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1、目录题目:冷却水污垢的实验研究摘要强化管是提高换热能力的一种换热元件,在电力、化工、石油及海水淡化等行业中得到了广泛的应用。有关强化管换热特性的研究较多,但关于污垢特性的研究还很少。本文以弧线管的污垢特性为研究重点,主要采用了对比实验(弧线管与光管)的研究方法。首先,在冷态下,进行了弧线管与光管的流动阻力特性的实验研究;在热态下,进行了传热特性的实验研究,得到了相关的特征曲线及关联式。实验结果表明:弧线管的流动压降和阻力系数高于光管。随Reynolds数的增大,它们的差距越来越大,弧线管的流动压降大约是光管的374%~909%。然后,采用
2、对比实验的研究方法,利用MgO颗粒或硬度为600mg/L和1200mg/L的人工硬水作为工质,弧线管在600mg/L下分别以流速为0.37m/s,0.49m/s做了对比试验,验证了流速越大,诱导期越长:流速越小,结垢越快。在流速为0.56m/s下,做了弧线管和光管在硬度为600mg/L条件下的对比试验。得出在实验条件下,弧线管微粒污垢热阻要小于对应光管的,污垢热阻渐近值大约为光管的0.9倍,而且弧线管的微粒污垢热阻的增长速度也比光管小,达到渐近热阻值的时间约为光管的2倍。关键词:弧线管;传热特性;污垢;污垢热阻;流动特性-VI-目录Tit
3、le:ExperimentalstudyofcoolingwaterfoulingAbstractEnhancedtubescanincreasestheheattransferperformances.andarewidelyusedinpower,chemical,petroleumandseadesaltfactories.Morepapersareontheheattransferperformancesofenhancedtubes,butfewonesareonthefoulingcharacteristicsofthetub
4、es.Inthispaper,characteristicsofenhancedtubeswithafocusondirt,themainuseofthecomparativeexperimentalresearchmethods.Firstly,experimentalstudiesarecarriedoutontheflowperformancesofthefourenhancedtubesatcoldposition;meanwhile,theheattransferperformancesofthesetubesaretested
5、atthermalstate.Therelatedperformancecurvesandthedimensionlesscorrelationaregot.Theresultsshowthat:flowPressuredropandresistancecoefficientofEnhancedtubeishigherthanfluorescenttubes.WiththeincreaseofReynoldsnumber,Agrowinggapbetweenthem.Then,useingComparativeexperimentalre
6、searchmethods.UsingMgOparticleswhichhardnessis600mg/Land1200mg/Lofartificialhardwaterasworkingfluid.Undertheconditionsof600mg/L,Enhancedtubeswascomparedtothetest(Velocityare0.37m/sand0.49m/s).Experimentsshow:Thegreaterthevelocity,thelongertheinductionperiod:thesmallerthef
7、lowrate,thefasterscaling.Ataflowrateof0.56m/s,Imadearctubeandfluorescenttubes'comparativetrialsinthehardnessof600mg/L.ParticulatefoulingresistanceofArctubeislessthanCorrespondingfluorescenttubes'.Asymptoticvalueoffoulingresistanceisapproximately0.9timesoffluorescenttubes'
8、,Arctube'growthrateoffoulingresistanceissmallerthanfluorescenttubes'.Timeisabout2timesoffluoresc