contra-rotating propeller modelling for open rotor ... · contra-rotating propeller modelling for...

Contra-Rotating Propeller Modelling For Open Rotor Engine Performance Simulations Alexiou, Frantzis, Aretakis, Riziotis, Roumeliotis, Mathioudakis

Click to edit Master title style

Contra-Rotating Propeller Modelling For Open Rotor Performance Simulations

by Alexiou, Frantzis, Aretakis,

Riziotis, Roumeliotis, Mathioudakis

National Technical University of Athens


Click to edit Master title style Motivation

2

The Open Rotor configuration enables ultra-high bypass ratio and high propulsive efficiency thus reducing fuel burn and emissions compared to an equivalent thrust turbofan

For open rotor preliminary design performance evaluations, 0-D cycle models are needed employing CRP performance maps for robustness and fast execution

Currently in the public literature, CRP performance models do not accurately represent the physics of a CRP system and or do not account for all the independent parameters that govern the operation of the CRP system


Click to edit Master title style Objectives

3

Develop a methodology for modelling contra-rotating propellers (CRP) for engine performance calculations: 1. Generate CRP performance characteristics taking into

account the effects of induced velocities, flight Mach number, speed ratio and blade pitch angles

2. Develop a mathematical model for CRP that uses these characteristics

3. Integrate the CRP component in an open rotor engine performance model and perform design and off-design simulations



4

FREE-WAKE LIFTING SURFACE MODEL o Theoretical Background o Implementation o Indicative Results

CRP PERFORMANCE MODEL o Simulation Environment - PROOSIS o CRP Performance Maps o CRP PROOSIS Component

CROR ENGINE MODEL

ENGINE CONTROL STUDIES

SUMMARY & CONCLUSIONS

Contents



5



CROR ENGINE MODEL



Contents


Click to edit Master title style Free-Wake Lifting Surface Model - GENUVP

6

The in house code GENUVP is a potential flow solver combining a panel representation of the solid boundaries (blades) with a vortex particle representation of the wake.



psi

87%

CN

0 90 180 270 3600

0.2

0.4

0.6

0.8

1

GENUVPMeasurements

6deg, descent 33m/s, MR, r/R=0.87

GENUVP Application Examples

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Aeroelastic analysis of Helicopter rotor Wind turbine aeroelastic simulation

GENUVP is used in the aerodynamic analysis of rotor/wing problems



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CRP Geometry in GENUVP (based on SR-7A)

00.1

0.20.3

-0.2-0.1

00.1

0.2

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

-0.25 -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

-0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

-0.25

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25


Click to edit Master title style Single Propeller Wake – Panoramic View

9

0

0.5

1

1.5

2

-0.20

0.2

-0.2

0

0.2

y [m] z [m]

x [m]


Click to edit Master title style SP Power Coefficient: M=0.7

10

0

0.5

1

1.5

2

2.5

3

2 2.5 3 3.5 4 4.5 5

CP

J

β=63.3⁰

β=60.2⁰

β=57.7⁰

Curves → Experimental Points → Predicted


Click to edit Master title style SP Thrust Coefficient: M=0.7

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0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

2 2.5 3 3.5 4 4.5 5

CT

J

β=63.3⁰β=60.2⁰

β=57.7⁰

Curves → Experimental Points → Predicted



00.2

0.40.6

0.81

1.21.4

-0.2

0

0.2

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

CR Propeller Wake – Panoramic View

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y [m]

z [m]

x [m]


Click to edit Master title style CR Propeller Wake – Meridional View

13

y [m]

z [m]


Click to edit Master title style Radial distribution of incidence angle

14

-1

-0.5

0

0.5

1

1.5

2

2.5

0.2 0.4 0.6 0.8 1

Inci

denc

e

r/R

SPFPBP

β1=β2=57.7º M=0.6 J=3.0 NR=1


Click to edit Master title style Radial distribution of Helical Mach number

15

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.2 0.4 0.6 0.8 1

Hel

lical

Mac

h nu

mbe

r

r/R

SP

FP

BP

β1=β2=57.7º M=0.6 J=3.0 NR=1


Click to edit Master title style Radial distribution of Induced Axial Velocity

16

0

5

10

15

20

25

30

35

0.2 0.4 0.6 0.8 1

Indu

ced

Axi

al V

eloc

ity [m

/s]

r/R

SPFPBP

β1=β2=57.7º M=0.6 J=3.0 NR=1


Click to edit Master title style Radial distribution of Induced Angular Velocity

17

-40

-20

0

20

40

60

80

0.2 0.4 0.6 0.8 1

Indu

ced

Ang

ulal

Vel

ocity

[rad

/s]

r/R

SPFPBP

β1=β2=57.7º M=0.6 J=3.0 NR=1



18

0

0.5

1

1.5

2

2.5

3

3.5

4

2 2.4 2.8 3.2 3.6 4 4.4 4.8

CP

J

SP, 63.3º

SP, 57.7º

CRP Power Coefficient: M=0.7, NR=1

FP : Front Propeller BP : Back Propeller SP : Single Propeller



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CRP Thrust Coefficient: M=0.7, NR=1

0

0.2

0.4

0.6

0.8

1

2 2.4 2.8 3.2 3.6 4 4.4 4.8

CT

J

SP, 57.7º

SP, 63.3º

FP : Front Propeller BP : Back Propeller SP : Single Propeller



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CROR ENGINE MODEL



Contents



Object-Oriented Steady State Transient Mixed-Fidelity Multi-Disciplinary Distributed Multi-point Design Off-Design Test Analysis Diagnostics Parametric Sensitivity Optimisation Deck Generation

