简介:CharacteristicsofR22anditsnewalternativerefrigerantR290flowingthroughadiabaticcapillarytubesareinvestigatedbasedonthehomogeneousmodel.Extensiveflowvariablesalongtubelengthsuchaspressure,temperature,viscosity,velocity,Reynoldsnumber,frictionfactorandvaporqualityetcarecomparedbetweenthetwofluidsunderthesameoperatingcondition.Twocasesareconsidered,namely,eitherthesametubelengthorthesamemassflowrateasinletcondition.TheresultsshowthatthemassflowrateinthecapillarytubeofR290is40%lowerthanthatofR22duetothedifferencesofphysicalpropertiesbetweenthetwofluids.Further,aparametricanalysisisperformedanditappearsthateffectsofgeometricandthermodynamicparametersonmassflowrateofR290areweakerthanthatofR22.Whenthecondensingtemperatureisincreasedfrom40℃to50℃,themassflowrateforR22isincreasedby16%,whiletheincreasingrateforR290is13%.
简介:【摘要】小学阶段是学生进行英语学习的初始时期,同时也是为学生今后深入学习英语学科奠定基础的关键时期,以往老师在为学生开展阅读理解时,更多的都是以自己为主体,为学生进行知识的讲解和教学,导致学生的阅读效果质量不佳,难以在阅读的过程中感受到英语学科的魅力和英语语言的学习乐趣。所以现在老师应该将 SQ3R学习法融入英语阅读理解之中,切实优化学生阅读效果,提高学生阅读质量。
简介:很多不可预知的事情发生在我们交汇的时光里,至于返回的路,我不会忘记,因为那里阳光的味道,我无法轻易舍弃。
简介:BorninHongKongandhavingemigratedtotheUnitedStatesatthetenderageof10,CoCoLeehadnoideashewouldbecomeaninternationalsingingsuperstar.Afterwinningthesecondplaceinasingingcontest(equilaventtoStarSearch)inHongKong,herlifewouldbeforeverchanged.