Icepak基础培训教材ppt课件

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1、Icepak Icepak Basic TrainingBasic Training Training schedule Day 1Morning session8:309:0010:0010:1511:1512:00IntroductionInterface and Demonstration ExerciseBreakTutorial SessionModel Building: GeometryLunchAfternoon session1:001:302:152:303:154:155:30Tutorial SessionModel Building: Icepak Objects “

2、No flow” objectsBreakModel Building: Icepak Objects “Flow” objectsTutorial SessionMeshingEnd Day 1 Training schedule Day 2Morning session8:309:3010:0010:1511:1512:00Model Building: Icepak Objects compound objects 1Non-conformal meshingBreakTutorial SessionModel Building: Icepak Objects Heat sinks, P

3、ackagesLunchAfternoon session1:001:302:152:303:454:455:30Tutorial SessionSolverBreakHeat Transfer PhysicsTutorial SessionPost ProcessingEnd Day 2 Training schedule Day 3Morning session8:309:3010:0010:1511:1512:00Profiles and Zoomin ModelingTutorial SessionBreakTutorial SessionMacrosLunchAfternoon se

4、ssion1:002:152:305:30CAD import featuresBreakTutorial SessionEnd Day 3Overview ATESSFIAavid-TaiwanFluent IndiaCFD-RESFluent Europe - Sheffield, EnglandFluent GermanyFluent SwedenFluent FranceFluent Italy+ network of11 distributorsFluent Inc. - Lebanon, NH- Evanston, IL- Ann Arbor, MI- Morgantown, WV

5、- Santa Clara, CAFluent Asia-Pacific Fluent Inc. mission is to provide flow and thermal analysis software and services that give our customers a significant competitive advantage by dramatically improving their designs and design processesFluent Inc. WoldwideFLUENT 6General purpose finite volume bas

6、ed CFD package suitable for incompressible/compressible and laminar/turbulent flows, including reacting flows and multiphase flowsFIDAPGeneral purpose finite element based CFD package suitable for incompressible laminar/turbulent flows involving Newtonian/Non-Newtonian fluids, free surfaces and flui

7、d-structure interactionPOLYFLOWFinite element based CFD package suitable for modeling highly viscous flows (as in rheology) and surface flowsMixSimSpecialized CFD software for modeling mixing processesIcepakSpecialized CFD software designed for thermal management of electronic packagesAirpakSpeciali

8、zed CFD software designed for thermal management of electronic packagesCFD softwares from Fluent Inc.hIcepak is an object-based modeling softwarehIt allows you to build your model from:hprimitive objects such as blocks, plates, fans, vents, resistances, etc., orhMacros such as IC packages, PCBs, rad

9、ial heat sinks, detailed fan trays, etc.Icepak: Object-based SoftwareSteady/ transient problemsLaminar/turbulent flowsForced/natural/ mixed convectionMulti-fluid problemsInternal/external flowsConjugate heat transferRadiation heat transferFixed/ moving/ symmetry B.C.sTemperature dependent properties

10、Icepaks capabilitiesIcepaks capabilitiesPowerful grid generator capable ofUnstructured conformal meshStructured meshNon-conformal unstructured mesh Mixed units User defined library of assemblies File imports from MCAD and ECAD packages Direct ProE-Icepak interface Advanced post-processing and report

11、ingSolution features such asParameterizationParallel processingGrid-to-grid interpolationZoom-in-modelingGETTING STARTED Topics How to start Icepak Icepak Graphic User Interface (GUI) Starting a new project Opening an existing project Icepak file structure job, model & problem files List of Icepak m

12、enusStarting IcepakWindows: Use the “Icepak4.0 desktop shortcut , or Click on Start/Programs/Fluent.Inc/Icepak4.0UNIX: Type icepak from system promptNew Icepak session Icepak starts Project selection window opens by defaultPrompts user to start:- Existing Icepak project or New Icepak project or Quit

13、 Icepak Unpack an Icepak job from a compressed *.tzr fileOpening a new projectSelecting New in the New/Existing window opens the New project window1b. Select Cancel to go back to New/Existing window1a. Select directory2. Enter project name3. Create projectOpening an existing projectSelecting Existin

14、g in the New/Existing window opens the Open project window2. OpenIcepak projects carry Icepak logoTitle/ notes specific to selected project1. Select projectEvery Icepak project is a Directory containing project filesProject name = Directory nameFiles are related to:Problem setup-JOB, MODEL & PROBLEM

15、 filesGridSolutionPost-processing/ Reporting Job, Model and Problem files are needed to be able to fully reproduce the projectIcepak file structureUnpacking/Packing a projectSelecting Unpack in the New/Existing window opens the File selection windowLook for *.tzr fileIcepak project directory can be

16、compressed to *.tzr formatOnly the job, model and problem files will get compressedTo compress go to FilePackTo uncompress the compressed project go to FileUnpackList of Icepak menusThe Icepak interface contains the following menus:File Open new/existing projects, delete files, CAD imports, pack/unp

17、ack projects, save/ save asEdit Edit current object/group, alignment, undo/redoView Visibility of objects, geometric measurementsOrient Orientation, zoom-in, user defined viewsModel Grid generation, CAD import, Radiation, PrioritiesTree Control over a model treeMacros Add new macro to the model from

18、 the macro librarySolve Solve, solution monitor, define trials, define reportsPost Graphic results, unit definitions for post processingReport Textual resultsWindows List of windows that are openHelpIcepak Interface Topics Icepak graphic user interface Introduction to Icepak objects Model toolbar Sh

19、ortcuts toolbar Model tree Mouse functions Model orientationInteractive editing toolsIcepak GUI mapGRAPHIC DISPLAY AREAPROJECT LABELMODEL TREEMESSAGESOBJECT GEOMETRYMain MenuShortcuts ToolbarMODELTOOLBARIcepak GUIgraphic display areamodeltreemessagesobject geometrymain menushortcuts toolbarmodeltool

20、barproject labelglobal coordinate axesIcepak GUI: Definitions8Project label: Name and solution version of the project loaded into Icepak8Main menu: All Icepak functions can be accessed with pull down menus8Model toolbar: Icons to - create objects, edit objects, alignment features8Shortcuts toolbar:

21、Icons for commonly used functions8Graphic display area (GDA): Image of the model is displayed8Messages window: Icepak “talks to the user here through text messages, examples - current state of Icepak, mesh quality, some post process reports8Current object geometry (COG): Geometric information of sel

22、ected object8Model tree: List of all objects that constitute the project model, libraries, settings for problem, solver and general options8Global coordinate axes (Axes): Shows the orientation of the model in GDA8NOTE: Place the mouse on an icon for a bubble message description of the iconIntroducti

23、on to Icepak objectsIcepak Objects are entities used to build your modelExamples of objects in a model. The Object Types are shown in bold.Package Type: PBGAHeat Sink Type: Pin-fin heat sink Grill TypeFan Type: Intake fan with characteristic curveCabinet: CFD domainBlock Type: Solid Hexagonal blockP

24、late Type: Inclined polygonal plateModel toolbar: Create objects Icepak has two Object Types: Simple and Composite Every Type has a unique icon in the upper half of Model ToolbarIcepak object type iconsassembliesnetworksheat exch.wiresopeningsgrillesourcesPCBsenclosuresplateswallsblocksfansvol. res.

25、heat sinkspackagesmaterials To create a new object, click the corresponding object type iconModel toolbar: Edit and align functions Bottom half of Model Toolbar contains editing and aligning iconsIcepak edit & align icons To create a new object, click the corresponding object type iconAlign facesAli

26、gn edgesAlign verticesAlign object centersAlign face centersMatch facesMatch edgesOpen Edit Form for selected object Delete selected objectMove/Scale/Rotate/MirrorMake copies of selected objectAlignment iconsEditing iconsShortcuts ToolbarNew projectOpen existing projectSavePrintCreate image fileFile

27、 icons .UndoRedoObject facePlane cutIsoSurfPointSurface probeVariation plotHistory plotTrials plotTransient settingsSolution IDSummary ReportPost processing iconsFlip viewOrientation icons Orient HomeZoominScale to fit1 port view4 port viewobject namespos X viewpos Y viewneg Z viewIsometricOpen mesh

28、 windowRadiation view factorsCheck modelSolver windowSolver icons .Model Tree: IntroductionThe top section of the model tree contains configuration parameters Problem definition Solver settings Options graphics, units, etc.The bottom section contains Trash bin The inactive bin The physical model bra

29、nch containing all objects that make up the modelThe mid-section contains Default and user defined libraries Access to groups collection of objects put together as a unit Postprocessed graphic objects Solution monitor pointsThe bottom section is described in the following pages. The other sections a

30、re covered later in more detailModel Tree: Physical model branchIf the Model branch is closed, only the cabinet (CFD domain) is visibletoggle for opening or closing a branchIf the Model branch is open but no object is selected, all objects are visible in greyModel Tree: Physical model branch If any

31、object is selected (blue highlight), all objects are visible in default (or specified) colors. The selected object is drawn in bold lines.An assembly type object, like the “Power-Supply in this example, is a collection of objects combined into a single compound objectAssembly sub-branches are expand

32、able like the Model branchWhen an assemblys component is selected, the assembly is visible in default object colors but the rest of the model is shown in grayCurrent object blue highlight in tree; bold in displayModel Tree: Inactive & trash branches From the tree, select one object with the mouse or

33、 multiple objects using Ctrl key + mouse Drag the objects to the Inactive branch or the Trash branch Objects put into the Inactive branch are removed from the model but shelved into the Inactive branch; drag back into the Model branch to make the object active again Empty Trash to permanently delete

34、 model objects; post objects are deleted when dragges into trashMouse FunctionsMODEL ORIENTATION FUNCTIONSDrag leftDrage middleDrag right up/downDrag right left/ rightRotate display in 3D Translate model and global coordsZoom-in/ zoom-outRotate model in 2D plane of the screenRESIZING AND POSITIONING

35、 FUNCTIONSShift + drag leftShift + drag middleShift + drag rightSelects objects click edge to select single object, drag a bounding box to select multiple objectsTranslate objectsResize objectMouse Functions: Mouse bindingsIn the Model Tree, expand the Options branch to access the Mouse BindingsDoub