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Simulation Platform

PROOSIS (PRopulsion Object-Oriented SImulation Software)



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Model Construction

Compressor BETA map

TURBO library of Gas Turbine Engine Components

Engine configuration constructed graphically

Turbine ZETA map


Click to edit Master title style Generation of Propeller Maps

23

M → 0.45, 0.60, 0.70, 0.75, 0.80, 0.85, 0.90 NR → 0.95, 1.00, 1.05 β1 → 57.7º, 63.3º β2 → 54.7º/57.7º (β1=57.7º) & 60.3º/63.3º (β1=63.3º)

× 3 J = 252 GENUVP runs

PROOSIS Propeller

Map

CP (BETA, β) CT (BETA, β) J (BETA, β)


Click to edit Master title style CRP Propeller Map Reading

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CP_1_3_3_2 (BETA, β2) CT_1_3_3_2 (BETA, β2) J_1_3_3_2 (BETA, β2)

Μ NR β1 # CP (M NR, β1) CT (M NR, β1) J (M NR, β1)


Click to edit Master title style PROOSIS CRP Component

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CRP Map file Front & Back Propeller Diameters CRP system inertia β1, β2 Flight Conditions: Pamb, Tamb, WAR, M N1, N2 BETA NR J, CP, CT (BETA, M, NR, β1, β2) Thrust, Power, Efficiency

DATA

CONTROL

BOUNDS

CALCULATED

ALGEBRAIC


Click to edit Master title style Contra-Rotating Turbine Modelling

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1 0.82 0.64

eff = 0.9

NR = 0.9

1 0.82 0.64

eff = 0.9

NR = 1.0

1 0.82 0.64

eff = 0.9

NR = 1.1

DP

Speed ratio NR = N1 / N2 Torque ratio trqR = trq1 / trq2

Shaft-1 Shaft-2

Wc (NR, NcRdes, ZETA) eff (NR, NcRdes, ZETA) trqR (NR, NcRdes, ZETA)



27



CROR ENGINE MODEL



Contents


Click to edit Master title style CROR Engine PROOSIS Model

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Dt1 [m] 3.56 Dt2 [m] 3.39 β1 [º] 59 β2 [º] 59

effP1 [-] 0.77 effP2 [-] 0.85 N1 [rpm] 1275 Dh/Dt1 [-] 0.425

eff [-] 0.91 power ratio 1


Click to edit Master title style Design Point Definition (ToC)

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Component Parameter [units] Value

InEng W [kg/s] 17.5

CmpL PR [-] 4.16

eff [-] 0.88

CmpH PR [-] 4.46

eff [-] 0.87

Brn

TET [K] 1500

effB [-] 0.995

Pressure loss [%] 6

TrbH eff [-] 0.843

TrbL eff [-] 0.87


Click to edit Master title style Design Point Results

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Parameter [units] Value Front propeller thrust [kN] 10.55 Back propeller thrust [kN] 11.65

Nozzle Thrust [kN] 1.05 Net Thrust [kN] 23.3

Specific Fuel Consumption [g/(kN∙s)] 14.4 Nozzle pressure ratio [-] 1.22 Propeller speed ratio [-] 1.02 Propeller torque ratio [-] 0.977

J1 [-] | J2 [-] 2.9 | 3.1 CP1 [-] | CP2 [-] 1.6 | 2.2 CT1 [-] | CT2 [-] 0.43 | 0.60

CRT PR 4.95


Click to edit Master title style OD Performance for Different Blade Settings

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β1=β2=62° β1=62°, β2=60°

β1=β2=59°

β1=59°, β2=57°


Click to edit Master title style Operating line on CRP map

32

NR=0.95 NR=1.0 NR=1.05

WF increases

β1=β2=59°

M=0.72



33



CROR ENGINE MODEL



Contents


Click to edit Master title style OD Performance for Different Control Strategies

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Constant Torque Split

Constant Propeller Speeds

Constant Blade Angle = 59°


Click to edit Master title style Propeller Blade Angle Variation

35



β1

β1

β2

β2


Click to edit Master title style Propeller Speed Variation

36


Constant Blade Angle

N1

N1

N2

N2



37

Operating lines on CRT map





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Operating line on CRP map

β1=β2=57.7°

β1=β2=63.3°

β1=β2 M=0.72

NR=1.02

WF increases



39



CROR ENGINE MODEL



Contents


Click to edit Master title style Summary & Conclusions

40

An approach to contra-rotating propeller performance modelling has been presented, based on a set of individual propeller maps generated by a free-wake lifting surface model of a specific CRP system for different values of Mach number, speed ratio and blade pitch angles.

A dedicated CRP component model is developed in an engine performance simulation environment that uses these maps to calculate CRP performance.

This CRP component is used to create a direct-drive open rotor engine performance model. The capabilities of the approach are demonstrated through design point and off-design engine studies while its flexibility is exemplified with a study of the effects of propeller blade control strategy on engine performance.



41

The accuracy of the presented approach can be further improved through:

o more accurate values of the aerodynamic coefficients (CL and CD) and

o extending the range of parameters simulated through the lifting surface model in order to reduce map interpolation and extrapolation errors.

Significant computer time savings could be achieved through:

o the use of a particle mesh approach for the far wake part downstream of the BP

o code optimization and parallelization



42

The CRP component developed can be used to study both DDOR and GOR configurations and is suitable for a variety of performance calculations at component, engine or aircraft mission analysis level.

Using the lifting surface model, maps for different combinations of propeller designs can be generated thus enabling multi-disciplinary design optimization studies.

Direct integration of GENUVP in PROOSIS as an external object will offer an advantage to the map approach both in terms of execution speed as well as modelling accuracy.



43

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