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500 个结果
  • 简介:The3-Dturbulentgas-particleflowsinaninnovativecombustorcalled“Spouting-CycloneCombustor”aresimulatedusingak-ε-Aptwo-phaseturbulencemodel.Theresultsshowthat:(1)THepredictedresultsinthespoutingzoneareingoodagreementwiththeexperimentalones;thepredictedgasflowfieldinthecyclonezoneisneartothatmeasured;(2)Inthespoutingzone,thereisalarge-sizegasparticlerecirculationzoneandasmall-sizeoneinthex-rplane,whichisfavorabletoburningcoarsecoalparticles;Inalmosteveryr-θplane,thereareseveralgas-particlevortices,whichisbeneficialtothemixing,heatandmasstransferbetweentwophases,thus,tothetwo-phasecombustion.(3)Thereisremarkablevelocityslipbetweengasandparticlephases;(4)Inthecyclonezone,predictionsshowtheoccurrenceofrecirculatingsecondaryflowsandcounterswirlingflowsinsomecrosssections,suchphenomenaaredifficulttobeobservedbyexperimentalmethods.

  • 标签: 燃烧室 气-粒子流 数字模拟
  • 简介:Thenonstaggeredgridsareadoptedinthispaperforsolvingthegoverningequationsofflowsinthecurvilinearcoordinatesystems.Thepresentpaperdemonstratesthebasicreasonandcorrespondingeliminatingmethodforthepressureoscillation,anddeducesthecorrectedexpressionsforthecurvilinearvelocitycomponentsinwhichandadditionaltermrepresentingthedifferencebetweenthe1-δand2-δdifferencevaluesforthepressuregradientappears.Thusifanoscillatorypressurefiledwerearisen,themagnitudeofthistermwouldbelargeandwouldacttoremovetheoscillation;whereasfornonoscillatoryfieldthemagnitudeofthistermremainssmall.Asexaminationforthenumericalmethod3-Dturbulentflowinasquareductwith90°bendand3-Dturbulentmixinglowinalobed-mixerwerecalculatiedrespectively.Thenumericalresultsaresatisfactory.

  • 标签: 涡流 压强振荡 曲线坐标系
  • 简介:Themillrollerbeatingismadeupofaninternalring,middlerollsandanexternalring,theanalysisofwhiehisamulti-bodiescontactproblem.Inthispaper,basedonthethree-dimensionalelasticcontactBEMwithoutfriction,andusingthestructuralcharacteristicsofrollerbearings,middlerollsarede-scribedbyelasticplateunitsofdifferentshapes,whichisplacedontheinternalring.Thediscontinuoustractionproblemofthecontactelementcanbedealtwithbythetractionsub-elementmethod.Thereforethecontactproblemcanbechangedfroinoneofmulti-bodiestooneoftwo-bodies.Asanelasticdeformationoftheplateelement,itcanbecalculatedbyanelasticcontactformulaandisregardedananequivalentgaptobeputintothetotalmatrixequality.Theface-to-facecontactconditionofdisplacementandtractionontheelementwillnerveastheconvergencejudgingcondition.Soconvergencesolutioncanbeobtainedbeforeanygeometryinconsistentonthecontactelementmaytakeplace.Therefore,thethree-dimensionaldistributionofloadofthemillrollerbearingcanbeachieved,Ithasbeenprovedthatthecalculatingmodelofthismethodisvisualizedandsimple,haslastconvergencesolutionandhigheraccuracy,makingitaneffectivenumericalmethodofdesigningandanalyzingloadcharacteristicsofthemillrollerbearing.

  • 标签: ROLLER bearing TRACTION sub-element METHOD elastic
  • 简介:这篇论文为一个三维的第四顺序的椭圆形的单个不安问题建议一个柔韧的有限元素方法。方法使用三维的莫利元素并且在相应于秒顺序的双线性的形式的部分代替有限元素功能由合适的近似的微分操作员。给如此的近似,为秒顺序问题的一个会聚的非一致的元素被构造。方法在不安参数一致地收敛,这被显示出。

  • 标签: 有限元 奇异扰动问题 椭圆方程 微分算子
  • 简介:Thispaperpresentsanexperimentalstudyofthethree-dimensionalturbulentflowfieldsinalowspeedannularcascadeofhighturningangleturbineblades.Detailedmeasurementswereperformedonthebladesurfacesandmid-streamsurfaceinthepassageandatthreeaxialplanesdownstreamofthecascadebyusingwallstaticpressuretaps,afive-holeprobeandahot-wireanemometer,Thetestdataincludestaticpressuredistributiononbladesurfaces,totalpressurelosscofeeicient,meanflowvelocitycomponents.radialflowangle,turbulenceintensityandReynoldsshearstress.Analysesofthethree-dimensionalcascadeflowcharacteristicsweremadeonthenosetlocationofhighlossvortices.thevariationofpressuregradientinsidethecascadepassageandthepropertiesofendwallboundarylayerstotalpressurelossdistributions,secondaryvortexturbulentdissipationandwakedecaydowntreamofthecascade.Theseexperimentalresultsarevaluableforrevealingthedetailsofthecomplexvortexflowstructureinmodernhighlyloadedaxialturbomachinesandvalidatingthethree-dimensionalflownumericalcomputationcodes.

  • 标签: 透平机叶片 级联损耗 紊流
  • 简介:Thefastions,producedinD-3Hefusionplasma,arethe14.7MeVprotonsand3.6MeVαparticles.Becausetheirslowingdowntimesarefinite,therefore,theydevelopacertainamountofadditionalbeta(fir)whichhastobesupportedbythemagneticfield.