36、le click to open the Mouse Bindings and make necessary changesModel Orientation: Menu and iconsOrient pull down menu with 14 optionsIcons for commonly used orientationsModel Orientation: Fixed axes viewsMeaning of orient positive x: Orient such that the positive X axis points normally into the scree

37、n; similarly, orient negative X and so on.Orient positive XIsometric ViewOrient negative YOrient positive ZModel Orientation: Using the mouseThe orientation shown in the figure above was obtained by mouse movements (left: rotation, middle: lateral, right: zoom-in)Model Orientation: Zoom/ un-zoom Zoo

38、m in: drag a box around the region/ objects that need to be zoomed into Scale to fit: resizes the view such that the cabinet completely fits in the graphics display area; current orientation is retained Home position: is equvalent to orient negative z and scale to fit; is the default view when a new

39、 model is startedScale to FitZoom InModel Orientation: Other optionsReverse orientation - horizontally flips the orientation (mirror image)Nearest axis - changes to the fixed orientation closest to current orientation;useful when orientation is changed using the mouseSave user view saves current ori

40、entation under the specified name in the query boxClear user views deletes all user viewsNearest AxisModel Orientation: Shortcut iconsHome positionZoom inScale to fitSingle displayPartitioned displayDisplay/hide object namesOrient -X+Y-ZIsometricReverse orientationInteractive tools: View menuView me

41、nu contains several useful tools for:Geometric measurementsView optionsGeometric measurements:Location display point* coords in messages windowDistance display dx, dy, dz and distance between selected points* in the messages windowAngle display angle between vectors defined by 3 points* in the messa

42、ges windowMarkers graphic version of Location functionRubber bands graphic version of distance functionMouse aided geometric measurementsView/ display options*Points should be selected with the mouse following screen instructions Rubber bandInteractive tools: View menuDefault background color is bla

43、ck; to change choose desired color from palateView optionsInteractive tools: View menuUnchecked = invisibleView options (continued)Tracks mouse“Snap to grid (not mesh)Interactive tools: Interactive editing form Recap mouse functions for translating and resizing objects This form controls how these m

44、ovements are applied Motion allowed movements only in checked directions Restrict to cabinet Objects cannot penetrate each other Move group with objects Default mouse translate/resize has continuous movement instead of “grid-digitized Specify “snap to grid size for X grid/Y grid/Z grid mouse movemen

45、t will now be “grid-digitized Can snap to grid if the grid is made visible through main menu “ViewDisplayVisible grid New object size factor ratio of new object dimension to corresponding cabinet dimension, default is 0.2; new object will be centeredModel Building: Geometry TopicsObject Shapes in Ic

46、epak Editing functions Alignment functions UnitsShapes in Icepak: Shapes of simple objects3D shapes Prism Cylinder: uniform/ non-uniform Polygon: uniform/ non-uniform Blocks can be Ellipsoid/Elliptical Cylinder2D shapes Rectangular Circular Inclined rectangular PolygonPlatesOpeningsGrillesWallsFansS

47、ourcesBlocksResistancesHeat Exch.Shapes in Icepak: Altering geometries of objects The shape, position, size and orientation of an object may be modified: Using the Current Object Geometry (COG) window located at the bottom right hand corner of the GUI Using the current objects edit form/ geometry se

48、ctionGeometry of an object includes: Shape, Position and Size Local Co-ordinates Orientation if 2-DShapes in Icepak: Object geometry window Current objects geometric details are displayed in the bottom right hand corner of the GUI Click on Apply or Enter the keyboard after making changesCurrent obje

49、ctShapes in Icepak: Object geometry window Name, Group and Shape Coordinates may be entered by start/end or start/lengthOptions to:Apply changes, Reset to defaults, or Edit object formShapes in Icepak: Options for 2D shapesRectangularInclinedCan also be defined by start/angle Change angle directionP

50、osition defined by co-ordinates of two points on the diagonalShapes in Icepak: Options for 2D shapes PolygonalCircularOptions to increase/decrease number of verticesSelect vertex location with mouseSelect options for mouseFans can also have an inner radius for the hubShapes in Icepak: Options for 3D

51、 shapes - PrismsRegular PrismPolygons - Uniform (high and low face identical)Polygons - Non-Uniform (high and low face not identical)Top and bottom faces can have different number of vertices - but must be parallelSame vertex options as for 2D- polygonal objectsShapes in Icepak: Options for 3D shape

52、s - cylindersUniform Cylinder - no inner radiusUniform Cylinder - with inner radiusNon-Uniform Cylinder - with inner radiiInner Radius set to model annulusOuter and Inner Radii on top and bottom of cylinder can be differentObject ModificationEditing ObjectsOpens up the Edit panel for the selected ob

53、jectPlaces the selected object(s) in the trash canOpens up the Move panel for the selected object(s) From the move panel, you can Scale Mirror Rotate TranslateOpens up the Copy panel for the selected object(s) You can group the copies, and also have same functionality as move available to youObject

54、Alignment: IconsAlign Face - 1 Dimension aligned Plane of Face MatchedAlign Edge - 2 Dimensions aligned Planes of Edge MatchedAlign Vertex - 3 Dimensions aligned Centre Object - Based on CentroidCentre Object - Based on Face CentreMatch Face - 2 Dimensions MatchedMatch Edge - 1 Dimension MatchedTher

55、e are two options Left Click on IconObject gets re-sized during alignment Right Click on IconObject size is preserved object is moved during alignment Can also use edit/alignment tools instead of iconsObject Alignment : Icons Object Alignment : Icons The alignment tools all work in the same way Clic

56、k on Icon or select from menu Choose the face/edge/vertex that you want to change with the LEFT MOUSE BUTTON The selection will be highlighted - if the wrong one was selected, then just click again and Icepak will select the next face/edge/vertex Once you have the correct selection use MIDDLE MOUSE

57、BUTTON Then select the face/edge/vertex with which to align/match using the LEFT MOUSE BUTTON Upon correct selection accept with the MIDDLE MOUSE BUTTON Instructions for the above steps are given in red in the bottom left hand corner of the display area At any point you can cancel the operation with

58、 the RIGHT MOUSE BUTTONObject Alignment: Coordinate snappingUsing Co-ordinate alignment: Next to the co-ordinates of the geometry in the COG there are options to snap that co-ordinate to an existing point on an edge in the model. Co-ordinates can be: Start (xS,yS,zS) End (xE,yE,zE) Length (xL,yL,zL)

59、 Centre (xC,yC,zC) VertexTo Use: Click on the “Orange panel for a co-ordinate, and then with the mouse click on a point in the model. Icepak will then set that co-ordinate value to the position selected.Editing Objects: the Edit FormThe current objects edit form can be opened in the following waysDo

60、uble clicking the object in the treeRight clicking the object in the tree and selecting “Edit object from the pull down menuSelect the object in the tree and click the “Open edit form icon in the vertical Model ToolbarFrom the main menu, picking “Edit/ Current object/ EditUsing the keyboard short-cu

61、t ctrl+lowercase e4 Sub-formsOptions Common to All Sub-FormsEditing Objects: Geometry Sub-FormContains all geometric information: Shape Local Co-ordinate system (if any) Orientation LocationCreate new local originCheck local originEdit a local originSelect local origin from existing onesPull Down Me

62、nuEditing Objects: Properties Sub-FormContains all flow/thermal properties:Object type - eg: Thermal model Block TypeThis area contains: Solid/Fluid and surface material specification Boundary conditions flow rates, power generation, temperature Side specification Any additional information required

63、 to implement the selected object type (eg: thickness)Editing Objects: Info and Notes Sub-FormsNotesAny relevant additional information user may want to addInfoNameCreation PriorityShading etc.Units Physical quantities can be specified in various different units Examples:LengthTemperatureFlow rateCo

64、nductivityPowerUnits: Global Units Every quantity (length/mass/etc) in Icepak has a default global unit To change the global unit for a quantity go under the Model Tree/ Options/ Unit Definitions and follow the steps shown below Units of a quantity may be changed at any time during model building Wh

65、en global units are changed, the new units are applied to new objects created after the change existing objects will continue to use the previous units1. Select the quantity to change2. Select or create the desired unit3. Click on Set as default to confirmOption to convert all quantities to SI/ Impe

66、rial/ Icepak default unitsUnits: Object Specific UnitsUse the pull down menu and change the units The units of a specific quantity can be changed so that they are different to the default units.Determines whether the quantity is converted when units change or the numeric value is remains unchanged w

67、hen units modified.Fix values on units are converted physical dimensions and quantities are unchanged (2 = 5.08cm)Fix values off units are changed, but numbers remain the same physical dimensions/ quantities are changedModel Building: Icepak Objects Topics Simple ObjectsNo flow objectsCabinet (defau

68、lt)WallsBlocksPlatesSourcesFlow objectsOpeningsGrilleVolumetric Resistances2D - FansHeat ExchangersMaterialsSolidFluidSurface Composite Objects3D FansEnclosuresPCBsAssembliesHeat SinksPackagesNetworksCreating New ObjectsWays to create and position objects in IcepakClick on object icon and edit it, o

69、r use the alignment tools to create itDrag the object icon into graphics display area If using this option, it is sensible to set a “snap grid in Options/Interactive menu to ensure that re-location/positioning is limited to the snap grid. For example you may set the snap to 1mm then position is limi

70、ted to nearest mmChange object type etc. To change properties of an objectSelect the objectEnter changes in the object edit form discussed in the previous section Defines the computational domain it is always cuboidal shape Exists by default when a new model is started Default dimensions: 1 x 1 x 1

71、m3 (or equivalent in other units) Default for new objects - they will be 1/5th the cabinet size and centered No object may wholly or partly exist outside the cabinet a warning message will prompt the user for an action as in the figure belowUndo the operation that caused the object to go out of cabi

72、netObject can remain outside temporarily, but this message will reappear Autoscale button in the cabinet form or COG resizes the cabinet to just fit all objects in the model Scaling/moving the cabinet using the move form scales/moves the entire modelCabinetCabinet: PropertiesDefault cabinet properti

