developments in modern aero-engines to minimize the impact...
TRANSCRIPT
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Developments in Modern Aero-Engines to minimize the Impact of Bleed Air
Dr. Dieter Peitsch
Rolls-Royce Deutschland Ltd. & Co. KGDahlewitz, Germany
Contact: [email protected]
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Outline
Why is Customer Bleed Air an issue for theengine?
What can be done to minimize the impact onto the engine?
Engine PerformanceHardware Design (Compressor)Safety
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
AE2100 (6,000 shp)
Tay (14,000lb thrust)
BR715(18,500-22,000lb thrust)
RB211-535(43,000lb thrust)
RB211-524(60,000lb thrust)
Trent 700(72,000lb thrust)
Trent 800(95,000lb thrust)
BR710(14,750lb thrust)
V2500(25-33,000lb thrust)
Trent 900(80,000lb thrust)
Trent 500(56,000lb thrust)
Trent 600(65,000lb thrust)
Trent 8104(104,000lb thrust)
Rolls-Royce Civil engine range
AE3007 (7,000lb thrust)T800 (1,350 shp) FJ44 (2,000lb thrust)
RR DeutschlandModel 250 (600 shp)
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Bleed Air for Cabin Air Pressurization
Rolls-Royce Deutschland BR715 Core Engine
HPC
Bleed Air taken from High Pressure Compressor (HPC)
Low High
Two Offtakes to cover Pressure and Temperature Requirements of ECS over Operating Range
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Impact of Bleed Air on Engine PerformanceIncrease in Fuel Consumption
0
1
2
3 BypassRatio 9:1
Fuel Consumption Increase (%)
BypassRatio 5:1
BypassRatio 2:1
No Bypass
Bleed Air taken from engine (% of total circulating Air in Cabin)
40 100
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Impact of Bleed Air on Compressor DesignTwo Offtakes affect Compressor Design concerning:
Casing Stiffness / Tip Clearance / Load Path along Casing Compressor Stability
Low Pressure Stage High Pressure Stage
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Minimize Impact of Bleed Air - Compressor Offtake
Optimize Customer Bleed Offtakes in Compressors
Divorce Customer Bleed Offtake from any other Offtake, e.g. for Secondary Air System to avoid negative Impact onto Engine Safety in Case of Customer Bleed Pipe Rupture
Design Offtakes such, that Pressure Losses in the System are at a minimum level to achieve required Air Flows
Target: Move Offtake to the most upstream location possible to minimize negative effect on engine performance
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Optimization of Compressor Offtakes - ResearchInstitute for Jet Engines (ISA), University of the German Armed Forces, Munich`Simple` Wind Tunnel with Pre-Swirl Stator and flexible offtake configurations
Stator
Offtake
Distributor Channel
Offtake Slot
Stator
Offtake
Distributor Channel
Offtake Slot
Stator
Offtake
Distributor Channel
Offtake Slot
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Flow Visualization in Distributor Channel
Top Wall
Line of Attachment
Line of Detachment
Line of Attachment
Line of Detachment
BottomWall
ISA, Munich
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Derivation of Flow Model in Distributor Channel
Lines of Attachment
Lines of Detachment
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Mach Number Distribution in Offtake MaE
0.4780.4680.4570.4470.4370.4260.4160.4060.395
Direction of Swirl
Direction of Main Flow ISA, Munich
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Optimization of Compressor Offtakes - Research
Computational Fluid Dynamics to assess flow paths of air flowing from compressor annulus to customer bleedport
Multiple Configurations
Loss Assessment and Validation against Experiments
Y
Z
X
ISA, Munich
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Impact on Aircraft Safety AssessmentAny oil leaking from an engine, entering the aircraft customer bleed offtake, is classified as HAZARDOUS
Customer Bleed Offtake
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Minimize Impact of Bleed Air – Bearing Chamber
Ensure reliable Sealing of Bearing Chambers
Advanced Concepts and Technologies
Prediction Capabilities forAir and Oil System
Operation during transient Engine Manoeuvres
Replace Labyrinth Seals:Reduce sealing air req‘mentsReduce Number of PartsLess Design Complexity
Numerical Simulation:Reduce req`d safety marginsIncrease Accuracy for
Component Specification
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Bearing Chamber Sealing – Major Design ChangesOld Design (Labyrinths):Scavenge and Vent required
High Air Flow Requirements for Sealing
Deterioration of Seals
New Design (Carbons):Combined Scavenge-Vent
Less Complexity
Seal Deterioration at minimum Level
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Improve Transient Prediction Capabilities for Air and Oil System Performance
Simulation of Components using MATLAB/Simulink Software
Component Characteristics dependent on Engine Powersetting, e.g. Feed and ScavengePumps driven by Accessory GearboxMass Flows, Pressures and Temperatures
Prediction of Time-accurate behaviour crucial to predict and avoid Oil Leakage from the Bearing Chamber
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Result from Transient Calculation during acceleration and deceleration of the Engine
Time (s)
Delta Pressureacross air/oilseal
+
0
-
Acceleration Deceleration
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Avoid negative Pressure Difference by better Scavenge Pump
Delta Pressureacross air/oilseal
+
0
-
Increased Flow
Capacity of Pump
Time (s)
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Avoid Oil Leakage during Transients by Introduction of a new scavenge pump control conceptAir Mass Flow through carbon seal (kg/s)
Time (s)
© (Rolls-Royce Deutschland 2003)International Aviation Conference, October 2003, London
Finally, where is Aircraft Propulsion going to?
Thank You!