简介:Severalindustrialapplicationssuchaselectronicdevices,heatexchangers,gasturbineblades,etc.needcoolingprocesses.Theinternalcoolingtechniqueisproperforsomeapplications.Inthepresentwork,computationalsimulationsweremadeusingANSYSCFXtopredicttheimprovementsofinternalheattransferintherectangularribbedchannelusingdifferentcoolants.Severalcoolantssuchasair,steam,air/mistandsteam/mistwereinvestigated.Theshearstresstransportmodel(SST)isselectedbycomparingthestandardk-ωandOmegaReynoldsStress(ωRS)turbulencemodelswithexperimentalresults.Theresultsindicatethattheheattransfercoefficientsareenhancedintheribbedchannelwhileinjectingsmallamountsofmist.Theheattransfercoefficientsofair/mist,steamandsteam/mistincreaseby12.5%,49.5%and107%overthatofair,respectively.Furthermore,incomparisontoair,theair/mistheattransfercoefficientenhancesbyabout1.05to1.14timeswhenthemistmassfractionincreasesfrom2%to8%,respectively.Thesteam/mistheattransfercoefficientincreasesbyabout1.12to1.27timeshigherthanthatofsteamovertheconsideredrangeofmistmassfraction.
简介:长江口海运历史绵远,优势独具,这才成为下西洋船队的航海出发地。夏原吉治水,"制淞通娄",娄江口水势骤增,造就了刘家港,而郑和下西洋远航从这里始发也取得了丰厚的收获。
简介:Fishareabletomakegooduseofvortices.Inacomplexflowfield,manyfishcontinuetomaintainbothefficientcruisingandmaneuverability.Traditionalman-madepropulsionsystemsperformpoorlyincomplexflowfields.Withfish-likepropulsionsystems,itisimportanttopaymoreattentiontocomplexflowfields.Inthispaper,theinfluenceofvorticesonthehydrodynamicperformanceof2-Dflapping-foilswasinvestigated.Theflapping-foilheavedandpitchedundertheinfluenceofinflowvorticesgeneratedbyanoscillatingD-sectioncylinder.Anumericalsimulationwasrunbasedthefinitevolumemethod,usingthecomputationalfluiddynamics(CFD)softwareFLUENTwithReynolds-averagedNavier-Stokes(RANS)equationsapplied.Inaddition,dynamicmeshtechnologyandpostprocessingsystemswerealsofullyused.Thecalculationsshowedfourmodesofinteraction.Thehydrodynamicperformanceofflapping-foilswasanalyzedandtheresultscomparedwithexperimentaldata.Thisvalidatedthenumericalsimulation,confirmingthatflapping-foilscanincreaseefficiencybyabsorbingenergyfrominflowvortices.
简介:在STCW公约马尼拉修正案的影响下,海事主管机关取消了实施多年的“雷达两证”,将相关内容纳入船员适任证书考试中。IMO新的雷达性能标准IMOMSC.192(79)决议案对航海雷达设备提出更多新的功能要求。通过分析“航海雷达”课程的发展历程,研究STCW公约马尼拉修正案和IMO新雷达性能标准对“航海雷达”课程的影响,提出满足履约要求、符合新雷达性能标准、提升教学质量的教学改革建议。
简介:3月12日为长三角运输一体化量身打造的《长江三角渊地区这路运输一体化规飘纲要》出台,《纲要》明确了建立以物流供应两为主干.区域加工配送踊为分支.物流信息两为纽带.打造三网叠扣的区域物流网络体系.到2020年.长三角将普遍应用定位监控服务技术.并在客车上全部开通互联网服务,《纲要》指出,到2020年建立起工业园区、货物集散中心.物流基地(中心).保税区(中心)、货运市场与内河港.铁路集装箱中心站.海港互动的集装箱运输体系。把长三角打造戍为链接国内国外两个市场的枢纽.全球资源和产品分拔中心.配套先选制造监基地的加工配送中心.亚太地区重要的物流信息中心,