出版社:卢天健、徐峰、文婷 科学出版社 (2013-03出版)
ISBN:9787030348142
章节摘录
Chapter1Introduction 1.1 IntroductionandSynopsis Inlate1990s,drivenbytheneedsofminimizingmanufacturingandoperationalcostsinsatellites,arevolutionaryconcept―Multifunctionalstructures(MFS)―wasdeveloped,whichcombineselectroniccomponents(multi-chipmodules,orMCMs)andsignalandpowerdistributioncablingwithinaloadbearingstructurewithembeddedthermalcontrol.Thisdesignconceptdramaticallychangedthedesignapproachforspacesystems,andinaddition,ledtoaparadigmshiftinthedesignmethodologyofthestructuresandcontrolcommunity[1～4]. Signi.cante.ortsinincorporatingtheMFSconceptintomaterialsen-gineeringhaveledtoanentirelynewcategoryofmaterials:multifunctionalmaterials.Cellularsolidsareagroupofmaterialswithmultifunctionalattributes,whichhavetailorablestructurestoachievesystem-levelperfor-manceasmaterialsthatcombinemechanical,thermal,electrical,acoustical,andpossiblyotherfunctionalities.Recently,therehasbeenanincreasedinterestintheuseofcellularsolidsasmultifunctionalmaterialsfortworeasons[5]:(i)novelmanufacturingapproacheshavebene.ciallya.ectedperformanceandcost;(ii)higherlevelsofbasicunderstandingaboutme-chanical,thermal,andacousticpropertieshavebeendevelopedinconjunc-tionwithassociateddesignstrategies. Multifunctionalityofcellularsolidsisaninterdisciplinaryresearchareathatrequiresaconcurrent-engineeringapproach.Theaimistoestablishstructure-propertyrelationshipsfortailoringmaterialstructurestoachievepropertiesandperformancelevelsthatarecustomizedforde.nedmultifunc-tionalapplications[6].Onesigni.cantapplicationareaisultralightmulti-functionalheatexchangersorheatsinksinlarge-scaleintegratedelectronicpackaging,wherecellularsolidsappeartobemoreattractivethanthecon-ventionalheatdissipationmediaastheheatdissipationmaterialisalsorequiredtosupportlargestructuralloads.Themultifunctionaldesignin- 2Chapter1Introduction herentlyfacilitatestheincreaseofintegrationscale,whichresultsinincreas-ingpowerdensitiesinelectronicpackaging.Therefore,highlye.ectiveandrobustthermalmanagementviathesecellularsolidsiscrucial.Withtherequirementsoncapabilityofcarryingbothmechanicalandthermalloadsinmind,thechallengesaretoestablishrelationshipsbetweentopologyandproperties,andtooptimizethegeometricparametersapplicabletovariousthermo-mechanicalapplications[7～9]. 1.2 CellularSolids Cellularsolidsarede.nedasthosemadeupofaninterconnectednetworkofsolidstrutsorplatesthatformtheedgesandfacesofcells.Theyarefoundinmanynatural(wood,cork,sponge,bone,etc.)andman-madestructures. Basically,therearetwobroadclassesofcellularsolids,asshowninFigure1.1:onewithastochasticstructureandtheotherwithaperiodicstructure[10～13].Cellularsolidswithstochasticstructuresaremainlyfoams,whichcanbefurtherclassi.edintotwotypesbasedontheirporestructure:open-cellfoamsandclosed-cellfoams,asshowninFigure1.2(a)and(b),respectively.Theformercontainporesthatareconnectedtoeachotherandformaninterconnectednetwork;whilethelatterdonothaveintercon-nectedpores.Cellularsolidswithperiodicstructuresarefoundinavarietyofstructures,amongwhichthemostfrequentlymentionedarethosewithlatticetrussstructures,asshowninFigure1.2(c),(d)and(e),andprismaticstructures,asshowninFigure1.2(f),(g)and(h). Onemayarguethedi.erencebetweentheperiodicengineeringstructuresandthecellularmaterialswithperiodicstructures.Ashby[14] pointedoutthattheydi.erinoneimportantregard:thatofscale.Scaleoftheunit 1.2 CellularSolids3 4Chapter1Introduction cellofcellularsolidsisoneofmillimetersormicrometers,anditisthisthatallowsthemtobeviewedbothasstructuresandasmaterials.Atonelevel,theycanbeanalyzedusingclassicalmethodsofmechanics,justasanyspaceframeisanalyzed.Butatanotherwemustthinkofthecellularstructuresnotonlyasasetofconnectedstruts,butasa‘material’initsownright,withitsownsetofe.ectiveproperties,allowingdirectcomparisonswiththoseoffullydense,monolithicmaterials. Variouspropertiesofacellularsoliddependontwoseparatesetsofpa-rameters:thosedescribingthegeometricstructureofthecellularsolid,andthosedescribingthepropertiesofthematerialofwhichthecellularsolidismade.Inotherwords,forcellularsolidswithdi.erentstructuresordif-ferentmaterials,theunderlyingmechanismsgoverningstructure-propertyrelationshipscanbeverydi.erent. 