1. Chapter 6 Introduction to Hexa – Workshop 2 3D Pipe Junction
ICEM CFD Introductory Course

2. 3D Pipe Junction 3D Pipe Junction
In this workshop contains 3D geometry
Here we will initialize a 3D block for this geometry
Generation of mesh after blocking

3. Set Working Directory Set Working Directory
File > Change Working Directory
This will pop up a window. Select the directory where geometry has placed.
It provides access to selected directory directly
All output files will be saved in same folder until user change the location

4. Open Geometry Open Geometry File > Open Geometry
Choose “geometry.tin” file
Click Open

5. Blocking Strategy Blocking strategy
Here we will be going for Top Down approach of blocking.
3D pipe junction has a simple blocking strategy to follow
User need to cut two blocks from initial block to create L-shape configuration to capture both the cylinder.
Create Cartesian blocking.

6. Initialize Blocking Begin blocking
Select Blocking > Create Block > Initialize Blocks
Change Type to 3D Bounding Box
Click Apply
This creates one block which encloses the entire geometry
Curves automatically change color (colored separately instead of by part) to allow you to see where the ends of curves are #1 #2 #3 #4

7. Split to Create Topology
Splitting 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 button to complete or Apply #1 #2 #3
Split this edge for the vertical splits #4
Split this edge for the horizontal split

8. Deleting Blocks Delete Block Select Delete Block
Select top right corner block as shown
Selected block turns Black
Apply or middle mouse
This doesn’t actually delete the blocks. It moves them to the part, VORFN, so they can be used again, if desired
To actually delete the blocks, select Delete permanently
By default VORFAN part is always disable #1 #2

9. Split to Create Topology
Splitting selected blocks only
Select Split Block > Split Block
Click on Selected button
Select the blocks to split then middle click to confirm selection
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
Repeat the procedure for second split
Delete unwanted blocks #1 #2 #3 #4
After deletion

10. Associate Edges to Curves
Select Associate > Associate Edge to Curve
Select 3 edges as shown
Select 3 inner curves as shown to left
Middle mouse or Apply
Curves automatically grouped to one
Note single color of grouped curve
Note color change of edges
White (boundary) to green (constrained to curve)
Repeat for 3 edges and 3 outer curves as shown below #1 #2 #3
Edges
Curves in green, yellow and pink color
After complete association

11. Move Vertices onto Geometry
Move required vertices
Select Move Vertex > Move Vertex
Select Multiple as method
Left click, hold, and drag to select multiple vertices in rectangular drag box
Middle click, hold and drag vertices to desire location and leave button when finished moving all vertices
In selected set one vertex and edges attached to it are not associated to any curve but when we middle click to move vertices it follows the path of vertex of associated edge. #1 #2 #3
Selection box #4
After move vertex

12. Move Vertices onto Geometry
Repeat previous move vertex operation on the vertices shown below
vertices
After move vertex

13. Global Mesh & Pre-Mesh setting#1 #5
Mesh Setup
Select Global Mesh Setup > Global Mesh Size
Set Max element to 3.5
Click Apply
Select Pre-Mesh Params > Meshing Parameters
Select Update All
This will update all the parameters for Hex Meshing #2 #6 #7 #3 #4 #8

14. Compute Mesh Compute Mesh Select Pre-Mesh in tree
This will pop up and window asking for re-compute mesh
Click on Yes
This will generate and display Pre-Mesh
Try changing the max size to 2.5 and re-compute mesh again
Mesh with 2.5 size
Mesh with 3.5 size

15. Edge Params Edge Params Select Pre-Mesh Params > Edge params#1
Edge Params
Select Pre-Mesh Params > Edge params
Select Edge
Set Nodes and middle click to confirm
Click Apply #2 #3 #4
Fine mesh vertically #5

16. Quality Check Quality Check
Select Blocking > Pre-Mesh Quality Histogram
Select Quality in Criterion
Click Apply
Right click on Histogram and select Show. This will display the selected elements. #1 #2
Bad quality elements are displayed #3
Elements selected to display

17. Quality Check Quality Check
Select Blocking > Pre-Mesh Quality Histogram
Select Determinant 2*2*2 in Criterion
Click Apply

18. Save File Save Project As… Select File > Save Project As..
This will directly open 3DPipeJuct directory as we have set working directory already
Enter project name 3DPipeJunct
Save files.