73、es:Walls are adiabatic Walls have zero velocityOvercome these constraints by placing following objects on cabinet sides:walls energy transfer onlyopenings, vents and fans flow and energy transferThe cabinet form lets you impose any of these objects on the entire side(s) of the cabinet these objects

74、will automatically resize when the cabinet size is changedOpeningOpeningWallWallDefaultWalls Can only be placed on cabinet sides or on faces of hollow blocks Inner side of walls see the fluid, while outer sides face the exterior conditionsThree Types: Stationary Symmetry Moving Wall thickness may be

75、 real or effective External material is always specified Solid and internal surface are specified only for walls with thicknessSolid materialSurface materialsDefault Icon:Default color: GreyWalls: Thermal dataDefault Icon:Default color: GreyStationary walls may have heat transfer specification to th

76、e outsideOutside heat fluxOutside temperatureExternal conditions/ heat transfer coefficientSymmetry walls - reduce model size when the model is symmetric about a planeAdiabatic and FrictionlessZero flux and flow through wallCan specify spatially varying profileMoving walls - account for motion in th

77、e plane of the wallThermal inputs of stationary wallsWall velocity vectorBlocksDefault Icon:Default color: PinkCan be meshed with either MesherMust be meshed with Tetrahedral -MesherBlocks: Thermal modelsDefault Icon:Default color: Pink4 Thermal ModelsHollow blocks No mesh within the block no equati

78、ons solved inside hollow block No heat conduction in the planar direction along the sides of the blockHollow Polygon blocks used to modify domainUses of hollow blocks: Mask off regions of the domain Simplified representation of modulesBlocks: Thermal modelsDefault Icon:Default color: PinkSolid block

79、s Versatile uses- can be used for almost any solid component Openings/fans/vents will cut through solid blocks if their dimensions are smaller than the blockFluid blocks - uses Multi-fluid models Carve out portions from solid blocksNetwork blocks Hollow block with thermal resistance network inside t

80、he block 4 Types of networks (Two resistor, Star, Shunt and General) Network values visible upon selecting blockUses of network blocks: Simplified representation of packages/ prismatic components with heat generationGeneral network 3 Junction network2 ResistorStar networkFull shunt networkBlocks: Th

81、ermal dataDefault Icon:Default color: PinkSurface data all block types Radiation Discussed Later Individual Side Specifications Thermal Properties -Total Power, Flux or Fixed Temperature Heat transfer coefficient to model conductance per unit areacontact resistanceRadiation specification for a sideB

82、locks: Thermal dataDefault Icon:Default color: PinkThermal data -Solid and fluid blocks Material specification Total power uniform through the volume Power options temperature dependence, Joule heating, transient power Note: In multi-fluid problems, fluid blocks must not have a common interfaceNetwo

83、rk blocks Mark the board side Junction power Resistance valuesHollow blocks Adiabatic inside and on surface No Heat Transfer to other objectsPlatesDefault Icon:Default color: Orange6 Thermal models: Conducting thick for compact PCBs, solid objects with small thickness Conducting thin for solid objec

84、ts with small thickness, thin layers (gives reduced mesh count) Contact resistance for adhesives, interface materials Adiabatic thin for baffles, non-conducting enclosures Hollow thick and Fluid identical to hollow blocks and fluid blocksSurface thermal data: Only 2 faces available cannot specify da

85、ta for the “edge faces Heat transfer coefficient/ contact resistance can be specified No power on individual sides Local Radiation controlsPlates: Thermal modelsDefault Icon:Default color: OrangeConducting thick: Plate thickness is modeled and meshed Power options constant, temperature dependence, J

86、oule heating, transient powerConducting thin: Plate thickness is effective only no mesh in the thickness Conduction in both the in-plane and through plane directions Constant power optionContact resistance: Plate thickness is effective only Conduction in the through-plane direction only Constant pow

87、er optionAdiabatic thin: No plate thickness Plate surface is adiabatic no heat transfer or power generationHollow thick: Identical to hollow block except surface data can be specified in only 2 facesFluid plate: Thickness is modeled and meshed No power specification or surface data Used to punch thr

88、ough a thick plateSolid Blocks vs Solid platesFollowing are differences between solid models of blocks and platesObject typeThermal modelWhat the mesher seesComputational costsThermal conductionRadiation heat transfer & Thermal specs on side facesBlockSolid3D object interior meshedHighestSolved in 3

89、DAll 6 side facesPlateConducting thick3D object interior meshedHighestSolved in 3DOnly 2 sides high & lowConducting thin2D object no interiorMiddleSolved in 3DOnly 2 sides high & lowContact resistance2D object no interiorLowestConducts only normal to planeOnly 2 sides high & lowSourcesDefault Icon:D

90、efault color: Green Sources can have 2D or 3D shapes Source material = material of the object it is mounted on / in No Flow across the face of a 2D source 2D Sources can also radiate Power can be specified as total power/ power density/ fixed temperature Power flux (2D sources) can be specified as a

91、 spatially varying profile (x,y,z,value) Total power can be temperature dependent with in a specified source temperature range eg: power = 3.0 W for Ts 30oC, but = 3.0 + 2.0 (Ts 30) for 30oC Ts 40o C Joule heating only for volumetric sources Uses power sources, packages, dies, component foot-printOp

92、enings: Free openingsDefault Icon:Default color: YellowTwo Types:Free openings - Flow and Thermal Data: X,Y,Z velocity components, temperature, static pressure Fixed values or spatially varying profiles Flow conditions applied only when placed on cabinet sides or hollow block faces Drill holes throu

93、gh thick/thin solid objects when placed within a model NOTE: Setting both velocity and pressure inputs should be avoided as this may lead to inconsistent or over-specified boundary conditionsUses: Natural Convection boundaries Computational wind tunnel where inlet velocity or pressure profile is kno

94、wnOpenings: Recirculating openingsDefault Icon:Default color: YellowUses: As a “black-box heat exchanger Simplified model for circular pipe bends Fixed flow rate internal fanRecirculating opening - a combination of a supply and an extract Extract takes flow from domain Supply supplies the same flow

95、to domain No CFD equations solved as flow goes from extract to supply Heat loss or gain may occur between extract and supply openings Both extract & supply openings must be placed on cabinet walls or on hollow blocks Shapes/ geometry can be differentFlow rate Mass flow Mass fluxHeat transfer Tempera

96、ture change from extract to supply Heat added/removed Effective conductance & external fluid temperatureGrillesUses: Simulates louvers, screens, internal vents, perforated plates etc Location: Anywhere in the model Shape: Any 2D shapeLoss coefficients quadratic/ linear/ combinationCan be calculated

97、using the following: Device velocity- must specify the free area ratio Approach velocity Automatic must specify free area ratio and type of grill Pressure loss curve dataSpecify pressure Inflow external pressure stagnation pressure Outflow external pressure is static pressure Default (ambient) press

98、ureFlow direction Normal In/Out Specified directionDefault Icon:Default color: GreenVolumetric Resistances3D flow resistances Shapes: Prismatic/ Circular/ Polygonal Properties pressure drop coefficients Device and Approach velocity options with quadratic/ linear/ combination loss coefficient specifi

99、cations Power law coefficient and exponent of velocity must be specifiedProperties total power can be specified Uses: Compact heat sink models, thick filters, loose wire bundles, power supply units, etc.Default Icon:Default color: PurpleVolumetric Resistances: ExamplesExample: Compact heat sink mode

100、l Appropriate loss coefficients for pressure drop Modified fluid properties within the resistance to take into account heat transferExample: Compact power supply model Use manufacturer data/Experimental information to define the equivalent volume using pressure drop relationship Test model in comput

101、ational wind tunnel to ensure model produces the correct pressure drop/ temperaturesDefault Icon:Default color: PurpleFansDefault Icon:Default color: Cyan Fans can be 2D (simple) or 3D (compound) Fan Flow inputs are identical for both models Exhaust flow normal pointing outwards Intake fans flow nor

102、mal pointing inwards Internal fans flow normal to fan in either positive or negative direction Fan direction is indicated by arrow in GDAFan Properties Select fan type1Fans: Flow dataDefault Icon:Default color: CyanInput fan flow rate - options: fixed volumetric/ mass flow Not applicable to internal

103、 fans linear fan curve (pressure head volumetric flow) Proper max head and flow must be given non-linear fan curve2 Input swirl Specify swirl magnitudeOr, Fan RPM assumption: only 5% of the fans tangential velocity is transferred to fluid3 Input Options If failed fan, specify a free area ratio Model

104、 the pressure drop across blade section (perforated plate is assumed)4Fans: Non-linear fan curvesDefault Icon:Default color: CyanPressure head valuesFlow rate values Fan curves may be specified by the text or graph editor. They can be saved/loaded using the graph editor.Text editor Enter flow and pr

105、essure head points in pairs - first flow rate then pressure head The first flow entry and the last pressure head entry must always be 0.0. Violation of the above rules can cause divergence or erroneous resultsGraph editor Follow the rules above Create curve using mouse follow instructions below the

106、graphleft mouse = zoommiddle mouse = create/moveright mouse = deleteHeat exchangerDefault Icon:Default color :PinkHeat ExchangerTwo loop heat exchangerparallel flow or counter flowsingle or multiple passesInner and outer loopsCan be the same or different fluidsinner loop is typically the air inside

107、Icepak cabinetHeat exchangerDefault Icon:MotivationImpractical to model both loops in detail for a system modeltoo costly computationallyEmploy compact modeling approachSimulation of heat exchanger without modeling both loops3d converted to a 2d representationsignificant cell count savingsEquivalent

108、 pressure drop through heat exchangerloss coefficient(s)Equivalent energy exchange between loopsuser specified heat transfer coefficientRequires data from eitherdetailed Icepak model of both loopsempirical measurementsvendorDefault color :PinkHeat exchanger : FlowDefault Icon:Default color:pinkPress

109、ure DropConstant loss coefficientuser specifies kLbased on empirical, computational or vendor dataPolynomialloss coefficient can be specified as a function of velocityuser specifies rn, which are polynomial coefficientsHeat exchanger: Heat transferDefault Icon:Default color:Pink Heat Transfer Fixed

