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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:8primitive objects such as blocks, plates, fans, vents, resistances, etc., or8Macros 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- Q
13、uit 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 Exi
14、sting 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 & PRO
15、BLEM 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
16、 be 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
17、/unpack 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
18、from 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 toolba
19、r Shortcuts toolbar Model tree Mouse functions Model orientationInteractive editing toolsIcepak GUI mapGRAPHIC DISPLAY AREAPROJECT LABELMODEL TREEMESSAGESOBJECT GEOMETRYMain MenuShortcuts ToolbarMODELTOOLBARIcepak GUIgraphic display areamodeltreemessagesobject geometrymain menushortcuts toolbarmodel
20、toolbarproject 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 toolb
21、ar: 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 o
22、f selected 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 GDANOTE: Place the mouse on an icon for a bubble message description of the iconIntrod
23、uction 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 bl
24、ockPlate 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.
25、res.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 face
26、sAlign 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 file
27、File icons .UndoRedoObject facePlane cutIsoSurf PointSurface 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
28、 mesh 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 mode
29、l branch 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 secti
30、ons are 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
31、 any 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
32、expandable 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 mo
33、use or 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
34、delete 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 POSIT
35、IONING 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 Bindin
36、gsDouble 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
37、 screen; 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-zo
38、om Zoom 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
39、 a new 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 curre
40、nt orientation 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 menuV
41、iew menu contains several useful tools for:4Geometric measurements4View optionsGeometric measurements:4Location display point* coords in messages window4Distance display dx, dy, dz and distance between selected points* in the messages window4Angle display angle between vectors defined by 3 points* i
42、n the messages window4Markers graphic version of Location function4Rubber 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
43、 color is black; 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 contro
44、ls how these movements 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 gr
45、id mouse movement 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 TopicsO
46、bject Shapes in Icepak 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 PolygonPlatesOpening
47、sGrillesWallsFansSourcesBlocksResistancesHeat 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
48、 form/ geometry sectionGeometry 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 c
49、hangesCurrent objectShapes 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 Chang
50、e angle directionPosition 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 Icep
51、ak: Options for 3D 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: Op
52、tions for 3D shapes - 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 f
53、or the selected objectPlaces 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 avail
54、able to youObject 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 Dim
55、ension MatchedThere are two options Left Click on Icon4Object gets re-sized during alignment Right Click on Icon4Object 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
56、in the same way Click 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 selecti
57、on use MIDDLE MOUSE 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 cance
58、l the operation with 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,z
59、E) Length (xL,yL,zL) 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
60、 the following ways8Double clicking the object in the tree8Right clicking the object in the tree and selecting “Edit object” from the pull down menu8Select the object in the tree and click the “Open edit form” icon in the vertical Model Toolbar8From the main menu, picking “Edit/ Current object/ Edit
61、”8Using the keyboard short-cut 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 f
62、rom existing onesPull Down MenuEditing 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 ad
63、ditional information required 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
64、:LengthTemperatureFlow rateConductivityPowerUnits: 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
65、time during model building When 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 conve
66、rt all quantities to SI/ Imperial/ 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
67、 value is remains unchanged when 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 Object
68、sNo flow objectsCabinet (default)WallsBlocksPlatesSourcesFlow objectsOpeningsGrilleVolumetric Resistances2D - FansHeat ExchangersMaterialsSolidFluidSurface Composite Objects3D FansEnclosuresPCBsAssembliesHeat SinksPackagesNetworksCreating New ObjectsWays to create and position objects in IcepakClick
69、 on object icon and edit it, or 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 sn
70、ap to 1mm then position is limited 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
71、 Default dimensions: 1 x 1 x 1 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 caus
72、ed the object to go out of cabinetObject 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: Pro
73、pertiesDefault cabinet properties:8Walls are adiabatic 8Walls have zero velocityOvercome these constraints by placing following objects on cabinet sides:8walls energy transfer only8openings, vents and fans flow and energy transferThe cabinet form lets you impose any of these objects on the entire si
74、de(s) of the cabinet these objects 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 Sy
75、mmetry Moving Wall thickness may be 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 hav
76、e heat transfer specification to the outside8Outside heat flux8Outside temperature8External conditions/ heat transfer coefficientSymmetry walls - reduce model size when the model is symmetric about a plane8Adiabatic and Frictionless8Zero flux and flow through wallCan specify spatially varying profil
