Helicopter Engine Optimization for Minimum Mission Fuel Burn

1. Helicopter Engine Optimization for Minimum Mission Fuel Burn Alexiou, Pons, Cobas, Mathioudakis & Aretakis Laboratory of Thermal Turbomachines National Technical University of Athens

2. Acknowledgements Collaborative & Robust Engineering using Simulation Capability Enabling Next Design Optimisation

3. Contents • INTRODUCTION • MODELLING ASPECTS • Simulation Environment • Engine Performance Model • Helicopter Performance Model • Mission Analysis • OPTIMIZATION METHODOLOGY • RESULTS • SUMMARY & CONCLUSIONS

4. Introduction Fuel Impact On Operating Costs (http://www.iata.org/pressroom/facts_figures/fact_sheets/pages/fuel.aspx)

5. Introduction Global Man-Made CO2 Emissions (ACARE Beyond Vision 2020)

6. Introduction Helicopter Uses

7. Introduction • Before this Work • Trajectory optimization of helicopter for minimum mission fuel burn • Objective of this work • To develop a generic methodology suitable for the preliminary engine design phase of optimizing a helicopter engine for minimum mission fuel burn • Requirements • Helicopter and engine performance models • Mission analysis capability

8. Contents • INTRODUCTION • MODELLING ASPECTS • Simulation Environment • Engine Performance Model • Helicopter Performance Model • Mission Analysis • OPTIMIZATION METHODOLOGY • RESULTS • SUMMARY & CONCLUSIONS

9. Simulation Platform PROOSIS (PRopulsion Object-Oriented SImulation Software) • Object-Oriented • Steady State • Transient • Mixed-Fidelity • Multi-Disciplinary • Distributed • Multi-point Design • Off-Design • Test Analysis • Diagnostics • Sensitivity • Optimisation • Deck Generation

10. Simulation Platform • TURBO library of gas turbine components • Industry-accepted performance modelling techniques • Respects international standards in nomenclature, interface & OO programming

11. Engine Performance Take-off power rating (design point) at sea-level standard conditions

12. Engine Performance

13. Helicopter Performance • Total helicopter power • Main rotor power • Induced • Profile • Fuselage • Potential energy change • Tail rotor power • Customer power extraction • Gearbox power losses

14. Helicopter Performance

15. Helicopter Performance MTOW / SL / STD SR = Vx / Wfuel

16. Oil & Gas • SAR 1800 1600 1400 1200 1000 Altitude [m] 800 600 400 200 0 0 10 20 30 40 50 -200 Time (min) Mission Fuel Calculation Mission definition H/C Specification e.g. velocity, time for each segment • Take-Off weight • air bleed/power off-take 2 Air Intake losses Exhaust losses 1 H/C PERFORMANCE MODEL MISSION PROFILE H/C operating conditions 3 H/C new weight 4 6 7 ENGINE PERFORMANCE MODEL H/C requirements (power, air cabin off take, Nrotor) Fuel Flow Rate 5 Mission Fuel

17. Mission Definition Cruise with Vbr for 400 km Descent with 12.5 m/s Climb to 1000m with Vbe & Vz,max

18. Contents • INTRODUCTION • MODELLING ASPECTS • Simulation Environment • Engine Performance Model • Helicopter Performance Model • Mission Analysis • OPTIMIZATION METHODOLOGY • RESULTS • SUMMARY & CONCLUSIONS

19. Optimization Methodology -30% < W2 < 30%, -30% < P22Q2 < 50% -20% < P3Q24 < 100% Optimization parameters & their range Assumed variation of compressor & turbine efficiency and engine weight with change in W2 Variation of turbine cooling flows with Tt41

20. Optimization Calculation: Flow Chart Establish baseline engine design and helicopter mission

21. Contents • INTRODUCTION • MODELLING ASPECTS • Simulation Environment • Engine Performance Model • Helicopter Performance Model • Mission Analysis • OPTIMIZATION METHODOLOGY • RESULTS • SUMMARY & CONCLUSIONS

22. Mission fuel burn optimization results

23. ΔSFC & ΔW2 vs ΔP3Q24

24. Mission fuel burn optimization results

25. Engine parameters for optimized cycle

26. Mission parameters for optimized cycle

27. Contents • INTRODUCTION • MODELLING ASPECTS • Simulation Environment • Engine Performance Model • Helicopter Performance Model • Mission Analysis • OPTIMIZATION METHODOLOGY • RESULTS • SUMMARY & CONCLUSIONS

28. Summary & Conclusions • A procedure has been proposed that allows the designer to optimize the engine cycle for minimum fuel burn of a helicopter mission. The approach takes into account changes in the turbomachinery component efficiencies and engine weight due to engine inlet flow rate changes. Limits are imposed for turbine rotor inlet temperature, surge margin and pressure ratio. Turbine cooling/sealing flows are established according to the turbine rotor inlet temperature. • For the specific engine-helicopter-mission combination, the total fuel burn benefit ranged from 5.8% to 9.4%, depending on the maximum value of turbine rotor inlet temperature that can be tolerated. • The proposed approach is generic allowing the optimization of the engine as well as the helicopter for different combinations of engines and helicopters and different missions or combinations of missions and according to the objectives and limitations set by the designer.

29. THANK YOU Laboratory of Thermal Turbomachines National Technical University of Athens