European Workshop on New Aero Engine Concepts Munich, 30 June – 1 July 2010 Numerical simulation of blade / casing rub interaction NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme (2002-2006) under Thematic Priority 4 Aeronautics and Space. Olivier Beaupain, Techspace-Aero PP Jeunechamps, JP Ponthot University of Liège, Belgium
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European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Numerical simulation of blade / casing rub interaction
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
Olivier Beaupain, Techspace-AeroPP Jeunechamps, JP Ponthot University of Liège, Belgium
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
2
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Technical approach : Overview
• Original numerical wear method• Validation of wear method on Sulzer rub test• Finite element simulation of a blisk test
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
3
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Original numerical wear method : framework
• Framework to numerically describe wear process:
No new global Degrees Of Freedom into the system
Focus on the blade/casing geometrical interaction (not on the local abradable behavior)
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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abradable behavior)
Define a wear profile on the contact tool (constant during any time step)
Use of constant wear profile to compute contact forces and achieve iterative equilibrium
Update wear at the end of the step (post processing operation)
⇒ Increase of CPU cost remains under control
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Original numerical wear method : Definition of wear surface
Abradable contact surface feature:- Must consist of 1 or several contact surfaces- Contact surface limited by a 4-lines wire- Contact surface can be a plane, a ruled surface, a
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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- Contact surface can be a plane, a ruled surface, a Coons, a revolution surface…
Meshed abradable contact surface
4 lines wire
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Original numerical wear method: definition of wear surface
Meshing of contact side:Transfinite meshWear cells = Quads (bilinear Coons)
Wear points:ξ, η in side isoparametric spaceInitial and final wear stored at each wear point
Contact side for wear
Blade topWear cell
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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wear pointCorrection of penetration of blade in abradable (≡ Gap) by interpolation inside each wear cellGeometrical wear law used:
newWear = α(gap - oldWear)α = wear parameter to be identifiedgap = penetration of blade in abradable, function of contact pressure.
eta
ksi
Meshed contact side in isoparametric space
Wear point
Wear cell
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Original numerical wear method : Detection of wearedpoints
• Detecting all active contact nodes at times tand t+∆t )
• Searching for every active “blade contact Edge” (edge of blade FEM mesh for which nodes are in contact at time t and t+ ∆t).
X,Y,Z space
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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• Defining a “wear quad” including all wear points to be weared between t and t+ ∆t
•For each wear point:• Compute if wear point is inside the wear quad• Compute local coordinate (ksi,eta) in wear quad space• Evaluate gap by bilinear interpolation• Update wear
eta
ksi
Blade edge at t Blade edge at t+ ∆t
Wear isoparametric space
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Original numerical wear method : Simple pin test application
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
8
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Validation on Sulzer rub test : Description of test
• Experimental data:• Rotation Speed : 3800RPM corresponding to tip speed of 200m/s• Incursion rate : 0.05mm/s• Incursion depth: 1mm
• Numerical model:
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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• Numerical model:• 2268 finite elements• Elastic-plastic model for blade behavior• Wear model parameters:
• CPU cost: between 1 and 2 days for 100 revolutions
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Validation on Sulzer rub test : correlation test
• Contact periodicity:• Experimental: essentially contact at every revolution (sometimes after 2 revolution)• Finite element: contact at every revolution (bright
Experimental Finite element
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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every revolution (bright blue lines correspond to top tours)
• Blade vibration modes OK
1st mode 2rd mode 3th mode 4th mode
Experimental 200Hz 900Hz 1150Hz 2300Hz
Finite element 250Hz 850Hz 1200Hz 1900Hz
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Validation on Sulzer rub test : onset of divergence for some wear parameters values, change in frequency modes
2 revolutionsbefore divergence
Beginningof divergence
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
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Divergence 2 revolutionsafter divergence
New frequenciesappear
Important bending of blade
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
– 25 elements along height– 22 elements along width– 2 elements along thickness
• Other blades:
Simulation of blisk test Overlength blade
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
• Other blades:– 8 elements along height– 11 elements along width– 2 elements along thickness
• Blisk imposed rotation at the some nodes• Initial unbalancing by applying a concentrated
mass of 29.4g.cm• Incompatible mesh between blades and blisk ⇒
sticking contact considered (tied interface)• Casing geometry: Revolution surface
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
y (mm) z (mm) Orientation (°)
SG1 208.7 21.2 90
SG2 222.7 17.3 -45
SG3 217.3 10.0 90
SG4 216.3 26.6 45
y
Simulation of blisk test : Strain gauges position
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Simulation of blisk test : Evolution of wear footprint
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Simulation of blisk test : Evolution of contact forces between overlength blade and casing ⇒⇒⇒⇒ irregular contact forces (bright blue lines corresponding to top tours)
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.
European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010
Conclusions and future work
• New numerical model able to accurately describe blade / casing interaction and able to describe the onset of divergence
• Wear model: only one simple wear model is implemented (geometry based). More sophisticated material models for abradable can be implemented but these models require relevant physical experiments to identify wear constitutive model parameters
NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.