strategy for turbine blade solid meshing using...
TRANSCRIPT
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
Strategy for Turbine Blade Solid
Meshing Using HyperMesh Oleg Rojkov
Siemens Industrial Turbomachinery AB
Turbine Mechanical Integrity Department
Abstract
The gas turbine development process has tendency for the time shortening of the whole development cycle.
The design phase takes the most of time and efforts involving several engineering disciplines in the process
and passing through several iterations. The analysis of the turbine components during design phase is based
on 3D models which can be rather sophisticated, like cooled blades and vanes. The FE 3D meshing process
becomes the compromise between the time of model creation, the model size and the quality taking into
account the specific requirements of different disciplines.
The Turbine Mechanical Integrity Department in Siemens Industrial Turbomachinary AB started to use
HyperMesh as the meshing tool in 2007. The experience of solid meshing in HyperMesh worked out a general
approach of cooled turbine blade model creation to satisfy both time restrictions and model quality, which can
be considered as the solid meshing strategy.
Page 2 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh
Contents
• Gas turbine design
• Cooled blade overview
• CAD formats used in SIT AB Finspång for importing to HyperMesh
• Requirements to the blade FE model
• Geometry and FE model structure
• Geometry cleaning and model meshing
• Blade root
• Cooling holes
• Blade core
• Airfoil, platform and shank
• Disc
• FE model modification
• Additional tasks after meshing
Page 3 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Gas Turbine Design
SGT-800B Gas Turbine
Page 4 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Gas Turbine Design
Compressor/Rotor Combustor Turbine
Core Engine Development
Design
Aerodynamics
Heat Transfer &
Secondary Air System
Mechanical Integrity
Hot gas parameters
Cooling air parameters
Project Team
• Project leader
• Aero
• Cooling
• Design
• MI
• Aero - Geometry of gas channel, 3D
distribution of gas parameters
• Cooling – Cooling scheme
• Design – 3D CAD model
• MI – 3D meshing
• Cooling – Conjugated hydralic/heat
transfer analysis
• MI – LCF, TMF, creep, oxidation,
frequency analyses
Cooled blade design process
Page 5 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Cooled Blade Overview
Blade with Multi-channel and Matrix
Page 6 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Cooled Blade Overview
Blade with Multi-channel and Matrix
Page 7 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Cooled Blade Overview
Blade with Film cooling and Matrix
Page 8 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Cooled Blade Overview
Blade with Film cooling and Matrix
Page 9 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. CAD Formats
CAD formats used in SIT AB
•NX
•VDA
•JT
• IGES (2D models only)
•Parasolid
Manual control of
cleanup tolerance
Page 10 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. FE Mesh Requirements
FE mesh requirements
•2nd order elements
•Fine mesh at known critical locations
•Keep fillets in blade core
•Mapped mesh with quad faces in contact areas of blade
attachment (recommendation from ABAQUS)
•Node to node connectivity of contact areas between blade
and disc (cooling group requirement)
•Controllable mesh density across and along film holes
•Mapped mesh in disc (preferable)
•Axial symmetry of FE mesh on disc segment cuts
(preferable)
•The same mesh for Cooling and MI analysis (preferable)
•Possibility of geometry modification
Page 11 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry and FE Model Structure
Partitioning the blade root
Geometrical components
Page 12 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Geometry cleaning
•Repair collapsed surfaces
•Remove cracks
•Suppress dummy edges
•Make additional trims
Release points
Stitch edges
Additional trims,
suppress edges
Page 13 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Partitioning root for mapped and free meshing
Offset lines of fir-tree contour
and simplify, if needed
Blade root
Trim back surface with
offset contour
Extrude (Drag) trimmed contour along root
and mutually intersect with all front surfaces
Page 14 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Volume for mapped meshing Tracks of disc contact surfaces
Partitioning root for mapped and free meshing
Page 15 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Finalizing volumes for mapped meshing
Some additional trims and partitions Only some trims of source surfaces for mapping
