简介：指南翼在井汽轮机被安装以便改进它的效率，自我旋转的特征并且离开设计性能与拖延。这个工作试图根据动量理论解释这些指南翼的角色。在上游的翼在比下游的提高效率是更有效的，这被显示出。为指南翼的一个设计方法基于试验性的数据和潜在的理论被建议。作者执行的试验性的研究证实理论求婚了。关键词井汽轮机-指南翼-串联-潜在的流动-波浪精力变换器-海洋工程CLC数字TK72

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简介：Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.

简介：Asoneofthemostimportantdevelopmentsinaircoolingtechnologyforhotpartsoftheaero-engine,filmcoolingtechnologyhasbeenwidelyused.Filmcoolingholestructureexistsmainlyinareasthathavehightemperature,unevencoolingeffectivenessissueswheninactualuse.Thefirststageturbinevanesoftheaero-engineconsumethelargestportionofcoolingair,therebytheresearchonreducingtheamountofcoolingairhasthegreatestpotential.Anewsteppedslotfilmcoolingvanewithahighcoolingeffectivenessandahighcoolinguniformitywasresearchedinitially.Throughnumericalmethods,theaffectingfactorsofthecoolingeffectivenessofavanewiththesteppedslotfilmcoolingstructurewereresearched.Thispaperfocusesonthecoolingeffectivenessandthepressurelossindifferentblowingratioconditions,thenthemostreasonableandscientificstructureparametercanbeobtainedbyanalyzingtheresults.Theresultsshowthat1.0mmistheoptimumslotwidthand10.0isthemostreasonableblowingratio.Underthiscondition,thevaneachievedthebestcoolingresultandthehighestcoolingeffectiveness,andalsoretainedalowpressureloss.

简介：Thermalfatigue(TF)isoneofthemostimportantfactorsthatinfluenceturbine'slife.Thispaperestablishesa3Dsolid-fluidcouplingmodelforasteadytemperatureanalysisofahigh-pressureturbinenozzleatdifferentturbineinletgastotaltemperatures(TIGTTs).Thetemperatureanalysissuppliesthetemperatureloadforsubsequent3Dfiniteelementanalysistoobtainthestrainvalues.Followingthis,thepredictionoftheTFlifeismadeonthebasisofequivalentstrainrange.TheresultsshowthatthestrainincreaseswithTIGTT,andthepredictedTFlifedecreasescorrespondingly.ThislifepredictionwasconfirmedbyoneTFtest.

简介：Thispaperpresentsasemi-empiricallumpedparametermodeldevelopedforanalysingthedynamicstabilityandperformancelimitationsofapressurecompensatedvanepumpforanautomotiveapplicationwithlow-costcomponents.Themodelcalculatescontinuousdisplacementchamberpressureprofilesandinertialeffectsforthedeterminationoftheinternalforcesactingonthevanepump'spivotingcam.Measurementsconductedonacustomteststandwereusedtodefineanonlinearlyprogressivebiasspringmodelandablackboxrepresentationofthepumpcontrolsystemvalves.Analysisofthecompletemodelrevealsthattheperformancelimitationsimposedbythecontrolsystemvalves,intermsofsystemstabilityandachievablecontrollerbandwidth,aremorerestrictivethanthelimitationsimposedbythelow-costvanepumpandlimitthethatbandwidthto1.84Hz.Thecontrolsystemalsoimposeslimitationstothesystemperformancebasedonresonancephenomenawhichmaybesignificantinsomeapplications.

简介：Inmanyengineeringpractices,frequentlyanimpulsivewaveisaconsequenceofdischargeofashockwavefromtheexitofatubeleadingtoanannoyingnoiselikasonicboom.Theimpulsivenoisehasoftenbeenamajorfactortolimittheperformanceofflowdevicesaswellastoaffecthazardousinfluencesonhumanbeing.Thecorrentpaperdescribesanewcontrolmethodforthereductionofimpulsivewave.Anexperimentusingasimpleshocktubewascarriedouttoexaminetheeffectofacavity/helicalvanesystemontheimpulsivewavestrength.Theresultingimpulsivewavewasinfluencedbythedetailedconfigurationofthehelicalvaneinsidethecavitywhichislocatedatthevicinityoftheexitofatube.Theeffectofthehelicalvanewascomparedwithnohelicalvaneteststoensurevalidationofthiskindofcontrolstrategy,Theresultsshowedthatthestrengthoftheimpulsivewavecouldbesignificantlyreducedbythecurrentpassivecontrolusingthecavity/helicalvanesystem.

