stress and in the offshore oil and gas

industry.

Table 83: Composition of INCOLOY® alloy A-286

Element % Comp. Element % Comp. Element % Comp. Element % Comp.

Ni 24-27 Cr 13.5-16 Ti 1.9-2.35 Mo 1-1.5

V 0.1-0.5 C 0.08 Mn 2 Al 0.35

S 0.03 B 0.001-0.01 Si 1 Fe Rest

The table above consists of the composition of INCOLOY® alloy A-286. The high concentration of nickel and chromium adds strength and high temperature resistance to the alloy. Therefore the physical properties of the alloy are enhanced and perfect for the extreme conditions it is subjected to. The table below provides a brief synopsis of the mechanical and thermal properties of the alloy. To provide a good reference to the strength and durability of the alloy, the properties of Alumina are compared alongside as well.

Table 84: Properties of INCOLOY® alloy A-286 compared with standard Alumina

Criteria INCOLOY® Alloy A-286 Alumina

Young’s Modulus (GPa) 201 70








17.7 8.1


INCOLOY alloy A-286 is readily fabricated by standard procedures for stainless steels and nickel alloys. Therefore it is not difficult to manufacture is readily available in sheets, rods, bars and plates. This makes the alloy prime material for the combustion chamber based on our low TIT and the material’s durability.

12.3.1 Thermal Barrier Coating (TBC)

The thermal barrier coating chosen for the combustion chamber and the HPT blades is Yttria stabilized Zirconia (YSZ). YSZ is used industry wide for thermally protecting materials even when the temperature is beyond their melting range. It has been proven that a 150 μm application on the material surface can protect the material to up to 170 K beyond its melting point. The two main reasons YSZ is used today is because of its low thermal conductivity and high thermal expansion coefficient. These two reasons

114

contribute to an increased component life and durability. The following table highlights the mechanical and thermal properties of YSZ.

Table 85: Properties of YSZ

Criteria Value Criteria Value Criteria Value

Young’s Modulus (GPa)

208.91 Endurance Limit (GPa)

0.638 Max Service Temp. (K)

2455

Bulk Modulus (GPa)

128.93 Density (g/cc) 5.92 Thermal Expansion.

Coefficient ( strain/ K)

3.914

Tensile Strength (GPa)

0.71 Melting Point (K) 2972 Thermal

Conductivity (kW/m.K)

0.832

12.3.2 Anti Oxidation Coating

The anti oxidation coating used on the combustion chamber is Nickel Chromium Aluminum Yttrium alloy (NiCrAlY). NiCrAlY alloy has two main properties that make it a lucrative material. The first reason is because the coating acts as an adhesive and allows the TBC to successfully attach to the nickel alloy and secondly they prevent the oxidation of the nickel alloy in the event of TBC failure. This acts as a last resort before the nickel alloy fails.

12.4 Turbine The turbine section is divided in to 3 parts namely the HPT, the IPT and the PT. The material that is to be selected should be able to handle the high temperatures and stresses of gases coming out of the combustion chamber while it should be strong enough and well equipped to spin the propfan with relative ease. MAR-M-247 has a unique property of getting stronger and sturdier as it is subjected to increasing temperatures. Table 86 provides the chemical composition of MAR-M-247.

Table 86: Composition of MAR-M-247

Element % Comp. Element % Comp. Element % Comp. Element % Comp. Element % Comp.

Ni 59 W 10 Co 10 Cr 8.25 Al 5.5

Ta 3 Ti 1 Mo 0.7 Fe 0.5 B 0.015

The high concentration of nickel and chromium adds strength and high temperature resistance to the alloy. The material also has trace amounts of tantalum in it which helps reduce grain boundary which thereby increases grain size and decreases boundary cracking. Table 87 below provides a brief synopsis of the mechanical and thermal properties of the alloy. To provide a good reference to the strength and durability of the alloy, the properties of Alumina are compared alongside as well.

115

Table 87: Properties of MAR-M-247

Criteria MAR-M-247 Alumina


Bulk Modulus (GPa) 140 76







13.9 8.1

Thermal Conductivity (kW/m.K) 12 30

The HPT blades will also have a 150 μm coating of YSZ TBC with NiCrAlY anti oxidation coating to further protect them from the high temperature and gases from the combustion chamber. MAR-M-247 is the standard material used today for HPT and LPT blades. The manufacturing process has been set in stone for the past 20 years and therefore should not be hard to manufacture.

12.5 Duct and Diffuser The engine has a one duct and one diffuser. The duct connects the IPT to the PT while the diffuser connects the HPC to the combustion chamber. Based on the mechanical and thermal properties of the various components in the engine, the ideal material to make both the duct and the diffuser is INCONEL Alloy 706. The alloy is strong enough to handle the highly compressed air and relatively high temperature from the HPC with ease. Also, even though the temperature of the gases coming out of the IPT are slightly elevated when compared to the HPC and since the pressure is much lower, the alloy is an ideal candidate for both, the duct and the diffuser.

