1、Workshop 8.4 3D Elbow PartIntroduction to ANSYSICEM CFD3D Elbow Part3D Elbow JunctionThis is a simplified model of an exhaust or intake port which passes over a valve stemThis tutorial demonstratesTwo uses of O-gridOne to capture geometryThe other to fix corner mesh in cylindrical tube geometryUse o

2、f various vertex movement techniques to fit blocking to the geometry and improve mesh qualityScan planeSet Working DirectorySet Working DirectorySelect File Change Working Dir This will pop up a directory selection window. Select the 3DElbowPart directory where the geometry exists.All output files w

3、ill be saved in this working folderOpening any files will default to this working directoryOpening a project or creating a new project is not necessaryYou can open and save files independently (geometry (*.tin), blocking (*.blk), mesh (*.uns), etc)Open GeometryOpen GeometryFile Geometry Open Geometr

4、y Choose “geometry.tin” fileClick Open Or use quick iconTurn on Geometry Surfaces in the model treeRight-click on Parts in the tree and select Create PartEnter INLET as the Part nameSelect Create Part by SelectionSelect the surface at the min-x end of the pipe and middle click to acceptRepeat with d

5、ifferent names for the other parts as shownMiddle click when doneRight-click on Parts in the tree and select “Good” colorsPart CreationINLETOUTLETELBOWCYLBeginning a part name with a number or the usage of most symbols makes in invalid part nameSave GeometryFile Geometry Save Geometry AsThe part cha

6、nges will be saved to the geometryIts good practice to save to a new name instead of overwriting, so you can always go backDecide on TopologyTubes are normally one-block topologiesSplits are added later where tubes bend a lotBut because of the valve stem hole, we must choose a less-desired L-shaped

7、topologyThis makes it possible to align grid lines with the valve stemGrid line alignmentInitialize Blocking#1#2#3#4Select Blocking Create Block Initialize BlocksEnter FLUID for the PartSet Type to 3D Bounding Box (default)Click ApplyThis creates one block which encloses the entire geometryCurves au

8、tomatically change color (colored separately instead of by part) to allow you to see the ends of curvesIf no geometry is selected, the block will be around everythingSplit to Create TopologySplit the block at 2 locationsSelect Blocking Split Block Split BlockSplit Method is Screen selectLeft click a

9、nd hold on the edge to splitThe new edge will be normal to the edge that you selectHold left mouse button and drag the split to desired locationMiddle mouse to complete#1#2#3Split this edge for the vertical split Split this edge for the horizontal splitDelete Blocks#1Delete BlockSelect Blocking Dele

10、te BlockSelect bottom left corner block as shownApply or middle mouseMiddle mouse again to exit selectionThis doesnt actually delete the blocks. It moves them to the part, VORFN, so they can be used again, if desiredTo actually delete the blocks, select Delete permanently (changes indices)By default

11、 VORFN part is always offDelete blockAssociate Edges to CurvesAssociate EdgesSelect Blocking Associate Associate Edge to CurveEnable Project verticesThis will automatically project vertices on associated curves after completion of the operation.Select the 4 edges bounding an INLET or OUTLET of the e

12、lbow, then the 4 curves at the same endRepeat for the other end of the elbow#1#3#2#4Move Vertices#1#2Blocking Associate Snap Project VerticesWith All Visible toggled on, press ApplyAll vertices will move to the nearest location on their assigned geometry entityAll external vertices and edges (black

13、or white) are, by default, assigned to the NEAREST ACTIVE (part turned on in model tree) surfaceMove Vertices Multiple MethodBlocking Move vertex Move VertexSet Method to MultipleFix ZSelect the +Z axis at the lower rightPress the select vert(s) buttonLeft click, drag and release to draw a box and s

14、elect 2 vertices within that box as shown belowMiddle click, hold and drag the vertices as shown below for 3 locationsThere needs to be room for the vertical grid lines to terminate on the right of the port tube#1#2#3#4#5L-grids are best with angle slightly less than 90oO-Grid CreationSelect Split B

15、lock OGrid blockSelect highlighted 2 blocks and middle click to confirm.Select top and bottom faces as shown to pass O-grid through these faces. Middle click to confirm.Click ApplyCreate First O-GridFirst snap project vertices since they were moved slightly off geometry from previous operation#1#5#4

