三相多管循环流化床蒸发器流动与传热特性的研究

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1、ABSTRACTThevapor-liquid-solid(V-L-S)circulatingfluidizedbedevaporatorcanenhanceheattransferandalsodefenseandcleanfoulingeffectively,whichmakesitoccupyapromisingapplicationprospect.Researchonthethree-phaseflowheatexchangerhasattractedwideattention.Inordertoresearchfurtheraboutitsperformance,atrans

2、parentmulti-tubethree-phaseforced-circulatingfluidizedbedevaporatorwasbuiltandacirculatingpumpwasusedasforced-circulationequipment.Theeffectsofcirculatingflowrate,heatfluxofheatingtubes,thevolumeandspeciesofaddedparticlesonsolidholdupofheatingtubebundle,thethermalefficiencyandpowerconsumptionofci

3、rculatingpumpwerestudiedwithsixkindsofparticlesasthesolidphasebyusingonlinedataacquisitionandprocessingsystemandtheCCDimagegatheringandprocessingsystem.Theresearchaboutthesolidholdupofheatingtubebundleshowsthatsolidholdupinheatingtubebundleincreaseswiththeincreaseinthecirculatingflowrate,butthein

4、creasedegreeineachtubevaries:alargerincreaseinNo.1andNo.5tube,andarelativelyflatincreaseinNo.24tube.Solidholdupineachtubeofheatingtubebundleshowsaslightincreasewhiletheheatfluxincreases,indicatingthattheinfluenceofheatfluxonthesolidholdupisveryweak.Solidholdupinheatingtubebundleincreasesclearlyw

5、iththeincrementofvolumeofaddedparticles,showsthattheincreaseintheamountofaddedparticlescaneffectivelyimprovethesolidholduptheheatingtubes.Todifferentparticlesettlingvelocityoftheparticles,solidholdupindifferenttubeshowdifferenttrends:solidholdupsinNo.1andNo.5tubedropdownastheparticlesettlingveloc

6、ityincreases,whileinNo.24tubes,maximumsolidholdupappearwhenaddedparticleis3.15mmPOM.Theinvestigationaboutthethermalefficiencyoftheevaporatorshowsthatthethermalefficiencyoftheevaporatorincreaseswhilethecirculatingflowrateincreases.Thethermalefficiencyincreasessignificantlywiththeincrementofheatf

7、lux,whichindicatesthatheatutilizationisbetterathighheatflux.Thethermalefficiencygrowswiththegrowthoftheamountofparticles,andtheincreasetendencyslowsdowngradually.Theamountofparticleshasamoreobviouseffectonthethermaleff