简介:Inagasturbineenginecombustor,highlyswirlingcombustionisusuallyadoptedtostabilizeflameandreducepollutantemissions.Swirlcup,asanairblastatomizer,iswidelyusedtoprovideauniformpresentationoffueldropletstothecombustordome.Thispaperinvestigatedtheeffectofsecondaryswirlerontheflowfielddownstreamoftheswirlcupusingparticleimagevelocimetry(PIV).Threeswirlcups’non-reactingflowfieldwerestudied:caseA,BandCwithsecondaryswirlervaneangle53°,60°and68°respectively.Detailedmeanandtransientvelocitiesandvorticityinthecenterplanewereobtained.FromthePIVresults,asharpcontrastflowfieldwasobtainedforcaseAtoothertwocasesduetothelowersecondaryswirlingintensity.TherecirculationzoneiscollapsedindisorderforthecaseA.Ignitiontestsofthethreecupswerecompletedinasinglecupcombustor.Ingeneral,theignitionperformanceincreaseswiththeincreasingofthesecondaryswirlingintensity.ForcaseA,theignitionperformanceisveryunstableandhasmuchrandomnessandthereisnoclearleanignitionboundarycanbegenerated.Thisworkcanfurtherunderstandtheswirlbehaviorandignitionmechanism.
简介:Melt-spunribbonswhicharetheimportantrawmaterialforhot-deformedmagnetscanbepreparedbysingle-rollermelt-spinning.Inordertopreparewell-structuredribbons,themodeloftemperaturefieldforsingle-rollermelt-spinningprocesswasconstructedinthiswork.Theheatconductioninthisprocesswassimplifiedasonedimensionalheatconductionproblem.Itwasshownbymodelingthat,thetemperaturefieldinthemelt-spinningbeforesolidificationinthismodelcouldbedescribedasthisequationT(x,t)=Tmoexp[–k(x–x0)–k2αt]+T0.ThetemperatureT(x,t)ofthealloymeltsdecreasedwithincreasedpositionxandcoolingtimetexponentiallyfromthewheel-freesurfacetothewheel-sidesurface.TheconstantkdeterminedthedecreasespeedofalloytemperatureT(x,t),whichwasproportionaltotheinterfacialheattransfercoefficienthandtheinterfacialareaofheatconductionA0,butinverselyproportionaltothethermalconductivityK.x0wasthethicknessofthealloymelt.Withincreasedx0,thetemperaturedifferencebetweenwheel-freesurfaceandthewheel-sidesurfacebecamelarger,whichwouldleadtolargerdifferenceingrainsize.Inexperiments,theinfluenceofmelt-spinningprocessparametersonthetemperaturefieldmodelwasdiscussed,suchascoolingrollermaterials,wheelspeed,andsoon.Melt-spunribbonspreparedbysingle-rollermeltspinningatdifferentwheelspeedwereinvestigatedandmagneticpropertiesofdie-upsetmagnetsfrommelt-spunribbonsondifferentcoolingrollerwereanalyzed.Thevariationofgrainsizeinthedepthdirectionconsistedwithtemperaturefieldmodel.Thismodelprovideddirectionsforthepreparationofmelt-spunribbonswithuniformlydistributedfinegrains,whichwereverynecessaryforproducinghot-deformedmagnetswithhighmagneticperformance.
简介:FromJuly23rdtoAugust15th,2001,afieldcultivationexperimentwascarriedouttodeterminethelimitationfactorsofphytoplanktonintheYangtzeRiverestuaryandtheadjacentareas.TheresultsindicatedthatthepotentiallimitingnutrientwasphosphorusintheYangtzeRiverdilutedwaterarea,nitrogenintheoffshoreoftheYangtzeRiverestuaryandtheconversionofphosphorustonitrogeninthemiddlearea.Ironandsiliconwerenotthepotentiallimitingfactors.Ifthereweresomekindsoflimitingfactorsinthewater,thegrowthofphytoplanktonwouldbelimitedobviously.Incaseofdisappearanceofthelimitingfactor,thephytoplanktonwouldgrowfast.WhentheNoctilucascintiuansbloomoccurred,thephytoplanktonbiomasslevelwasverylowinashorttimeduetothegrazingpressure.Whenthegrazingpressuredisappeared,thephytoplanktonwouldgrowquicklyinabundantnutrientscondition.