Page 16 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Shell mapped meshing
• Choose mapping directions
• Mesh contact surfaces and fillets
with quads and all smoothing
options switched off
• Mesh guiding surfaces with quads to
avoid mesh inconsistency between
volumes
Switch off smoothing
The main attention to contact surfaces
and transition fillets
Page 17 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Solid mapped meshing
4-teeth root mapped in several steps 2-teeth root, each side mapped in one step
Mainly, “General” method for solid
mapping was used
“One volume” method for solid
mapping was used
Page 18 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Transition from mapped to free mesh
Shell coating of mapped mesh inner side Split quads to trias
Page 19 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade root
Free solid meshing
• Mesh the rest of root surfaces with trias using free
and R-trias methods
• Check trias for free edges, quality (Jacobian and Min
angle), duplicates, penetration
• Repair bad trias if needed (Cleanup and Replace
methods)
• Mesh with tetras using “Tetra mesh” method and all
trias fixed
• Check tetras quality (Jacobian and Volume skew) to fit
ABAQUS quality requirements
• Repair bad tetras (mainly, Node edit->Align node)
Page 20 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Film holes
• Split holes at least in 2 surfaces in axial direction to
have mappable quad surfaces
• Mesh holes with R-trias and all smoothing options
switched off
Independent control of the mesh density in axial and
circular directions.
Page 21 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Blade core (inner channels)
The structured mesh of the core is preferable for cooling model because of the hydraulic net attaching
Mesh matrix and internal
cooling holes (R-trias)
Mesh surfaces near cooling
holes (R-trias)
Mesh long channels
(R-trias)
Mesh the rest of
surfaces with free trias
Page 22 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Airfoil, platform and shank
Shell meshing
• Fillets near blade root (R-trias)
• Sealing strips grooves (R-trias)
• Transition fillets of airfoil (R-trias)
• Shank (free or R-trias)
• Surfaces with cooling holes (free
mesh)
• Trailing edge and airfoil (R-trias)
• The rest of surfaces (free or R-trias)
Page 23 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Airfoil, platform and shank
Solid meshing
• Check free edges for inner, outer, cooling
holes and transition shells
• Check shells quality and repair, if needed
• Mesh with tetras using “Tetra mesh” method
and all trias fixed
• Check quality of tetras and repair, if needed
Page 24 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Disc Partitioning 4-teeth disc for mapped meshing
Tracks of blade root
contact surfaces
Page 25 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Disc Partitioning 2-teeth disc with air supply hole for mapped meshing
Page 26 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Disc
• Choose mapping directions
• Partition disc taking into account
axial symmetry and mesh density
transitions
• Mesh source mapping surfaces with
any method and guiding surfaces
with quads and smoothing options
turned off
• Mesh source surfaces of Spin
volumes with any method
Page 27 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Geometry Cleaning and Meshing
Disc
Solid mapping
• Map disc attachment and
transitions with General method
• Map the rest with Spin method
• Equivalence coincident nodes
Page 28 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Model Modification
Free mesh modification
• Delete tetra mesh of modified component
• Delete shell mesh on modified surfaces
• Insert new geometry
• Remesh modified surfaces and create tetra mesh
Example of inserting 3 holes in platform
Page 29 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Additional Tasks
Standard tasks in HyperMesh
• Creating contact groups
• Applying constraints or creating
node sets for constraints
Master surfaces of contact Slave surfaces of contact
Page 30 November 11
Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
RCTM Oleg Rojkov
Strategy for Turbine Blade Solid Meshing Using
HyperMesh. Additional Tasks
Non-standard tasks solved with external tools
• BIQUAD MPC or EQUATION to bind
diagonal nodes in transition from
tetra to mapped solids
• Two UNSORTED (“ordered” in
HyperMesh) node sets for axial
symmetry of disc used in EQUATION
• 3D layer of elements for TBC (thermal
barrier coating)
Merged nodes
Midside node on diagonal
Mesh with TBC layer TBC thickness distribution