1. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Presented by A. Alexiou Laboratory of Thermal Turbomachines National Technical University of Athens

2. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 2  INTRODUCTION  PERFORMANCE MODELLING o Simulation Environment o Mean Line Analysis o Component Maps o Component Model Development  APPLICATION EXAMPLE o Engine Performance o Mission Analysis o Sensitivity Analysis  SUMMARY & CONCLUSIONS Contents

3. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleIntroduction: the past 3 Tupolev Tu-95 MS Spitfire Mk XIX GE-36-UDF

4. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleIntroduction: the future? 4 Contra-Rotating Fan Contra-Rotating LP Turbine

5. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleIntroduction: work objectives 5 To present a methodology for modelling contra- rotating turbomachinery components in engine performance simulations. 1. Derive physics-based component performance characteristics 2. Develop component models that use these characteristics 3. Integrate components in engine performance model

6. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 6  INTRODUCTION  PERFORMANCE MODELLING o Simulation Environment o Mean Line Analysis o Component Maps o Component Model Development  APPLICATION EXAMPLE o Engine Performance o Mission Analysis o Sensitivity Analysis  SUMMARY & CONCLUSIONS Contents

7. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style  Object-Oriented  Steady State  Transient  Mixed-Fidelity  Multi-Disciplinary  Distributed  Multi-point Design  Off-Design  Test Analysis  Diagnostics  Sensitivity  Optimisation  Deck Generation 7 Performance Modelling: Simulation Platform PROOSIS (PRopulsion Object-Oriented SImulation Software)

8. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 8 Performance Modelling: Model Construction  TURBO library of gas turbine components  Industry-accepted performance modelling techniques  Respects international standards in nomenclature, interface & OO programming Compressor BETA map Turbine ZETA map

9. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title stylePerformance Modelling: Mean Line Analysis 9  estimate design parameters (e.g. blade angles) through a velocity triangles analysis  use modified 1-D mean line analysis codes, taking into account flow angle deviation and pressure losses through empirical correlations from cascade experimental data  further refine flowpath and blade geometry applying basic design rules (e.g. flow coefficient, pressure rise coefficient, De Haller number) and previous experience from existing conventional compressors and turbines Contra-rotating compressor velocity triangles Contra-rotating turbine velocity triangles

10. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style Contra-Rotating Experimental Rig 10

11. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title stylePerformance Modelling: Component Maps 11 1 0.8 0.6 eff = 0.89 NR = 0.9 1 0.8 0.6 eff = 0.89 NR = 1.0 1 0.8 0.6 eff = 0.89 NR = 1.1 DP 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

12. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title stylePerformance Modelling: Component Maps 12 Compressor Pressure ratio, PR Mass flow rate, Wc Efficiency, eff Torque ratio, trqR BETA/ZETA Corrected speed, NcRdes Speed Ratio, NR Turbine Mass flow rate, Wc Efficiency, eff Torque ratio, trqR Surge PR (Wc, NR) PR min & PR max (NcRdes, NR)

13. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title stylePerformance Modelling: Component Models 13 Speed ratio NR = N1 / N2 Torque ratio trqR = trq1 / trq2 BETA NcRdes NR PR eff Wc trqR trq1 = f(pwr, NR, trqR, N1) Shaft-1 Shaft-2

14. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 14  INTRODUCTION  PERFORMANCE MODELLING o Simulation Environment o Mean Line Analysis o Component Maps o Component Model Development  APPLICATION EXAMPLE o Engine Performance o Mission Analysis o Sensitivity Analysis  SUMMARY & CONCLUSIONS Contents

15. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: GTCRC Model 15 Inlet Booster CR-HPC Burner CR-HPT Bypass Nozzle Gearbox Fan LPT Core Nozzle

16. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: Performance 16 ToCT/OCr Var.GTF & GTCRCGTFGTCRC % diffGTFGTCRC % diff W1 [kg/s]224.7535.10.22217.2-0.05 BPR [-]11.7012.76-0.0512.95-0.37 FAN PR [-]1.5471.4340.131.457-0.11 HPC PR [-]15.1015.16-0.7513.93-0.42 OPR [-]47.3537.270.3139.20-0.04 FN [kN]28.2100.10.4222.2-0.43 PARAMETERGTF & GTCRC ConditionT/OToCCr Altitude (m)010668 Mach Number0.250.78 ΔT ISA (K)15100 Comparison Between Model Predictions and NEWAC Specifications for GTCRC

17. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: OD Performance 17 Operating ModeThrust setting Time in operating mode [minutes] GTF FB [kg] GTCRC FB % diff Take-off100 % Foo0.738.12-0.16 Climb85 % Foo2.299.11-0.30 Approach30 % Foo4.059.17-2.39 Taxi/ground idle7 % Foo26.0120.09+0.39 316.49-0.42

18. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: Mission 18 PARAMETERVALUE TOW (t)79 Pax No150 Engines2 Wing Area (m 2 )115.3 Distance (km)1000 Cruise Altitude (m)10668 Cruise Mach No.0.78 Aircraft & Mission Parameters

19. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: Results 19  for this aircraft-mission combination and assuming same engine weight and drag, the fuel burn (FB) saving of GTCRC is 0.59% compared to GTF  a contra-rotating core could save up to 10% of engine weight. The engine dry weight for this thrust class is around two tonnes, so a 10% weight saving translates to 400 kg for two engines  if the same mission is executed with 400 kg less aircraft TOW (same payload), then a further 0.52% reduction in block FB is predicted for GTCRC. Hence, a total of 1.1% FB reduction is achieved compared to GTF  assuming a fixed aircraft TOW for a given mission and directly converting engine weight reduction to payload increase a 3.2% reduction in FB per 100Pkm can be achieved

20. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: Results 20

21. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleApplication Example: Sensitivity Study 21 -4% Wcl → -0.2% FB

22. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 22  INTRODUCTION  PERFORMANCE MODELLING o Simulation Environment o Mean Line Analysis o Component Maps o Component Model Development  APPLICATION EXAMPLE o Engine Performance o Mission Analysis o Sensitivity Analysis  SUMMARY & CONCLUSIONS Contents

23. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleSummary & Conclusions 23  a method of modelling contra-rotating components for engine performance calculations was presented  using suitably modified one-dimensional mean line codes for compressor and turbine, appropriate performance characteristics are generated that take into account the speed ratio between contra-rotating shafts  components are then developed that simulate the operation of contra- rotating compressors and turbines by integrating the corresponding maps  the model of a geared turbofan with contra-rotating core is created and used to execute a mission with a short range aircraft  compared to a similar configuration with a conventional core of identical design-point performance and engine weight, a fuel burn benefit of 0.59% is predicted due to off-design performance differences between the two models

24. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleSummary & Conclusions 24  assuming a contra-rotating core design can result in a 10% engine weight saving and this is used to reduce the aircraft take-off weight then a further 0.52% fuel burn reduction is possible compared to the conventional core model (total of 1.1%)  If the engine weight saving is used to increase payload then a total of 3.2% fuel burn reduction per 100 passenger kilometre can be achieved  a further benefit could have been predicted if a lower amount of turbine cooling flow was assumed for the CRC since there are reduced cooling and sealing requirements in this configuration as there is no stator between the two turbine rotors. This also means reduced friction losses (less wetted area) and improved HP turbine efficiency. However, it was decided not to implement this cooling flow reduction in order to have the same reference design point for both configurations.

25. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title styleSummary & Conclusions 25  mechanical complexity  increased windage losses between the outer rotor and compressor casing and between the discs, especially the turbine ones, due to higher relative velocities and more complex and turbulent vortex interactions between contra-rotating discs  mechanical design solutions are also required to enable starting (e.g. a brake on the outer rotor) and for sealing the front and real ends of the outer drum and around the bleed manifolds of the compressor.

26. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 26 THANK YOU Laboratory of Thermal Turbomachines National Technical University of Athens

27. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style 27

28. Modelling Contra-Rotating Turbomachinery Components For Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case Alexiou, Roumeliotis, Aretakis, Tsalavoutas, Mathioudakis Click to edit Master title style GTCRC Design Point Performance 28 ParameterCompressorTurbine PR15.14.22 eff0.9050.9 Wc17.962.37 NcRdes11 BETA/ZETA0.540.48 NR11 trqR1.281.30