116

12.6 Inlet and Exit Cone The inlet cone is made of Hastelloy alloy X which is a solid solution strengthened super alloy. It is one of

the most widely used materials for fabricated parts in a gas turbine engine. The properties of Hastelloy

alloy X is elaborated in

Table 88 below.

Table 88: Mechanical and Thermal Properties of Hastelloy alloy X

Criteria Hastelloy alloy X Alumina

Young’s Modulus (GPa) 139 70

Bulk Modulus (GPa) 189 76







16.6 8.1


The alloy is highly machineable and is easily available in sheet and billet form. The inlet cone is coated with a polyurethane material to act as a protective layer.

117

1. References

1. CFM-CFM International. “LEAP56,LEAP-X, and Open Rotor” Jane’s Aero-Engines. : Jan. 31,2011

2. CFM. 2011. 30 January 2011 < http://www.cfm56.com/products/cfm56-7b>

3. Dickens, Tony, and Ivor Day. "The Design of Highly Loaded Axial Compressors." Journal of

Turbomachinery 133 (2011). Print.

4. U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION TYPE

CERTIFICATE DATA SHEET E00049EN (2007). Print.

5. “Full Scale Technology Demonstration of Modern Counterrotating Unducted Fan Engine

Concept” GE, NASA Contract No. NAS3-24210, CR-180867, December 1987

6. John E. Donelson, William T. Lewerenz, and Roger T. Durbin. “UHB Technology Validation – The

Final Step.” American Institue of Aeronautics and Astronautics. AIAA-88-2807. 1988.

7. Norris, Guy. “New-Generation GE Open Rotor and Regional Jet Engine Demo Efforts Planned”

Aviation Week. May 11,2008.

8. Peters, Andreas. “Assesment of Propfan Propulsion Systems for Reduced Environmental Impact”

Diplomarbeit (Thesis). RWTH Aachen University (Germany) and Massachusetts Institute of

Technology. January 2010

9. Turner, Aimme. “R-R achieves ‘very big step’ in open rotor Technology.” Flight International. Vol.

174. Issue 5160 (2008): pg 9

118

2. Appendix

Sample calculations

Compressor On Design

AERODYNAMICS

2 1

2

2

*(1 )

0.234*(1 0)

0.234m

m m m

m

m

r r r

r

r

3 2

3

3

*(1 )

0.234*(1 0)

0.234m

m m m

m

m

r r r

r

r

2 1

2

2

*(1 )

204.5* 1.10

184.1

ax ax ax

ax

ax

v v v

v

mvs

3 2

3

3

* 1

184.1*(1 0.08)

198.8

ax ax ax

ax

ax

v v v

v

mvs

1 12

2

2

2

77044 362.6* 21.5

362.6

191.0

o UU

U

U

h U VV

U

V

mVs

3 3 3

3

3

* tan( )

198.8* tan(11.5 )

40.4

U ax

o

U

U

V V

V

mVs

119

191.0 362.6

171.6

U U

U

U

W V U

W

mWs

1

1

tan

191.0tan

184.1

46.1

U

ax

o

V

V

1

1

tan

171.6tan

184.1

43.0

U

ax

o

W

V

2 2

2 2184.1 191.0

265.2

ax UV V V

V

mVs

2 2

22184.1 171.6

251.7

ax UW V W

W

mWs

THERMODYNAMICS

3 6 2 9 3

3 6 2 9 3

3.64 1.101*10 * 2.466*10 * 0.942*10 *

287 3.64 1.101*10 *407.5 2.466*10 *407.5 0.942*10 *407.5

1015.2*

p guess guess guess

p

p

C R T T T

C

JCkg K

1015.2

1015.2 287

1.394

p

p

C

C R

120

1

1 1 3

3

1

1.3938 1

1.3938

*

1011.2*1.69 1020.41020.4

.88

1011.2

1.183

avg

avg

p o p

p

tto

p

o

o

C CC

C

3 1

3

3

*

393.3*1.18

469.3

o o o

o

o

T T

T

T

3 3 3

3

3

*

1020.4*469.3

474721

o p o

o

o

h C T

h

Jhkg

3 1

474721 397677

77044

o o o

o

o

h h h

h

Jhkg

3 1

3

3

*

156035*1.69

263785

o o o

o

o

P P

P

P Pa

2

3

2 3

2

2

2

* *

2

.04*1.63*202.8263785

2

266085

guess

o o

o

o

VP P

P

P Pa

* *

265.2

1.392*287*431.6

.639

VM

R T

M

M

121

12

1.392

1.392 12

11 *

2

266085

1.392 11 *.639

2

202482

oPP

M

P

P Pa

2

2

2*

218.3431.0

2*1015.2

407.5

o

p

VT T

C

T

T K

3

*

202482

287*431.6

1.63

P

R T

kgm

.

2

*

30

1.63*184.1

.0997

ax

mA

V

A

A m

RADIAL EQUILIBRIUM

*

.234*191.0

.201

223.2

mid UmidUhub

hub

Uhub

Uhub

r VV

r

V

mVs

_ _

_ 184.1

ax hub ax mid

ax hub

V V

mVs

122

*

362.6.201*

.234

310.2

midhub hub

mid

hub

hub

UU r

r

U

mUs

OFF DESIGN AERODYNAMICS

3:Select

2 2OD DP

2 3

2

2

0 32.6

32.6

STATOR

o

CAMBER

22

2 2

2

2

tan( ) tan( )

380.9

tan(32.6) tan( 43)

242.5

ax

ax

ax

UV

V

mVs

.

