简介:Comparedtootherunderwatervehicles,supercavitatingvehiclescanattainahighspeedbecausetheyeliminatedragbycreatingalargecavity,thusestablishingtheso-called"supercavitatingcondition."Suchacavityisdifficulttodevelopundernormalconditions,hence,ventilationisusedtoattainthesupercavitatingconditionintheinitialphaseofflight.Inthispaper,wefocusonthehydrodynamiccharacteristicsofaventilatedsupercavitatingvehicle.First,dynamicmodelingofthesupercavitatingvehicleisperformedtocalculatethehydrodynamicforce/momentactingonthevehicleforagivensizeofcavity.Wethendefinetherelationshipbetweentheventilationrateandthecavitationnumberbasedonanairentrainmentmodeloftheventilatedcavity.Numericalsimulationswereperformedtoanalyzethephysicalfeasibilityandcharacteristicsofthemodeling.Theresultsshowthatthecavitylength/radiusincreaseswiththeventilationrate,provingthatventilationcanbeusedtoattainthesupercavitatingcondition.
简介:Itpresentstheone-dimensionalunsteadydensetransportequationinthetubeforMHDpulverizedcoalfeed.ThesimplifiedfrictionalforcetermintroducedbyLiuisusedintheequation.ThenumericalsolutionhasbeengotbyusingMacCormackmethod.Theresultsshowthatthereexistsoptimalloadingrateinwhichstatevelocityisnotoscillationalongatube.Itiswellagreedwithmeasurement;italsopreventsasedimentinthetube.
简介:ExperimentalStudyonoil-watertwo-phaseflowpatternsandpressurelosswasconductedonahorizontalsteelpipeloopwith26.1mminnerdiameterand30mtotallength.Theworkingfluidsarewhiteoil,dieseloilandtapwater.Severalinstruments,includinganewtypeofliquid-probearesuccessfullyintegratedtoidentify7differentflowpatterns.Thecharacteristicsoftheflowpatternsandthetransitionprocesswereobservedanddepictedinthispaper.Investigationrevealedthatthepressurelosswasmainlydependedontheflowpatterns.
简介:ParticleImageVelocimetry(PIV)techniquewasemployedtostudyexperimentallygas-liquidtwo-phaseflowinanaerationtank.IntermsofthePIVprinciples,analgorithmofPIVbasedontheFastFourierTransformation(FFT)wasworkedout.ThePIVprogramwasdevelopedandverified,andthenwasusedtomeasurethreekindsofstatesinthetestingdevice.Theprogramwasalsousedtocalculateandanalyzetherelatedparameters.Theexperimentaldataindicatethatthebubblesintestingdevicehavethelongestresidenttimeandstrongerturbulentintensityforthegas-liquidtwo-phaseflowinaspecialcase(Case3),resultingingreatincreaseoftheoxygentransferringspeedandefficiency,wherebyprovidingthebasisfortheselectiondesignofaerationtank.
简介:为测量处理方法的一幅图象即时二维(2D)在高水泡数字密度的本地空部分被建议。它基于计算在水泡羽毛图象和真实空部分的局部地平均的亮度之间的关联。方法从设想的图象用本地空部分的2D分发被测试,在在局部地平均的亮度和设计虚空部分之间的关联被在各种各样的条件下面介绍水泡图象的重叠概率的理想导出的地方。这研究被用来与方面比率of1.0学习冒泡的流动的行为1.5,和2.0。现在的方法被用于即时测量。为有产生流动率的三个不同水泡的三不同方面比率的水泡羽毛的空部分在冒泡的流动的行为上为水泡的效果的澄清被测量。煤气的流动率上的空部分的相关性被测量并且与其它相比源于文学。在我们的实验的范围,坦克的方面比率不仅影响羽毛的结构,而且在坦克的煤气的流动率影响羽毛的结构,这被观察。