Strategy for Turbine Blade Solid Meshing Using HyperMesh

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Strategy for Turbine Blade Solid Meshing Using HyperMesh

  1. 1. Strategy for Turbine Blade SolidMeshing Using HyperMeshOleg RojkovSiemens Industrial Turbomachinery ABTurbine Mechanical Integrity DepartmentAbstractThe 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 processand passing through several iterations. The analysis of the turbine components during design phase is basedon 3D models which can be rather sophisticated, like cooled blades and vanes. The FE 3D meshing processbecomes the compromise between the time of model creation, the model size and the quality taking intoaccount the specific requirements of different disciplines.The Turbine Mechanical Integrity Department in Siemens Industrial Turbomachinary AB started to useHyperMesh as the meshing tool in 2007. The experience of solid meshing in HyperMesh worked out a generalapproach of cooled turbine blade model creation to satisfy both time restrictions and model quality, which canbe considered as the solid meshing strategy. Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.
  2. 2. Strategy for Turbine Blade Solid Meshing UsingHyperMesh 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 2 November 11 Oleg Rojkov RCTM
  3. 3. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Gas Turbine Design SGT-800B Gas Turbine Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 3 November 11 Oleg Rojkov RCTM
  4. 4. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Gas Turbine Design Core Engine Development Compressor/Rotor Combustor Turbine Hot gas parameters Cooling air parameters Design Aerodynamics Cooled blade design process Project Team Heat Transfer & • Aero - Geometry of gas channel, 3D Secondary Air System distribution of gas parameters • Project leader • Aero • Cooling – Cooling scheme Mechanical Integrity • Cooling • Design – 3D CAD model • Design • MI – 3D meshing • MI • Cooling – Conjugated hydralic/heat transfer analysis • MI – LCF, TMF, creep, oxidation, frequency analyses Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 4 November 11 Oleg Rojkov RCTM
  5. 5. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Cooled Blade Overview Blade with Multi-channel and Matrix Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 5 November 11 Oleg Rojkov RCTM
  6. 6. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Cooled Blade Overview Blade with Multi-channel and Matrix Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 6 November 11 Oleg Rojkov RCTM
  7. 7. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Cooled Blade Overview Blade with Film cooling and Matrix Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 7 November 11 Oleg Rojkov RCTM
  8. 8. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Cooled Blade Overview Blade with Film cooling and Matrix Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 8 November 11 Oleg Rojkov RCTM
  9. 9. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. CAD Formats CAD formats used in SIT AB • NX • VDA • JT • IGES (2D models only) • Parasolid Manual control of cleanup tolerance Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 9 November 11 Oleg Rojkov RCTM
  10. 10. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. FE Mesh RequirementsFE 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 10 November 11 Oleg Rojkov RCTM
  11. 11. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry and FE Model Structure Partitioning the blade root Geometrical components Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 11 November 11 Oleg Rojkov RCTM
  12. 12. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and MeshingGeometry cleaning• Repair collapsed surfaces• Remove cracks Release points• Suppress dummy edges• Make additional trims Stitch edges Additional trims, suppress edges Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 12 November 11 Oleg Rojkov RCTM
  13. 13. Strategy for Turbine Blade Solid Meshing Using HyperMesh. Geometry Cleaning and Meshing Blade root Partitioning root for mapped and free meshingOffset lines of fir-tree contour Trim back surface with Extrude (Drag) trimmed contour along rootand simplify, if needed offset contour and mutually intersect with all front surfaces Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 13 November 11 Oleg Rojkov RCTM
  14. 14. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Blade root Partitioning root for mapped and free meshing Volume for mapped meshing Tracks of disc contact surfaces Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 14 November 11 Oleg Rojkov RCTM
  15. 15. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Blade root Finalizing volumes for mapped meshing Some additional trims and partitions Only some trims of source surfaces for mapping Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 15 November 11 Oleg Rojkov RCTM
  16. 16. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Blade root Shell mapped meshing Switch off smoothing The main attention to contact surfaces and transition fillets • 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 16 November 11 Oleg Rojkov RCTM
  17. 17. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. 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 “One volume” method for solid mapping was used mapping was used Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 17 November 11 Oleg Rojkov RCTM
  18. 18. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Blade root Transition from mapped to free mesh Shell coating of mapped mesh inner side Split quads to trias Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 18 November 11 Oleg Rojkov RCTM
  19. 19. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. 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) Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 19 November 11 Oleg Rojkov RCTM
  20. 20. Strategy for Turbine Blade Solid Meshing Using HyperMesh. Geometry Cleaning and Meshing Film holesIndependent control of the mesh density in axial andcircular directions.• 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 20 November 11 Oleg Rojkov RCTM
  21. 21. 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 attachingMesh matrix and internal Mesh surfaces near cooling Mesh long channels Mesh the rest ofcooling holes (R-trias) holes (R-trias) (R-trias) surfaces with free trias Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 21 November 11 Oleg Rojkov RCTM
  22. 22. Strategy for Turbine Blade Solid Meshing Using HyperMesh. Geometry Cleaning and Meshing Airfoil, platform and shankShell 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) Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 22 November 11 Oleg Rojkov RCTM
  23. 23. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 23 November 11 Oleg Rojkov RCTM
  24. 24. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Disc Partitioning 4-teeth disc for mapped meshing Tracks of blade root contact surfaces Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 24 November 11 Oleg Rojkov RCTM
  25. 25. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Geometry Cleaning and Meshing Disc Partitioning 2-teeth disc with air supply hole for mapped meshing Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 25 November 11 Oleg Rojkov RCTM
  26. 26. 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 26 November 11 Oleg Rojkov RCTM
  27. 27. Strategy for Turbine Blade Solid Meshing Using HyperMesh. Geometry Cleaning and Meshing DiscSolid mapping• Map disc attachment and transitions with General method• Map the rest with Spin method• Equivalence coincident nodes Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved. Page 27 November 11 Oleg Rojkov RCTM
  28. 28. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 28 November 11 Oleg Rojkov RCTM
  29. 29. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. 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 Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 29 November 11 Oleg Rojkov RCTM
  30. 30. Strategy for Turbine Blade Solid Meshing UsingHyperMesh. Additional Tasks Non-standard tasks solved with external tools• BIQUAD MPC or EQUATION to bind Midside node on diagonal diagonal nodes in transition from tetra to mapped solids• Two UNSORTED (“ordered” in HyperMesh) node sets for axial Merged nodes symmetry of disc used in EQUATION• 3D layer of elements for TBC (thermal barrier coating) Mesh with TBC layer TBC thickness distribution Copyright © Siemens Industrial Turbomachinery AB 2007. All rights reserved.Page 30 November 11 Oleg Rojkov RCTM

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