77、eMoving walls - account for motion in the plane of the wall8Thermal inputs of stationary walls8Wall velocity vectorBlocksDefault Icon:Default color: PinkCan be meshed with either MesherMust be meshed with Tetrahedral -MesherBlocks: Thermal modelsDefault Icon:Default color: Pink4 Thermal ModelsHollow
78、 blocks No mesh within the block no equations 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 modelsD
79、efault Icon:Default color: PinkSolid blocks 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 bloc
80、k with thermal resistance network inside the 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 Resist
81、orStar networkFull shunt networkBlocks: Thermal dataDefault Icon:Default color: PinkSurface data all block types Radiation 4 Discussed Later Individual Side Specifications 4 Thermal Properties -qTotal Power, qFlux or qFixed Temperature4 Heat transfer coefficient to model qconductance per unit areaqc
82、ontact resistance4Radiation specification for a sideBlocks: 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 problem
83、s, fluid blocks must not have a common interfaceNetwork 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
84、 with small thickness Conducting thin for solid objects 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 t
85、hermal data: Only 2 faces available cannot specify data 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 me
86、shed Power options constant, temperature dependence, Joule 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 Condu
87、ction in the through-plane direction only Constant power 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
88、 power specification or surface data Used to punch through 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 face
89、sBlockSolid3D object interior meshedHighestSolved in 3DAll 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 norma
90、l to planeOnly 2 sides high & lowSourcesDefault Icon:Default 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 tem
91、perature Power flux (2D sources) can be specified as a 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
92、 power sources, packages, dies, component foot-printOpenings: 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
93、 cabinet sides or hollow block faces Drill holes through 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
94、tunnel where inlet velocity or pressure profile is knownOpenings: 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 Extrac
95、t takes flow from domain Supply supplies the same flow 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 diff
96、erentFlow rate Mass flow Mass fluxHeat transfer Temperature 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 coeffi
97、cients quadratic/ linear/ combinationCan be calculated 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 exter
98、nal pressure is static pressure Default (ambient) pressureFlow 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
99、quadratic/ linear/ combination loss coefficient specifications 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: PurpleVolumetr
100、ic Resistances: ExamplesExample: Compact heat sink model 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 volum
101、e using pressure drop relationship Test model in computational 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 Exh
102、aust flow normal pointing outwards Intake fans flow normal 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:
103、 fixed volumetric/ mass flow 4Not applicable to internal fans linear fan curve (pressure head volumetric flow)4 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 Inp
104、ut Options If failed fan, specify a free area ratio Model 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/lo
105、aded using the graph editor.Text editor4 Enter flow and pressure head points in pairs - first flow rate then pressure head4 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 editor4 Follow the rules a
106、bove4 Create curve using mouse follow instructions below the graphqleft mouse = zoomqmiddle mouse = create/moveqright mouse = deleteHeat exchangerDefault Icon:Default color :PinkHeat ExchangerTwo loop heat exchangerparallel flow or counter flowsingle or multiple passesInner and outer loopsCan be the
107、 same or different fluidsinner loop is typically the air inside 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 converte
108、d to a 2d representationsignificant cell count savingsEquivalent 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 colo
109、r :PinkHeat exchanger : FlowDefault Icon:Default color:pinkPressure 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: H
110、eat transferDefault Icon:Default color:Pink Heat Transfer Fixed 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:Defaul
111、t color: None Ways to assigning a material to an object/ surface4use the relevant pull down menu and select the material4select material in the tree and drag into the object in the tree Materials are split into three main categories with sub-types 4Solids: Insulators/Semi-conductors/Metals and Alloy
112、s/Plastics etc.4Fluid: Gases/Liquids etc.4Surface: Used to specify emissivity and surface roughness Created through 8Materials icon8Materials 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 be8Edited8C
113、hecked - values displayed in the message window8Default Icepak materials cannot be editedMaterials: PropertiesDefault Icon:Default color: None Fluid and Solid properties values maybe4Constant,4Linearly dependant on temperature4Piecewise linear For Fluids the conductivity can also vary with velocity4
114、Compact heat sink design For Solids the conductivity may also be4Isotropic4Orthotropic input X, Y, Z values4Anisotropic - define using a tensor4For both Orthotropic and Anisotropic conductivities, the conductivity in a given direction equals the nominal value Multiplied by the conductivity multiplie
115、r Example:kX = kY = 20 W/m-K; kZ = 0.3 W/m-KMaterialsDefault Icon:Default color: None 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 automati
116、cally load up a local library Add a new library containing materials to the modelMain Material Library Model Specific Materials Groups Groups feature allows grouping of objects To create a group 4select objects from the model tree, then right click and select “Create group” option4right click the “G
117、roups” branch in the tree and create a new (empty) group, then drag objects into the group Operations on groups:4Right click an existing group to see the group functions4Add/ remove objects4Copy/move group4Simultaneously edit group contents (ensure contents are same type/sub-type)4Activate/ Deactiva
118、te/ Delete all contents, etc Deleting a group will only delete the grouping, not the objects 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 th
119、e cowling and a block for the hub (if present). In Geometry enter the Size and Thickness of 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