1.3 PeriodicCellularSolids Whilecommercialmetalfoamswithopencells,whicharetypicalstochas-ticcellularstructures,aregoodcompactheatexchangersandrelativelycheapwhenmadebysintering,theirload-bearingcapabilityismuchinfe-riortoperiodicstructureshavingthesameweight.Thisarisesbecausetheirdeformationundermechanicalloadingisdominatedbycellwallbendingasopposedtocellwallstretchinginmostperiodicstructures[18].Nonetheless,ascross-.owheatexchangerstheycanprovideahighthermalconductivitypathforheattransport,averyhighsurfaceareafordissipationintoacool-ing.uidlocatedintheporesandacontiguouspathforforcingthecoolantthroughthestructure. Therapidadvanceinmanufacturingtechniquessuchaslithographyandrapidprototypinghasmadepossibletoconstructnewtypesofcel-lularmaterialswithperiodicmicrostructures.Thesecellularstructureshavethermalandstructuraladvantagesoverotherconventionalheatdissi-pationmediaandotherperformancecharacteristics[13,19～23].Theprecisecontroloftopologiesduringthemanufacturingstagedi.erentiatesthenewcellularmaterialsfromconventionalheatdissipationmedia.Awidevari-etyofprocess-routeshavebeendevelopedtomanufacturecellularmetalswithrelativedensitiesof1%～20%andcellsizesfrom100μmtoseveralcentimetres[12]. 1.3.1 2Dperiodiccellularsolids Two-dimensional(2D)cellularsolids,withthesimpleststructuresamon- 1.3 PeriodicCellularSolids5 gstdi.erentcellularsolids,aregenerallyselectedasthefundamentalgeom-etryformodellingmorecomplicatedcellularsolidssuchasfoams[24].Moreimportantly,certainstructuralandthermalpropertiesof2Dcellularsolidsaresuperiortothoseoffoamswithequivalentdensities[18]. 2Dcellularsolidsarecomposedofatwo-dimensionalarrayofpolygonswhichpackto.llaplaneareasuchasthehexagonalcellsofabeehivehoneycomb[25].Anexampleofa2DcellularsolidisshowninFigure1.2(a).Itisobviousthat,topologically,2Dcellularsolidsareanisotropic.Twodirectionscanbede.nedin2Dcellularsolids:oneisnormalorlateraltothecellprincipalaxes,y-zplaneshowninFigure1.2(b),whichislateraldirection;theotherisparalleltothecellprincipalaxes,xdirectionshowninFigure1.2(c),whichisaxialdirection. 2Dcellularsolids,sometimes,areusedassandwichcorestoformasandwichpanel.Inthesecases,correspondingly,thesandwichpanelwithface-sheetsnormaltothecellprincipalaxes,asshowninFigure1.2(g),iscalledasandwichpanelwithaxialcoressincetheloads(mechanical,ther-mal,etc.)aregenerallynormaltotheface-sheetsandequivalentlyparalleltothecellprincipalaxes;andthesandwichpanelwithface-sheetsparalleltothecellprincipalaxes,asshowninFigure1.2(h),isnamedasasandwichpanelwithlateralcoresforsimilarreasons. 1.3.2 3Dperiodiccellularsolids Forthree-dimensional(3D)cellularsolids,themostoftenusedislattice,suchastetrahedrallattice,pyramidallattice,Kagomelatticeandwoventextile,asshowninFigure1.2(c)～(e). Thepotentialuseofametalweavecon.gurationasoneoftheperiodicmaterials,coupledwithanovelbondingschemetofabricateperiodiccel-lularstructureswasreportedbyTian[11].Diversedesignsofthistextilecon.gurationhavebeenattemptedandsomeofresultswerereportedbyLi&Wirtz[26] and Xu & Wirtz[27].Thetetrahedrallattice,asshowninFigure1.2(c),hasthreetrusseseachmeetingatafacesheetnode,whilethepyramidalstructurehasfourtrussesmeetingatafacesheetnode,asshowninFigure1.2(d).Bothtopologieshavedirectionswhicharenotobscuredfor.uid.ow:threeofthesechannelsinasinglelayerofthetetrahedralstructureandtwointhepyramidalsystem[17].Anotherexampleforthethree-dimensionalperiodicmaterialswasreportedbyHo.mann[28],referredtoasaKagometopology.Thebasictopologyissomewhatsimilartothatofthebankofcylinderarrays,showingstructuralandaerodynamicanisotropy, 6Chapter1Introduction asshowninFigure1.2(e). Otherlatticetrusstopologieshavealsobeenproposedbaseduponmanu-facturingconsiderations[17].Figure1.2(f)～(h)showsexamplesthatareeasytomakefromwires.Thediamondtextilestructureismadefromlayersofaplainweavemetalfabricthathavebeenbondedtoeachother. 