简介：Thephysicalmechanismforgenerationofstreamwisevortices(orribvortices)inthecylinderwakeisnumericallyinvestigatedwithafinite-differencescheme.Rayleigh’stheoryofcentrifugalinstabilityforinviscidaxisymmetricflowisextendedtoanalyzethe2-Dprimaryflows.Accordingly,ananalyticaldimensionlessgroupRay=-(r/vθ)■vθ/■r-1isderived,wherevθrepresentsthevelocityofafluidelementrelativetotheoncomingflow,risthelocalcurvatureradiusoftheelementpathline.CentrifugalinstabilityoccurswhenRay>0.StabilityanalysesarecarriedoutwiththisdiscriminantforprimaryflowsatdifferenttimelevelsinahalfsheddingperiodofthevonKarman(orvK)vortices.UnstableareasareidentifiedandthelocationsofribvorticesarecoincidentwellwiththeunstableareaswithinthefirstwavelengthofvKvorticesbehindthecylinder.Thenumericalresultsalsoshowthatribvorticesexperienceamplificationinthisregion.Itisapparentthatcentrifugalinstabilityplaysanimportantroleinthegenerationofribvorticesinthecylinderwake.

简介：这份报纸报导巨浪的试验性、理论的学习发生在原型一台极端微离心的压缩机。作为第一步，10次缩放有40公里的一台极端微离心的压缩机的模型外部直径被设计并且生产。为有B参数的几不同价值的巨浪的短暂行为的详细试验性的调查被执行。试验性的结果在巨浪期间与非线性的lumped参数理论获得以便为微离心的压缩机验证理论巨浪模型的有效性的那些相比。作为结果，巨浪的相当不同的行为在实验并且在分析为B的不同价值出现了。关键词微离心的压缩机-澎湃-lumped参数模型CLC数字TK474.8+2

简介：Surgeandrotatingstalloccurringinacentrifugalcompressorsystemareinvestigatedbyusingaphaseportraitreconstructionmethod.Fromexperimentallymeasuredtimeseriesofdata,themethodclarifiedthecyclicbehaviorofsurge.Forrotatingstall,therestillremainproblemsinthephaseportraitduetothechaoticbehavior.However,theresultsobtainedbythepresentmethodareabletoprovidenewinsightstothemodelingsforsurgeandrotatingstall.Surgeandroattingstalloccurringinacentrifugalcompressorsystemareinvestigatedbyusingaphaseportraitreconstructionmethod.Fromexperimentallymeasuredtimeseriesofdata,themethodclarifiedthecylcicbehaviorofsurge.Forrotatingstall,therestillremainproblemsinthephaseportraitduetothechaoticbehavior.However,theresultsobtainedbythepresentmethodareabletoprovidenewinsightstothemodelingsforsurgeandrotatingstall.

简介：Inthisstudy,weattempttheanalysisofthepassageflowinthecentrifugalimpellerusingFEMwith/withouttheturbulencemodel,andcomparethisresultwiththeexperimentalresult.TheturbulencemodelisthelowReynoldsk-εmodelproposedbyChien.WeusetheGSMACmethodfortheReynoldsaveragedNavier-Stokesequations,theEulerexplicitmethodforthetransportequationsoftheturbulentkineticenergyandthedissipationrate.AllequationsarediscretizedbytheGalerkin'smethod.Atthemidpassageofthecentrifugalimpeller,thepassagewisevelocitycomponenttendstoincreaseinthepressure-to-suctiondirection,andtheothercomponenttowardthepressuresurfacetendstobelargeintheregionofthemiddleblade-to-bladetothehubside.Thetipleakagesappeararoundtheregionofthemiddleblade-to-bladenearthecasingtogetherwiththesecondaryflowtowardthesuctionsurface.Thesephenomenacorrespondwiththeexperimentalresult,qualitatively.

