Numerical Modeling of Fluid Flows ( BMEGEÁTAM 5)

1. Numerical Modeling of Fluid Flows (BMEGEÁTAM5) 2014. 02. 19.

2. Farkas, Balázs • farkas[at] ara.bme.hu • www.ara.bme.hu/~farkas/CFD/workbench • http://www.ara.bme.hu/oktatas/tantargy/NEPTUN/BMEGEATAG26/MAGYAR_kepzes/2013-2014-II/ea

3. Most ImportantRule USE: - UPPER- and lowercase - Latin characters - Numbers - Character _ NO SPECIAL CHARACTERS AND SPACE ALLOWED DURING USE OF ANSYS WORKBENCH GOOD: Path: C:/Work/Andras_Job_01 NamedSelection: „Velocity_inlet1” BAD: C:/Asztal/András Jób 01 NamedSelection: „Velocityinlet 1” NEVER: ÖÜÓŐÚÉÁŰÍ Öüóőúéáűí space

4. Aim of Exercise 2 – Pump (2D, periodicboundaryconditions)

5. 1. Chapter: The geometry

6. Download of baseconstructionpointsethttp://www.ara.bme.hu/oktatas/tantargy/NEPTUN/BMEGEATAG26/MAGYAR_kepzes/2013-2014-II/ea/

7. Start Screen of ANSYS Workbench Drag and droptheelement Fluid Flow(Fluent) Intothe Project Schematicarea

8. Starting Design Modeler 1) Clickon Advanced GeometryOptions ChangeAnalysistypeto 2D 2) Double-clickonGeometryto start Design Modeler

9. Settingunits SelectMillimeter unit inUnitsmenu

10. Workplaneselection SelectXYPlane, right click, thenselectLookAttoalignplanetoforntalview

11. Readingconstructionpoints Togeneratebasicconstructionpointsontotheplane, Use File/Run Script Find and selectthedownloaded script file

12. Constraints 2) AtConstraintsgroup, findAutoConstarints and checktheCursorbox 1) Aftertheappearance of points, changetoSketching panel

13. Drawingcirculararcs UseDraw/Arc by 3 pointscommandtodrawthepressure (upper) side of blade (firstselectendpoints, thenmiddlepoint)

14. Drawingcirculararcs Dothesamewithleadingedge and suction (lower) side

15. Drawingcirculararcs Trailingedge is an Origin-centered arc (useArcby center)

16. Constraints Fix endpoints of leadingedge and leadingedge arc usingConstraints/Fixed command

17. Drawing a Spline Connectwith a splinetheendpoints of computationaldomain (youmayhaveto roll down inmenu) – Afterendpoint, right click and select Open End inthecontextmenu

18. Copy/Pastetheperiodicboundary 1 3 Modify/Copy Selectspline Right click:End/Useplaneoriginashandle –(youclosetheselection and settheOriginasthebasepoint of Pastecommand 2

19. Copy/Pastetheperiodicboundary 2 1 AutomaticchangetoPastecommand Cahnge r valueto 60° Right click: Rotateby –r

20. Copy/Pastetheperiodicboundary ClickonOriginwiththecursor: Copy/Pastefinished

21. Drawinginlet and aoutletboundaries Inlet/OutletboundariesareOrigin centered arcs (Arc by center)

22. Publication of input parameters SelectDimensions/Radiuscommand Set (type) trailingedgeradiusto 125 mm Bycheckingthebox, Publishparameter and nameitas R_out 1 2 3 2

23. CreatingSurface 3 1)Go to Modelling panel 2) Select Sketch1 3) SelectConcept/Surfacefromsketches 2 1

24. Contd. Apply

25. Contd. 2) ClickonGeneratetoapplycommand and makesurface 1) Select Add frozen 3) Close Design Modeler

26. 2. Chapter: The Mesh

27. Mesher start Save Project (NO spaces and $pecialchäracters WHATSOEVER) DoubleclickonMeshMesher is started

28. Initialmesh In Project Tree, ClickonMeshthenon Update toseecurrentmesh

29. SettingboundariesasNamedSelections 1 Select Line SelectionTool Selectinletboundary Right clickon line, selectCreateNamedSelectioncommandformthecontextmenu 2 3

30. SettingboundariesasNamedSelections Nameitasvelocity_inlet

31. SettingboundariesasNamedSelections 6 2 1 7 5 3 4 Similarlycreate: Pressure_outlet Per1 Per2 Leading_edge Trailing_edge Pressure_side Suction_side

32. Settingmeshsizing • Open (explore) Sizingmenu • Set Min size: 1 mm • Set Max FaceSize: 2 mm • Set Max Sizelargerthanbothifconflictappears Publish Max FaceSizebycheckingbox

33. Refiningboundarylayermesh Update mesh Right clickonMeshInsertInflation

34. Refiningboundarylayermesh 1 2 SelectSurfaceSelectionTool Geometry: wholesurface Apply 2,3

35. Refiningboundarylayermesh 1 2 Select Line SelectionTool Boundary: 4 edges of blade (hold ctrltoselectmultiplelines) Apply 2,3

36. Refiningboundarylayermesh Transition ratio: 0.6 Maximum layers: 4 Growthrate: 1.5

37. Refiningboundarylayermesh Update

38. Refiningboundarylayermesh – transition ratio Usetransition ratio tosetrelativethickness of boundarylayermesh. Range: 0-1 transition ratio: 0.6 transition ratio: 0.2

39. Refiningboundarylayermesh – # of layers Use # of layersto… set… numberoflayers?! (number of celllayersgeneratedbytheInflation, belongingtotheBoundarylayermesh) Numb. of layers: 4 Numb. of layers: 10

40. Refiningboundarylayermesh– growthrate UseGrowthratetosetthethicknes ratio of twoconsecutivecelllayers Growthrate: 1.5 Growthrate: 1.1

41. CloseMesher CloseMesher

42. 3. Chapter: PhysicalmodelSetup, Runningsimulation

43. FLUENT start DoubleclickonSetup FLUENT starts

44. FLUENT start • LauncherWindow of FLUENT Possible input: • Number of Processors • NumberPrecision • ColorScheme of GUI • Leaveasit is, justclick OK now

45. Definiton of periodicity InBoundaryConditionsmenu, Typeof per1 and per2 Zones must be setfromwalltointerface 1 2

46. Definiton of periodicity • Setperiodicity of computationaldomainbyusingMeshInterfaces/Createcommand: • MeshInterface: per • interface zone1: per1 • interface zone2: per2 • interterfaceoptions: periodicboundarycondition • Type: rotational • CheckAutoComputeOffset • ClickCreate • (ClickCloseifneeded) 2

47. Turbulencemodel • SetturbulencemodelinModels/Viscosusmenu: • k-epsilon • Realizable • Enhancedwalltreatment

48. Materialproperties 3 1 2 4 InMaterialsmenu, weobtainwatermaterialpropertiesby: Doubleclickon Fluid: air ClickonFluentDatabase…. Search and selectwater-liquid (<h2o <l>) Copy Closebothwindows

49. Fluid Zones InCellZonesmenu, Settheproperties of oursinglezone Materialname: waterliquid Framemotion: check Rotationalvelocity: 62.8 rad/s 1 2 3

50. Velocityinlet • InBoundaryConditionsslecetvelocity_inlet and clickon Edit: • Velocitymagnitude 3.5 m/s, Absoluterefernceframe • Turbulence • Intesity, 10% • Hydr. Diam, 0.01 m 1 2