汽轮机汽流激振CFD数值分析与转子动力稳定性研究

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1、东南大学博士学位论文汽轮机汽流激振CFD数值分析与转子动力稳定性研究姓名：刘晓锋申请学位级别：博士专业：动力机械及工程指导教师：陆颂元20070401东南大学博j：学位论文CFDNumeHcalAnalysisofSteamExcitedVibrationinSteamTurbineandRotordynamicStabilityStudyAbstractTheRotorinstabilityinducedbyfluiddynamicismianfailuresforturbomachinery．It’scriticaltoidenti

2、fythedominatesourceofflowexcitingforcetoeliminatethefailures，whichatheoritiepuzzles．Themajorgoalsofthisresearchweretoanalyzetherotordynamicforceinlabyrinthsealsandbladetipwiththree-dimensionalCFDprogramandstudythecorrelativefactorstoimprovethepredictionprecision；andfindt

3、hemethodtoidentifythesourceoftroubleexactly．TheflowfieldinsideawhirlingIabyrinthsealisinherentlyunsteady．However,foracenteredsealthewhirling,unsteadyproblemistransformedintoasteadyonebysolvingthethree-dimensional，eccentricflowfieldintheframeofreferebecattachedtothewhirli

4、ng．Thestandardk一占modelisusedforturbulence．TheenhancementwallfunetionisappliedtowallbeundaryconditiellsandprovidesthebestresuItsofcircumferentialvelocity．AssumetherotorwhirlsaroundtIlestatorcenterwithsmalleccentricity,whilespinningaroundowncenffe．Performingaleast-squaresa

5、nalysisgeneratestheskew-symmetricstiffness，dampingmatrices．Determinetheinfluenceofupstreamanddownstreamofthelab。yrinthsealtooptimalthe鲥dforlabyrinthmodel．Presenttheresultofaparametricstudyoftherotordynamiccoe衙cientssensitivitytoparame!terssuchasshmspeed,preswirl．differen

6、tialpressure．geometryofsealandsoon．Onthebaseofperturbationapproach,functionofthecircumferentialvariationinthelabyrinthwasderived．Studythecomputationalmethodforperturbatlonquantities．111efunctionofcireumferentialvariationforflowparameterwasincorporatedinFLUENTmodelthrough

7、theuser-programmingfeatureintheformofsubroutinestospeeifytheinletbeundaryconditionsofupstreamlabyrinth，Demonstratetheusemlnessoftheperturbationboundaryconditionsinthree-dimemionalrotordynamicmodel．Forwhirlingturbinerotor,thetipclearancesareasymmetric，whichgeneratesThomas

8、／Alfordforce．TheclassicalThomas／Alfordforceequationisnotabletoofferimightonactualwhirlingrotorandsecond