简介：数字、试验性的调查在舞台被扫向後面的splitteredunshroudedimpeller和vaned填写了的一台接近音速的离心的压缩机被进行更弥漫。在inducer的流动的详细分析(即在主要的片前缘和splitter片前缘之间的impeller的入口地区)被建议从窒息澎湃。稳定、不稳定的模拟用代码elsA被执行，它在结构化的网孔上使用一条多域途径并且解决可压缩的RANS方程，在旋转原则与二方程的骚乱模型k-l联系了。1MWLMFA-ECL测试钻塔被用于在压缩机阶段执行测试。直到150kHz的不稳定的压力大小和激光Doppler风力测定大小在inducer被执行。就算，一个好协议在试验性、数字的数据之间被获得一过去驱散在数字结果被注意。在流动模式从的变化窒息澎湃主要由于在弄直的尖端漏流动轨道的一个变化，近导致一个单个段落的流动阻塞笼罩。一光谱分析证明仅仅传递频率和它的泛音的片填写获得从的各种各样的系列窒息澎湃。

简介：基于海军司烧方程和Spalart-Allmaras骚乱模型，在有long-mid-short片建筑群impeller的离心的泵的三块维的狂暴的流动地数字地计算、分析。在flowpart的相对速度和压力分布被获得。在复杂impeller的经过的流动由于在涡囊和impeller之间的联合行动是不对称的，这被发现。逆流区域在长片的吸方面的入口，在长片的压力方面和短片的吸方面的插头的中间的部分附近。涡囊喉咙附近的流动被涡囊极大地影响。相对速度大，在涡囊喉咙附近在复杂impeller的插头带回来流动是容易的。静电干扰和全部的压力在impeller从入口一致地升起到插头。在impeller插头，压力周期性地严厉地从压力方面减少到吸方面，然后静态的压力喉咙附近的上升。试验性的结果证明在impeller的背流动在泵的表演上有重要影响。

简介：Thispaperperformsanumericalsimulationofthree-dimensionalflowfieldinacentrifugalcompressorwithlonginletandoutletpipesusingCFXsoftware.Byarrangingvirtualprobesatdifferentpositionsinbothinletandoutletplanes,theaerodynamicperformanceofthecentrifugalcompressorismeasuredandcomparedwitheachother.Theneffectsofmeasuringpositionsonmeasurementresultsarediscussed.Theresultsshowthatitwillgeneratenotablemeasuringerrorsofthepressureratioandefficiencyiftheinlettotalpressureismeasuredusingasingle-pointprobe.Theinlettotalpressuredatacanbeaccuratewhentheyaremeasuredusinga3-pointrake.Theoutlettotalpressureandtotaltemperaturedatacannotbeaccurateiftheyarerespectivelymeasuredatonecircumferentialpositionevenusingamulti-pointrake.Increasingtangentialmeasuringpositionsattheoutletiseffectivetoimprovethetestaccuracy.Whentheoutlettotalpressureandtotaltemperaturearerespectivelymeasuredat3tangentialpositions,thedatacanbealmostaccurate.

简介：这份报纸与vaned在一台离心的压缩机向旋转货摊从正常操作条件在这个过程上汇报数字研究更弥漫。目的更好在在离心的impeller和vaned之间的相互作用下面在货摊点附近理解流动特征更弥漫。数字结果证明在就先于货摊点的某些条件下面，尖端漏旋涡开始波动在粗略地过去的片的一半频率。这现象类似于在轴的压缩机的旋转不稳定性。与流动，率进一步减少了impeller货摊并且五个货摊房间在旋转速度被发现的85%impeller的频率宣传。

简介：以便调查设计方法因为一台微离心的压缩机，它是一台极端微煤气的汽轮机的最重要的部件，有2-dimensional片的离心的impeller的二种类型被设计，生产并且测试。这些impellers与对方一起在南方的飞机上有中心的不同形状。而且，impeller的这些类型为5被成为次和期末考试的6次尺寸与4mm的外部直径指向离心的impeller以便为impellers估计类似。在impellers的表演特征之中的比较在表演和压缩机的类似上揭示了南方的配置的影响。

简介：在一台接近音速的离心的压缩机发展的流动的完整的体环模拟在二个稳定的操作点(山峰效率和近的巨浪)并且在路径期间被执行澎湃。以稳定的条件，流动地性质被比较用落后途径以前执行了的一个阶段与试验性的数据和数字模拟分析。关于舞台外套表演，一个优秀协议在数字结果之间被获得(两个与时间落后途径和完整体环的计算)并且实验。从完整体环的模拟，在到巨浪的从山峰效率的流动模式的变化被发现非常类似于用时间从模拟获得了那落后途径。特别地，如果操作的点是稳定的，流动证明是chorochronic.The完整体环模拟在法律在数字领域的出口使用了的throttle在一个唯一的小面值硬币以后被继续。集体流动，压力比率和效率然后显著地更加掉时间进步。模拟变得不稳定并且很好在进行之中的巨浪开始。澎湃的路径被发现由于根据从chorochronic模拟和实验得出的结论的更弥漫的翼的吸方面上的边界层分离的增大。但是当时间进行，流动失去它的chorochronic特性。在约7%转子速度点旋转的货摊房间在约5条革命开发并且导致巨浪。