120、 thick plates Open sides are free boundaries Can assign power and radiation to the closed sides 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 m
121、odelled through equivalent orthotropic thermal conductivity Detailed Board and individual layers 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
122、:Default color:YellowCompact PCB: Board thickness + material Total dissipation Layer information High and Low surface layers Internal layers - assumed identical. Icepak calculates an appropriate orthotropic conductivityPCBs: DetailedDefault Icon:Default color:YellowDetailed PCB: Specify thickness +
123、material of substrate (FR4) Power Total Dissipation Dissipation from each Face Layer information 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 P
124、CB4 Surface material4 Component Height4 Dissipation q Total q Fluxq Per component + number of components4 % 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
125、 - PCBs in system/sub-system level model Detailed - PCBs in component/package level model Hollow - PCBs 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 c
126、an be internal or external Internal Created within the project in the following ways4Select objects, then right mouse click and use create assembly option4Convert an existing Group of objects to Assembly right mouse click4Create an assembly, select objects and drag them into the assembly External -
127、Loaded from external location4An external assembly is just an Icepak project containing the objects making up the assembly4Ideally stored in either a personal library or in a central repository4Good practice to- Locate “origin” at sensible position in the parent model- Size the parent cabinet to the
128、 assembly Note: Deleting an assembly will delete all its contents Default Icon: Assemblies can be used to: Organize 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 edi
129、ted in the usual way, or separate from the rest model Right Mouse Click and choose View Separately Only objects 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 P
130、anelChoose how to: Define the assembly Position and Scale Mesh the assembly Discussed in more detail during meshingObjects 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 spe
131、cified for Extruded/Bonded fin only- Detailed heat sink Model individual fin as solid block- Simplified heat sink 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 pi
132、nExtrudedCross-cut extrusionBonded fin Cylindrical pinDefault Icon:Detailed heat sink: Fin geometryInline coneStaggered cylinderExtruded/Cross cut/Bonded fin count, space, thickness specificationCylindrical pin fin fin arrangement fin count in both directions pin type (cylinder / cone) pin radiusDef
133、ault Icon:Detailed heat sink: Options Effective only Use thin conducting plates to model thin fins Thickness 10% 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 concep
134、t Fin bonding Modeled as contact resistance plates Bonded fin onlyDefault Icon:Heat sink object - SimplifiedSimplified 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
135、 size and computation time Result is more mesh independent May need to tune the macro (takes more time) Larger 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:Simpli
136、fied heat sink: Automatic correlation(1) Use geometry based correlation Check use geometry-based correlation Specify 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
137、 Icon:Simplified heat sink: Use curve(2) Specify thermal and hydraulic resistance curveFlow resistance specify loss coefficient input pressure drop curveThermal resistance constant input RthV curveDefault Icon:Package: Modeling options in IcepakDefault Icon:ModelAccuracy Mesh sizeEffort neededApplic
138、ationSolid block(k 10 W/m-K)PoorLow( 10 cells)Minimum: approximate die power neededSystem/board level - no information2 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
139、 other value has to be estimated/ computedSystem/board if both qjband qjc are availableMulti-resistor networkFair - better than 2 resistorVery low(zero)Very high: Depends on required network topology; necessary to characterize with detailed packageSystem/ boardLumped conduction modelGood (10%);More
140、data further improvedMedium(100)Minimum: if you can see the package and know the die power use thisSystem/ board/ heat spreading studies/ heat sink optimizationDetailed packageVery good (less than 5%)High( 10,000)High: Detailed information, usually proprietary, may be neededPackage characterization
141、and optimizationPackageDefault Icon: Select from 5 available package types:44 ball grid array models41 quad flat pack Specify available inputs dimensions, substrate, solder and die/mold information Select model type from 4 thermal models:4Detailed package4Compact conduction model4Characterize juncti
142、on to case4Characterize junction to board sideInputs for Package Package: Schematic Button Default Icon:Clicking on 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 g
143、uided by the objective of package modelinguObjective in board and system Level modelsTo obtain accurate dissipation of heat from the package to board, surrounding fluid and neighboring componentsTo estimate package die temperaturesTo estimate package case temperaturesuObjective in package level mode
144、lsDesign of the package - effect of metal slug, substrate materials, compare design optionsCharacterization of 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
145、and system level models due to mesh bleeding All details modeled:- die- substrate- case- solder ballsPackage: Compact modelIcepak compact models for board and system level: Solid block with appropriate representative conductivity 2 Resistor network block (qJC, qJB) Multi-resistor network block Compa
146、ct conduction model (CCM)Refer notes on Block and Network objectsPackage: 2 Resistor networkJunctionCaseBoardAmbientq qcaq qjcq qjbq qbaExternal to Package. Depends on fluid flow, radiaton and system configuration. Icepak will solve for this.Internal to package. Dependent on IC package construction.
147、Can be obtained from Package/ device data sheets From q qjc & q qjb characterization models in Icepak package objectsDependents on IC construction as well as environment.Icepak will predict this based on q qjc & q qjbAmbientPackage: qjb & qjc Characterization modelDefault Icon:Junction to board char
148、acterizationsimulation of JEDEC standard qjb conduction modelsource power = 1 WPCB side wall temperatures = 0oCThen qjb = max package temperatureJunction to case characterizationAll sides except the top are insulatedUniform h = 25 W/m2-K specified on top wallJEDEC prescribed PCBPackageuComponents of
149、 the package forming critical heat conduction pathway are modeleduSuch components are simplified by lumping repetitive objects and assigning them effective propertiesu Exploits the power of thin conducting plates in modeling very thin, highly conducting layersCompact Conduction ModelDefault Icon:sol
