学科分类
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152 个结果
  • 简介:在高职航海类专业学员的学习动机、策略、习惯以及学习体验都发生了较大变化的情况下,文章开展了高职航海类专业的学情调查,对调查结果进行了分析,找寻学情发生变化的原因,并提出了对应的策略。

  • 标签: 高职航海类专业 学情调查 数据分析 教学改革
  • 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.

  • 标签: heat transfer RIB ROUGHNESS MIST rectangular
  • 简介:文章分析了南通港集装箱运输的优势、弱势、机会和威胁,在此基础上,提出了南通港集装箱运输发展策略。

  • 标签: SWOT 南通港 集装箱运输
  • 简介:近年来,在深海进行油气开发的技术进展日新月异,全世界的海洋工程公司都在用更新的科技手段努力向更深的海域拓展,向深海进军已经成为了整个海洋石油工业的总体趋势.作为连接平台设备和海底的重要设备,深海海洋立管的设计和使用也越来越趋向标准化.该文以某深海立管为例,从操作工况和悬挂工况两个方面探讨了钻井立管的整体分析中遇到的主要问题并进行了相关的校核.该文的具体工作包括计算了立管在钻探模态下的旋转角度和应力分布,确定了操作半径、浮箱数目等要素,并根据API规范进行了校核.根据计算的结果可以看出,所选的立管在恶劣海况下的操作半径相对较小,而确定的浮箱数略多,相关结论对立管的初步设计具有较好的参考意义.

  • 标签: 钻井立管 操作工况 悬挂工况 有限元分析
  • 简介:OnMarch26,2010anunderwaterexplosion(UWE)ledtothesinkingoftheROKSCheonan.TheofficialMultinationalCivilian-MilitaryJointInvestigationGroup(MCMJIG)reportconcludedthatthecauseoftheunderwaterexplosionwasa250kgnetexplosiveweight(NEW)detonationatadepthof69mfromaDPRK'CHT-02D'torpedo.KimandGitterman(2012a)determinedtheNEWandseismicmagnitudeas136kgatadepthofapproximately8mand2.04,respectivelyusingbasichydrodynamicsbasedontheoreticalandexperimentalmethodsaswellasspectralanalysisandseismicmethods.ThepurposeofthisstudywastoclarifythecauseoftheUWEviamoredetailedmethodsusingbubbledynamicsandsimulationofpropellersaswellasforensicseismology.Regardingtheobservedbubblepulseperiodof0.990s,0.976sand1.030swerefoundincaseofa136NEWatadetonationdepthof8musingtheboundaryelementmethod(BEM)and3Dbubbleshapesimulationsderivedfora136kgNEWdetonationatadepthof8mapproximately5mportsidefromthehullcenterline.Hereweshowthroughanalyticalequations,modelsand3Dbubbleshapesimulationsthatthemostprobablecauseofthisunderwaterexplosionwasa136kgNEWdetonationatadepthof8mattributabletoaROKlittoral'landcontrol'mine(LCM).

  • 标签: CEPSTRUM SPECTROGRAM BUBBLE pulse TOROIDAL BUBBLE
  • 简介:某双机双桨客滚船在试航过程中,由于主机滑油系统调压阀故障,造成主机在110%负荷试验时由于滑油供油量不足导致曲轴轴瓦严重烧蚀。现对事故原因给予分析,阐述机损维修过程,对避免此类事故的发生给出建议。