简介：现在的纸给在SAFRAN直升飞机引擎设计并且造的一个离心的压缩机阶段获得的试验性的结果。压缩机由入口指南翼组成，被扫向後面的splitteredunshroudedimpeller，splitteredvaned光线的更弥漫、轴的插头指南翼。以前的数字模拟以部分旋转速度揭示了一个特别S形状压力上升特征并且在vaned预言了一个交替的流动模式光线在低质量更弥漫流动率。这个交替的流动模式包含二个邻近的翼段落。一个段落展出很低的动量和低压力恢复，而邻近的经过在经过入口有很高的动量并且高效地扩散。就算稳定性限制试验性地比数字地预言发生在更高集体的流动，试验性的大小证实压力上升特征的S形状。在低集体流动，交替的货摊模式由于高周波的压力传感器获得的数据被证实。当压缩机被扼杀，到不稳定性的路径被登记了，巨浪开始的第一种情形被给。压缩机首先经历一个稳定的交替的货摊在更弥漫。作为集体流动减少，交替的货摊在vaned放大并且被触发温和巨浪更弥漫。不稳定的行为源于交替的货摊和温和巨浪的相互作用。最后，当压力坡度变得太强壮时，交替的货摊征服，压缩机进入深巨浪。

简介：在这研究，一件涡轮充电器的离心压气机试验性地并且数字地被调查。压缩机的表演特征被转子速度和流动参数的大小在压缩机的入口和插头试验性地获得。在impeller的三个维的流动领域并且更弥漫与SST骚乱用一个完整的海军司烧节目数字地被分析模型。压缩机的表演特征数字地被获得，它当时与试验性的结果相比。比较显示出好同意。而且，区域比率的效果和性能参数和流动地上的尖端清理数字地被学习。impeller区域比率被切impeller出口轴改变从到5.1公里的最后的价值的4.1公里的起始的价值的宽度，从0.792～0.965导致区域比率。为有出口的转子4.6公里的轴的宽度，性能为0.0，0.5和1.0公里的尖端清理被调查。当效率在0.878的区域比率的更高的价值达到顶点时，在设计点的这模拟的结果证明压缩机压力比率在0.792的区域比率达到顶点。另外，从0～1公里的尖端清理的增长导致了20%效率减少。

简介：Theaccuratemodelingandpredictionoftherotatingstallinacentrifugalpumpisasignificantchallenge.Oneofthemodelingtechniquesthatcanimprovetheaccuracyoftheflowpredictionsisthelargeeddysimulation(LES).ThequalityoftheLESpredictionsdependsonthesub-grid-scale(SGS)modelimplementedintheLES.ThispaperassessestheinfluenceofvariousSGSmodelsthataresuitableforpredictingrotatingstallinalow-specificspeedcentrifugalpumpimpeller.TheSGSmodelsconsideredinthepresentworkincludetheSmagorinskymodel(SM),thedynamicSmagorinskymodel(DSM),thedynamicnon-linearmodel(DNM),thedynamicmixedmodel(DMM)andthedynamicmixednon-linearmodel(DMNM).TheresultsobtainedfromthesemodelsarecomparedwiththePIVandLDVexperimentaldata.TheanalysisoftheresultsshowsthattheSGSmodelshavesignificantinfluencesontheflowfield.Amongthemodels,theDSM,theDMMandtheDMNMcansuccessfullypredictthe'two-channel'stallphenomenon,butnottheSMandtheDNM.Accordingtothesimulations,theDMNMgivesthebestpredictiononthemeanvelocityflowfieldandalsoindicatesimprovementsforthesimulationoftheturbulentflow.Moreover,thehighturbulentkineticenergypredictedbytheDMNMisinthebestagreementwiththeexperimentdata.

