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《螺紋管內(nèi)單相流動(dòng)換熱與污垢沉積的數(shù)值分析與優(yōu)化設(shè)計(jì)》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。
1、萬(wàn)方數(shù)據(jù)AbstractRecently,internalhelicallyribbedtubebecomesoneofthemostwidelyusedpassiveheattransferenhancementtechnique，becauseofitseffectiveheattransfereffect，lowpressuredroplossandlowcostofmassproduction．Andfoulinginenhancedheattransferexchangersisaninen
2、vitableandcomplexproblem，whichhasmanyinfluentialfactors，SOmorcandmoreinvestigationsareneededinthedetailresearchesofheattransferandfoulingperformance．Frommassbalanceintheinvestigation，thispaperusesVon—Karmananalogytopredictthefoulingperformanceandnumeric
3、allystudytheeffectonheattransferenhancementandfoulingofeachmainparameterinhelicallyfibbedtubes，whichCanbeusedtooptimizethedesignofhelicallyribbedtubegenerallyandbroadenitsfurtherapplications．Resultsareasfollows：(1)Thenumericalanalysisofheattransferandpr
4、essuredropforturbulentflowineighthelicallyribbedtubeswith15．54mminsidediameterhasbeenperformed．Theturbulentmodelisselectedcarefullyandtheeffectof鰣dindependenceisextensivelyexamined．Thecomputationalresultsmatchwellwiththeexperimentaldatatovalidatetheaccu
5、racyofthenumericalmodel．(2)ThefoulingmodelisestablishedbasedonKern—SeatonmassbalancemodelandVon-Karmananalogy．Combinedwithnumericalmodel，heattransfereffectandfoulingperformanceonthehelicalsurfacecallbeobtained．Bycomparingtheresultswithexperimentalfoulin
6、gdata,theinvestigationmethodthepaperusedisright．(3)Theeffectofeachmainparameter：ribshape，ribstarts，helixangle，andribheight，onheattransferandpressuredropisinvestigated．Everyparameterhasbeenanalyzedandcomparedbyenhancementfactor，7’carefully,SOthatwecansel
7、ecttheoptimumgeometry：ribshapeofrectangle，trapezoidandtrianglewithsmallincluededanglearebetterthanothershapes；ribstartsisbetteraroud50andhelixangleisbestat25。-35。；ribheightlookslikethehigherthebetter．(4)Consideringfoulinginpracticalsituation，theratioofp
8、itchoverribheightisanimportantparametertoselectthetubes．ItisadvisabletoselectthetubeswithpitchOVerrib111萬(wàn)方數(shù)據(jù)heightratiogreaterthan3．5，whichhavebetterheattransferandlowerfoulingpotential．Therefore，whenribstartsis50andhelixangleis2