150、der Contact Res.Thin conducting plate dieShell plate die padAir contact res.Only one more horizontal edge than the single 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 FrameDetail
151、ed VersionThin Plate VersionStill only one more horizontal edge than the single block modelAir gap contact res.Thin Conducting 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, b
152、oundary and internal nodes Faces must be placed on hollow blocks or on the cabinet Faces can connect to internal nodes/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 ne
153、ed to specify capacitance in addition to resistance (mass and specific heat of nodes) Variety of thermal simulations Complicated 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 Def
154、ine Face locations Create the network by editing it from the properties panel Right mouse creates a link Double click on 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 resi
155、stance of outer populated area to PCB Mesh with conduction/fluid flow etc.Resistance network if Text is unknownhAhAhAhAmCpmCpmCpmCpmCpTinletT1T2T3T4External heat exchangerT1, T2, T3, T4 are all unknowns, so the fluid heats up from the inlet temperature (Tinlet) as it travels along the H/XToutletNetw
156、orks - ExampleDefault Icon:MeshingChoice of three meshers available:Two Hexahedral meshersSuited for most (99%) of electronics cooling applications.Unstructured It can be used for most applications satisfactorilyCartesian Tetrahedral mesher Intended for some complex geometryMust be used for ellipsoi
157、ds, elliptical cylinders, or polygonal ductingIcepak automatic meshing: OverviewAll the methods are fully automatedCan generate computational meshes at varying levels of complexity 4No parameters set4Parameters defined on an object by object basisAfter meshing, Icepak loads the mesh and checks the k
158、ey quality measure, and reports the minimum value in the message window. If there are cells with poor quality, Icepak will 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 coun
159、tLow and High element size/ratio to refine around objectsInward height/ratio to refine within an object Outward height to 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
160、quality using diagnosticMaintain sufficient mesh density to capture physicsGenerate First Cut MeshCoarse default options 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 m
161、esh for initial solutions and for observing trends Use suitably refined mesh for final solutionTwo Hexahedral Meshers 4Unstructured-Mesh will follow the geometry -Uses all element types to fit the mesh to the geometry-Background mesh is made of hexahedral elements4Cartesian-Mesh will be structured m
162、esh consisting only of hexahedral elements-Stair-step approximations to non-rectangular geometryBoth of these meshers can be used 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
163、process for the hexahedral meshers, Icepak uses the separation value to check the model. Icepak calculates the distances between 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 approxima
164、tely 1/10th of the smallest dimension in the model. This will ensure that any changes in volume will not significantly alter the results.If the separation is set higher than 10%, but less than 50% of the smallest dimension, Icepak will prompt you to either-Stop meshing and change manually-Continue a
165、nd change automatically to 10%-Ignore and continueIf the separation is larger than 50%, Icepak will prompt you to -Stop meshing-Continue and change automaticallyThe separation can be set either in the meshing panel or in the settings configuration panelChecking during meshingIcepak operates on a “co
166、cooning” methodology 4Each object is meshed individually as close to the specifications defined as possible4First combines adjacent objects togetherCreates single group of multiple objects to “O” grid together 4Then creates the background Cartesian meshMax Cell size is controlled by Max x, Max y and
167、 Max z values4Cuts out a section of the mesh around the grouped objects and replaces the mesh with an unstructured mesh - the “O”-Mesh regionThis allows for a finer mesh to be generated close to objectsIn open spaces between objects the mesh is tessellated with larger elements Minimize computational
168、 costsMeshing is the most critical aspect of CFD modeling: A good mesh is absolutely essential for a good solutionHexa-unstructured meshing methodologyElements of an Icepak meshGlobal Settings - for refining meshDefault Settings - mesher type, background mesh settingsPanels to generate, Display, Che
169、ck quality, and Export to IdeasHexahedral meshing: Generation panelMesher TypeHexa-Unstructured, Hexa-Cartesian, TetrahedralUnits to useMax 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 with
170、in the modelObject ParamsIndividual parameters SeparationTolerance used when meshing to remove any small gaps/misalignmentsDefault settingsMax 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
171、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 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 se
172、t this to 10% of the smallest dimension in your model for typical calculations to prevent any large volume changes occurring that might lead to inaccuracies in the results.RecommendationsNormal Mesher Provides an acceptable mesh for most situations provided background grid is reasonableCoarse Mesher
173、 Provides a coarse mesh “first cut” mesh that can be refined locallyMesher default settings include: Min elements in fluid gap -Minimum number 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-gr
174、id height-Maximum height of the O-grid region from the surface of an object Min elements in fluid gap = 2Min elements in fluid gap = 3Global settings (1)Maximum Size RatioControls the growth rate of cell size The Growth ratio of elements away from surfaces can be controlled using this setting. x2 /
175、x1 0.01 can result in poor meshValue 1e-5 can result in Huge meshCells in gap Number of cells between objectsEdge criterionControls placement of elements near object edge Natural size factor (NSF)Specifies smallest element size = NSF*smallest feature lengthNatural size refinementThe minimum number o
176、f nodes on a curved edgeVolume assignment passesTetrahedral meshing parametersDefault max curve/surface sizeSpecifies max size of element on a curve or surface Add intersection curvesSpecifies that the curve at the intersection of two objects is calculated explicitly Use where have curved objects in
177、tersecting other objectsAutomatic hole repairUse with existing meshes to try to fix problems during meshingReuse existing outputUse with exiting meshes as a starting pointWrite surfaceUse if have problem mesh for display purposesTetrahedral meshing parametersNon-Conformal MeshingA non-conformal mesh