  • 标签: 电流放大系数 快离子 聚变等离子体 质子 Α粒子
  • 简介:在这份报纸,用水泡功能,我们构造一个长方体元素解决第四份订单在三种尺寸的椭圆形的单个不安问题。我们证明nonconformingC0长方体元素关于不安参数一致地在精力标准收敛。[从作者抽象]

  • 标签: 奇异摄动问题 非协调元 一致收敛 椭圆 四阶 3-D
  • 简介:Theimportantintermediateforsynthesesofvariousanti-HIVnucleosideanalogues,methyl2,3-dideoxy-3-fluoro-6-O-(p-methylbenzoyl)-a-D-ribofuranoside,wassynthesizedstartingfrom2-deoxy-D-ribosein5stepswithanoverallyieldof24%.Thisstrategycanbealsousedforsynthesizingotheranalogueswithvarioussubstitutionsat3-Cposition.

  • 标签: NEW method STEREOSELECTIVE synthesis 2 3-dideoxy-3-substituted-D-ribofuranoside
  • 简介:Comparativemolecularfieldanalysis(CoMFA),athreedimensionalquantitativestructure-activityrelationship(3D-QSAR)methodwasappliedtoaseriesofdiindolylmethane(DIM)analogstostudytherelationshipbetweentheirstructureandtheirinductionofCYP1A1-associatedethoxyresorufin-O-deethylase(EROD)activity.ADISCOmodelofpharmacophorewasdervedtoguidethesuperpositionofthecompounds.Thecoefficientofcross-validation(q^2)andnoncross-validation(r^2)forthemodelestablishedbythestudyare0.827and0.988respectively,thevalueofvarianceratio(F)is103.53andstandarderrorestimate(SEE)is0.044.ThesevaluesindicatethattheCoMFAmodelderivedissignificantandmighthaveagoodpredictionforthecatalyticactivityofDIMcompounds.Asaconsequence,thepredictedactivityvaluesofnewdesignedcompoundswereallhigherthanthatofthereportedvalue.

  • 标签: 3D-QSAR COMFA CYPIAI 比较分子场分析 三维定量构效关系 模拟分析
  • 简介:Thispaperdescribesanewmethodwhichhasbeendevelopedforthesolutionofdirectandinverseproblemsof3-Dcompressibleflowsinturbomachinery.Twotypesofstreamfunctionsarepropsedinthepaperandtheatreamfunction-coordinatesystemisappliedinnumericalcomputations,Thealgorithmisappliedtostatorbladesandtheresultsarecomparedwithexperimentaldata.Itisthownthatthecomparisonsareverysatisfactory.

  • 标签: 透平机 空气动力设计程序 空气热力学
  • 简介:沙粒病毒(Arenaviruses)遍布全球,其中的拉沙热病毒可引起致命的拉沙热.通过应用比较分子场分析(CoMFA)和比较相似性指数分析法(CoMSIA)对47个广谱沙粒病毒抑制剂进行了三维定量构效关系(3D-QSAR)分析.使用立体场、静电场、疏水场和氢键受体场组合获得最优模型CoMSIA的统计结果为Q2=0.518,R2ncv=0.972,R2pre=0.911,说明该模型的可靠性和较好预测能力.此外,模型等势线图直观地解释了分子结构与其活性的关系,为进一步设计新型高效的沙粒病毒抑制剂提供了理论依据.

  • 标签: 沙粒病毒 LASV 苯并咪唑衍生物 三维定量构效关系
  • 简介:Numericalanalysisofthree-dimensionalsoundpropagationinsoft-softorsoft-hardcircularductswithcircumferentialandaxialmodesofsoundsourcesattheinlethasbeencarriedout.Inthispaper,thenumericalmethodandthesamplesareofferedandtheeffectsofcircumferentialandaxialmodesonnumericalresultsarediscussedindetail.

  • 标签: INLET lined AXIAL circular CONVERGENT DISCONTINUITY
  • 简介:Inthispaper,weareconcernedwiththeglobalexistenceandconvergenceratesofthesmoothsolutionsforthecompressiblemagnetohydrodynamicequationswithoutheatconductivity,whichisahyperbolic-parabolicsystem.TheglobalsolutionsareobtainedbycombiningthelocalexistenceandaprioriestimatesifH3-normoftheinitialperturbationaroundaconstantstatesissmallenoughanditsL1-normisbounded.Aprioridecay-intimeestimatesonthepressure,velocityandmagneticfieldareusedtogettheuniformboundofentropy.Moreover,theoptimalconvergenceratesarealsoobtained.

  • 标签: 磁流体方程组 整体存在性 三维可压缩 收敛速度 热导率 光滑解
  • 简介:ThecrystalstructureofN-(2,3,4,6-tetra-O-acetyl-β-D-gly-cosyl)-thiocarbamicbenzoylhydrazine(C22H27N3O9S)wasdeterminedbyX-raydiffractonmethod.Thehexopyranosylringadoptsachairconformation.Alltheringsubstituentsareintheequatorialpositions.Theacetoxyl-methylgroupisinsynclinalconformation.TheSatomisinsynperiplanarconformationwhilethebenzoylhydrazinemoietyisanti-periplanar.Thethiocarbamicmoietyisalmostcompanarwiththebenzoylhydrazinegroup.Therearetwointramolecularhydrogenbondsandoneintermolecularhydrogenbondforeachmoleculeinthecrystalstructure.Themoleculesformanetworkstructurethroughintermolecularhydrogenbonds.

  • 标签: 晶体结构 N-(2 3 4 6-四-间-乙醚基-β-D-糖基)硫氨基甲酸苯甲酰肼 氢键 构象