Icepak-Intro_14.5_L07_Meshing-non-conformal-HD

• • • • Other N/C assemblies Thin conducting Plate type Network blocks Network Objects
• Use the Macro Automatic Case Check Tool to detect teometric Scales in Electronics Systems
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Packages (microns)
Wirebonds, traces, solder balls and bumps substrates, vias, die, and mold
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Board (cm)
Power, ground, and signal planes, through holes, packages, mounting holes, and the board itself
• Note: creation of an assembly does not automatically enable separate meshing; the “Mesh separately” field must be checked on • N/C assemblies are colored in purple in the graphic display, and also in the model tree
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© 2012 ANSYS, Inc.
December 5, 2012
Release 14.5
Assembly Rules: Assembly-assembly intersections
• Multiple assemblies can be Non-Conformal assemblies provided the bounding boxes of the assemblies: do not intersect (overlap) • Use the Macro Automatic Case Check Tool to detect the assembly-assembly intersections.
Select default Mesh Type
Toggle on Mesh separately, Toggle on Mesh assemblies separately and Allow different subgrid types
5 © 2012 ANSYS, Inc. December 5, 2012
Thermal/Fluid performance related to all scales
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© 2012 ANSYS, Inc.
December 5, 2012
Release 14.5
Non-Conformal Meshing - Interface
• Non-Conformal Meshing
• Non-Conformal Meshing • Mesher-HD
• Multi-Level Meshing
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© 2012 ANSYS, Inc.
December 5, 2012
Release 14.5
Motivation for Non-Conformal Meshing
Scale Disparity:
• Mesh in Separately Meshed Non-conformal (N/C) assemblies can be isolated from the outer mesh • Hexa (unstructured and cartesian) and Hex Dominant can all be mixed
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© 2012 ANSYS, Inc.
December 5, 2012
Release 14.5
Zero-Slack Assembly
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No mesh bleeding at assembly boundaries
Assembly Boundary
8 © 2012 ANSYS, Inc. December 5, 2012 Release 14.5
Lecture 6 Non-Conformal, Mesher-HD and Multi-Level Meshing 14.5 Release
Introduction to ANSYS Icepak
1 © 2011 ANSYS, Inc. December 5, 2012
Chapter Contents
Object is not part of the assembly. Hence it is not allowed to be completely inside assembly bounds. Either the slacks need to be adjusted, or the objects included within the assembly. Orphaned object -Not allowed
• Default bounding box is sized to the min/max extents of the objects within. • Adding slack region propagates the finer mesh within by the indicated distance useful with heat sinks and natural convection • The orange MinX, MinY, etc buttons can be used as snap tools to align slack values to existing objects
Zero-Slack Assembly
• Zero Slack Recommendations
• It is recommended that the boundary box not touch a CAD object except when the CAD surface is located on the boundary of the computational domain. • If slack values are defined as zero, ensure the assembly boundary does not touch 2D objects like fans, openings, grilles, conducting thin plates etc. or touch the sides of blocks with specified properties. • If radiation for a side is specified, it is essential that the side does not touch the interface of the assembly with zero slack. • If the cabinet type is set as NONE and if there is a symmetry wall at the boundary, then the non-conformal interface can't touch the boundary wall.
Select the Mesh type for sub-region
Release 14.5
Slack input for an Assembly
• Slack Settings:
• Turn on the option to “Mesh separately ” under Meshing • Add a “slack” region around the assembly
Note: Although Zero slack is allowed in Icepak, using slacks are recommended if possible to avoid interface problem in Fluent.
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© 2012 ANSYS, Inc.
December 5, 2012
Mesh in Assembly
NC interface
Mesh in Main Model
Non-conformal Interface
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© 2012 ANSYS, Inc.
December 5, 2012
Release 14.5
Meshing: Meshing Assemblies Separately
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Systems (m)
Packages, boards, vents, heat sinks, fans/blowers, chassis, enclosures
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Environment (10 x m or larger)
Closets, rooms, and the ambient
• Accuracy Requires Adequate Resolution
10 © 2012 ANSYS, Inc. December 5, 2012
slack
Assembly Objects
slack
Release 14.5
Assembly Rules: NC assemblies Intersection
• Sides of a N/C assembly can intersect any object type or shape • Exceptions:
Release 14.5
Assembly Rules: Orphan Objects
• An object that does not belong to the assembly CANNOT lie completely within the N/C assembly bounding box • Use the Macro Automatic Case Check Tool to detect Orphan objects.