简介:Concerningthespecificdemandonsolvingthelong-termconjugateheattransfer(CHT)problem,anewalgorithmoftheglobaltightly-coupledtransientheattransferbasedonthequasi-steadyflowfieldisfurtherputforward.Comparedtothetraditionalloosely-coupledalgorithm,thecomputationalefficiencyisfurtherimprovedwiththegreatlyreducedupdatefrequencyoftheflowfield,andmoreovertheupdatestepoftheflowfieldcanbereasonablydeterminedbyusingtheengineeringempiricalformulaoftheNusseltnumberbasedonthechangesoftheinletandoutletboundaryconditions.Takingaductheatedbyinnerforcedairflowheatingprocessasanexample,thecomparingresultstothetightly-coupledtransientcalculationbyFluentsoftwareshowsthatthenewalgorithmcansignificantlyimprovethecomputationalefficiencywithareasonableaccuracyonthetransienttemperaturedistribution,suchasthecomputingtimeisreducedto22.8%and40%whiletheductwalltemperaturedeviationare7%and5%respectivelyusingtwoflowupdatetimestepof100sand50sonthevariableinlet-flowrateconditions.
简介:Accordingto350MWand600MWboilers,underoxygenfuelcondition,throughthereasonablecontroloftheprimaryandsecondaryflowandthecorrectoptionandrevisionofmathematicalmodel,thetemperaturedistribution,heatfluxdistributionandabsorptionheatdistribution,etc.wasobtainedwhichcomparedwiththoseunderaircondition.Throughcalculation,itisobtainedthattheprimaryandsecondaryflowmixedwell,goodtangentiallyfiredcombustioninfurnacewasformed,thetemperatureunderairconditionobviouslyhigherthanthetemperatureunderO26condition.Theadiabaticflametemperatureofwetcyclewasslightlyhigherthanthatofdrycycle.Themaximumheatloadappearedonthewaterwallaroundtheburnerarea.Theheatloadgraduallydecreasedalongthefurnaceheightupanddowninburnerarea.TheheatabsorptioncapacityofthefurnaceunderO26waslowerthanthatundertheaircondition.Theheatabsorptioncapacityoftheplatenheatingsurfaceunder026wasequaltothatunderaircondition.AndtheheatabsorbingcapacityofwaterwallunderO26wasabout7%~12%lessthanthatunderaircondition.
简介:Bioluminescenceimagingisakindofemergingdetectiontechnologyatcellular,molecularandgeneticlevel.Themostpopularbioluminescenceimagingmodelisdiffusionapproximation(DA).However,becauseoftheill-posednessoftheDA-basedinverseproblemandtheinstabilityofreconstructionalgorithms,thelocationaccuracyofthereconstructedsourcesislow.Radiativetransferequation(RTE),whichconsidersthedirectionofthephotonmigrationandtheeffectofabsorptionandscatteringintissues,canaccuratelyexpressthetransmissionofbioluminescentphotonsthroughthetissues.Inthispaper,westudiedthebioluminescenceimagingbasedontheRTE.2Dsimulationswereperformed,andquantitativeevaluationwasgivenbytheabsolutesourcepositionerror,therelativesourceareaerrorandtheminimumboundingbox.TheresultsoftheexperimentshowedthattheimagingqualitybasedonRTEwasbetterthanthatonebasedonDA.
简介:Theeffectsofdifferentrefrigerantsonheattransferperformanceofpulsatingheatpipe(PHP)areinvestigatedexperimentally.Theworkingtemperatureofpulsatingheatpipeiskeptintherangeof20℃-50℃.Thestartuptimeofthepulsatingheatpipewithrefrigerantscanbeshorterthan4min,whenheatingpowerisintherangeof10W-100W.Thestartuptimedecreaseswithheatingpower.ThermalresistancesofPHPwithfillingratio20.55%wereobviouslylargerthanthosewithotherfillingratios.ThermalresistanceofthePHPwithR134aismuchsmallerthanthatwithR404AandR600a.ItindicatesthattheheattransferabilityofR134aisbetter.Inaddition,acorrelationtopredictthermalresistanceofPHPwithrefrigerantswassuggested.
