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500 个结果
  • 简介:为在一个三维的围住的领域的不可压缩的二进制液体混合物的进化的二个不同模型被考虑。他们由3D组成不可压缩的海军司烧方程,使外部力量遭到到时间依赖者并且结合了一个对流Allen-Cahn或Cahn-Hilliard方程。如此的系统能被看作海军司烧方程的归纳到二阶段的液体。用轨道途径,作者为两个系统证明轨道引起注意的人的存在。

  • 标签: 流体混合物 三维轨迹 吸引子 STOKES方程 二元 不可压缩
  • 简介:Hydrodynamicandthermalcharacteristicsinapipewithsinusoidalwavysurfaceforsteadylaminarflowareinvestigatednumericallyinthepresentstudy.TheintegralformsofgoverningequationsarediscretizedusingcontrolvolumebasedFinitevolumemethodwithcollocatedvariablearrangement.SIMPLEalgorithmisusedandTDMAsolverisappliedforsolutionofsystemofequations.Apipeoflengthequalto4λisconsidered.Effectofsurfacewaviness,determinedbywavelength-amplituderatioλ/a(=L^*),onflowandthermalfieldispresented.ThesimulationworkhasbeencarriedoutforL^*=11.0-30.0foraReynoldsnumberrange50to2000.Resultsarepresentedintheformofstreamfunction,isothermallines,velocityandvorticityprofiles,changeofmeanfrictionfactor,variationinskinfriction,localandaverageNusseltnumberwithReynoldsnumber,wavenumber(n)andL^*.Foraparticulargeometry,lengthofcirculationzoneincreaseswithreynoldsnumberandapproachesalimitingvalueforhigherReynoldsnumber.Wallshearstressinthebulgepartofthechannelshowssmallervaluesthataffectlargely.therateofheattransferandNusseltnumbershowsminimumvaluesinthisregion.Thiscirculationzonedrasticallyincreaseswiththeincreaseofsurfacewavinessshowinghighmeanfrictionfactorperwavelength.MeanfrictionfactorinverselyvarieswithReynoldsnumber.Acorrelationisproposedforcalculatingfrictionfactorintheformf=C/(Re)^m,where‘C’and‘m’representstwopolynomialsofdegree4and2respectivelyandarefunctionofL^*.Higherwavinessofthesurfaceshowsthehigherheattransferratethanlowerwaviness.Heattransferratefallsalmostexponentiallyalongtheaxialdirectionwiththeincreaseofwavenumber.

  • 标签: 流体 波形管 热交换 特征
  • 简介:ResearcheffortsmadesofartosimulatefibresuspensionflowsarelimitedtofibresuspensionsinNewtonianfluids.Thoughshortfibrecompositesaremostlymadeofpolymers,lackofsuitableconstitutiveequationsforfibresuspensionsinviscoelasticfluidsfrustratesattemptstosimulateflowsofthesesuspensions.ApreliminaryworkdonebytheauthorledtoaconstitutiveequationforsemiconcentratedfibresuspensionsintheOldroyd-Bfluid.Thispaperdescribesthemathematicalformulationoftheflowproblemsforsuchasuspensionandthenumericalproceduretosolvethem.Somenumericalresultsofflowpastasphereinatubearealsopresented.

  • 标签: suspension finite element METHOD TIME-DEPENDENT METHOD
  • 简介:Inthispaper,effectsonofsixtypeofresinsthedecolorizationofD-ribosezymoticfluidhavebeenstudiedforthefirsttime.TheresultsshowthatresinNKA-IIhasthebesteffect.thedecolorizationrageofD-ribosezymoticfluidis91%atvelocityof1.0BV/hrand25℃,theadsorptioncapacitycanreachupto5.7BV.Theeffectsofadsorptionconditionsaswellasconditionsofresinregenerationontheresindecolorizationcapabilitywerealsostudied.

  • 标签: D-核糖 脱色 树脂吸附
  • 简介:Hydrotalcitecanactasaco-stabilizerwithothermainstabilizerforpoly(vinylchloride)(PVC).ThethermalstabilityandfluidpropertyofPVCfilledwithhydrotalcitesurface-treatedwithtitanateandsilanewerestudiedinthiswork.OrganicSnisamainstabilizerandhydrotalciteisastabilizingassistant.ThestabilityofthePVCresinmixedwithorganicSnandhydrotalciteisbetterthanthatofthePVCresinmixedwithorganicSnalone.ItisshownthatthePVCresinfilledwithhydrotalcitepossessesabetterstaticanddynamicheatstability.Moreover,hydrotalcitecanimprovethefluidpropertyofPVC,whichisadvantageoustotheprocessingofPVC,andtheoptimumcontentofhydrotalciteisabout1%-2%(massfraction).

