ICEM CFD/AI*Environment 5.0 Hexa Workshop 2 3D Pipe Junction

ICEM CFD/AI*Environment 5.0

Hexa Workshop 2

3D Pipe Junction

6/18/04

Workshop

ANSYS ICEM CFD / AI*Environment 5.0Inventory #002090

C3-WS-2

Import Geometry

• Select File > New Project

– Create New folder, relabel as “Pipes”

– Type in project File name (any name)

– Select Save

• Select File > Import Geometry > ParaSolid

– Browse to 3DPipeJunct

– Select pipes.x_t and select Open

• Move the geometry on the screen (only curves are displayed by default)

– Left mouse button – 3D screen rotate

– Middle mouse button – Translate

– Right mouse button – left/right 2D screen rotate; up/down zoom in/out

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Workshop


C3-WS-3

Check the Geometry Topology

–Select Geometry > Repair Geometry > Build Diagnostic Topology

– Automatically extracts curves/points from surface (or imported solid) data

– Use default Tolerance (0.003)

• Automatically calculated from minimum edge length of geometry

• Adjust as necessary to produce desired results

• Reload original tetin (geometry) file if results are unsatisfactory

– Enable Filter points and Filter curves

• Removes unnecessary curves/points

– Based on feature angle (only hard features needed to be captured)

– Duplicates within tolerance

– Apply

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C3-WS-4

Set Up Parts for Curves and Points

– Right-click on Geometry > Curves in the model tree

– Curves are automatically displayed with Color by Count

• Color coding to view potential geometry problems

• Red curves = double edge (curve connected to two adjacent surfaces)

• Yellow curves = single edge (curve connected to only one surface – single edge) usually indicates gap or hole in geometry

• Blue curves = multiple edge (curve shared by three or more surfaces) usually indicates junction or sliver surface (edges of surface within tolerance)

• Green curves = unattached (not logically associated to geometry)

• Turn off the Color by Count

• Expand the Parts branch in the Model tree

– Note that the displayed curves are now colored by part – PS_EDGE (for any original curves) and PS_FACE (for any newly created curves extracted from surface)

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C3-WS-5

Set Up Parts for Surfaces

–Turn on Geometry > Surfaces in the model tree

–Right-click on Parts in the tree and select Create Part

–Enter INLET as the Part name

–Select Create Part by Selection

• Select (left-click) the surface at the free end of the large cylinder and middle-click to accept, then right-click to cancel selection for the part

–Repeat for other parts shown

INLET

OUTLET

PIPES

ROD

SYMM

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C3-WS-6

Clean up Parts, Create a Body, Save the Project

• Right-click on Parts in the tree and select Delete Empty Parts and Good Colors

• Select Geometry > Create Body

– Enter FLUID_MATL as the Part

– Click on Material Point

– Select 2 screen locations as shown

– Right click to exit operation

– Turn on Geometry > Bodies in model tree

– Rotate the geometry on the screen to ensure the material point is inside the region to mesh – inside the main cylinders and outside the rod

• Right-click on Parts in the tree and select Good Colors

• Select File > Save Project

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C3-WS-7

Initialize Blocking

Begin Blocking

– Blocking -> Create Block -> Initialize Blocks

– Change Part to LIVE

– Type = 3D

– Select Entities

– Select “a” for all or “all entities” from Select geometry bar

– Initial block will encompass all entities (entire geometry)

– Display the surface as Solid & Wire and Transparent (right-click on Surfaces in the model tree)

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C3-WS-8

Split to Create Topology

Underlying topology is “L” shaped

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Split blocks

– Select Split Block > Split Block

• Left click on the edge to split

• The new edge will be normal to the edge that you select

• Hold left mouse button and drag the split to desired location

• Middle mouse to complete or Apply

• One vertical and one horizontal split as shown

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C3-WS-9

Deleting Blocks

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– Select Delete Block

– Select upper corner blocks as shown

– Apply or middle mouse

– Two more splits and delete blocks as shown

– To carve out small cylinder

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C3-WS-10

Associate Blocking to Geometry

Associate edges to curves

– Turn on Curves in Model tree > Geometry

– Select Association > Associate Edge to Curve

– Select the five edges around the free end of the large cylinder (INLET side) and middle mouse

• Edges will highlight in red

– Select the underlying curve (half arc) and middle mouse or Apply

• Curve will highlight in white

– The selected edges turn green indicating they are associated (constrained) to a curve

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C3-WS-11

Associate Edges

–Continue associating blocking edges to geometry curves as shown

–Right mouse when finished to exit operation

–Right mouse select Blocking > Edges and select Show association

• This shows arrows from each block corner (vertex) and edge to the associated geometry

• White edges are associated to the closest surface by default

–Correct any mis-associations by re-associating (no need to undo).