110、heat fluxif the total heat exchange between loops is knownHeat transfer coefficientconstant user specifies hpolynomial as a function of velocityuser specifies hnexternal temperature is inlet for external loopMaterialsDefault Icon:Default color: None Ways to assigning a material to an object/ surface

111、use the relevant pull down menu and select the materialselect material in the tree and drag into the object in the tree Materials are split into three main categories with sub-types Solids: Insulators/Semi-conductors/Metals and Alloys/Plastics etc.Fluid: Gases/Liquids etc.Surface: Used to specify em

112、issivity and surface roughness Created through Materials iconMaterials pull down menu in objects properties form contains the option to create new material and assign it to the object Also on assignment properties can beEditedChecked - values displayed in the message windowDefault Icepak materials c

113、annot be editedMaterials: PropertiesDefault Icon:Default color: None Fluid and Solid properties values maybeConstant,Linearly dependant on temperaturePiecewise linear For Fluids the conductivity can also vary with velocityCompact heat sink design For Solids the conductivity may also beIsotropicOrtho

114、tropic input X, Y, Z valuesAnisotropic - define using a tensorFor both Orthotropic and Anisotropic conductivities, the conductivity in a given direction equals the nominal value Multiplied by the conductivity multiplier Example:kX = kY = 20 W/m-K; kZ = 0.3 W/m-KMaterialsDefault Icon:Default color: N

115、one New materials are saved with the project and are only available within that project Materials can be saved to form a local library Model/Create material library Choose the materials you want to save out To automatically load up a local library Add a new library containing materials to the modelM

116、ain Material Library Model Specific Materials Groups Groups feature allows grouping of objects To create a group select objects from the model tree, then right click and select “Create group optionright click the “Groups branch in the tree and create a new (empty) group, then drag objects into the g

117、roup Operations on groups:Right click an existing group to see the group functionsAdd/ remove objectsCopy/move groupSimultaneously edit group contents (ensure contents are same type/sub-type)Activate/ Deactivate/ Delete all contents, etc Deleting a group will only delete the grouping, not the object

118、s in the group3-D FanDefault Icon:Default color: Cyan Simulates the cowling and hub of fan, and adds option to specify pressure drop due to fan guard. Creates a single object made up of the fan, a block for the cowling and a block for the hub (if present). In Geometry enter the Size and Thickness of

119、 the case and location relative to fan face. In properties specify the Guard Free Area Ratio and hub powerEnclosures 3D-box like object made up of plates Sides can be open or closed Closed sides can be thin or thick plates Open sides are free boundaries Can assign power and radiation to the closed s

120、ides Uses - chassis, any box-like structureDefault Icon:Default color: BluePCBsDefault Icon:Default color:YellowRectangular PCBs can be created automatically within IcepakThere are three types: Compact Board modelled through equivalent orthotropic thermal conductivity Detailed Board and individual l

121、ayers modelled Hollow High/Low side dissipation and component height can be specified Board in effect a hollow block/plateFor all types: Specify the number in rack and the rack spacingPCBs: CompactDefault Icon:Default color:YellowCompact PCB: Board thickness + material Total dissipation Layer inform

122、ation High and Low surface layers Internal layers - assumed identical. Icepak calculates an appropriate orthotropic conductivityPCBs: DetailedDefault Icon:Default color:YellowDetailed PCB: Specify thickness + material of substrate (FR4) Power Total Dissipation Dissipation from each Face Layer inform

123、ation Internal layers are identical Each copper layer assigned the appropriate thermal conductivity (Cu)PCBs: HollowDefault Icon:Default color:YellowHollow PCB Specify parameters for Low and/or High sides of PCB Surface material Component Height Dissipation Total Flux Per component + number of compo

124、nents % dissipated from this side Icepak generates a hollow thin (if component heights are zero) or else a thick objectPCBs: Thermal model selectionDefault Icon:Default color:YellowUses: Compact model - PCBs in system/sub-system level model Detailed - PCBs in component/package level model Hollow - P

125、CBs in initial level analysis of a system to gain information on ambient conditions/flow trendsAssembliesAssemblies are collections of objects grouped together and stored as a single unit Assemblies can be internal or external Internal Created within the project in the following waysSelect objects,

126、then right mouse click and use create assembly optionConvert an existing Group of objects to Assembly right mouse clickCreate an assembly, select objects and drag them into the assembly External - Loaded from external locationAn external assembly is just an Icepak project containing the objects maki

127、ng up the assemblyIdeally stored in either a personal library or in a central repositoryGood practice to Locate “origin at sensible position in the parent model Size the parent cabinet to the assembly Note: Deleting an assembly will delete all its contents Default Icon: Assemblies can be used to: Or

128、ganize objects making up a single component Mesh regions separately (non-conformal meshing) Create sub-models Create libraries of commonly used components Objects within assemblies can be edited in the usual way, or separate from the rest model Right Mouse Click and choose View Separately Only objec

129、ts within the assembly are displayedAssembliesDefault Icon: Assembly attributes can also be edited using the regular edit functionality. Edit Object Ctrl + lowercase “e etc.Assemblies Edit PanelChoose how to: Define the assembly Position and Scale Mesh the assembly Discussed in more detail during me

130、shingObjects included in the assembly are listed below the assembly in the model treeDefault Icon:Heat sink objectHeat sink object- Heat sink type Detailed vs. simplified- Flow direction specified for Extruded/Bonded fin only- Detailed heat sink Model individual fin as solid block- Simplified heat s

131、ink Fin portion of the heat sink is modeled as volume resistanceDefault Icon:Heat sink object - DetailedDetailed heat sink- Fin type Extruded/ Cross-cut extrusion/ Bonded fin/ Cylindrical pinExtrudedCross-cut extrusionBonded fin Cylindrical pinDefault Icon:Detailed heat sink: Fin geometryInline cone

132、Staggered cylinderExtruded/Cross cut/Bonded fin count, space, thickness specificationCylindrical pin fin fin arrangement fin count in both directions pin type (cylinder / cone) pin radiusDefault Icon:Detailed heat sink: Options Effective only Use thin conducting plates to model thin fins Thickness 1

133、0% of fin pitch Extruded/Bonded fin only Fin & base material Can be specified separately Interface material Model thermal pad etc. between heat sink & component Use contact resistance concept Fin bonding Modeled as contact resistance plates Bonded fin onlyDefault Icon:Heat sink object - SimplifiedSi

134、mplified heat sink - Methodology Use loss coefficient to account for flow pressure loss through fins Increase local fluid conductivity to account for fin heat transfer- Pros/Cons Reduce mesh size and computation time Result is more mesh independent May need to tune the macro (takes more time) Larger

135、 error for downstream heat sink if multiple in series- 2 models for simplified heat sink Use automatic geometry-based correlation Specify thermal and flow resistance curveDefault Icon:Simplified heat sink: Automatic correlation(1) Use geometry based correlation Check use geometry-based correlation S

136、pecify fin geometry and material Icepak calculates pV & RthV curve using correlation Correlation applies for laminar flow Velocity range 0.53.0 m/s Error (10%) Extruded heat sink onlyDefault Icon:Simplified heat sink: Use curve(2) Specify thermal and hydraulic resistance curveFlow resistance specify

137、 loss coefficient input pressure drop curveThermal resistance constant input RthV curveDefault Icon:Package: Modeling options in IcepakDefault Icon:ModelAccuracy Mesh sizeEffort neededApplicationSolid block(k 10 W/m-K)PoorLow( 10 cells)Minimum: approximate die power neededSystem/board level - no inf

138、ormation2 Resistor network( q qjb, q qjc )Poor (30%) accuracy when used in non-calibrated conditionsVery low(zero)High: Usually only 1 value ( qjb or qjc ) is available from data sheets, the other value has to be estimated/ computedSystem/board if both qjband qjc are availableMulti-resistor networkF

139、air - better than 2 resistorVery low(zero)Very high: Depends on required network topology; necessary to characterize with detailed packageSystem/ boardLumped conduction modelGood (10%);More data further improvedMedium(100)Minimum: if you can see the package and know the die power use thisSystem/ boa

140、rd/ heat spreading studies/ heat sink optimizationDetailed packageVery good (less than 5%)High( 10,000)High: Detailed information, usually proprietary, may be neededPackage characterization and optimizationPackageDefault Icon: Select from 5 available package types:4 ball grid array models1 quad flat

141、 pack Specify available inputs dimensions, substrate, solder and die/mold information Select model type from 4 thermal models:Detailed packageCompact conduction modelCharacterize junction to caseCharacterize junction to board sideInputs for Package Package: Schematic Button Default Icon:Clicking on

142、Schematic Button will show an image relating to the inputs - in this case the data describing the Solder Balls on a PBGA Package: Thermal model selectionDefault Icon:uModel selection guided by the objective of package modelinguObjective in board and system Level modelsuTo obtain accurate dissipation

143、 of heat from the package to board, surrounding fluid and neighboring componentsuTo estimate package die temperaturesuTo estimate package case temperaturesuObjective in package level modelsuDesign of the package - effect of metal slug, substrate materials, compare design optionsuCharacterization of

144、package to estimate thermal resistances (qJA, qJB, YJT) under standard test environmentsPackage: Detailed modelDefault Icon: Suitable for package level model only Not recommended for board and system level models due to mesh bleeding All details modeled: die substrate case solder ballsPackage: Compa

145、ct modelIcepak compact models for board and system level: Solid block with appropriate representative conductivity 2 Resistor network block (qJC, qJB) Multi-resistor network block Compact conduction model (CCM)Refer notes on Block and Network objectsPackage: 2 Resistor networkJunctionCaseBoardAmbien

146、tqcaqcaqjcqjcqjbqjbqbaqbaExternal to Package. Depends on fluid flow, radiaton and system configuration. Icepak will solve for this.Internal to package. Dependent on IC package construction.Can be obtained from Package/ device data sheets From qjc & qjb characterization models in Icepak package objec