178、 is one where there is transition from many cells to one cellIn Icepak, assemblies of objects can be meshed non-conformally -A “slack” or envelope can be defined around a particular assembly and the resulting region is meshed independent of the mesh outsideThis enables embedding a fine mesh within t
179、he assembly sub-region without leading to cell bleeding, while the model outside the assembly has a course meshMesh for AssemblyMesh in 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
180、a “slack” region around the assembly-By default the bounding box of the assembly is the min/max extents of the objects making up the component-Slack region allows the user to re-define the bounding box, to make it slightly larger than the objects making up the component. Assembly defining slackThe a
181、ssembly bounding box must have sufficient slack so that its sides do not touch any Icepak objectCabinet, walls and hollow block are the only objects that may touch the sides of a non-conformally meshed assemblyAll objects except conducting thin plates and hollow blocks can intersect an non-conformal
182、 assembly the portion within will be meshed non-conformallyAny object can lie completely within the non-conformal assembly even though 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 assembly-By default the bou
183、nding 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 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 allo
184、wed by the solver-Adequate slack must be specified, as in the figure below, so that the assembly bounding box does not touch the heat 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)Boundi
185、ng Box of AssemblyPCBMultiple assemblies can be meshed separately provided:-Assemblies are not be embedded within each other In this instance, 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
186、So the bounding box of one assembly cannot share a surface with the bounding box of a second assembly-Assemblies do not intersectRules for 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
187、 lies inside that for the heat sink-The best option here, is to mesh the heat sink separatelyBounding box for Heat SinkBounding box for TO220Example: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 m
188、esh the model and embed a finer mesh on the assembly region.Both the Hexa-Unstructured and Hexa-Cartesian methods can be used to mesh assemblies separately.Conformal Mesh - 111,329 cellsNon-Conformal Mesh - 77,149 cellsMeshingSolver Topics Problem setup basic parameters Solution settings Solver Moni
189、toring solution progress Parametric studies Transient solutionsProblem setupModel Tree Problem setupProblem setup panelParametric trials panelTitle and notes panelDefine time variation: steady state transientDefine equations to solve: Variables solved Flow situation Heat transfer modeDefine default
190、values: Ambient values Default materials Initial valueProblem setup: Basic parametersMiddle portion of problem setup panel Check Flow to solve Navier-Stokes equation Check Temperature to solve energy equation Check Gravity vector to include buoyancy terms in the Navier-Stokes equation (free convecti
191、on) Radiation on include radiation heat transfer in energy solution Appropriate flow regime Laminar or Turbulent (zero equation/ 2 equation/ RNG models)Problem setup: Equations to solveProblem setup: Equations to solveUseful NotesConduction only problems4Check only Temperature and uncheck Flow 4Ensu
192、re appropriate heat transfer from wallsForced convection problems4flow is usually independent of energy equation4possible to solve for flow alone first and then for energy aloneNatural convection problems4flow and energy equations are interdependent and must be solved together4Radiation heat transfe
193、r is significant and should be includedTurbulent flow4Zero equation is sufficient for most cases in electronic cooling42 equation and RNG models may be used for detailed wake behavior, jet impingement, etcSolution settings Solver setupPurpose Solver termination criteria Max. no. of iterations Conver
194、gence criteria for- Flow equations- Energy equationSelect Accept to accept changes Reset changes all fields to default values- also displays the Reynolds/ Grashoff* number for the problem in the messages window*These numbers are based on maximum cabinet dimension, characteristic velocity and tempera
195、ture, and only serve as a very approximate guideline. The user should judge whether the flow will be laminar or turbulent.Advanced solver controls Discretization scheme Under-relaxation factors Multi-grid linear solverPrecision level single/ doubleSolution Settings Advanced solver setupUnder-relaxat
196、ion a note This determines the relative amount of change in the variables after each iteration for simple forced convection situations use 0.3 for pressure and 0.7 for momentum for natural convection, or complex forced convection situations (examples twisted flow passages, sudden changes in cross se
197、ction, densely packed models) use 0.7 for pressure and 0.3 for momentumSolving the momentum eqs for velocity (V) using current pressure (p) filedSolve the V-p coupling eq. for pressure using the new V fieldSolve the T, k, e e eqs using the new v, p fieldConverged?StopYesNoSolver - The SIMPLE SchemeS
198、olver Starting the Fluent solverThe basics:Solution ID - type in a unique ID-default is +Write overview of results summary report of mass and energy balance, fan operating points, etc.Start solution starts the Fluent solver-residuals window opens-shows residual curves for each equation: continuity,
199、momentum in x, y, z directions and energy-solution will stop when the residual curves satsify convergence criteria, or number of iterations (both specified in Solver Setup panel)Solver Residuals and Overview reportStop solverChange scalePlot optionsResidual windowOverview reportSolver Advanced featu
200、resRestart from an existing solutionSpecify the existing solution IDSelect Full data if the current mesh is the same as in the restart solutionSelect Interpolated data if mesh is differentJob can be submitted to any computer on the network and at any timeAvailable in forced convection problems - fir
201、st solves flow equations alone till convegence, then solves energy equation - useful in large modelsCan disable radiation hereAuto-save interval =N solution is saved after every N iterationsMonitoring solution progressMonitor object center:4Drag selected objects into the Monitor points branch4Then d
202、ouble click the object to open the variables panel4Select variables to monitor and acceptMonitor any defined point:4Go to Main menuSolve Solution monitor4Define points and variable to monitor at that pointDouble click Why monitor: One more way to ensure convergence Possible to monitor velocity, temp
203、erature or pressure at specified points 2 ways to define point monitors: monitor object center, or any defined pointParametric studies Defining variables Uses: optimization tool allows definition of variables and generates solutions for each value of the variable How to define a variable instead of