1.4 MultifunctionalApplications Wellestablisheddataonthemechanicalpropertiesofcellularsystemswitheitherperiodicorstochasticmicrostructuresdemonstratethattherel-ativelyhighsti.nessandyieldstrengthachievableatlowdensitycreatesanopportunityforlightweightstructures[5,29～33].Periodiccellularmet-alshavebeenexploitedformultifunctionalapplications[17].Forexample,some,suchashexagonalhoneycomb,arewidelyusedtoenablethedesignoflightweightsandwichpanelstructures[34],forcreatingunidirectional.uid.ows[35],forabsorbingtheenergyofimpacts[36],toimpedethermaltrans-portacrossthefacesofsandwichpanelsandforacousticdamping,forblastwavemitigation[37～39]. Inaddition,theopentopologieswithhighsurfaceareadensityhavethermalattributesthatmayenableapplicationswhichrequireastructureforheatdissipationaswellasmechanicalsti.ness/strength.Thestructureshaveahighsurfaceareadensityandmaybeconstructedoutofhighcon-ductivitymaterials.Thesecombinationsmakethecellularmaterialscapableheatdissipationmediathatcanbeusede.ectivelyforcoupledthermalandstructuralapplications,forexampleasajetblastde.ectoronanaircraftcarrier.Insuchanapplication,highmechanicalcompressionisexertedonthede.ectorplatewhenanaircraftrollsovertheretractedde.ectorandthensubsequentlyahighthermalloadfromthejetisappliedattake-o..Thejetblastde.ectorisinclinedatapproximately50. withrespecttothedecksurfaceduringtake-o..Inthissituation,thehotjetofsurfacetem-peraturewithradialvariationsimpingesthe.atplatethathasconvectioncoolingmechanismunderneathtocooltheplatedowntoacertainleveloftemperatureinashortperiodoftime.Toenhancethisconvectionheattransfer,avarietyofstructuredlattice-materialscanbeused.However,con-ventional.ntypeheatexchangersarenotsuitableduetothemechanicalloadings. Whilstcommercialmetalfoamswithstochasticcellularmorphologiesareingeneralgoodcompactheatexchangersandrelativelycheap(ifpro-cessedviathesinteringroute),theyarenotstructurallye.cient,astheir
内容概要
Dr.Tian Jian Lu is a professor at the School of Aerospace,Xi’an Jiaotong University,Xi’an,China.Dr.Feng Xu is a professor at the Key Laboratory of Biomedical Information Engineering of Ministry of Education,School of Life Science and Technology,Xi’an Jiaotong University.Dr.Ting Wen is now an engineer at Shell Global Solutions Inc.Dr.Lu and Dr.Xu are also affiliated with Biomedical Engineering and Biomechanics Center,Xi’an Jiaotong University.
书籍目录
Chapter 1 Introduction1.1 Introduction and Synopsis1.2 Cellular Solids1.3 Periodic Cellular Solids1.3.1 2D periodic cellular solids1.3.2 3D periodic cellular solids1.4 Multifunctional Applications1.5 Aims and Outline of the BookReferencesChapter 2 Experimental and Numerical Methods2.1 Introduction2.2 Experimental Methods2.2.1 Experimental setup2.2.2 Experimental procedure2.2.3 Data analysis2.3 Numerical Method2.3.1 Computational domain2.3.2 Mesh generation2.3.3 Physical boundary conditions2.3.4 CFD solver2.3.5 Mesh sensitivityReferencesChapter 3 2D Periodic Cellular Metals3.1 Introduction and Synopsis3.2 Characterization and Fabrication of 2D Cellular Solids3.2.1 What are 2D cellular solids3.2.2 Characterizing 2D cellular solids3.2.3 Fabrication of 2D cellular solids3.3 Mechanical Properties of 2D Cellular Metals3.3.1 General mechanical behaviour3.3.2 Comparisons of 2D cellular metals with different cell shapes3.3.3 Comparisons of 2D cellular metals with other cellular metals3.4 Fluid-Flow Behaviour and Pressure Loss3.4.1 Local pressure loss3.4.2 Frictional pressure loss3.4.3 Overall pressure loss3.5 Heat Transfer3.5.1 Conjugated conduction-convection heat transfer process3.5.2 Local temperature and heat flux distributions3.5.3 Overall heat transfer characteristics3.6 SummaryReferencesChapter 4 3D Periodic Cellular Metals I.Textile4.1 