1. Project COMP10: Designing for Blade Aeromechanical Integrity
TURBO POWER Program Conference 2014
Project COMP10: Designing for Blade Aeromechanical Integrity 

2. Aeromechanical integrity
What we want
What we don’t want
The mission:
To prevent blade failure due to high-cycle fatigue (HCF)
The consequences of a blade failure are extremely costly!

3. Designing a blade Aerodynamic performance Mechanical integrity
Aeromechanical
integrity
Forced vibrations
Flutter (instability)

4. Aeromechanical Vibrations
Rotor-stator interactions  Dynamic excitation
Aerodynamic coupling & damping
Mechanical damping  Material  Contact friction
Dissipative  Damped
Neutral  Limit-cycle
Unstable  Flutter!

5. unsafe Blade vibratory response sensitivity and uncertainty
 Variability in excitation, damping, geometry, etc...
Vibratory stresses and high cycle fatigue
Need small models (ROMs) for probabilistics!
107 cycles
unsafe
safe
HCF  Haigh Diagram

6. Industrial example: Burner can hot streak excitation
Estimated inlet temperature profile
Circumferential direction
Circumferential-axial temperature variation

7. Industrial example: Burner can hot streak excitation
Predicted vibratory stresses and HCF risk
Predicted excitation forces on airfoil
Predicted friction damping in shroud interlock

8. Challenging uncertainties…
Manufacturing tolerances
Inlet temperature distribution estimation
Tip leakage effects
Computational mesh sensitivity
Aerodynamic scaling effects
Mixing-out of hot streak
Blade temperature distribution
Shroud contact conditions – point, line, or surface?
Contact force
Friction coefficient
Eigenfrequency / resonant speed variations
Stress concentration capture
HCF material data
Etc…
In brief: We need this COMP10 project!

9. After design predictions… Reality!
Rapid answers at prototype test
Strain gauges
Tip timing
Site operation and monitoring
Tip timing

10. Challenges during strain gauge testing
Large number of measurement points
Different blade rows
Mistuning effects
Account for different mode shapes
How to quickly analyze the data to identify critical conditions during test?
~ 60 gauges simultaneously
VIBMON tool
Mode identification (resonant frequency and MAC)
Maximum measured gauge (most reliable) vs. alarm levels in any blade of same row
Rapid evaluation & overview

11. Blade health monitoring by tip timing
Delayed
Undesired event – accident!
Interrupted operation
In time
Reduced maintenance costs
Increased availability
Crack
Tip-timing
measurements
Blade tip arriving time  blade tip amplitude, resonance frequency, damping
Crack initiation area
Modified resonance frequency, vibration amplitude, and damping due to breathing crack

12. After design predictions… Reality!
Rapid answers at prototype test
Strain gauges
Tip timing
For both strain gauge and tip timing
measurement techniques, robust
numerical models are crucial for
successful vibration measurement
setup and data evaluation
Site operation and monitoring
Tip timing

13. One overall COMP10 goal is to enable aeromechanically an engine efficiency increase of at least 0.4% by 2015
Dh +0.4%
COMP10

14. Implications on aeromechanical integrity
Max efficiency  fuel usage, pollution
Flex operation  eco-cycles, bio-fuels
Low weight  fuel usage, pollution
Low cost  competitiveness
Novel aggressive designs
Reduced turbine cooling
Blade environment chemistry
Working media characteristics
Combustor hot/cold streaks
Fewer & more loaded blades
Low damped integral solutions
Composite materials
Fewer & more loaded blades
Lower-grade materials

15. Aeromechanical Prediction Robustness
The strive towards more eco-friendly turbomachine-based energy and transport solutions require significant leaps in technology and design
Qualifying new technologies and design solutions mandates robust early-stage predictions of aeromechanical behavior
Robust blade vibration predictions require a multi-disciplinary synthesis tool that…
is general enough to allow expansions into new design regimes
offers a suitable accuracy vs. computational efficiency balance
can account efficiently for design parameter variability towards systematic and probabilistic aeromechanical integrity assessments
The mission of project COMP10

16. COMP10 History & Future Phase III 2016 – … Phase I 2008-2011 Phase II
AROMA III
Innovative concepts for
sustainable engines
Phase I
AROMA I:
Proof of concept
Integrated HCF
prediction tool
Phase II
AROMA II:
Industry-level ROM
Validated industrial
HCF prediction chain
Uncertainty quantification
I will start with the history of AROMA

17. WP2 Aerodynamic Damping and Forcing
COMP10
WP2
WP3
WP4 X
WP1 Synthesis
WP3 Structural Damping
WP2 Aerodynamic Damping and Forcing
WP4 HCF Life