  • 标签: 曲轴轴瓦 烧蚀 事故分析
  • 简介:Stronghydrodynamicinteractionsduringtheside-by-sideoffloadingoperationbetweenfloatingliquefiednaturalgas(FLNG)andliquefiednaturalgascarrier(LNGC)caninducehighrisksofcollision.Theweathervaneeffectofasingle-pointmooringsystemnormallyresultsinthesatisfactoryhydrodynamicperformanceoftheside-by-sideconfigurationinheadseas.Nevertheless,thechangesinwavedirectionsinrealseaconditionscansignificantlyinfluencetherelativemotions.Thisarticlestudiestherelativemotionsoftheside-by-sidesystembyusingthetheoreticalanalysismethodandthenumericalcalculationmethod.Basedonthethree-dimensionalpotentialtheorymodifiedbyartificialdamping-lidmethod,thefrequency-domainhydrodynamiccoefficientscanbeimprovedtocalculatetheretardationfunctionsforthemulti-bodyproblem.Anin-housecodeisthendevelopedtoperformthetime-domainsimulationoftwovessels,throughwhichtherelativemotionsaresubsequentlyobtained.Arangeofobliquewavesarechosenfortheextensivecalculationofrelativemotionsbetweenthetwovessels,whicharefurtheranalyzedintermsofthephaseshiftofmotionresponsesinducedbyspecificresonantwavepatterns.Investigationresultsshowthatwavedirectionshaveasignificantinfluenceontherelativesway,roll,andyawmotions.Underthecircumstancethattheabsolutephaseshiftbetweentherollmotionsoftwovesselsapproaches180°,strongerrelativemotionsareinducedwhenLNGCisontheweatherside.Moreover,thegapwaterresonancesathighfrequenciestendtocausethedangerousopposedoscillationoftwovesselsintheswayandyawmodes,whereasFLNGreducesthegapwaterresonancesandrelativemotionswhenlocatedontheweatherside.

  • 标签: FLOATING liquefied natural gas(FLNG) Multi-body system
  • 简介:Inordertostudycavitationcharacteristicsofa2-Dhydrofoil,themethodthatcombinesnonlinearcavitationmodelandmixed-iterationisusedtopredictandanalyzethecavitationperformanceofhydrofoils.ThecavitationelementsarenonlinearlydisposedbasedontheGreenformulaandperturbationpotentialpanelmethod.Atthesametime,themethodthatcombinescavityshapeforfixedcavitylength(CSCL)iterationandcavityshapeforfixedcavitationnumber(CSCN)iterationisusedtoworkoutthethicknessandlengthofhydrofoilcavitations.Throughanalysisofcalculationresults,itcanbeconcludedthatthejumpofpressureandvelocitypotentiallyexistbetweencavitationendareaandnon-cavitationsareaonsuctionsurfacewhencavitationoccursonhydrofoil.Incertainanglesofattack,thecavitationnumberhasanegativeimpactonthelengthofcavitations.Andunderthesameangleofattackandcavitationnumber,thebiggerthethicknessofthehydrofoil,theshorterthecavitationslength.

  • 标签: 2-D HYDROFOIL CAVITATION performance nonlinear theory
  • 简介:为能更好解决码头建设后对现有VTS雷达站可能被遮挡的影响分析和在通航安全论证中又无法对其进行较好的论证和合理的预见,并提供有效的解决方案.为此,提出了利用航海模拟器构建相应三维实景数据库和雷达反射库,建立可移动的虚拟VTS雷达站的解决方案,实验证明其方案既能保证通过合理的预见其可能产生的后果,又能提出VTS雷达站优化的解决方案.

  • 标签: 航海模拟器 VTS 雷达站 盲区 建模
  • 简介:T0KY0MOU组织港口当局累计检查船舶38067艘次,无缺陷通过11933艘次,滞留1422艘次,滞留率3.7%;滞留船舶中,船龄15年及以上的老旧船舶802艘次,占564%,船龄最老的当属1954年建造的客轮“PRINCESS”号。设备老化且疏于维护保养是导致滞留的主要原因。

  • 标签: 滞留率 组织 备忘录 滞留船舶 老旧船舶 维护保养
  • 简介:由于跨江桥梁钢箱梁吊装工艺的特殊性,施工过程中对水域通航产生碍航,为避免产生船舶碰撞事故,本文以虎门二桥所跨坭洲桥梁处为横截面的船舶AIS数据为基础,针对桥梁建设中的水上交通环境在时间上划定阶段性、在空间上划定区块性进行分析,针对性提出临时交通管制、推荐航路航道转换等面向水上交通风险的对策.研究成果为海事监管部门提供了实践性指导意见,减小了对桥梁周围水域航行船舶碍航性及降低警戒力量的投入,所提出的移动安全作业区、航路转换、合理布置警戒力量等通航安全保障措施以期为同类施工作业提供基于情景案例的实践参考.