简介:沿着陡峭的斜坡的分开的岩石块的下坡的运动是沿着一个斜坡并且在山谷底部上的脚危及基础结构的安全的一个重要过程,但是仅仅有限的知识在对如此的块的运动的速度和距离的各种各样的因素的影响上是可得到的。我们在斜坡上讨论团的影响和岩石块,斜坡的险峻,和overburden的厚度的形状,在岩石的运动的距离上,不同地在256个领域实验被观察与的块与176m的高度在斜坡上从3个不同位置塑造了块。地测试的结果的统计评估证明斜坡坡度调节并且压垂是主要因素,岩石群众的表格是第二个因素,并且团是第三个影响因素。当岩石群众的团是15m时,它是为岩石群众的运动的最大的平均加速<27kg,岩石群众的表格是薄片,坡度的条件是平均59.6潣摮湥慳整?慨楶杮栠杩敨?慰慲晦湩愠摮氠睯牥愠潲慭楴楣祴琠慨?敲楳畤污漠汩s吗?
简介:PhysicalsimulationisusedtostudythemovementofnonmetallicparticlesinAlmeltinelectromagneticfield.ItisfoundthattheterminalvelocityofparticlesindifferentReynoldsnumberrangehasdifferentfunctions.ByconfirmingdragforcecoefficientofnonmetallicparticleswithReynoldsnumberintherangeof0.2~10and10~25respectively,twofunctionsofterminalvelocityforsphericalnonmetallicparticleshavebeengotaccordingly,whichprovideatheoreticalbasisforseparatingnonmetallicinclusionsfromAlmeltinelectromagneticfield.
简介:Manystudieshaveinvestigatedevaporationofsessiledropsinanattempttounderstandtheeffectofwettingontheevaporationprocess.Recentlyinteresthasalsoincreasedinthedepositionofparticlesfromsuchdrops,withevaporativemassfluxbeingdeemedtoberesponsibleforring-likedeposits,andcounteractionofthemassfluxbyMarangoniconvectionexplainingmoreuniformdepositionpatterns.Understandingofsuchdepositionprocessesisimportantinbiologicalapplications,suchastheLitostest-systemendorsedbytheRussianMinistryofHealthfordiagnosisofurolithiasisandtheevaporationofcolloidaldropsfordepositingandorganizingproteinsandDNA.Inmostcaseswheredepositionfromevaporatingdropshasbeenstudied,velocityinformationisinferredfromthefinaldepositionpatternorfrommathematicalmodelingbasedonsimplifiedmodelsofthephysicsoftheevaporationprocess.Inthisstudywehavedirectlymeasuredtheflowvelocitiesinthebaseofsessiledrops,usingmicroparticleimagevelocimetry,viewingthedropfrombelow,throughthecoverslide.Forwaterdrops,aradialpatternofflowwasobservedwithamaximumvelocityclosetobutnotatthepinnedouteredge.For‘azeotropic’ethanol/watermixtures,thevelocityfieldismorechaotictobeginwith,passingthroughaphaseinvolvingthreeorfourrecirculationcellsandfinallyhavingthesameradialpatternasforwaterdrops.
简介:Thereciprocitymeasurementtheoryinanomalousreverberantsoundfieldswasinvestigated.AnimprovedmethodWasproposedduetotheinterrelatederrors.ThesourcevolumevelocityWascorrectedbyspatialaverageofmeasurementresultsandevaluationofthereverberantsoundfieldinfluenceonacousticenergydensity.Theresultwasvalidatedinunderwaterexperiment,correctedreciprocitymeasurementresultswerealmostthesameasdirectmeasurementresults.Itindicatesthatreverberantsoundfielddoesnotaffectthevaliditvoftheprinciple,butinfluencestheobtainmentofsourcevolumevelocity,theninfluencesthemeasurementoftransferfunctionswiththeprinciple.Theproposedmethodissimpleandeffectiveinanomalousreverberantsoundfields.Thestudymavbevaluablefortheapplicationswhicharebasedontheprinciple.