简介：High-pressureratioandwideoperatingrangearehighlyrequiredforaturbochargerindieselengines.Arecirculationflowtypecasingtreatmentiseffectiveforflowrangeenhancementofcentrifugalcompressors.Tworinggroovesonasuctionpipeandashroudcasingwallareconnectedbymeansofanannularpassageandstablerecirculationflowisformedatsmallflowratesfromthedownstreamgroovetowardtheupstreamgroovethroughtheannularbypass.Theshapeofbaselinerecirculationflowtypecasingismodifiedandoptimizedbyusingamulti-pointoptimizationcodewithametamodelassistedevolutionaryalgorithmembeddingacommercialCFDcodeCFXfromANSYS.Thenumericaloptimizationresultsgivetheoptimizeddesignofcasingwithimprovingadiabaticefficiencyinwideoperatingflowraterange.Sensitivityanalysisofdesignparametersasafunctionofefficiencyhasbeenperformed.Itisfoundthattheoptimizedcasingdesignprovidesoptimizedrecirculationflowrate,inwhichanincrementofentropyriseisminimizedatgroovesandpassagesoftherotatingimpeller.

简介：AbstractIntroduction:Scarring and non-scarring alopecias have rarely been described to occur together in the same patient. Distinguishing these two different types of alopecia is important as treatment and prognosis can be different.Case presentation:Here, we report the first case of simultaneous alopecia areata (AA) and central centrifugal cicatricial alopecia (CCCA) in a 35-year-old woman. New alopecic patches were noted on her frontal and vertex scalp. Biopsy of the frontal scalp revealed miniaturized hair follicles and dense lymphocytic infiltrate surrounding the hair bulbs, consistent with AA; while biopsy of the vertex scalp revealed decreased hair follicles, perifollicular fibroplasia with eccentric atrophy of the follicular epithelium, and premature desquamation of the inner root sheath at the level of the lower isthmus, consistent with CCCA.Discussion:Proposed mechanisms of these two alopecia types occurring together include loss of immune privilege, genetic predisposition, as well as unknown external factors that trigger an autoimmune lymphocytic response. Most recently, the peptidylarginine deiminase type III gene has been implicated in both diseases. Although treatment options can overlap between the two diseases, treatment response can differ and CCCA tends to have a worse prognosis.Conclusion:Awareness of this concomitant presentation of two alopecic types is important for appropriate treatment and prognostication.

简介：

简介：摘要：针对给定设计条件下的离心式雾化喷嘴进行了结构优化设计，分别对比分析了螺旋槽数、螺旋槽截面、整流锥形状、出口直径等几何参数对介质出口特性的影响。结果表明，对于不同结构的雾化喷嘴，流通面积等比例增大或螺旋槽头数增加时，流阻增加导致出口流速增大。

简介：Wedescribetheearlierunknown,whenappliedtoglobaltectonics,centrifugalinertialmechanismoflithosphereplatemovingundertheeffectofforcesappearingasaresultofEarth'splanetaryrotation.Themechanismstatedgivesaninsightintoglobaltectonicsofplateswiththeindirectparticipationofemanationstreamswhich,intheirturn,arethederivativesofcentrifugalandinertialforcesofplanetarymotion.Theapplicationofthismechanismprovidesalogicalexplanationfortheregularitiesofglobaltectogenesisincludingtheformationofmountainridgesmainlyofsubmeridionalandsublatitudinalstrike,andalsothedriftofcontinentalplatesfromtheeasttothewestandfromthesouthtothenorth.ThemechanismclarifiesthesignificanceoftheArcticandtheAntarcticCirclesasgeodynamicbarriers.

简介：二phenylethanoidglycosides(PhGs)被高效第一次从Plantagoasiatica的天线部分孤立并且净化用乙醇acetate-n-butanol-ethanol-water的离心的分区层析(HPCPC)(0.5:0.5:0.1:1，v/v/v/v)。化合物2的化合物1和293.8mg的45.6mg的一个总数从P的n-butanol摘录的1341mg被净化。asiatica。当由electrospray电离的plantamajoside和acteoside或isoacteoside多在否定离子模式上演双人脚踏车团spectrometry(ESI-MSn)，二PhGs的结构尝试性地被识别。

简介：Theindustrialmanufactureprocessesofthreekindsofrollcoreusedductileironshavebeeninvestigatedviasystematicalexperiments.EffectsoftheratioofC/Si,pigiron,nodularizerandalloyingmethodonthemicrostructureandmechanicalpropertiesoftheheavysectionductileironhavebeenanalyzed.IthasbeenfoundthatwhentreatedwithRE-MgplusSb,highqualitynodularcastingscanbeproducedevenifmuchantispheroidizingalloyelementsareincludedinthepigiron.ThealloyelementSbplayedanimportantroleinthecontrolofgraphitemorphology.