An Introduction to Recent CFD Technique from CAD to Solver (CATIA-ICEM CFD-CFX 5.7)
BeomSeok KIM
Department of Mechanical Engineering, Graduate school of Korea Maritime University
The 2004 KIT-KNCT-KMU Lab. Joint SeminarKorea Maritime University, BUSAN30 July – 01 August, 2004
Procedure of General CFD AnalysisProcedure of General CFD Analysis
3D Modeling
Meshing
Solving
Design
Post-processing
CATIA, Solidworks, Pro-Engineer
Convergence problem?Coarse? – Quality check!!
Rough surface?
Modification?
3D Modeling CATIA, Solidworks, Pro-Engineer etc.
Meshing ICEM-CFD 5.0, Grid Pro, Hyper Mesh etc.
Solving CFX-5.7, CFX-TASCflow, Fluent, Star-CD etc.
Post-processing AVS, Ensight, Field View, Amira etc.
Procedure of General CFD AnalysisProcedure of General CFD Analysis
3D-Modeling for Flow Meter: CATIA V5 R13
Inlet Filter
Casing
Pivot Shaft
Bearing
Shaft Guide
Rotor
Guide Vain
Casing Cover
ICEM-CFDICEM-CFD
• ICEM: Integrated Computational Engineering and Manufacturing
- CFD VersionPre and Post Processor without Load, Constraint and Properties tabs. Includes Prism meshing. Write mesh for 100+ CFD solvers.
- FSICombination of FEA and CFD features
• Modernized and Integrated GUI• Wide CAD support• Mid-Plane Extractions/Extensions• Geometry Creation/Repair/Simplification
Ref. : The 2004 International ANSYS Conference, Pittsburg, USA
• Powerful Meshing tools
• Tetra from CAD, CAD and mesh, or mesh
• Shell meshing, patch dependent, patch independent, mapped, structured/unstructured
• Hex-dominant, unstructured hexa, structured hexa, extruded quads
• Advanced mesh editing
• Hexa Meshing Structured/Unstructured
• Boundary Conditions
• Output to 100+ Solvers
• Post processing
• Scriptable … and much more…
I-DEASI-DEAS
SolidWorksSolidWorks
Pro/EngineerPro/Engineer
UnigraphicsUnigraphics
Solid EdgeSolid Edge
CATIACATIA
• 3rd Party Cad• IGES• ACIS• Parasolid• DWG/DXF• GEMS
• Faceted Data• STL• VRML• NASTRAN, P
ATRAN, ANSYS, LS-DYNA
Wide CAD Support
Tetra Meshing
• Automatic Surface and Volume Meshing• Patch Independent• Surface mesh not required to generate volume mesh
• Surface mesh can be saved independently• Very tolerant of imperfect geometry
Tetra Meshing
• Most commercial Tet mesh generators• First generate a Tri surface mesh
• surface-by-surface• Every edge of every surface must be resolved
• sensitive to • sliver surfaces, • bad surface parameterization• surface connectivity (gaps)
• If the surface mesh is complete• volume mesh is generated from surface mesh Mesh detail
Tetra Meshing
• ICEM Tetra uses patch-independent, Octree method• Volume mesh
• generated independent of surface model• Mesh is projected to model surfaces, curves and
points• Surface mesh is created
• Resulting mesh is independent of the underlying arrangement of surfaces
Sliver ignored
Hexa Meshing
• High-powered hexahedral grid generation• Top-down or Bottom-up blocking approach• Allows rapid creation of complex topologies• Fast Iteration Cycle
• Elastic blocking can be fit to schematically similar geometry
• Replay Files for parametric geometry changes
• Prism layer • improve boundary layer resolution for
tetrahedral mesh• Hex and Tet zones joined by a pyramid layer
Hybrid Meshing
Mesh Generation – Flow Meter
• Inletpipe : 140,000 nodes• Outpipe : 100,000 nodes• Using Hybrid Mesh : Tetra - Prism• Complex Domain : Created by separately
Inletpipe
Outpipe
Prism Layer
Mesh Generation – Flow Meter
• Rotating Part : 510,000 nodes• Using Hybrid Mesh : Tetra - Prism• Complex Domain : Created by separately
Mesh Generation – Flow Meter
CFX-5.7CFX-5.7
• Advanced coupled multigrid linear solver technology • Unmatched meshing flexibility • Superb parallel efficiency • Excellent pre and post-processing capabilities • A wide range of physical models that interoperate with each other providing real answers to industrial problems
- Multiphase Flows - Bubbly Flows- Free Surface Flows- Particle Tracking- Mass Transfer : Cavitation, Boiling, Condensation, Evaporation
Ref. :http://www.cfxkorea.com
Boundary Conditions – Flow MeterInlet : 0.4444kg/sec.
Outlet : Pressure (Averaged at Whole Surface)
GGI Grid Surface matching : Frozen Rotor
GGI Grid Surface matching : Frozen Rotor
Rotating : 800 rpm
Grid Interface
=
=
• Non overlap regions are created if interface sides do not fit perfectly (this should be avoided where possible)• Completely overlapping integration point faces• Partly non-overlapping integration point faces• Complete non-overlapping integration point faces
• Slip walls are used at non-overlapping regions
Ref. :CFX-5.7 Basic Training Course, CFX-Korea
Compressor and Scroll
Combined Tet and Hex mesh
Interface Model : Frozen Rotor
Computation Results : Flow Meter
• 720,000 node
• Hybrid Mesh• Steady State/Frozen Rotor• RNG-KE/Water at 25• Rotating Speed: 800RPM• Mass Flow-rate: 0.444kg/s
• • Velocity vector at mid-sectionVelocity vector at mid-section
• • 3-D Clipping View 3-D Clipping View
• • Velocity vector at inlet pipe Velocity vector at inlet pipe • • Velocity vector at out pipe Velocity vector at out pipe
Computation Results : Flow Meter
• Calculated Torque at Rotating Blade : 0.0017592N M
• • StreamlinesStreamlines • • Surface pressureSurface pressure
Computation Results : Butterfly Valve• • Computational MeshComputational Mesh
• 98,000 nodes• Hybrid Mesh : Tetra-Prism• RNG-KE/Steady State• Approaching Velocity : 3m/s• Water at 25
InletInlet
OutletOutlet
SymmetrySymmetry
Computation Results : Butterfly Valve
• Pipe Length : 2m• Diameter : 0.4m• Axis Symmetric Flow Field• Open Angle : 45 deg.
• • Isometric ViewIsometric View
• • Surface PressureSurface Pressure
Computation Results : Butterfly Valve• • Stream Lines behind Valve PlateStream Lines behind Valve Plate • • Stream Lines from Inlet to OutletStream Lines from Inlet to Outlet
• • Velocity VectorVelocity Vector • • Surface PressureSurface Pressure
• Calculated Torque at V/V Plate : 30.4568 N M
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