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C3-WS-12

Move Vertices onto Geometry

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Project/Move vertices

– Select Associate > Project Vertices

• Automatically snaps vertices to nearest position on geometry

• Green vertices will snap to associated curves

• Won’t always move to desired location!

– Select Move Vertex > Move Vertex

– Left click, hold, and drag the vertex to desired location

• Make sure to move corner vertices to curve ends

• Middle click when finished moving all vertices

– Right mouse key will undo previous movement; NOT exit the function

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C3-WS-13

Split Blocks

–Right mouse select Blocking and select Index Control

–Toggle in I row up one in Min and down two in Max columns (set Min to 2, Max to 3)

• To turn off side blocks

–Split Blocks as shown

• Just outside of ROD geometry

• Perpendicular to cylinder direction

–Select Index Control > Reset

• Split only propagates through visible blocks

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C3-WS-14

Align Vertices for Rod

–Select Move Vertex > Align Vertices

–Select one of the edges running the length of the rod and a vertex at the top of the rod

–Set Move in plane to XZ

–Apply

• Note how bottom vertices line up with top in Y direction

–File > Blocking > Save Blocking As

• Enter filename (different than previous!)

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C3-WS-15

Create Ogrid

Create O-grid

– Select Split Block > Ogrid Block

– Select Faces as shown

• All faces on flat portions of the geometry (SYMM, INLET OUTLET faces)

• Selecting the face will also select the adjacent blocks

• Cluttered screen? Use F9 to toggle to dynamic mode, reorient model for better view, F9 again to toggle back to selection mode.

– Middle mouse and Apply

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C3-WS-16

Create Ogrid

• Set Index Control as shown– Isolate block around ROD

• Select Split Block > Ogrid

• Select faces at both ends of ROD

• Apply

• File > Blocking > Save Blocking As

– Enter block file name (different than previous)

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C3-WS-17

Associate Edges

• Set Index Control to limits as shown

• Select Associate > Associate Edge to Curve

• Select the four edges (thin arrows) at one end of the rod to associate to the nearest two curves as a composite curve (wide arrows)

– Two curves will automatically be grouped as one

• Repeat for other end

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C3-WS-18

Hex Mesh Blocking – “Delete” Blocks, Move Vertices

–Select Delete Block and click ‘v’ on the keyboard for visible

–Right-mouse to exit selection

–Select Associate > Project Vertices

– Apply

• The vertices move to the closest associated geometry location

–Select Index Control > Reset

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C3-WS-19

Set Mesh Sizes

Set mesh sizes on surfaces

– Select Mesh > Set Surface Mesh Size

– Type “a” for all or select Select all appropriate icon from selection bar

– Toggle on CUBE and SPHERE families

– Set Maximum element size = 0.2

– Display surfaces with Hexa Sizes

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C3-WS-20

Compute/View Mesh

Compute mesh

– Turn on Blocking > Pre-Mesh in model tree

• Select Yes when prompted to re-compute

• Default will be to Project Faces (can change by right clicking on Pre_Mesh)

• Turn off Geometry and Blocking > Edges and review surface mesh

• Toggle on/off certain parts

– e.g. turn off PIPES to look at ROD/SYMM mesh

– Can also toggle on Solid (right mouse click on Pre-Mesh)

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C3-WS-21

Reset edge distributions

Change edge distribution

– Select Update Sizes > Edge Params

• Select one of the radial edges

• Change number of nodes to around 6 and set Spacing 1 to 0.01

• Bias nodes close to the wall (PIPES)

• Recompute mesh (simply click on Pre-mesh)

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C3-WS-22

Checking Quality

Checking Quality

– Select Pre-Mesh Quality

– Change Criterion to Determinant 2x2x2

– Select Replot

– Enter a small Max Y height value so that you can see the smallest bars at the left, e.g. 20

– Accept

– Click on the farthest left bar, and the elements in this range will show

– Change Criterion to Angle and repeat

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C3-WS-23

Write Mesh to Solver

–Convert to unstructured mesh

• Right select Pre-Mesh > Convert to Unstruct Mesh

–Select Output > Select Solver

• Select solver from list

–Select Write input

• Select Yes when prompted to save project

–Set the Output file to ./pipes_hex_cfx5.dat

–Select Done (accept defaults)

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Documents

ICEM CFD/AI*Environment 5.0 Hexa Workshop 2 3D Pipe Junction