Project COMP10: Designing for Blade Aeromechanical Integrity TURBO POWER Program Conference 2014 Project COMP10: Designing for Blade Aeromechanical Integrity  2014-04-09

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!

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

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

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

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

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

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!

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

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

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

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

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

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

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

COMP10 History & Future Phase III 2016 – … Phase I 2008-2011 Phase II AROMA III Innovative concepts for sustainable engines Phase I 2008-2011 AROMA I: Proof of concept Integrated HCF prediction tool Phase II 2012-2015 AROMA II: Industry-level ROM Validated industrial HCF prediction chain Uncertainty quantification I will start with the history of AROMA

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