204、numerical value, enter a string as the variable name Variable name must always begin with $ In the example shown here the heatsink overall height “$HS_ht” and the fan flow rate “$cfm” are the variables After the variable is defined Icepak prompts the user for the initial numerical value of the varia
205、ble Additional values can be assigned to the variables under Model tree Problem setup Parameters Parametric variables can be used in equations for example: for the heat sink specify Overall height as “$extra_ht + 4” mm The characters -, , # should not be used in parameter namesParametric studies set
206、ting 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 “Select trials” panel and opens the “Trial naming” prompt- Numbered: solution ID is serially numbered with a prefix- Values: solution I
207、D is named based on the value of the parametric variables Solving: in the solve panel select “perform multiple trials”Parametric studies select/ set/ restart IDAll checked trials will be solved uncheck to excludeSet button- applies the combination of parameter values in that row to the model- useful
208、 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 restart from a different solution enter the required solution ID in the Restart trial ID columnSelect Transient in Problem setupSpe
209、cify start and end timeEdit parametersSelect size of time stepsuniform or variableSolution save intervalCaution: setup here needs to synchronize with the corresponding model parameters that change with timeTransient power specification feature in blocks and sourcesTransient solutionsHeat Transfer Ph
210、ysics ModelsTopics Governing equations Turbulence models in Icepak Natural convection Radiative heat transfer Mesh refinement Multi-fluid problemsGoverning equationsThe equations that govern fluid flow and heat transfer used by Icepak are, 1.The continuity equation (governing conservation of mass):2
211、.The momentum equations (governing velocity distribution):3.The energy equation (governing the temperature distribution):Where, u = velocity vector = densityT = temperaturep = pressuret = time=stress tensorg = gravity vectorb = volumetric expansion coefficientCp = specific heat at constant pressurek
212、 = thermal conductivityQ = volumetric heat sourceTurbulence models in IcepakTurbulence is unsteady, aperiodic motion in which all three velocity components fluctuate mixing matter, energy, and momentumTime-averaged statistics of turbulent velocity fluctuations are modeled using functions containing
213、empirical constants and information about the mean flowIcepak offers 3 options of turbulence models which can be selected in the problem setup panel:4Zero equation model4Two equation model4RNG modelZero equation model is economical and accurate for most electronic cooling situationsTwo equation and
214、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 of certain dimensionless groups1.Reynolds number - appropriate measure for forced convection1.Re 105 - use turbulence
215、 model 2.Re 109 - use a turbulence model2.Ra30, where where, y = distance of cell center from the surface, uf = freestream velocity, cf = local friction coefficient, n = kinematic viscosityRNG modelDerived from the instantaneous Navier-Stokes equations using a rigorous statistical technique called r
216、e-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 rapidly strained flowsEffect of swirl on turbulence is includedUses an analytical formula for the turbulent Prandtl n
217、umbers 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 viscosity that accounts for low-Reynolds number effects.Effective use of this feature depends on appropriate treatment
218、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 convection To include buoyant forces in the momentum equation switch on the gravity vector g in the problem setup panel
219、 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. Therefore solve the momentum and energy equtions simultaneously - do not attempt to solve them sequentiallyqxygxgygbuoyancy
220、 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 density Icepak provides a choice of 2 models for the temperature effect on density Boussinesq approximation and ideal
221、 gas law Boussinesq approximation:4neglects all variable properties in the governing equations except for density in the momentum equation4approximates the density difference term as where b is the volumetric coefficient of thermal expansion (=1/T for ideal gas) Boussineq approximation is the Icepak
222、 default model and works very well for the vast majority of electronic cooling applicationsNatural convection: Boussinesq modelNatural convection: Ideal gas modelDoes not make simplifications like the Boussinesq approximation should be used when fluid density fluctuations in the model are expected t
223、o 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 set an operating (mean) densityOpen environement:The domain needs to be sufficiently large so that the default bound
224、ary 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 captured accurately 1/2x width on either side If pole mounted - 1x height below Use openings to model sides of the domain t
225、o “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 transfer happens through wall objects on cabinet boundaries Otherwise the problem is not well defined and will divergeRa
226、diative heat transferIcepak includes a surface-to-surface radiation modelRadiative heat flux between surfaces depends onSurface temperature (specified BC or computed)Surface emissivity (specified material property)Form factor from one surface to the other (computed or specified before solution)When
227、to include radiation calculations in the modelInsignificant in forced convection problems exclude radiationOften critical in natural convection/ mixed convection problemsRadiation: Assumptions in IcepakFluid medium is usually airThus absorption, re-emission, scattering by medium can be ignoredOnly s
228、urface-to-surface radiation is modeledSurfaces are gray Emissivity and absorptivity are independent of wavelength Kirchoffs law emissivity ( )=absorptivity ()Surfaces are diffuseReflectivity is independent of outgoing or incoming directionsSurfaces are opaque to thermal radiation (in the infrared sp
229、ectrum)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 flux between the two surfaces (Watts in SI)s = Stefan-Boltzmann constant (5.669e-8 W/(m2K4) = emissivity (has a value
230、 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 radiation calculationsMay chose which surfaces participateMay also specify radiation to a fixed temperatureObject surfaces t
231、hat 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 etcAlternatively, objects to take part in the calculation can be chosen from the form factor panel using theicon fr