147、tsDependents on IC construction as well as environment.Icepak will predict this based on qjc & qjbAmbientPackage: qjb & qjc Characterization modelDefault Icon:Junction to board characterizationsimulation of JEDEC standard qjb conduction modelsource power = 1 WPCB side wall temperatures = 0oCThen qjb

148、 = max package temperatureJunction to case characterizationAll sides except the top are insulatedUniform h = 25 W/m2-K specified on top wallJEDEC prescribed PCBPackageuComponents of the package forming critical heat conduction pathway are modeleduSuch components are simplified by lumping repetitive

149、objects and assigning them effective propertiesu Exploits the power of thin conducting plates in modeling very thin, highly conducting layersCompact Conduction ModelDefault Icon:solder Contact Res.Thin conducting plate dieShell plate die padAir contact res.Only one more horizontal edge than the sing

150、le block modelDetailed VersionCCM VersionCCM of a BGA packageDefault Icon:BGA: Ball Grid Array packagesCCM of a QFP packageDefault Icon:Air gap contact res.Wire bondLead FrameDetailed VersionThin Plate VersionStill only one more horizontal edge than the single block modelAir gap contact res.Thin Con

151、ducting Wire bond Thin Conducting Lead frame Thin Conducting Die QFP: Quad Flat Pack type of packagesNetworks A general representation of network blocks Networks consist of faces, boundary and internal nodes Faces must be placed on hollow blocks or on the cabinet Faces can connect to internal nodes/

152、other faces Boundary nodes can only be connected to internal nodes Links can be convective (C) or diffusive (R) Transient analysis calculations for non-convective network objects need to specify capacitance in addition to resistance (mass and specific heat of nodes) Variety of thermal simulations Co

153、mplicated IC packages with multiple heat sources External heat exchangers (open loop)Default Icon:Networks Edit PanelsDefault Icon: Define the number of faces and internal nodes Define Face locations Create the network by editing it from the properties panel Right mouse creates a link Double click o

154、n link to set values Double click on face or node to change name etc.Networks - ExampleDefault Icon:Network representation of a PBGA including central stand-off resistance, and resistance of outer populated area to PCB Mesh with conduction/fluid flow etc.Resistance network if Text is unknownhAhAhAhA

155、mCpmCpmCpmCpmCpTinletT1T2T3T4External heat exchangerT1, T2, T3, T4 are all unknowns, so the fluid heats up from the inlet temperature (Tinlet) as it travels along the H/XToutletNetworks - ExampleDefault Icon:MeshingChoice of three meshers available:Two Hexahedral meshersSuited for most (99%) of elec

156、tronics cooling applications.Unstructured It can be used for most applications satisfactorilyCartesian Tetrahedral mesher Intended for some complex geometryMust be used for ellipsoids, elliptical cylinders, or polygonal ductingIcepak automatic meshing: OverviewAll the methods are fully automatedCan

157、generate computational meshes at varying levels of complexity No parameters setParameters defined on an object by object basisAfter meshing, Icepak loads the mesh and checks the key quality measure, and reports the minimum value in the message window. If there are cells with poor quality, Icepak wil

158、l automatically display them.The Key measures are:Face Alignment for HexahedralAspect Ratio for TetrahedralAutomatic meshingFor higher mesh count across an object - use x,y,z countLow and High element size/ratio to refine around objectsInward height/ratio to refine within an object Outward height to

159、 refine mesh away from planar objectsBackground mesh - set Max X, Y, Z sizesUse fluid blocks to refine the mesh locallyExamine mesh using surface plots and cut planesAlways check quality using diagnosticMaintain sufficient mesh density to capture physicsGenerate First Cut MeshCoarse default options

160、with Max X,Y,Z set to 1/10th or 1/20th of domain sizeRefine the MeshExamine the MeshSolveGenerate new MeshYesNoRe-examine the Mesh OK?Meshing steps and considerations Use coarse mesh for initial solutions and for observing trends Use suitably refined mesh for final solutionTwo Hexahedral Meshers Uns

161、tructuredMesh will follow the geometry Uses all element types to fit the mesh to the geometryBackground mesh is made of hexahedral elementsCartesianMesh will be structured mesh consisting only of hexahedral elementsStair-step approximations to non-rectangular geometryBoth of these meshers can be use

162、d to mesh assemblies separately. This will be discussed in more detail later.Both meshers have the same global and per-object settings.Hexahedral meshingDuring the meshing process for the hexahedral meshers, Icepak uses the separation value to check the model. Icepak calculates the distances between

163、 objects in each co-ordinate direction and will align objects where their separation is smaller than the tolerance set.As a rule of thumb, the tolerance should be approximately 1/10th of the smallest dimension in the model. This will ensure that any changes in volume will not significantly alter the

164、 results.If the separation is set higher than 10%, but less than 50% of the smallest dimension, Icepak will prompt you to eitherStop meshing and change manuallyContinue and change automatically to 10%Ignore and continueIf the separation is larger than 50%, Icepak will prompt you to Stop meshingConti

165、nue and change automaticallyThe separation can be set either in the meshing panel or in the settings configuration panelChecking during meshingIcepak operates on a “cocooning methodology Each object is meshed individually as close to the specifications defined as possibleFirst combines adjacent obje

166、cts togetherCreates single group of multiple objects to “O grid together Then creates the background Cartesian meshMax Cell size is controlled by Max x, Max y and Max z valuesCuts out a section of the mesh around the grouped objects and replaces the mesh with an unstructured mesh - the “O-Mesh regio

167、nThis allows for a finer mesh to be generated close to objectsIn open spaces between objects the mesh is tessellated with larger elements Minimize computational costsMeshing is the most critical aspect of CFD modeling: A good mesh is absolutely essential for a good solutionHexa-unstructured meshing

168、methodologyElements of an Icepak meshGlobal Settings - for refining meshDefault Settings - mesher type, background mesh settingsPanels to generate, Display, Check quality, and Export to IdeasHexahedral meshing: Generation panelMesher TypeHexa-Unstructured, Hexa-Cartesian, TetrahedralUnits to useMax

169、X, Max Y, Max Z Control the size of the largest cell allowable in the background meshInit HeightMaximum height of first cell into the domain on all objects within the modelObject ParamsIndividual parameters SeparationTolerance used when meshing to remove any small gaps/misalignmentsDefault settingsM

170、ax X, Y, ZBy default this is 1/20th of the cabinet dimensions1/10th of the domain size is sufficient for a coarse gridValues smaller than 1/20th domain size is rarely needed and is not recommendedThese are not meant to be used to refine the mesh close to objects, but purely to generate a reasonable

171、background meshInit HeightRecommended that you do not set this on large models as it can result in very large mesh countsSeparationIt is recommended that you set this to 10% of the smallest dimension in your model for typical calculations to prevent any large volume changes occurring that might lead

172、 to inaccuracies in the results.RecommendationsNormal Mesher Provides an acceptable mesh for most situations provided background grid is reasonableCoarse Mesher Provides a coarse mesh “first cut mesh that can be refined locallyMesher default settings include: Min elements in fluid gap Minimum number

173、 of cells in between adjacent faces of closely spaced objectsMin elements on solid edge Minimum number of cells to be placed on the edge of an objectMax O-grid heightMaximum height of the O-grid region from the surface of an object Min elements in fluid gap = 2Min elements in fluid gap = 3Global set

174、tings (1)Maximum Size RatioControls the growth rate of cell size The Growth ratio of elements away from surfaces can be controlled using this setting. Dx2 / Dx1 0.01 can result in poor meshValue 1e-5 can result in Huge meshCells in gap Number of cells between objectsEdge criterionControls placement

175、of elements near object edge Natural size factor (NSF)Specifies smallest element size = NSF*smallest feature lengthNatural size refinementThe minimum number of nodes on a curved edgeVolume assignment passesTetrahedral meshing parametersDefault max curve/surface sizeSpecifies max size of element on a

176、 curve or surface Add intersection curvesSpecifies that the curve at the intersection of two objects is calculated explicitly Use where have curved objects intersecting other objectsAutomatic hole repairUse with existing meshes to try to fix problems during meshingReuse existing outputUse with exiti

177、ng meshes as a starting pointWrite surfaceUse if have problem mesh for display purposesTetrahedral meshing parametersNon-Conformal Meshing1.A non-conformal mesh is one where there is transition from many cells to one cell2.In Icepak, assemblies of objects can be meshed non-conformally 3.A “slack or

178、envelope can be defined around a particular assembly and the resulting region is meshed independent of the mesh outside4.This enables embedding a fine mesh within the assembly sub-region without leading to cell bleeding, while the model outside the assembly has a course meshMesh for AssemblyMesh in

179、Main ModelNon-conformal InterfaceNon-Conformal meshing - AssemblyThe first thing to do is to edit the assembly, and turn on the option to mesh separately.Next, add a “slack region around the assemblyBy default the bounding box of the assembly is the min/max extents of the objects making up the compo

180、nentSlack region allows the user to re-define the bounding box, to make it slightly larger than the objects making up the component. Assembly defining slack1.The assembly bounding box must have sufficient slack so that its sides do not touch any Icepak object2.Cabinet, walls and hollow block are the

181、 only objects that may touch the sides of a non-conformally meshed assembly3.All objects except conducting thin plates and hollow blocks can intersect an non-conformal assembly the portion within will be meshed non-conformally4.Any object can lie completely within the non-conformal assembly even tho

182、ugh it may not be a part of the assemblyRules for non-conformal meshing (1)For example, in this model a 1U heat sink design is modelled as an assemblyBy default the bounding box would be the the size of the base in the x-z dimensions, and extend to the top of the fan casing. Where the fins touch the

183、 default bounding box, there would be a solid cell on the internal side of the interface, and a fluid side on the outside of the interface - this is currently not allowed by the solverAdequate slack must be specified, as in the figure below, so that the assembly bounding box does not touch the heat

184、sink fins After specifying the slack the assembly can cut through a solid or fluid object, as the PCB is cut in this exampleRules for non-conformal meshing (2)Bounding Box of AssemblyPCBMultiple assemblies can be meshed separately provided:Assemblies are not be embedded within each other In this ins