简介:在生物体之发光断层摄影术(BLT)问题,在从光信号的一个小动物内的生物体之发光来源分发在动物身体表面上检测了的一构造份量上。BLT问题是提出病的,经常,Tikhonov规则化被用来获得稳定的近似答案。在常规Tikhonov规则化,选择一个合适的规则化参数平衡近似解决方案的精确性和稳定性是关键的。在这份报纸,一个参数依赖者联合了基于的复杂边界方法(CCBM)Tikhonov规则化被用于放射的转移方程(RTE)管理的BLT问题。由适当地处于知更鸟边界条件调整参数,我们完成一个重要性质:调整答案关于规则化参数是一致地稳定的以便规则化参数能被选择完全基于答案精确性的考虑。分离纵标的有限元素的方法被用来计算数字答案。数字结果被提供说明建议方法的表演。
简介:Abinaural-loudness-model-basedmethodforevaluatingthespatialdiscriminationthresholdofmagnitudesofhead-relatedtransferfunction(HRTF)isproposed.Astheinputofthebinauralloudnessmodel,theHRTFmagnitudevariationscausedbyspatialpositionvariationswerefirstlycalculatedfromahigh-resolutionHRTFdataset.Then,threeperceptualrelevantparameters,namelyinterauralloudnessleveldifference,binauralloudnesslevelspectra,andtotalbinauralloudnesslevel,werederivedfromthebinauralloudnessmodel.Finally,thespatialdiscriminationthresholdsofHRTFmagnitudewereevaluatedaccordingtojust-noticedifferenceoftheabove-mentionedperceptual-relevantparameters.AseriesofpsychoacousticexperimentswasalsoconductedtoobtainthespatialdiscriminationthresholdofHRTFmagnitudes.Resultsindicatethatthethresholdderivedfromtheproposedbinaural-loudness-modelbasedmethodisconsistentwiththatobtainedfromthetraditionalpsychoacousticexperiment,validatingtheeffectivenessoftheproposedmethod.
简介:Inthispaper,wepresentathreedimensionalnumericalinvestigationofheattransferinaparabolictroughcollectorreceiverwithlongitudinalfinsusingdifferentkindsofnanofluid,withanoperationaltemperatureof573Kandnanoparticleconcentrationof1%involume.Theoutersurfaceoftheabsorberreceivesanon-uniformheatflux,whichisobtainedbyusingtheMonteCarloraytracingtechnique.Thenumericalresultsarecontrastedwithempiricalresultsavailableintheopenliterature.AsignificantimprovementofheattransferisderivedwhentheReynoldsnumbervariesintherange2.57×104≤Re≤2.57×105,thetube-sideNusseltnumberincreasesfrom1.3to1.8times,alsothemetallicnanoparticlesimproveheattransfergreatlythanothernanoparticles,combiningbothmechanismsprovidesbetterheattransferandhigherthermo-hydraulicperformance.
简介:轧了nanorods用诱导地联合的血浆与Ninano岛面具蚀刻被制作。poly[2-methoxy-5-(2乙醇)hexoxy-1,4-phenylenevinylene](MEH-PPV)/GaN-nanorod混血儿结构被扔MEH-PPV电影在上制作由使用纺纱涂层过程轧了nanorods。在混合结构,空间分离被最小化完成高效率的非放射的反响的精力转移。由MEH-PPV/GaN-nanorod混合结构组成的一台新奇设备的光性质被分析光致发光(PL)学习系列。与相比纯轧了nanorods,乐队边排放的PL紧张在MEH-PPV/GaN-nanorods轧了像黄乐队的三次,和紧张稍微被压制一样,被提高。获得的结果被精力转移在之间分析轧了nanorods和MEH-PPV。一个精力转移模型被建议解释现象。
简介:Inthepresentwork,theheattransferstudyfocusesonassessmentoftheimpactofbedtemperatureonthelocalheattransfercharacteristicbetweenafluidizedbedandverticalrifledtubes(38mm-O.D.)inacommercialcirculatingfluidizedbed(CFB)boiler.Heattransferbehaviorina1296t/hsupercriticalCFBfurnacehasbeenanalyzedforGeldartBparticlewithSautermeandiameterof0.219and0.246mm.TheheattransferexperimentswereconductedfortheactiveheattransfersurfaceintheformofmembranetubewithalongitudinalfinatthetubecrestunderthenormaloperatingconditionsofCFBboiler.AheattransferanalysisofCFBboilerwithdetailedconsiderationofthebed-to-wallheattransfercoefficientandthecontributionofheattransfermechanismsinsidefurnacechamberwereinvestigatedusingmechanisticheattransfermodelbasedonclusterrenewalapproach.ThepredictedvaluesofheattransfercoefficientarecomparedwithempiricalcorrelationforCFBunitsinlarge-scale.