简介:这篇论文介绍一条新途径给连续统结构的结构的拓扑学优化。材料点独立变量被介绍在流行拓扑学优化方法说明材料点和他们的附近的存在条件,或不存在的东西而不是元素或节点。拓扑的变量地被少些在网孔被用作形状功能的动人的最不方形的近似构造方法。与有限元素分析,不是仅仅棋盘模式和网孔依赖现象结合了由这个连续、光滑的拓扑的变量领域,而且地点被克服,拓扑的变量的数字能是任意的。包括照点的数字的参数,可伸缩的参数,重量功能等等,在最佳之上,拓扑的配置被讨论。二个经典拓扑学优化问题被建议方法成功地解决。方法被发现柔韧,没有数字不稳定性与合适的参数被发现。
简介:Weexperimentallyinvestigateprobetransmissionsignals(PTS),thefour-wavemixingphotonicbandgapsignal(FWMBGS),andthefluorescencesignal(FLS)inaninvertedY-typefourlevelatomicsystem.Forthefirsttime,wecomparetheFLSofthetwoground-statehyperfinelevelsofRb85.Inparticular,thesecond-orderandthefourth-orderfluorescencesignalsperformdramaticdressingdiscrepanciesunderthetwohyperfinelevels.Moreover,wefindthatthedressingfieldhassomedressingeffectsonthreesuchtypesofsignals.Therefore,wedemonstratethatthecharacteristicsofPTS,FWMBGS,andFLScanbecontrolledbyfrequencydetunings,thepowersorphasesofthedressingfield.Suchresearchcouldhavepotentialapplicationsinopticaldiodes,amplifiers,andquantuminformationprocessing.
简介:把没有庄稼植被,广泛地在国外被使用的平衡模型,温度和湿度在完整的照明回答联合温室土壤的模型的精力基于表面被建立。就在温室,弱太阳的放射和土壤的很少表面蒸发的相对关上的环境而言,在不同土壤层的水内容的每日的变化可以被忽视,然后,温度和湿度地联合模型被简化到一个一个维的热散开模型。简化模型和湿度地联合模型采用了土壤的一样的计算方法物理参数和热散开的分离格式微分方程,并且没有庄稼植被,在完整的照明在温室土壤被用于温度地的连续模拟。通过在模拟结果和试验性的数据之间的比较,简化模型的精确被验证。在24h周期的土壤热流动变化的典型规则也被获得。
简介:电影冷却是一项重要措施启用一台煤气的汽轮机并且从而的入口温度的增加,到改进它的全面效率。冷却剂在片或endwalls通过洞的spanwise排被逐出建立防护材料的一部电影。洞经常在下游的方向被使倾向并且产生一个肾旋涡。这是相反旋转的旋涡对,与在二个旋涡之间的一个向上的流动方向,它趋于上升离开表面并且局部地在对外面向片喂热空气。颠倒旋涡的旋转感觉颠倒这二个缺点进优点。在考虑盒子中,一个反肾旋涡用两个都使倾向的洞的二随后的排被产生有内错角的下游、偏航的spanwise。在以前的研究,我们执行了大旋涡的模拟(它集中了于充分狂暴的边界层)凉下来电影、比较的这个反肾旋涡他们到一个相应物理实验。现在的工作详细分析模仿的流动领域,在全体会议开始(在片或endwall内)通过直到有热边界层的混合的洞。识别在吝啬的流动并且在即时流动发现的旋涡的结构,我们主要使用2标准和显示的线积分卷绕旋转(LIC)技术部分优化。流动区域(冷却剂全体会议,洞,和边界层)随后被学习并且连接了到对方。在整个边界层追踪反肾旋涡,我们建议基于涡度的二个标准并且在LIC结果上。这使我们能在墙把喷气旋涡与冷却有效性联系,它是电影冷却的特色。
简介:AZ31镁合金的团结的微观结构上的一个搏动的磁场的效果被调查。当搏动的磁场被用于AZ31合金的团结时,试验性的结果证明显著微结构精炼被完成。AZ31合金的当演员组微观结构的平均谷物尺寸被精制到107m。由熄灭AZ31合金,不同主要-Mg微观结构在团结的功课期间被保存。微观结构进化表明主要-Mg与搏动的磁场在球状的形状产生并且成长,有没有搏动的磁场的树枝状的形状的对比。搏动的磁场原因在团结期间融化传送对流,它做全部的温度融化一致,并且在液体/固体接口前面生产一个undercooling地区,它使成核率增加并且禁止的大树突。另外,在melt导致的朱尔热效果也加强谷物精炼效果和树突手臂的spheroidization。
简介:Thispaperpresentsthedetaildesignconditions,designcriteriaandmethodsaswellasdesignconclusionsoftheprocess,structureandcorrosionoftheproductionflowlinesandhighpressurewaterinjectionlinesinBZ34-2/4oilfieldinBohaiBay.AtpresentthisdesignrepresentsthedesigncapabilityandlevelinthefieldofthesubmarinepipelineengineeringofChina.
简介:
简介:TheopticalabsorbanceinnearUVwavelengthregioninSnO2nanoclustersinanexternalelectricfieldisdeterminedatroomtemperature.Theabsorbancespectraasapplicedfieldandtheabsorbancevariationswiththeappliedfieldareobtained.Therelationbetweenabsorbancechangeandappliedfieldisnon-linear.andissaturatedathighfieldregion.