185、tance, choose not to mesh the embedded assembly separately. Then it will be included in the non-conformal interface of the larger assembly.Assemblies do not touch So the bounding box of one assembly cannot share a surface with the bounding box of a second assemblyAssemblies do not intersectRules for

186、 non-conformal meshing (3)In this example, either the TO220 can be meshed separately, or the heat sink can be meshed separately, as the bounding box for the TO220 lies inside that for the heat sinkThe best option here, is to mesh the heat sink separatelyBounding box for Heat SinkBounding box for TO2

187、20Example:Once the regions have been defined for each assembly, then under the meshing panel, turn on the option to mesh assemblies separately.Icepak will then mesh the model and embed a finer mesh on the assembly region.Both the Hexa-Unstructured and Hexa-Cartesian methods can be used to mesh assem

188、blies separately.Conformal Mesh - 111,329 cellsNon-Conformal Mesh - 77,149 cellsMeshingSolver Topics Problem setup basic parameters Solution settings Solver Monitoring solution progress Parametric studies Transient solutionsProblem setupModel Tree Problem setupProblem setup panelParametric trials pa

189、nelTitle and notes panelDefine time variation: steady state transientDefine equations to solve: Variables solved Flow situation Heat transfer modeDefine default values: Ambient values Default materials Initial valueProblem setup: Basic parametersMiddle portion of problem setup panel Check Flow to so

190、lve Navier-Stokes equation Check Temperature to solve energy equation Check Gravity vector to include buoyancy terms in the Navier-Stokes equation (free convection) Radiation on include radiation heat transfer in energy solution Appropriate flow regime Laminar or Turbulent (zero equation/ 2 equation

191、/ RNG models)Problem setup: Equations to solveProblem setup: Equations to solveUseful NotesConduction only problemsCheck only Temperature and uncheck Flow Ensure appropriate heat transfer from wallsForced convection problemsflow is usually independent of energy equationpossible to solve for flow alo

192、ne first and then for energy aloneNatural convection problemsflow and energy equations are interdependent and must be solved togetherRadiation heat transfer is significant and should be includedTurbulent flowZero equation is sufficient for most cases in electronic cooling2 equation and RNG models ma

193、y be used for detailed wake behavior, jet impingement, etcSolution settings Solver setupPurpose Solver termination criteria Max. no. of iterations Convergence criteria for Flow equations Energy equationSelect Accept to accept changes Reset changes all fields to default values- also displays the Reyn

194、olds/ Grashoff* number for the problem in the messages window*These numbers are based on maximum cabinet dimension, characteristic velocity and temperature, and only serve as a very approximate guideline. The user should judge whether the flow will be laminar or turbulent.Advanced solver controls Di

195、scretization scheme Under-relaxation factors Multi-grid linear solverPrecision level single/ doubleSolution Settings Advanced solver setupUnder-relaxation a note This determines the relative amount of change in the variables after each iteration for simple forced convection situations use 0.3 for pr

196、essure and 0.7 for momentum for natural convection, or complex forced convection situations (examples twisted flow passages, sudden changes in cross section, densely packed models) use 0.7 for pressure and 0.3 for momentumSolving the momentum eqs for velocity (V) using current pressure (p) filedSolv

197、e the V-p coupling eq. for pressure using the new V fieldSolve the T, k, e eqs using the new v, p fieldConverged?StopYesNoSolver - The SIMPLE SchemeSolver Starting the Fluent solverThe basics:Solution ID - type in a unique IDdefault is +Write overview of results summary report of mass and energy bal

198、ance, fan operating points, etc.Start solution starts the Fluent solverresiduals window opensshows residual curves for each equation: continuity, momentum in x, y, z directions and energysolution will stop when the residual curves satsify convergence criteria, or number of iterations (both specified

199、 in Solver Setup panel)Solver Residuals and Overview reportStop solverChange scalePlot optionsResidual windowOverview reportSolver Advanced featuresRestart from an existing solutionSpecify the existing solution IDSelect Full data if the current mesh is the same as in the restart solutionSelect Inter

200、polated data if mesh is differentJob can be submitted to any computer on the network and at any timeAvailable in forced convection problems - first solves flow equations alone till convegence, then solves energy equation - useful in large modelsCan disable radiation hereAuto-save interval =N solutio

201、n is saved after every N iterationsMonitoring solution progressMonitor object center:Drag selected objects into the Monitor points branchThen double click the object to open the variables panelSelect variables to monitor and acceptMonitor any defined point:Go to Main menuSolve Solution monitorDefine

202、 points and variable to monitor at that pointDouble click Why monitor: One more way to ensure convergence Possible to monitor velocity, temperature or pressure at specified points 2 ways to define point monitors: monitor object center, or any defined pointParametric studies Defining variables Uses:

203、optimization tool allows definition of variables and generates solutions for each value of the variable How to define a variable instead of numerical value, enter a string as the variable name Variable name must always begin with $ In the example shown here the heatsink overall height “$HS_ht and th

204、e fan flow rate “$cfm are the variables After the variable is defined Icepak prompts the user for the initial numerical value of the variable Additional values can be assigned to the variables under Model tree Problem setup Parameters Parametric variables can be used in equations for example: for th

205、e heat sink specify Overall height as “$extra_ht + 4 mm The characters -, , # should not be used in parameter namesParametric studies setting values & solving Specify values for the variables in the “Parameters panel Then click on “update trials This updates all combinations of the variables in the

206、“Select trials panel and opens the “Trial naming prompt Numbered: solution ID is serially numbered with a prefix Values: solution ID is named based on the value of the parametric variables Solving: in the solve panel select “perform multiple trialsParametric studies select/ set/ restart IDAll checke

207、d trials will be solved uncheck to excludeSet button applies the combination of parameter values in that row to the model useful to check the different trials in a modelRestart trial ID each parametric trial is restarted from the previous trial solution by default using interpolated restart to resta

208、rt from a different solution enter the required solution ID in the Restart trial ID columnSelect Transient in Problem setupSpecify start and end timeEdit parametersSelect size of time stepsuniform or variableSolution save intervalCaution: setup here needs to synchronize with the corresponding model

209、parameters that change with timeTransient power specification feature in blocks and sourcesTransient solutionsHeat Transfer Physics ModelsTopics Governing equations Turbulence models in Icepak Natural convection Radiative heat transfer Mesh refinement Multi-fluid problemsGoverning equationsThe equat

210、ions that govern fluid flow and heat transfer used by Icepak are, The continuity equation (governing conservation of mass):The momentum equations (governing velocity distribution):The energy equation (governing the temperature distribution):Where, u = velocity vectorr = densityT = temperaturep = pre

211、ssuret = time=stress tensorg = gravity vectorb = volumetric expansion coefficientCp = specific heat at constant pressurek = thermal conductivityQ = volumetric heat sourceTurbulence models in IcepakTurbulence is unsteady, aperiodic motion in which all three velocity components fluctuate mixing matter

212、, energy, and momentumTime-averaged statistics of turbulent velocity fluctuations are modeled using functions containing empirical constants and information about the mean flowIcepak offers 3 options of turbulence models which can be selected in the problem setup panel:Zero equation modelTwo equatio

213、n modelRNG modelZero equation model is economical and accurate for most electronic cooling situationsTwo equation and RNG models are computational intensive and should only be used in severe cases of turbulence, such as jet impingementTurbulence1.The nature of the problem is determined by the values

214、 of certain dimensionless groups2.Reynolds number - appropriate measure for forced convection3.Re 105 - use turbulence model 4.Re 109 - use a turbulence model7.Ra30, where where, y = distance of cell center from the surface, uf = freestream velocity, cf = local friction coefficient, n = kinematic vi

215、scosityRNG modelDerived from the instantaneous Navier-Stokes equations using a rigorous statistical technique called re-normalization group theory (RNG).Similar in form to the standard k- model but includes the following refinementsAdditional term in the transport equation that improves accuracy for

216、 rapidly strained flowsEffect of swirl on turbulence is includedUses an analytical formula for the turbulent Prandtl numbers as opposed to constant valuesWhilst the standard k- model is a high-Reynolds number model, the RNG theory provides an analytically-derived differential formula for effective v

217、iscosity that accounts for low-Reynolds number effects.Effective use of this feature depends on appropriate treatment of the near-wall regionNatural convection General form of momentum equation (excluding non-gravitational body forces): By default buoyancy forces are ignored appropriate for forced c

218、onvection To include buoyant forces in the momentum equation switch on the gravity vector g in the problem setup panel Define gravity vector g by specifying its x,y and z components g = (0, -9.80665,0) by default Note: Temperature gradients are the driving force in natural convection problems. There

219、fore solve the momentum and energy equtions simultaneously - do not attempt to solve them sequentiallyqxygxgygbuoyancy forces In a steady state pure natural convection problem (no fans/ blowers/ velocity openings /pressure openings) the momentum equation can be simplified to where is the bulk medium

220、 density Icepak provides a choice of 2 models for the temperature effect on density Boussinesq approximation and ideal gas law Boussinesq approximation:neglects all variable properties in the governing equations except for density in the momentum equationapproximates the density difference term as w

221、here b is the volumetric coefficient of thermal expansion (=1/T for ideal gas) Boussineq approximation is the Icepak default model and works very well for the vast majority of electronic cooling applicationsNatural convection: Boussinesq modelNatural convection: Ideal gas modelDoes not make simplifi

222、cations like the Boussinesq approximation should be used when fluid density fluctuations in the model are expected to be large to apply ideal gas law, open the advanced panel under the gravity vector in problem setup panel = (Pop/R T) Must set an appropriate operating (mean) pressure Option also to

223、set an operating (mean) densityOpen environement:The domain needs to be sufficiently large so that the default boundary conditions do not effect the results gradients of variables normal to the sides should be small.Rule of thumb (without reference): 2x unit height above, so thermal plume is capture

224、d accurately 1/2x width on either side If pole mounted - 1x height below Use openings to model sides of the domain to “expose the unit to the open environmentNatural convection: Type of environment 2x height of unitUnit modeled 1/2 width of unit 1x height of unitClosed environment: Ensure heat trans