16、#3#2Turn off ELBOW, INLET, and OUTLETRight click on Blocking in the model tree and select Index ControlSet the O3 index (the O-grid direction) from 1 to 1Right Click on Parts Create PartEnter DEAD for the part nameSelect Blocking Material, Add Blocks to PartPress v on the keyboard with (mouse over m

17、odel window) for all visible blocks, middle click to exit selectionNote the edges turn from blue (internal) to white (or black) when they e external or between partsVertices and edges between different parts default to surface associationMove Blocks to Different Part#1#2#3#4#5Move Vertices#1#2Blocki

18、ng Associate Snap Project VerticesWith All Visible toggled on, press ApplyAll the visible vertices, which are surface associated due to the previous block movement to another part will move to the nearest surfaceIt is very important to note these vertices move to the NEAREST ACTIVE surface. If the E

19、LBOW part were left active, some of the vertices would jump to the outer surfacesThis happens if the other parts are left active#3Edge AssociationsSelect Blocking Associate Associate Edge to CurveTurn on Project verticesSelect the 4 edges and related curves(s) at each end of the cylinder With Projec

20、t vertices ON, it does the snap project immediately for the selected vertices#1#2#34 edges2 curves4 edges1 curveMove Vertices Align VerticesEdgeVertexBlocking Move Vertex Align VerticesSelect one of the edges along the length of the cylinderSelect any vertex at the OUTLET endSet Move in plane to XZA

21、pplyBlocking Associate Snap Project Vertices#1#2#3#4#5#6“Align vertices” matches up 2 coordinates within a plane for multiple verticesBlocking Move Vertex Set LocationSet Method to Set Position (default)For Reference From, choose ScreenFor Ref. Location, press the Select Location(s) button and then

22、Toggle allow on Mesh/Block selection buttonMove Vertices Set Location“Set location” sets coordinates to one specific valueSelect roughly the middle of the edge shown. Youll need to zoom in. Middle click. (Turn surfaces off)Turn on Modify YFor Vertices to Set, Select the Select vert(s) button, and se

23、lect the 4 vertices just up from OUTLET. Middle clickApply#1#2#3#4#5#6#7#8#9Create Second O-GridFirst press Reset, then Done in the index controlReset shows the full blockingBlocking Split Block O-grid BlockPress the Select block(s) button and add all the blocks by typing v or box selecting everythi

24、ngPress the Select face(s) button and select 1 face at the inlet and 5 faces at the outlet. Middle click.Set Offset to 0.6 (Every O-grid radial edge will be 0.6 of its original length) (same function as Rescale Ogrid which can be done afterward)Apply#1#4#5#6#2#3#7#8View OUTLET faces down the edge an

25、d box selectSurface Mesh Sizes#1#2Mesh Part Mesh SetupSet sizes as indicatedApply and DismissBlocking Pre-Mesh Params Update SizesAccept defaults and ApplyThis transfers surface and curve sizes to the blocking edgesTurn off DEAD partTurn on Pre-Mesh in the tree and press Yes to puteRight-click on Pr

26、e-mesh and select Solid & WireTurn on ELBOW, INLET, and OUTLET#3#4#5#6Parts containing blocks will not have mesh computed if off during the compute pre-meshPre-Mesh QualityFirst turn off Pre-meshBlocking Pre-Mesh Quality HistogramsSet Criterion to Determinant 2x2x2ApplyClick on the first few histogr

27、am bars to display the elements ( Projected Mesh ShapeEach time a change is made to the blocking, it will constantly ask to pute the mesh, so use this tool only for inspection, then turn OFF when done.The bad determinants will be in the inner block#1Scan PlaneIf you cant make out what is wrong when

28、viewing the bad elements, then view a scan plane through the elementsPre-mesh Scan planes in model treePress Select buttonSelect one of the edges running in the z-direction as shown belowThe scan plane will be normal to the selected edgeThis will turn on #2 dimension (k vector)Check ON SolidThe Grid

29、 Index arrows will allow you to scroll through mesh layersSelect this edge#1#2#3Blocking Move Vertex Move VertexSet Method to SingleTurn off Fix ZImprove angles by moving the indicated internal/un-projected vertices toward the elbow surfaceLeft-click and hold CLOSE to one vertex, ON THE EDGE (which highlights red) extending to the surface. Move it slightly outward, and release. It will constrain to moving along the red edgeRepeat for the other vertexMiddle click when