  • 标签: Hydrotalcite PVC Thermal stability FLUID PROPERTY
  • 简介:EffectsoftheorientationandapexangleonthesettlingvelocityofconicalparticlesinBinghamplas-ticfluidsarenumericallyinvestigatedoveraReynoldsnumberrangeof1≤Re≤100,Binghamnumberrangeof0≤Bn≤100,andconeanglerangeof20≤α≤150°.Governingequations(ofcontinuityandmomentum)aresolvednumericallyusingthefiniteelementmethodtoobtainvelocityandpressurefieldsthatarepostprocessedtoobtainvaluesofthedragcoefficien.Futthermore,theeffectofconeori-entationontheflowfieldisvisualizedandexploredintermsofstreamlinecontoursandthemorphologyofyielded/unyieldedregions.Finally,theobtainedvaluesofdragarecorrelatedviaasimplepredictiveexpressionintermsofthemodifiedReynoldsnumber.Theeffectoftheconeangleondragisfoundtobemoderatebecausethedragforceactingonthelateralsurfaceisasmallfractionoftheoveralldrag.

  • 标签: BINGHAM NUMBER REYNOLDS NUMBER Yielded/unyielded REGIONS
  • 简介:Preliminarydesignandsimulationofafreepistonenginesuitableforsmall-scaleenergyproductionindistributedenergysystemsispresentedinthispaper.Theproperties,particularlythepropertiesofgassealsoftheenginearesimulatedusingasimulationprogramdevelopedforthiscase,andtheresultsareutilizedinpreliminarymaindesignparameterselection.TheenginesimulationprogramwasdevelopedbycombiningandmodifyingthesourcecodesofthesimulationandcalculationprogramsobtainedfromHelsinkiUniversityofTechnology,TampereUniversityofTechnology,andLappeenrantaUniversityofTechnology.Becauseofthecontact-freelabyrinthsealusedinthepiston,theefficiencyofthemotorislowerthantheefficiencyofaconventionalmotorwithoillubricatedpistonrings.Ontheotherhand,thelackofbearinglosses,andthelackoflossesassociatedwithacrankshaftsystemandagearbox,aswellasthelackoflubricationoilexpenses,compensatesthiseffect.Asanetresult,thisnewmotorwouldperformslightlybetterthantheconventionalone.Beingcompletelyoil-free,itisveryenvironmentallyfriendly,anditsexhaustgasesarecompletelyfreeofoilresidualswhicharecausingproblemsinnormalgasmotors.

  • 标签: 自由活塞发动机 迷宫密封 流体动力学模型 分布式能源系统 模拟仿真 密封性能
  • 简介:BecauseofnoexactnameaboutobesityintraditionalChinesemedicine,clinicallytherehavenounifiedsyndrometypesaboutobesity.Thepresentpaperusestheoriginalsyndromedifferentiationofbodyfluidandselectsclassicalacupunctureandmoxibustionprescriptionstotreatobesity,whichisconducivetofurthersystematizingclassicalacupunctureandmoxibustionprescriptionsandprovidingsufficientbasisforclinicalpopularization.

  • 标签: 治疗方法 肥胖症 综合病症 中药 针刺疗法
  • 简介:Fluid-particleinteractionunderpinsimportantbehaviorofgranularmedia.Particle-scalesimulationmayhelptoprovidekeymicroscopicinformationgoverningtheinteractionandofferbetterunderstandingofgranularmediaasawhole.Thispaperpresentsacoupledcomputationalfluiddynamicsanddiscreteelementmethod(CFD-DEM)approachforthispurpose.ThegranularparticlesystemismodeledbyDEM,whilethefluidflowissimulatedbysolvingthelocallyaveragedNavier-StokesequationwithCFD.ThecouplingisconsideredbyexchangingsuchinteractionforcesasdragforceandbuoyancyforcebetweentheDEMandCFD.Theapproachisbenchmarkedbytwoclassicgeomechanicsproblemsforwhichanalyticalsolutionsareavailable,andisfurtherappliedtothepredictionofsandheapformationinwaterthroughhopperflow.Itisdemonstratedthatthekeycharacteristicofgranularmaterialsinteractingwithporewatercanbesuccessfullycapturedbytheproposedmethod.

  • 标签: 粒子相互作用 计算流体力学 颗粒状物料 颗粒介质 数值模拟 NAVIER-STOKES方程
  • 简介:Anumericalstudywasconductedforthefullydevelopedlaminarflowinrotatingcurvedellipticalpipe.Duetotherotation,theCoriolisforcecanalsocontributetothesecondaryflow.Theinteractionofrotationandcurvaturecomplicatestheflowcharacteristics.Theboundary-fittedcoordinatewasadoptedtostudytheflowcharacteristicintherotatingsystems.Theeffectsofrotationontheflowtransitionwerestudiedindetail.Thegenerationandmergenceofvorticesinrotatingcurvedellipticalpipeswerealsocapturedforthefirsttime.Thesimulationresultsshowthattheflowforthecaseoflargeaspectratioofthecross-sectionismorelikelytobeunstablethanthatforsmallerone.