225、fer happens through wall objects on cabinet boundaries Otherwise the problem is not well defined and will divergeRadiative heat transferIcepak includes a surface-to-surface radiation modelRadiative heat flux between surfaces depends onSurface temperature (specified BC or computed)Surface emissivity

226、(specified material property)Form factor from one surface to the other (computed or specified before solution)When to include radiation calculations in the modelInsignificant in forced convection problems exclude radiationOften critical in natural convection/ mixed convection problemsRadiation: Assu

227、mptions in IcepakFluid medium is usually airThus absorption, re-emission, scattering by medium can be ignoredOnly surface-to-surface radiation is modeledSurfaces are gray Emissivity and absorptivity are independent of wavelength Kirchoffs law emissivity ( )=absorptivity ()Surfaces are diffuseReflect

228、ivity is independent of outgoing or incoming directionsSurfaces are opaque to thermal radiation (in the infrared spectrum)Transmissivity can be neglectedRadiation: EquationsThe heat transfer due to radiation from surface 1,temperature T1 to surface 2, temperature T2 is given by:Q = radiative heat fl

229、ux between the two surfaces (Watts in SI)s = Stefan-Boltzmann constant (5.669e-8 W/(m2K4)e = emissivity (has a value between 0 and 1)f = view factor ( the fraction of energy leaving surface 1 that is intercepted by surface 2)T = absolute temperature (K=C+273)User has options for controlling radiatio

230、n calculationsMay chose which surfaces participateMay also specify radiation to a fixed temperatureObject surfaces that are to take part in the calculation can be defined using the edit panel for that object.Radiation can also be defined on a side by side basis, with sides having different materials

231、 etcAlternatively, objects to take part in the calculation can be chosen from the form factor panel using theicon from the shortcuts toolbarSetting up radiation calculationsForm factors panelSpecify which objects participate in radiation User may override computed form factorsSelect objects to have

232、form factors displayedSelect sides of object to display form factors forControl of mesh coarsening used in preparing input for form factor calculation (-1 disables coarsening)Set minimum value for displaying or loading form factors - recommend setting load min to 0.0Choose which approach, and accura

233、cy of calculationCompute form factorsForm factor options Hemicube MethodView factors of all participating surfaces are computed together AdaptiveView factors are computed on a pair-by-pair basisSo called because the algorithms used change based on the geometric environmentView factors are chosen bas

234、ed on a number of algorithmsFor un-obscured surfaces Analytic - where very close; Gauss quadrature - for other surfacesFor partially obscured surfaces Monte-CarloEach methodEnsures that view factors add to one from each surface (conservative)if domain is “closedEnsures that view factor reciprocity i

235、s satisfied (consistent)Form factor options: ComparisonsComparison:Hemicube is faster for large complex modelsKeep reference level at 7 for higher accuracy (default)Reduce reference level to 3 to reduce computation timeAdaptive faster for simple modelsThe Coarse option will be faster but less accura

236、te16 packetsThe Refined option will be slower but more accurate64 packetsTry re-using view factors as much as possibleIf geometry changes are minimalTurn on the “Dont re-compute optionEspecially important for parametric trialsView factors all only based on geometryLoad any view factor file using the

237、 Load optionUse that file for subsequent runsRadiative heat transfer: TipsTry re-using view factors as much as possible For minimal geometry changes switch on the “Dont re-compute option time saver in parametric trials load any view factor file using the Load option use that file for subsequent runs

238、 For non-convex shapes example radiation between heat sink fins turn on “Show with self in the form factors panel Export/ Import to save view factors to/ to read view factors from ascii file Reduce the size of the calculation by De-activating objects that are insignificant to radiation Calculate for

239、m factors Export Re-activate all objects Import Viewing form factorsMesh refinement Aims of a refined mesh Accurate prediction of heat flow in solid and fluid media accurate prediction of fluid flow especially in the boundary layers achieve the above two aims with minimum time loss Increase mesh den

240、sity in areas of high gradients of temperature or velocity Add sufficient cells to capture physical phenomena Turning/Recirculating flows Velocity profiles - heat sink channels Contraction and expansion regions Maintain reasonable growth ratios For areas where the gradients of velocity and temperatu

241、re are small, a ratio of between 5 and 10 is acceptable Where needed reduce to between 1.2 and 2Mesh refinement Flow boundaries such as grilles/ openings/ fans use 3 cells or more in each direction Number of elements in small gaps (such as between heat sink fins) atleast 3 and ideally 4 Natural conv

242、ection problems refine the mesh around power sources, thermally conductive solids and wallsIncrease mesh density in areas of high gradients of temperature or velocity Add sufficient cells to capture physical phenomena Turning/Recirculating flows Velocity profiles - heat sink channels Contraction and

243、 expansion regions Maintain reasonable growth ratios For areas where the gradients of velocity and temperature are small, a ratio of between 5 and 10 is acceptable Where needed reduce to between 1.2 and 2 By default the cabinet is assumed to be occupied by air, Specified in Problem Setup/Basic Param

244、eters menu. Switch to a different default fluid if required by changing the material assignment To incorporate a secondary fluid that is different from the cabinet fluid, use fluid blocks and assign a new fluid material Various shapes of blocks can be used: Prism, Cylinder, etc. Several blocks can b

245、e connected to form a channel (conduit) of the secondary fluid. Actual fluid is modeled The fluid blocks must be separated from the cabinet fluid by a solid surface For example to construct a cylindrical shaped secondary fluid (e.g. for cold plate analysis) First, construct a solid block Second, con

246、struct a fluid cylinder inside the solid block giving it a smaller diameter than the solid block dimensions The combination of these two blocks forms a secondary fluid body inside a solid conduit.Multiple fluid problemsPost-Processing and ReportingObject facePlane cutIsosurfProbePointVariation along

247、 a lineHistory plot (transient)Trial plot (multiple solutions)Transient solutionLoad solution I.D.Summary reportPost-Processing Tool BarMost of the functionality is common to both the tool bar and the menu optionsIn addition from the menu there are options to save out the post-processing objects, ch

248、ange their units, and review the report generated during the solution (if created)Zoom-in models can also be generated from this menuPost-Processing menu optionsVariables in post-processing and reportingCreates a plot on the surface of one or more objects, assemblies or groupsSelect the object(s) fr

249、om the pull down list and choose which sides and type of display to look at.Click Create to view the results on those surfacesObject FaceDisplays the results on a plane cut through the modelChoose how to set the position, and enter values if necessaryChoose what to display and clip Icepak will plot

250、the data on the planeThe plane can be “dragged through the display using the scroll barThe plane can also be animated so that it steps through either the entire model or the clipped regionPlane CutUsing the Clip to box option, a box within the model can be defined, and the view displayed on the post

251、-processing object is limited to the region lying within that boxClip To BoxDisplays the results on a surface defined by a specific value of a particular variable.Again, can clip the display to a particular box.Iso-SurfaceCreate or use existing points to examine the temperature at specific point in

252、the modelOptions include ability to display the local velocity vector at that pointSource point particleUsing the shift+left mouse key can also drag the point through the modelIcepak Reports the position and result data in the bottom right hand corner of the GUIPointOnce a post-processing object has

253、 been created, you can use the mouse probe to find out temperatures at specific points on the active object.Create the object, or activate an existing objectClick on probe in the Icepak edit panelUse Left mouse button to click on a point on the object, Icepak reports the value of the variable being

254、plotted at that point in the GDAToggle between selection and translation of the model using F9 keyRight mouse button to quitFor multiple point probes click on the probe icon for each new pointProbeContours can beSolid plots with smooth shading or banded shadingLine plotsBoth With line or banded shad

255、ing options the levels can be defined usingIntervalSet a start point and incrementFixedChoose number of bandsInputUser defines valuesColour Levels can beSpecifiedCalculated - global limits, current object or the range currently visible Contour ParametersVelocity vectors can be colored by a the local

256、 value of a scalar variable, or have a fixed color, or be colored by velocity magnitudeThey can be displayed at the mesh nodes, or uniformly over a surface or planeThe arrow head can either be displayed or not by changing the arrow styleThe vectors can be scaled based on A multiplying factorMax leng

257、th for VectorVectors above a specified value can be suppressed from the viewColor levels can be based on global, current or visible rangesVelocity ParametersParticles can be seeded form any surface, plane or point Seeding can be based on a uniform distribution, or using the mesh nodesThe start and e

258、nd time of the trace must be set, together with the increment to useThe colour range is controlled in the same way as for contour plotsParticle Track Parameters (1)Tracks can be Dye trace and/orSeparate ParticlesTracks can be animated, with full control on defining the frame stepping and can be writ

259、ten to fileParticle Track Parameters (2)Display of Particle Tracks from FanPlots the variation of a variable along a lineThe line can be defined using The point and normal directionFrom the ScreenSet the view and click on a point on screenIcepak automatically calculates the point, and the directionF

260、rom two point objectsVariations along different lines can be displayed simultaneouslyData can be saved to file and loadedVariation PlotPlot CreatedWhere there are more than one solution available for a particular project, for example when a parametric case has been run, the value of a variable at sp

261、ecified points can be used to compare the various versions of the model. Trial PlotPlot CreatedFrom the top level menu you have options to createHTML reportsSummary reportsPoint reportsFull reportsNetwork block valuesJunction Temperature of network blocksFan operating pointOperating point of any Fan

262、 using a characteristic curveAlso option to export data for use with AutothermReporting OptionsCreates a web-based report that can include,Title, Text Modelling informationProblem SpecificationSource DissipationsFan informationVent informationCreating an HTML ReportAlso can items such asFiguresPost-

263、Processing Objects for different solution IDs,Also can change viewing position, to change the orientation of the modelReports for different Solution IDsText above and below any item addedCreating an HTML ReportChoose Object(s) to report onSelect solution ID to report, or time step if unsteadyWrite t

264、o file and/or screenChoose Variable to reportCombine data on all sides of all selected objectsActiveCreate a new reportLimit report to specific SidesClick to generate reportCan select multiple solutionsSummary ReportsOutput of Summary ReportIf you want to create a summary report of heat flux or heat

