循環(huán)流化床鍋爐出口區(qū)域顆粒濃度分布和運(yùn)動特性的研究.pdf

1、天津大學(xué)碩士學(xué)位論文循環(huán)流化床鍋爐出口區(qū)域顆粒濃度分布和運(yùn)動特性的研究姓名：孟向軍申請學(xué)位級別：碩士專業(yè)：熱能工程指導(dǎo)教師：李惟毅20030801英文摘要ABSTRACTThestructIⅡ℃ofgas—solidtwophaseflowinCirculatingFhiidizedBedBoilersfCFBB)isextraordinarilycomplexityanddistinctiveAdetailedandelaborati

2、veresearchonitisimportanttotlnderstandingthecharacteristicofcombustionandheaItrailsferinCFBB，aswellastoitscorrectdesigningoperationandcontrollingHowever，thecorrelativefimdamentalresearcheslaggedbehindthedevelopmentofthec

3、ombustionpracticeIt’sdifficulttofindsomeunifiedorcompletetheorytodescribetheflowpatternsinsideaCFBB，evensomeachievementsandviewpointsarenotcorrect，forexample，theunderstandingoftheparticieconcentrationdistributionandflowa

4、tthetopregionandtheexitzone。Atpresent，thecommonviewpointsoftheflows缸u(yù)cnlreinCFBBisthatthebottompartcomposedofcoarseparticlesforrusadensephaseandinconditionofbubblingfluidizedstateAstothetopregionmostpeopledeemitadilutere

5、gionandintheconditionofpneumatictransportThesingleparticlecan’tforillclustersandinter—circulationwlllneverappearMeanwhilesomeworksfocusingontheexiteffcctofCFBBconcludethatparticlesveillcollidewillthetopwallandthusconcent

6、rateatthisregion，engenderingaCshapedconcentrationdistributioninmostcircumstances11ⅡDugllanalyzingandinvestigatingofthegassolidflowcharacteristicsinthisregionthethesisthinksthatthesetwokindsofpreyailingknowledgeontheexitz

7、oneisdisparitywiththepracticesandrequiresfurtherdiscussionTllisworksurveysandfocusesonthecharacteristicofgassolid倆ophaseflowattheexitregionAccordingtotherelatedmeasurementdataandpracticetheauthorproposedanewmodelofpartic

8、lesconcentrationdistributionandclustersmovementattheexitregionintheCFBBConcludethatthepracticalheightofexitishiglaerthanthelengthofparticledecelerationlength，thegravityeffectonparticleswillbedramaticDHetothedirectionchan

9、gingofairflowthevelocitydifferencebetweendifferentsizeparticlesemergedDuringtheprocessofrisingandfalling，theinteractionsbetweenparticleslcadstoIocalconcentrationformingadownwardflowofclustersattheregionbeneaththeexitandn

10、earthebackwallTheparticlesdisplayacharacteristicofupper—denseandbottomdilutedistribution111egassolidflowpatternattheexitregionisveryimportanttounderstandingthewholecirculationinCFBB，butunfortunatelytherearefewworkshaddon

11、eonthisproblemtitlnowInordertodemonstratethevalidityofthenovelmodelonthegas—solidflowstructureatthisregionauthorappliesbothnumericalsimulationandexperimentalmethods乃eresultsconfnrned0111conceptionoftheparticleconcentrati