  • 标签: 旋转弯曲椭圆管道 边界-配置坐标 数值仿真 二次流
  • 简介:Fluidinclusionsinmineralsfilledinporesofreservoirrockscanbeusedasagoodindicatorofporegenesisanddevelopmentsoastoshedlightonoilgeneration,migrationandaccumulation.TherelationshipbetweenporeevolutionandoilgenerationhasbeenestablishedbasedonfluidinclusionstudiesontheLowerOrdoviciancarbonatereservoirstrataintheOrdosBaisn,NorthwestChina.Sevenstagesofporositydevelopmentcanberecogmized.i.e.,thepenecontemporaneous,theearlyandmiddle-latediagenetic,thesupergene,theearly,middleandlatere-buryingstages.Thedissolutionporesanfissuresformedinthesupergeneandmiddle-latereburyingstageandthestructuralfracturesformedinthelatere-buryingstageconstitutethemajortrapsofoilandgas.ThemajorphaseofoilmigrationandaccumulationtookplacebetweenLateJurassicandCretaceous,Correspondingtothemiddleandlatere-buryingstages.ThegenerationandaccumulationofoilcanbecloselyrelatedtoYenshaniantectonics.

  • 标签: 流体包裹体 碳酸盐 多孔性 地球化学 沉积物
  • 简介:在水下圆柱的壳结构被发现了一许多设计领域里的申请宽例如水兵的元素,给平台上油,等等。联合颤动分析是为这些的一个热问题在水下结构。颤动特征在水下结构不仅被水动力学压力而且由相应于不同的水深度的静水力学的压力影响。在这研究,一个声学的有限元素方法被用来评估在水下结构。以起始的压力僵硬考虑静水力学的压力,听觉的液体结构联合了分析在水下圆柱的壳被做了在自然频率和健全放射上学习水动力学压力的效果。由与频率基于Bessel功能由声学的有限元素方法并且由增加的集体方法获得了作比较,现在的分析的有效性被检查。最后,使硬的圆柱的壳的健全放射的测试样品被泛音获得声学的分析。结果证明静水力学的压力在与水深度决定健全放射变化的一个大沉没身体运动,和特征起一个重要作用。而且,分析方法和结果具有为另外的复杂海底的结构的研究的重要参考价值。

  • 标签: 水下结构 流体结构连接分析 初始应力 振动
  • 简介:ThispaperestablishesthevelocityfieldandtheadequateshearstresscorrespondingtothemotionofanOldroyd-BfluidbetweentwoinfinitecoaxialcircularcylindersbymeansoffiniteHankeltransforms.Theflowofthefluidisproducedbytheinnercylinderwhichappliesatime-dependentlongitudinalshearstresstothefluid.Theexactanalyticalsolutions,presentedinseriesformintermsofBesselfunctions,satisfyallimposedinitialandboundaryconditions.ThegeneralsolutionscanbeeasilyspecializedtogivesimilarsolutionsforMaxwell,secondgradeandNewtonianfluidsperformingthesamemotion.Finally,somecharacteristicsofthemotionaswellastheinfluenceofthematerialparametersonthebehaviorofthefluidmotionaregraphicallyillustrated.

  • 标签: COUETTE流动 流体运动 HANKEL变换 轴向 纵向剪应力 贝塞尔函数
  • 简介:Thepropagationofmultipolemodalwavesalongthewell-axisinafluid-filledboreholesurroundedbyelasticandnonelastic,infiniteandfiniteformationisanalysedbyusingthewaveequations.Thephasevelocitydispersionandtheexcitationcurvesarenumericallycalculated.Thewaveformsexcitedbyattenuatingburstsarealsocalculated.Themeasurementswithlong-spaceddipoletransducersmadeofPZTthindisksvibratinginbendingmodearecarriedoutinaconcretemodelwellandtheexperimentalresultsarecomparedwiththetheoreticalresults.

  • 标签: DIPOLE EXCITED FLEXURAL BOREHOLE FILLED analysed
  • 简介:2004年即将过去,崭新的2005年就要来到了,空气中开始充斥着冬天的气息,北国的冬季总是来得很早而没有丝毫的征兆,就这样随着风飘来,慢慢吞噬一切温暖,而这个时候,也正是编辑部最忙碌的时候,年底了,一定得准备最好的文章送给大家,感谢大家在这一年里对我们的关怀!

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  • 简介:对今年后期进出口走势的判断,如果非典不出现比较严重的反复,第四季度进出口将继续在高位运行,出口退税政策对第四季度的影响不是很大。预计全年进出口有可能突破600亿美元.其平出口405至410亿姜元左右,进口195亿美元左右。

  • 标签: 2004年 中国 经济政策 企业 经营环境 对外贸易