简介：In-situvanesheartestisfrequentlyperformedtodetermineshearstrengthforslopestabilityanalysisinTianjinNewHarbor.However,thesoilshearstrengthvarieswiththeshearplaneorientation.Apossiblemeanstoreducetheeffectofdirectionaldependencyofshearstrengthistoconvertthein-situvaneshearstrengthintoundrainedshearstrengthparameters.Amethodofconvertingin-situvaneshearstrengthintoundrainedshearstrengthparametersispresented.Theshearstrengthparametersdeterminedforallofthein-situvaneshearstrengthsaresubjectedtostatisticalregressionanalysistotakeintoconsiderationthepossibleeffectofnon-homogeneityinthesoftclaydeposit.Usingtheregressedshearstrengthparameters,slopestabilityanalysesareperformedforfiveexistingsoilslopes.Theresultsofstabilityanalysesindicatethatthesafetyfactorsobtainedfromtheconvertedparametersreflectthestateoftheslopesanalyzedmuchbetterthanthoseobtainedfromin-situvaneshearstrengthandlaboratoryconsolidated-undrainedandunconsolidated-undrainedstrengthparameters.Itisconcludedthatthepresentedmethsodofdeterminingundrainedshearstrengthparametersforin-situvaneshearstrengthiseffective.

简介：Thecoldflowcharacteristicsareinvestigatedtoshowtheeffectofthestructuralparametersoftheflowguidevaneonthetrappedvortexcombustor(TVC).TheresultsshowthatthestructuralparametershavesignificanteffectsontheTVC.Asa/Hincreases,thetotalpressureloss,thewallshearstressatthebottomofthecavityandtheturbulentintensityinthemaincombustionzoneincrease.b/Bdoesnothaveasignificanteffectonthecavityflowstructureandthetotalpressureloss,andthewallshearstressatthebottomofthecavityincreasesasb/Bincreases.Thereisnosignificantincreaseoftheturbulentintensitywiththeincreaseofb/B.Theincreaseofc/Lhaslittleeffectonthetotalpressureloss,anditisnotconducivetoastablecombustion.Asc/Lincreases,thewallshearstressatthebottomofthecavitydecreases.Whena/H=0.4,b/B=0.4,c/L=0.1,adesirabledual-vortexstructureisformedwithanacceptablepressurelosstoachieveastablecombustion.Moreover,toascertainthattheflameisstablefordifferentvaluesofVmawiththeoptimalstructuralparameters,theeffectofVmaontheflowfieldisdiscussed.Resultssuggestthatthedual-vortexstructurehasnorelationshipwiththeincreaseofVma.Furthermore,anunsteadysimulationisconductedtoshowthegenerationandthedevelopmentofthedual-vortex.

简介：摘要目的比较结合压缩感知技术与敏感度编码技术的3D mDixon序列以及3D Vane序列在肝脏检查中的应用价值。材料与方法使用3.0 T MR对23名健康志愿者（男性13例，女性10例）分别采用自由呼吸3D Vane、屏气3D mDixon sensitivity encoding (SENSE）与3D mDixon Compressed SENSE (CS，压缩感知）序列进行上腹部MR扫描，按照上述技术分为A、B、C组。由2名观测者分别对肝脏图像质量进行5分制主观评分，并在肝门水平肝脏的肝右叶前、后段和肝左叶内、外段及其相应层面同一相位方向的右侧竖脊肌划定感兴趣区，测量三组图像肝脏及竖脊肌的信号值（signal，SI)、噪声（standard deviation，SD）值，分别计算图像信噪比（signal to noise ratio ，SNR)、对比噪声比（contrast to noise ratio，CNR)。分别使用Wilcoxon检验以及卡方检验对三组肝脏肝右叶前、后段和肝左叶内、外段SNR、CNR及三组图像质量评分结果进行组间统计学分析。结果2名观测者对A、B、C三组图像的客观测量数据与图像主观评分的一致性良好(Kappa和ICC值均大于0.75)。三组图像质量评分分别为4.3±0.56、4.7±0.56、4.7±0.56。B、C组图像质量评分均明显高于A组(P<0.05)。三组肝右叶前、后段和肝左叶内、外段的SNR、CNR分别为8.03±3.08、29.25±7.08、29.25±7.08、8.03±3.08；15.75±5.37、43.89±10.30、40.27±12.49、11.37±5.42；16.95±5.48、46.55±10.47、46.56±10.48、16.95±5.48。B、C组图像肝右叶前、后段的SNR、CNR均明显高于A组(P<0.05）；C组图像肝左叶内、外段SNR、CNR也均明显高于A组(P<0.05）；B、C组间图像肝右叶前、后段、肝左叶内外段的质量评分及SNR、CNR差异均无统计学意义(P>0.05)。3D Vane的扫描时间为111 s；相对于结合SENSE的3D mDixon序列，结合CS的3D mDixon序列扫描时间缩短约15.3% (15.1 s与13.1 s)。结论相对于自由呼吸3D Vane序列，屏气结合SENSE的3D mDixon序列与结合CS的3D mDixon序列能有效提高图像的信噪比、对比噪声比，提高图像质量，并且显著缩短扫描时间。而CS技术可以进一步缩短扫描时间（减少约15.3 %)，对于难以坚持屏气15 s以上的患者的肝脏扫描时有较好的临床应用前景。