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:超大型全冷式液化气船(VLGC)是液化气船中结构最为复杂的船型,其结构设计是该高附加值船型的关键点和难点。从VLGC结构设计的角度,阐述了中横剖面设计、温度场计算、菱形液舱设计、支承系统设计、结构布置、低温钢焊接、晃荡分析及有限元强度和振动分析等,通过近600项工艺评定,攻克了关键技术。这些研究为该型船舶的成功研制和实船建造打下了坚实基础。
简介:宣城市地处安徽省东南部,东接浙江,北连江苏,南靠黄山,西临长江,自古有“上江人文之盛首”之誉。该市现辖5县1市1区,273万人口,道路总长4362公里,318和205国道及芜(湖)杭(州)高速公路穿境而过。全市拥有机动车15.7万辆,驾驶员20.2万人。过去,凡到过宣城的人一提起宣城市区的交通总会皱起眉头说:“那里的摩的(二轮摩托车营运带客)、达雅机(机动三轮车)又多又乱。”而前不久记者到宣城采访时,宣州城区却全然不见了“摩的”、“达雅机”的踪影,出租轿车和公交车成了客运的主角,城区交通流畅,井然有序。短短几个月,宣城交通秩序发生了根本性改观。为此,记者采访了宣城市公安局副局长、交警支队长刘平