265、 flow, you need to specify whether you want Icepak to calculate the inflow value, the outflow value, or both. If you specified the temperature on the side of a solid block or on a 2D source, you should select Both for that surface. If you specified the heat flux on the side of a solid block or on a

266、2D source, you should select Both for that surface. If you have two objects touching each other, the inflow for one object will be the outflow for the other object. For example, if block.1 and block.2 touch each other (and there is no generation at the interface), then a report of outflow of heat fo

267、r block.1 would be a report of the amount of heat leaving block.1 and entering block.2. A report of the inflow of heat for block.1 would be a report of the amount of heat entering block.1 from block.2. In all other cases you should use Outflow to find the heat leaving the boundary in question. Heat

268、flow and Heat flux reportingIf you select Heat tr. coeff under Value, you need to specify the reference temperature for the heat transfer coefficient. To specify the reference temperature, Click the Edit button under Params to the right of the Value text field Enter the Ref temp in the Heat tr. coef

269、f panel (default is ambient)Reporting Heat Transfer CoefficientOperates in a similar way to summary report, Choose the point or enter co-ordinates in the usual way and Choose Variable to report onWrite to file or windowIcepak creates report with position of the point + value of the specified variabl

270、ePoint ReportConvenient way to report min/max/average values throughout the entire cabinet, a particular sub-region, or a particular objectEntire objectMin XMax XFull ReportMass and heat balance Is there sufficient cooling in the system?Where are the hot spots/problem areas?Fan operating point Is it

271、 reasonable?Is it shunting ?Should swirl be included?Vent positioningCould the flow into/out of a vent be improved by repositioning the vent?Is the vent necessary?Flow through systemHow is the fluid being moved through the system?Re-circulation/Stagnant zonesShort circuitsCould the flow pattern be i

272、mproved?Principle mode of heat loss in the systemHeat loss to surroundsSystem Level QuestionsKey temperatures - junction temperature, surface temperature of components and board Split of heat losses from top/sides/base of component - which is the dominant conduction path Efficiency of cooling mechan

273、ismComponent/Package Level QuestionsProfiles and Zoom-In Modeling A profile condition is a spatially varying boundary conditionProfiles use a grid-grid interpolation routine to create profile of temperature or velocity components on openings or wallsUses Include:Zoom in/Zoom out solutionsApplying a

274、fully developed channel profile Calculate the developed profile in a simple model of wind tunnel section (without equipment under test)Apply to model with equipmentReduces size of upstream section neededReduces meshOptimizes model runtime and efficiencyIncreases accuracyProfile Boundary Conditions1.

275、Profiles of variables can be applied to both Walls and Openings 2.Openings3.Pressure4.Temperature 5.X, Y, Z, velocity components6.Walls7.Outside heat flux8.Outside temperature9.External heat transfer coefficient 10.Reference temperature fixed11.Sources12.Profiles of heat flux per unit areaIcepak Obj

276、ects that can use ProfilesCreate profiles manuallyObjective: Create a temperature distribution in a wall object, as shownIn the walls edit form/properties sub-panel/ outside temp check “Profile and click the “Edit buttonThe curve specification form opensSpecify the x, y, z values of the center of ea

277、ch region (20oC, 25oC, 30oC regions), and the temp b.c. in that region each row will therefore contain 4 numbers: xyzTThe 4 values can be separated by spaces or tabs20oC25oC30oC0.20.30.10.30.150.2Profiles are automatically created if you use the zoom-in model creation feature. Profiles can be writte

278、n from any post-processing contour plot Object face, plane cut, etcUnder Parameters option to “Save ProfileSaves point co-ordinates and valueCreating profiles by post processingZoom-in modeling: introductionComponentBoardSystemDimensions range: mm (dies), mm (fins/solder), m (enclosure)System/ board

279、 level model with full details huge mesh count increased computational power requirements simplifications yield “a solution accuracy?What do we do: Zoom-in model is a good option to eliminate all the above bottle necksZoom-in Modeling: Procedure Simplify the system level model using suitable approxi

280、mationsExample thermo-volumetric models of heat sinks, uniform lumped source to replace closely spaced power sources Solve and post-process the simplified system level modelDetermine fan operating points, capture flow and temperature fieldsTemperature field trends are more important than accuracyFlo

281、w field - possible to capture with good accuracyDecide region to zoomin - capture velocity, pressure & temperature profiles at the faces of the zoomin box Build sub-system level model within the zoomin boxUse detailed components eliminate system level simplificationsImpose the captured velocity, pre

282、ssure and temperature profiles as boundary conditions of the sub-system level model EXACT BCTo open the zoom-in panel, go to main menu/ Post/ create zoom-in modelSelect location of bounding box (white bold outline) with the mouse, or enter the co-ordinates, or snap using the “Select buttonSpecify th

283、e type of boundary condition on each side inflow/ outflow/ wallIcepak creates a new project consisting of objects within the zoom-in box - overlapping objects can either bere-sized to fit, or excluded from the zoom-in modelProfiles of velocity, pressure and temperature are automatically generatedIce

284、pak automatic zoom-in1.Different sets of variables are profiled, depending on the type of boundary condition specified2.Inflow boundary:3.Free opening in zoom-in model4.variables - ux, uy, uz, T (components of velocity, temperature)5.Outflow6.Free opening in zoom-in model7.variables - P, T (static p

285、ressure, temperature)8.Wall9.Stationary wall in zoom-in model10.variables - T11.Note:12.If boundary openings are specified in the zoom-in model at least one should be outflow13.Should be placed where most of the flow will be out of the sub-regionProfile variables in zoom-inSystem level solution has

286、no details of componentsChoose the bounds the region of interestWrite out inflow/outflow/wall conditionsChange the zoom-in model to add in board layout detail System levelSub-system levelExampleFor the following example, all 6 boundaries were flow boundariesThe min/max x, y faces were set as inflow

287、boundariesThe min z face was set as a outflowThe min z face was set as a wall System Level ModelZoom-In ModelExampleCAD Imports IGES ImportImport IGES files created from your CAD package directly into IcepakThe procedure: Model the design using any CAD productExport the CAD data as IGES formatRead t

288、he IGES file into IcepakModel/ CAD DataConvert the CAD geometry into Icepak objectsApply boundary conditionsConduct CFD in IcepakIcepak can import Surfaces Curves Points or a combination of ALL THREEIcepak converts the IGES file into TETIN file Native ICEM CFD geometry format Tetin file read into Ic

289、epakThe model must already contain a cabinetLoading and IGES FileLoad IGES file using Model/ CAD DataChoose to import formats IGES Tetin available if previously read in and quickerOn clicking ACCEPT, Prompted for the units to use Multiple IGES files can be read into sameIcepak model (repeat the proc

290、edure above)Select the IGES file and choose what data you want to import Surfaces Curves Points Combination of THREE CAD Import OptionsOptions available via Model/CAD Import/Options onImporting your CAD GeometryUse Autoscale to fit the cabinet to the imported CAD geometry Can scale after import by u

291、sing cabinet autoscaleMinimum Feature size Sets global tolerance that controls the level of detail transferred, objects below not imported Removes CAD geometry that is smaller than a specified size after importConverting CAD Geometry into Icepak ObjectsThere are THREE ways in which you can translate

292、 your CAD geometry into IcepakSelect a surface or group of surfaces and convert them into an Icepak objectSelect a family or several families and convert them into objectsSelect a region of the model, divide it into segments, convert the CAD geometry in each segment into an objectConverting CAD Geom

293、etry into Icepak Objects(i) define a region of the model you want to work on and (ii) divide the region into segments.Icepak then converts the CAD geometry in each segment into an Icepak objectSurfaces to be used to create plates inside a regionWhen prompted draw lines to create regions h-horizontal

294、, v-verticalDivide the region up using vertical linesMiddle mouse to acceptRubber-band select a region containing surfaces (remember m) Middle mouse to finishIcepak converts surface to a plate for each regionIDF ImportIcepak can import Intermediate Data Format (IDF) Files (exported from and ECAD pac

295、kage)IDF is a neutral file format supported by many ECAD packages Allegro from CadenceBoardstation from MentorVisula from Zuken-RedacAlso some mechanical CAD packages support IDFPro/EngineerSCRC/IDEASUnigraphicsIcepak supports IDF 2.0 and IDF 3.0 - IDF 4.0 (once packages export to this format)IDF 2.

296、0Board File - data on outline of board, thickness and component positionsLibrary File - data on component sizes, thermal and electrical propertiesIDF 3.0Board and Library filesOptional Panel File - Rack placement informationAlso includes junction to case thermal resistance information and operating

297、power Not in IDF 2.0Simple importBoard modeled as a block, power applied as a single distributed value to blockFirst cut analysisDetailed importMore control over features to be imported from ECAD to Icepak Importing an IDF file into ICEPAKGo to File/Import and click on IDF file in the menuThis will

298、open the Import IDF file menuSpecify the files to be used for the board, library and panelClick the pink Browse button to launch the browser and choose a fileEnter a project name to be used ( or use the default project name Icepak assigns)Click NEXT to move onto to specify details on feature importI

299、cepak will automatically detect which version of IDF you are usingImport SpecificationChoose Board OrientationMake board Rectangular of PolygonalPolygonal - cutouts at edge retainedImport Drilled Holes:If Active can specify the hole size below which holes are ignoredConvert polygonal components to p

300、risms optionClick Next to move onMinimum feature size- for polygonal imports onlyCutouts smaller than feature size will be ignoredImport TypeSimple - Board only imported, and no further inputs needed - click next to finishDetailed - Board features and componentsAdditional Imports for Detailed Import

301、 OnlyKeep components that are larger than a specified sizeOr keep components with a dissipation greater than a specified value - include only those that are important to the thermal modelClick Next to move onAdditional Imports for Detailed Import OnlyChoose component model and cutoff height for 3D c

302、omponentsLoad data from file or specify values for each componentRound to a sensible value eg: 5mm in this caseClick Finish to create Icepak model of board and componentsDetailed representation (solid blocks)Detailed representation - all components modeled as solid blocksDetailed Representation (Sources)Detailed representation - all components modeled as planar sources