  • 标签: 跨江桥梁 钢箱梁吊装 移动安全作业区 船舶AIS交通流时空特征 对策分析
  • 简介:针对工科研究生培养中普遍存在的创新能力严重不足的问题,认为其根源在于师生双方都有弱于创新思维构建的主观主动指向;指出强化问题意识及系列化的质疑设问是引领创新的有效途径,并举例论述质疑训练的实施方法,阐释在导师指导下的不断实训是一个教学相长的过程,以实现从问题中来到问题中去。

  • 标签: 工科研究生 创新思维 模式培养 质疑设问
  • 简介:轮机管理专业开设《轮机节能分析》课程的必要性和可行性刘超,任福安,姜培源,殷红,鞠玉玲(大连海事大学)随着船用燃油价格的上涨和常规能源的日趋减少。轮机工程中能源的有效利用和合理使用越来越为人们所重视,并已成为当今世界的重大科研课题之一。人们已将“节...

  • 标签: 轮机管理 节能分析 节能技术 热力学第二定律 热力学第一定律 轮机工程
  • 简介:交通部教育司为贯彻《中国教育改革与发展纲要》,推进部属院校教育改革深入发展,组织有关专家于1996年11月下旬对部属有关航海院校航海类专业学生进行了英语水平测试。本文就这次英语测试进行了试题分析,汇总了测试结果及有关分布情况、测试中反映的问题,并提出了对航海专业学生英语教学的几点建议。这次“全面、突然、随机、公平”的英语测试,必将在各院校引起强烈的反响,必将促进各院校英语教学水平的提高。

  • 标签: 部属航海院校 航海类专业学生 英语水平测试 英语教师队伍建设
  • 简介:一、案情简介某海事部门诉中石化粤东石油公司救助合同纠纷一案,广州海事法院于2005年5月19日受理后,依法组成合议庭,于7月7日召集双方当事人进行庭前证据交换,同日公开开庭进行了审理,本案现已审理终结。

  • 标签: 石油公司 海事部门 中石化 法律分析 粤东 合同纠纷
  • 简介:Strongrestrictionsonemissionsfrommarinepowerplants(particularlySOx,NOx)willprobablybeadoptedinthenearfuture.Inthispaper,acombinedsolidoxidefuelcell(SOFC)andsteamturbinefuelledbynaturalgasisproposedasanattractiveoptiontolimittheenvironmentalimpactofthemarinesector.TheanalyzedvariantofthecombinedcycleincludesaSOFCoperatedwithnaturalgasfuelandasteamturbinewithasingle-pressurewasteheatboiler.ThecalculationswereperformedfortwotypesoftubularandplanarSOFCs,eachwithanoutputpowerof18MW.Thispaperincludesadetailedenergyanalysisofthecombinedsystem.Massandenergybalancesareperformednotonlyforthewholeplantbutalsoforeachcomponentinordertoevaluatethethermalefficiencyofthecombinedcycle.Inaddition,theeffectsofusingnaturalgasasafuelonthefuelcellvoltageandperformanceareinvestigated.Ithasbeenfoundthatahighoverallefficiencyapproaching60%maybeachievedwithanoptimumconfigurationusingtheSOFCsystem.Thehybridsystemwouldalsoreduceemissions,fuelconsumption,andimprovethetotalsystemefficiency.

  • 标签: marine STEAM TURBINE natural gas FUEL