232、om the shortcuts toolbarSetting up radiation calculationsForm factors panelSpecify which objects participate in radiation User may override computed form factorsSelect objects to have form factors displayedSelect sides of object to display form factors forControl of mesh coarsening used in preparing
233、 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 accuracy of calculationCompute form factorsForm factor options Hemicube MethodView factors of all participating surfaces a
234、re 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 based on a number of algorithmsFor un-obscured surfaces Analytic - where very close; Gauss quadrature - for other surfa
235、cesFor partially obscured surfaces Monte-CarloEach methodEnsures that view factors add to one from each surface (conservative)if domain is “closed”Ensures that view factor reciprocity is satisfied (consistent)Form factor options: ComparisonsComparison:Hemicube is faster for large complex modelsKeep
236、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 accurate16 packetsThe Refined option will be slower but more accurate64 packetsTry re-using view factors as much as possi
237、bleIf 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 Load optionUse that file for subsequent runsRadiative heat transfer: TipsTry re-using view factors as much as pos
238、sible 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 For non-convex shapes- example radiation between heat sink fins- turn on “Show with self” in the form facto
239、rs 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 form factors- Export - Re-activate all objects- Import Viewing form factorsMesh refinement Aims of a refi
240、ned 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 density in areas of high gradients of temperature or velocity Add sufficient cells to capture phys
241、ical 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 temperature are small, a ratio of between 5 and 10 is acceptable Where needed reduce to between 1.2 and
242、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 convection problems refine the mesh around power sources, thermally conductive solids and walls-Inc
243、rease 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 expansion regions Maintain reasonable growth ratios For areas where the gradients of velocity
244、 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 Parameters menu. Switch to a different default fluid if required by changing the material assignmen
245、t 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 be connected to form a channel (conduit) of the secondary fluid. Actual fluid is modeled The fl
246、uid 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, construct a fluid cylinder inside the solid block giving it a smaller diameter than the solid blo
247、ck 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 a lineHistory plot (transient)Trial plot (multiple solutions)Transient solutionLoad solution
248、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, change their units, and review the report generated during the solution (if created)Zoom-in mode
249、ls 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) from the pull down list and choose which sides and type of display to look at.Click Create to vi
250、ew 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 the data on the planeThe plane can be “dragged” through the display using the scroll barThe pl
251、ane 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-processing object is limited to the region lying within that boxClip To BoxDisplays the resu
252、lts 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 the modelOptions include -ability to display the local velocity vector at that point-Source p
253、oint 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 been created, you can use the mouse probe to find out temperatures at specific points on t
254、he active object.-Create the object, or activate an existing object-Click on probe in the Icepak edit panel-Use Left mouse button to click on a point on the object, Icepak reports the value of the variable being plotted at that point in the GDA-Toggle between selection and translation of the model u
255、sing F9 key-Right mouse button to quit-For multiple point probes click on the probe icon for each new pointProbeContours can be-Solid plots with smooth shading or banded shading-Line plots-Both With line or banded shading options the levels can be defined using-IntervalSet a start point and incremen
256、t-FixedChoose number of bands-InputUser defines valuesColour Levels can be-Specified-Calculated - global limits, current object or the range currently visible Contour ParametersVelocity vectors can be colored by a the local value of a scalar variable, or have a fixed color, or be colored by velocity
257、 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 factor-Max length for VectorVectors above a specified value can be suppressed from the vie
258、wColor 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 end time of the trace must be set, together with the increment to useThe col
259、our range is controlled in the same way as for contour plotsParticle Track Parameters (1)Tracks can be -Dye trace and/or-Separate ParticlesTracks can be animated, with full control on defining the frame stepping and can be written to fileParticle Track Parameters (2)Display of Particle Tracks from F
260、anPlots the variation of a variable along a lineThe line can be defined using -The point and normal direction-From the ScreenSet the view and click on a point on screenIcepak automatically calculates the point, and the direction-From two point objectsVariations along different lines can be displayed
261、 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 specified points can be used to compare the various versions of the mode
262、l. Trial PlotPlot CreatedFrom the top level menu you have options to create-HTML reports-Summary reports-Point reports-Full reports-Network block valuesJunction Temperature of network blocks-Fan operating pointOperating point of any Fan using a characteristic curve-Also option to export data for use
263、 with AutothermReporting OptionsCreates a web-based report that can include,-Title, Text- Modelling informationProblem SpecificationSource DissipationsFan informationVent informationCreating an HTML ReportAlso can items such as-Figures-Post-Processing Objects for different solution IDs,Also can chan
264、ge viewing position, to change the orientation of the model-Reports for different Solution IDs-Text above and below any item addedCreating an HTML ReportChoose Object(s) to report onSelect solution ID to report, or time step if unsteadyWrite to file and/or screenChoose Variable to reportCombine data
265、 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 flow, you need to specify whether you want Icepak to cal
266、culate 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 2D source, you should select Both for that surface. If yo
267、u 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 for block.1 would be a report of the amount of heat leavin