简介:Asystemofjointlytransferringtimesignalswitharateof1pulsepersecond(PPS)andfrequencysignalsof10MHzviaadensewavelengthdivisionmultiplex-based(DWDM)fiberisdemonstratedinthispaper.Thenoisesofthefiberlinksaresuppressedandcompensatedforbyacontrolledfiberdelayline.Amethodofcalibratingandcharacterizingtimeisdescribed.The1PPSissynchronizedbyfeed-forwardcalibratingthefiberdelaysprecisely.Thesystemisexperimentallyexaminedviaa110kmspooledfiberinlaboratory.Thefrequencystabilitiesoftheuserendwithcompensationare1.8×10-14at1sand2.0×10-17at104saveragetime.Thecalculateduncertaintyoftimesynchronizationis13.1ps,whereasthedirectmeasurementoftheuncertaintyis12ps.Next,thefrequencyand1PPSaretransferredviaametropolitanareaopticalfibernetworkfromonecentralsitetotworemotesiteswithdistancesof14kmand110km.Thefrequencystabilitiesof14kmlinkreach3.0×10-14averagedin1sand1.4×10-17in104srespectively;andthestabilitiesof110kmlinkare8.3×10-14and1.7×10-17,respectively.Theaccuraciesofsynchronizationareestimatedtobe12.3psforthe14kmlinkand13.1psforthe110kmlink,respectively.
简介:Inthispaper,weconsiderthemulti-dimensionalasymptoticpreservingunifiedgaskineticschemeforgrayradiativetransferequationsondistortedquadrilateralmeshes.Differentfromtheformerscheme[J.Comput.Phys.285(2015),265-279]onuniformmeshes,inthispaper,inordertoobtaintheboundaryfluxesbasedontheframeworkofunifiedgaskineticscheme(UGKS),weusetherealmulti-dimensionalreconstructionfortheinitialdataandthemacro-termsintheequationofthegraytransferequations.Wecanprovethattheschemeisasymptoticpreserving,andespeciallyforthedistortedquadrilateralmeshes,anine-pointscheme[SIAMJ.SCI.COMPUT.30(2008),1341-1361]forthediffusionlimitequationsisobtained,whichisnaturallyreducedtostandardfive-pointschemefortheorthogonalmeshes.Thenumericalexamplesondistortedmeshesareincludedtovalidatethecurrentapproach.
简介:Thevariationinarccharacteristicsandbehaviorofmetaltransferwiththechangeinpulseparametershasbeenstudiedbyhighspeedvideocameraduringpulsecurrentflux-coredarcwelddeposition.Acomparativestudyofsimilarnaturehasalsobeencarriedoutduringflux-coredarcwelddepositioninglobularandspraytransfermodes.Theeffectofpulseparametershasbeenstudiedbyconsideringtheirmeancurrentandarcvoltage.Thearccharacteristicsstudiedbyitsrootdiameter,projecteddiameterandlength,andthebehaviorofmetaltransfernotedbythemetaltransfermodelandthedropletdiameterhavebeenfoundtovarysignificantlywiththepulseparameters.TheobservationmayhelpinunderstandingthearccharacteristicswithrespecttothevariationinpulseparameterswhichmaybebeneficialinusingpulsecurrentFCAWtoproducedesiredweldquality.
简介:电影动量和在加速上的薄有限幂定律液体的热运输特征上的内部加热来源的效果不稳定的水平拉长的接口被学习。不同于这块地里的很古典的工作,为改变热电导率的液体电影和概括Fouriers法律的一般表面温度分布被考虑。适当类似转变被用来与一组二点的平常的微分方程(颂诗)把强烈非线性的管理部分微分方程(PDE)变换成一个边界价值问题。在液体电影厚度和摇摆参数之间的通讯在MATLAB用BVP4C节目被导出。自我类似颂诗的数字答案用与一个Runge-Kutta重复程序和牛顿计划相结合的射击技术被获得。液体上的深奥物理参数的效果水平速度和温度分发被介绍并且讨论。
简介:Cr的Nanopowder:Cr的GGG和nanopowder,Nd:有从0.1at.%到1.5at.%的Cr3+的不同集中的GGG被大音阶的第五音胶化方法用醋酸和乙烯乙二醇综合。热gravimetric分析和微分扫描热量测定(TGA-DSC),X光检查衍射(XRD)和光致发光光谱学被用来描绘粉末。当在1000点对待时,雏晶尺寸是大约58nm?????????????????猯灵?匠?猼'T资???猼灵?????????猯'T??猼灵???? ̄?????猯'T????猯灵??猼'T?????吗????????????????‵渠????????浮??