Introduction and Synopsis4.2 Characterization and Fabrication of Woven Textiles4.2.1 Topology of textile core4.2.2 Porosity and surface area density4.2.3 Fabrication4.3 Mechanical Properties of Woven Textiles4.4 Flow and Pressure Loss Behaviour4.4.1 Model4.4.2 Experimental result4.5 Heat Transfer4.5.1 Effective thermal conductivity4.5.2 Convective heat transfer4.5.3 Volumetric heat transfer coefficient4.6 SummaryReferencesChapter 5 3D Periodic Cellular Metals II.Lattice-Frame Materials5.1 Introduction and Synopsis5.2 Characterization and Fabrication of Lattice-Frame Materials(LFMs)5.2.1 Topology5.2.2 Manufacturing process5.3 Mechanical Properties of the LFM5.4 Fluid Flow Behaviour in the Lattice-Frame Material5.4.1 Fluid-flow in the lattice-frame material5.4.2 Flow in x-y plane5.4.3 Flow on strut surfaces5.4.4 Fluid-flow in the LFM5.4.5 Surface flow patterns on the endwall plates5.5 Pressure Loss Behaviour in the Lattice-Frame Material5.5.1 Pressure loss per unit cell5.5.2 Pressure loss mechanisms in the LFM5.5.3 Effects of topological parameters on the overall pressure losses5.6 Heat Transfer5.6.1 Introduction5.6.2 Thermo-fluid characterisation of the LFM5.6.3 Local temperature distribution in forced air convection5.6.4 Overall heat transfer behaviour5.6.5 Effect of entry and exit regions on the overall endwall heat transfer5.6.6 Effects of thermal conductivity on the overall heat transfer5.6.7 Heat transfer due to flow mixing vs.convection from extended surface5.6.8 Endwall surface heat transfer distribution5.6.9 Details of the heat transfer on the strut surfaces(Orientation A)5.6.10 Vortex structures in heat transfer5.6.11 Contribution of the local flow features to the overall heat transfer5.6.12 Effects of porosity and surface area density on the overall heat transfer5.6.13 Optimum porosity for both the pressure loss and heat transfer in the LFM5.7 Summary5.7.1 Flow5.7.2 Pressure loss5.7.3 Heat transfer5.7.4 The LFM as a multifunctional heat exchangerReferencesChapter 6 Overall Evaluation of Thermo-Fluid Performance6.1 Introduction and Synopsis6.2 Evaluation of Overall Pressure Loss6.3 Evaluation of Overall Heat Transfer6.4 Overall Thermo-Fluid Performance Evaluation6.4.1 Thermal efficiency index6.4.2 Comparisons of overall thermal performance6.5 SummaryReferencesChapter 7 Theoretical Analysis7.1 Introduction and Synopsis7.2 Fin Analogy Model of 2D Periodic Cellular Solids7.2.1 Description of the problem7.2.2 Case IIsothermal surfaces7.2.3 Case IIConstant heat flux surfaces7.2.4 Optimal thermal design7.3 Fin Analogy Model of 3D I.Woven Textile7.3.1 Problem description7.3.2 Governing equation of fin model7.3.3 Overall heat transfer rate of woven textile7.3.4 Model verification7.3.5 Discussions7.4 Fin Analogy Model of 3D II.Lattice-Frame Materials7.4.1 Formulation of a governing fin equation7.4.2 Empirical heat transfer data input7.4.3 Model verification7.4.4 Discussions7.5 Analysis of 2D Periodical Cellular Metals with Developing Flow7.5.1 Introduction7.5.2 Problem description7.5.3 Analysis7.5.4 Validation of optimization analysis7.5.5 Case studies and discussions7.6 SummaryReferencesChapter 8 Future8.1 Multi-layered LFM8.2 Optimal Design for 2D Cellular Materials8.2.1 Optimal design of 2D cellular materials for multifunctional applications8.2.2 Optimal design of 2D cellular materials with graded rectangular cells8.3 Thermo-Fluid Characteristics of 2D Cellular Materials with Micro Cells8.4 Heat Transfer Enhancement Techniques to 2D Cellular Metals8.5 Woven Screens with Hollow Struts8.6 Effects of Flow Unsteadiness on the Heat Transfer Enhancement8.7 Multi-block 2D Periodic Cellular Metals8.7.1 Pressure loss8.7.2 Heat transfer8.7.3 Multi-block:worthwhile or not8.7.4 ConclusionsReferences
编辑推荐
Tian Jian Lu、Feng Xu、Ting Wen编写的这本《周期性多孔金属材料的热流性能(英文版)》旨在揭示多功能超轻周期性多孔金属材料和结构在强制对流条件下传热传质机理，为研制以多功能超轻多孔材料为基本材料、具有优良传热性能和力学性能的高效紧凑式换热器、微热管等提供理论依据和指导。