268、g 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 flow and Heat flux reportingIf you select Heat tr. coeff
269、 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. coeff panel (default is ambient)Reporting Heat Transfer Co
270、efficientOperates in a similar way to summary report, -Choose the point or enter co-ordinates in the usual way and -Choose Variable to report on-Write to file or window-Icepak creates report with position of the point + value of the specified variablePoint ReportConvenient way to report min/max/aver
271、age 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 reasonable?-Is it shunting ?-Should swirl be inc
272、luded?Vent positioning-Could the flow into/out of a vent be improved by repositioning the vent?-Is the vent necessary?Flow through system-How is the fluid being moved through the system?Re-circulation/Stagnant zonesShort circuitsCould the flow pattern be improved?Principle mode of heat loss in the s
273、ystemHeat 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 mechanismComponent/Package Level QuestionsProfiles
274、 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 solutions-Applying a fully developed channel profile Calculate
275、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 ConditionsProfiles of variables can be applied to both
276、 Walls and Openings Openings-Pressure-Temperature -X, Y, Z, velocity componentsWalls-Outside heat flux-Outside temperature-External heat transfer coefficient Reference temperature fixedSources-Profiles of heat flux per unit areaIcepak Objects that can use ProfilesCreate profiles manuallyObjective: C
277、reate 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 each region (20oC, 25oC, 30oC regions), and the temp b.c. in t
278、hat 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 written from any post-processing contour plot -Object face, plane
279、cut, etc-Under Parameters option to “Save Profile”Saves point co-ordinates and valueCreating profiles by post processingZoom-in modeling: introductionComponentBoardSystemDimensions range: mm (dies), mm (fins/solder), m (enclosure)System/ board level model with full details huge mesh count increased
280、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 approximations4Example thermo-volumetric models of heat sinks,
281、uniform lumped source to replace closely spaced power sources Solve and post-process the simplified system level model4Determine fan operating points, capture flow and temperature fields4Temperature field trends are more important than accuracy4Flow field - possible to capture with good accuracy4Dec
282、ide region to zoomin - capture velocity, pressure & temperature profiles at the faces of the zoomin box Build sub-system level model within the zoomin box4Use detailed components eliminate system level simplifications4Impose the captured velocity, pressure and temperature profiles as boundary condit
283、ions 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 the type of boundary condition on each side inflow
284、/ 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 generatedIcepak automatic zoom-inDifferent sets of variables
285、 are profiled, depending on the type of boundary condition specifiedInflow boundary:4Free opening in zoom-in model4variables - ux, uy, uz, T (components of velocity, temperature)Outflow4Free opening in zoom-in model4variables - P, T (static pressure, temperature)Wall4Stationary wall in zoom-in model
286、4variables - TNote:-If boundary openings are specified in the zoom-in model at least one should be outflow-Should be placed where most of the flow will be out of the sub-regionProfile variables in zoom-inSystem level solution has no details of components-Choose the bounds the region of interestWrite
287、 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 boundaries-The min/max x, y faces were set as inflow boundaries-The min z face was set as a outflow-The min z face was se
288、t 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 the IGES file into IcepakModel/ CAD DataConvert the CAD geometry in
289、to 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 IcepakThe model must already contain a cabinetLoading and IGES FileL
290、oad 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 procedure above)Select the IGES file and choose what data you want to
291、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 using cabinet autoscaleMinimum Feature size Sets global tolerance t
292、hat 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 your CAD geometry into IcepakSelect a surface or group of surface
293、s 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 Geometry into Icepak Objects(i) define a region of the model you want
294、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, v-verticalDivide the region up using vertical linesMiddle mouse
295、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 package)IDF is a neutral file format supported by many ECAD packages
296、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 2.0Board File - data on outline of board, thickness and component po
297、sitionsLibrary 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 power Not in IDF 2.0Simple importBoard modeled as a block, power a
298、pplied 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 open the Import IDF file menuSpecify the files to be used for the
299、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 importIcepak will automatically detect which version of IDF you are using
300、Import 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 prisms optionClick Next to move onMinimum feature size- for polygon
301、al 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 OnlyKeep components that are larger than a specified sizeOr keep
302、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 componentsLoad data from file or specify values for each componentR
303、ound 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 so
304、urcesMajpjMVcyzj21HLfrvy96dv02lPPfYgxUS7IYmZkyEmZ0kGeYZS3bpLCkYH1lt4EK7CxmUX3ijoYSOer7ZuaVWYgz4EpZrUirVpMzzvNtf1XZw5oswSXOtFaejnOcmfE1lZgnN1RSXg8wLCG8CVQ3XPJMvodPFWcpiYJgZazNSEPNIaklYSu7qSd1UpaxmZDlpN9zW7kljfsLCLi26Yv109ffbnDH8LbUN1G6ACURQ39eG12KHL9tXsZ1jzgoCK8g1kuNOh5eFvcmVT5ZYVQt9zk3rp3qLnf02FovEX
305、xVRxjCcFRNppiJljNiOuk6fONnyX7fyGg7sXZ49BmCN5oy9VesHpKzdjTKwjrkCEQCFDehVmGax3lrOEbw63VscA3YSijtUKoCyiLzAlVRp7l4QgPNHxvJFFDyjUVN3oHlMah0XBd4uTbkfPIhHtw0evPmYOrdhEDoPwvYhzlGplU1AU9mpyiCXH8gpPCBRYjq77VcnbXumNE1yGfyTsbSj89J63kRTKDkKUg3mdS5sJ4X5cQ8dK7oW9IkScssECQdz2O9UTlpRjAFPChjhLdzopQzwxQf8ozdzOhogwAooX
306、pUF83BX4C3jRgjDJiiXEUDMaNz4vQ4n164vspddHvOIVuBBdMA4xp1YhiHk0vOJ8TL1BxogzVlMpmod6ianYGmksQq6NWCEd56hZF4wfaNyZcrGfNxnPiG6ZAxSkfmhJAKtNmCqbRmppeXp8inz4eq3HkWCMSORyMMX522xpHG6basNr6KQfbZsFbHjzyNlJrruLolKFcC84dqfijBO5Dy2NaBcNEBPgQrT12PgpcKx2or2YChN5DPjs80zzdtdAdTKuW4uVv9bbZu3K2SZ2aEhTlIC1UqrIWibkzwHh6p8gLv26zr01mJybfOzFc4T7kQH1IpPwOzMDnAKPLsLrznXGjFNIA9bSWWms6ibKZwQIKrMzalwbFrQJvOP1rPH8rx2KkyYqrtQk5VRwM1HSX