3

3

3

*

30

3.28*.086

231.5

ax

guess

ax

ax

mV

A

V

mVs

OFF DESIGN THERMODYNAMICS

2 2 1 1

380.9*154.8 380.9*( 22.8)

67656

o U U

o

o

h U V U V

h

Jhkg

123

1 1

3

3

3

3

*

67656 1015.2*431.0

1024.0

493.4

o p o

o

p

o

o

h C TT

C

T

T K

3

1

493.4

431.0

1.145

oo

o

o

o

T

T

13 1 1

3

1.392

1.392 1

*

.88 1024.0*1.145 1015.2 1015.2

1024.0

1.526

avg

avgtt p o p p

o

p

o

o

C C C

C

Propfan Calculations

_

_

_

0 10.9

/ 0.2

0.12 2

0 0.42600.1 .006917 0.02865 0.06615 0.1183 0.1811 0.2514 0.3283 0.4074 0.4713

2 2

0.2072

no loss

no loss

no loss

T T

TT

r R

T

T

dC dC

dCdr drCdr

C

C

_1 ( 2 ) /

1 ( 2 0.2072) /13

0.95

no lossTB C NOB

B

B

124

_

_

_

1 1(( ( (1 )) / 2) (1 )

0.4260 0.4713((0.4260 (0.4260 (1 0.95)) / 2) (1 0.95)

1.0 0.9

0.0218

Tip

Tip Loss

Tip Loss

Tip Loss

T

T T T

T

T

dCC C C B B

dr

C

C

_ _

0.2072 0.0218

0.185

No Loss Tip LossT T T

T

T

C C C

C

C

2

3 2 2

( )

0.185 0.00073821( / ) 48.5 (702.52 / )

3269

TT C A R

T slug ft ft ft s

T lb

0 00 1

0

0

0

0

.9

/ .2

0.1

2 2

0 0.013890.1 0.00001305 0.0001081 0.0003769 0.0009138 0.001801 0.003131 0.005039 0.007664 0.01121

2 2

0.00372

Q Q

Q

Q

r R

Q

Q

dC dC

dCdr dr

C

dr

C

C

0 1

0.9

_

/ 0.1

_

_

0.1

2 2

0 0.38850.1 0.001018 0.007944 0.02603 0.05890 0.1072 0.1699 0.2465 0.3328 0.4114

2 2

0.1556

Qi Qi

Qi

Qi no loss

r R

Qi no loss

Qi no loss

dC dC

dCdr drC

dr

C

C

1

_

_

_

1

1 0.9505 0.3885

0.192

Qi

Qi Tip loss

Qi Tip loss

Qi Tip loss

dCC B

dr

C

C

125

_ _

0.1556 0.0192

0.1364

Qi Qi Qino loss tip loss

Qi

Qi

C C C

C

C

0

0.00372 0.1364

0.1401

Q Q Qi

Q

Q

C C C

C

C

2

2 0.1401

0.8803

p Q

p

p

C C

C

C

830 /

28.47 1/ 7.856

3.71

VJ

RPS D

ft sJ

s ft

J

0.1853.71

0.8803

0.78 78%

T

P

CJ

C

126

830.496 /3269

0.78

3480630.0( / ) 6328.4 4719100.7

VP T

ft sP lb

P ft lb s HP W

2

830.496 / 912.69 /

2

871.6 /

inlet exitavg

avg

avg

V VV

ft s ft sV

V ft s

.

2.

3

.

7.8560.0237( / ) 871.6 /

2

1001.3( / ) 455.1 /

avgm V A

ftm lb ft ft s

m lb s kg s

0 .

0

0

4719100.7

455.1( / )

10369.4 /

Ph

m

Wh

Kg s

h J Kg

22

2 2702.52 / 830.4 /

1087.7 /

1087.7 /

973.1 /

1.1

Tip forward

Tip

Tip

Tip

Tip

Tip

Tip

V R V

V ft s ft s

V ft s

VM

a

ft sM

ft s

M

127

3

0

4

0

4 4 4 4 4 4 4 4 4 4 4

100000

16

100000

16 4

16.82 17.61 17.61 17.61 17.29 16.50

0 0.1 0 0.2 0.1 0.3 0.2 0.4 0.3 0.5 0.4

100000 94.272 94.272 94.272 94.272 94.272 94.272

15.16 4

D

D

c r r

AF d

D R R

r

cR

AF

D

in in in in in in

in in in in in in

AF

4 4 4 4 4 4 4 4 4 439 14.28 13.17 11.26 7.61

0.6 0.5 0.7 0.6 0.8 0.7 0.9 0.8 1.0 0.9

94.272 94.272 94.272 94.272 94.272

187

in in in in in

in in in in in

AF

Documents

Final Report